[Show abstract][Hide abstract] ABSTRACT: For patients with non-Hodgkin's lymphoma (NHL) undergoing blood or bone marrow transplantation (BMT), the use of autologous grafts has often been preferred to that of allogeneic stem cells because of a significantly lower incidence of non-relapse mortality. If complications associated with allo-BMT could be minimized without compromising efficacy, then it might become a preferred strategy for certain subsets of patients. In this report, we describe the toxicity and long-term efficacy of T cell-depleted allogeneic BMT using anti-CD6 monoclonal antibody and complement alone to reduce the risk of GVHD and its sequelae. Twenty-two patients, aged 18-60 years, with high (n = 10), intermediate (n = 9), or low (n = 3) grade NHL underwent HLA-identical allogeneic BMT from siblings. Patients had either relapsed after at least one remission or never achieved a full remission with chemotherapy. Twenty patients had a history of marrow involvement. Bone marrow was depleted of CD6+ T cells with T12 monoclonal antibody and complement as the sole form of GVHD prophylaxis. Stable hematopoietic engraftment occurred in all 22 patients. Four patients developed grade 2 and 1 patient grade 3 GVHD (23% grades 2-4 GVHD). Chronic GVHD has occurred in three patients. Treatment-related mortality was very low. Only one patient died while in remission. Thirteen patients are alive and free of disease with a median follow-up of 30 months. Estimated event-free and overall survivals are 54 and 59%, respectively. CD6 allogeneic marrow transplantation is associated with a low risk of transplant-related complications and may offer advantages for certain patients with recurrent NHL felt to be at high risk for relapse after autologous transplantation.
Full-text · Article · Jul 1998 · Bone Marrow Transplantation
[Show abstract][Hide abstract] ABSTRACT: The widespread use of allogeneic bone marrow transplantation (BMT) is limited by the availability of suitable donors. Recent attempts to expand the donor pool by employing HLA matched unrelated marrow have been partially successful. However, severe graft-versus-host disease (GVHD) and graft failure remain obstacles and contribute to the substantial morbidity and mortality associated with matched unrelated BMT. The use of genotypically nonidentical related or unrelated donor marrow could have wider application if problems associated with GVHD could be overcome. Based upon the low incidence of GVHD in recipients of HLA-matched related donor marrow depleted of T cells with T12, an anti-CD6 monoclonal antibody, we applied this approach to 27 adult recipients of HLA mismatched related bone marrow. Ten patients received marrow mismatched at 2 HLA loci, 13 received 1 antigen mismatched marrow, and 4 received phenotypically identical marrow from a non-sibling. Immediately prior to admission, patients were treated with total lymphoid irradiation (750-1050 cGy) to suppress host derived. T lymphocytes capable of mediating graft rejection. The ablative regimen consisted of cyclophosphamide (60 mg/kg x 2 days) followed by total body irradiation (1400 cGy in 7 fractions over 4 days). Patients then received marrow depleted of T cells with T12 (CD6) plus complement. No immune suppressive medications were administered to prevent GVHD. Twenty-four of 27 patients displayed stable hematologic engraftment, achieving an absolute neutrophil count of 0.5 x 10(9)/L at a median of 19 days post-BMT. Degree of HLA disparity did not influence engraftment. Among engrafting patients, grades 2-4 acute GVHD occurred in 40% and grade 3-4 GVHD in 8%. Chronic GVHD developed in 5 patients. Patients mismatched at 2 loci were more likely to develop GVHD than those mismatched at 0-1 loci (logrank, p = .04). Disease relapse has occurred in only 3 patients receiving mismatched marrow. Estimated overall survival for mismatched patients is 56% at 2 years and is independent of HLA disparity. Among the patients transplanted for chronic myelogenous in stable phase or acute leukemia in first remission, estimated event free survival is 69% at 2 years compared to 20% for patients with more advanced disease. Our results suggest that transplantation of mismatched related marrow using modalities designed to reduce GVHD without immune suppressive medication (CD6 depletion) is feasible and should prompt wider investigation into the extended families of patients in the search for potential marrow donors. This approach also merits investigation in recipients of matched unrelated marrow as a potential means of reducing transplant-related toxicity.
Full-text · Article · May 1997 · Biology of Blood and Marrow Transplantation
[Show abstract][Hide abstract] ABSTRACT: The appropriate timing of bone marrow transplantation (BMT) for adults with acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) is controversial. Although allogeneic transplantation results in a lower risk of disease recurrence than intensive chemotherapy alone, overall outcome following BMT may not be improved due to the higher incidence of therapy-related fatal complications, frequently as a result of the development of graft-versus-host disease (GVHD). Selective T-cell depletion of donor marrow can reduce the incidence of GVHD and thereby limit transplant-related toxicity. Herein we report the risk of GVHD, incidence of transplant related mortality (TRM), likelihood of disease relapse, and overall survival in adult patients undergoing BMT with CD6 depleted allogeneic marrow for acute leukemia in first remission. Forty-one consecutive allogeneic transplants were performed on patients with acute leukemia and high-risk features (28 AML, 13 ALL) using T12 monoclonal antibody and complement to remove CD6+ T cells from donor marrow. No pre- or posttransplant immune suppressive medications for GVHD prophylaxis were administered. The actuarial estimated risk of grade 2 to 4 acute GVHD was 15% in patients receiving HLA identical grafts. Chronic GVHD developed in five patients. The estimated risk of TRM for patients in first complete remission was 5% at Day +100 and 16% at 2 years. Fatalities attributable to infection with cytomegalovirus or Epstein-Barr virus occurred in only three patients. Estimated probabilities of relapse, overall survival, and event-free survival at 4 years were 25%, 71%, and 63%, respectively. No significant differences in GVHD, TRM, relapse rate, or survival was observed for patients with AML compared with those with ALL. Allogeneic transplantation with CD6 depleted bone marrow is effective in consolidating remissions of high-risk patients with acute leukemia in first remission without excessive toxicity.
[Show abstract][Hide abstract] ABSTRACT: R24 is a monoclonal antibody that recognizes the disialoganglioside GD3 expressed on the surface of malignant melanoma cells. Once bound, it can mediate destruction of these cells through both complement-mediated lysis and antibody-dependent cellular cytotoxicity. Agents such as interleukin 2 (IL-2), which can augment effector cell function and promote destruction of antibody-coated tumor cells, might produce improved antitumor responses when combined with R24. In this series, we evaluated the combination of R24 and IL-2 in a Phase 1b study in patients with metastatic melanoma. Twenty-eight patients with metastatic melanoma were entered into the protocol at two institutions. Patients received 8 weeks of IL-2 by continuous i.v. infusion at a dose (4.5 x 10(5) Amgen units/m2/day) designed to selectively expand natural killer (NK) cells. In weeks 5 and 6, patients received R24 for a total of four doses. Twenty-four h after each R24 infusion, patients received a 2-h bolus dose of IL-2 to help promote activity of NK effectors against antibody-coated melanoma targets. Additional IL-2 boluses were administered in weeks 7 and 8. Doses were escalated through two bolus doses of R24 (5 or 15 mg/m2) and two bolus doses of IL-2 (2.5 or 5.0 x 10(5) units/m2). Although one patient experienced severe capillary leak syndrome during IL-2, therapy was otherwise well tolerated. At the higher dose level of R24, two of four patients experienced transient but severe abdominal and chest discomfort, necessitating dose reduction. One patient with ocular melanoma and liver metastases had a partial response. Two additional patients had minor responses. A dramatic increase in NK cell number was noted as a result of treatment, as was augmentation of cytolytic activity against cultured NK-sensitive targets. Antibody-dependent cellular cytotoxicity against cultured melanoma cells in the presence of exogenous R24 or in the presence of serum obtained from patients following R24 infusion also increased during treatment. Our experience indicates that R24 and low-dose IL-2 can be safely combined in patients with metastatic melanoma and that this combination can promote destruction of cultured melanoma cells. The clinical activity of this combination against ocular melanoma may merit further investigation.
Full-text · Article · Feb 1997 · Clinical Cancer Research
[Show abstract][Hide abstract] ABSTRACT: Interleukin 2 (IL-2) administered at low doses for prolonged periods can markedly expand the number of CD56(+) natural killer (NK) cells in patients with metastatic cancer. The cytotoxic capacity of NK cells obtained from patients receiving IL-2 in vivo can be dramatically augmented by additional exposure to IL-2 in vitro. These observations formed the basis of a clinical trial in which patients with metastatic cancer were treated with low-dose continuous daily infusions of IL-2 to increase the number of their NK cells in conjunction with intermittent boluses of additional IL-2 to stimulate this expanded pool of cytotoxic cells. Twenty-three patients were registered to receive IL-2 at 4.5 x 10(5) units/m2/day for 8 weeks by continuous i.v. infusion. After 4 weeks of "priming" with low-dose continuous infusion IL-2, cohorts of three to five patients received 5 weekly 2-h boluses of IL-2 at doses ranging from 2.5 x 10(5) units/m2 to 1.0 x 10(6) units/m2. Low-dose continuous infusion IL-2 was usually well tolerated; 2-h bolus infusions of IL-2 were often associated with high fevers and constitutional symptoms that resolved after several hours. Low-dose continuous infusion IL-2 resulted in the progressive expansion of circulating CD56(+)CD3(-) NK cells. In contrast, each bolus infusion of IL-2 resulted in an immediate dramatic decrease in both the number of NK cells and activated T lymphocytes with recovery noted within 24 h. Bolus doses of IL-2 as low as 2.5 x 10(5) units/m2 were capable of producing these effects. Cytolytic activity against NK-sensitive and -resistant targets correlated with the presence of circulating activated NK cells. Our results demonstrate that NK cells expanded by low-dose continuous infusions of IL-2 can be further activated in vivo by exposure to very low doses of IL-2 as a 2-h i.v. bolus. This capacity to manipulate human NK cells in vivo through varying the dose and schedule of IL-2 administration may help in defining the therapeutic potential of these cytotoxic effectors in the treatment of both neoplastic and infectious diseases.
Full-text · Article · Apr 1996 · Clinical Cancer Research
[Show abstract][Hide abstract] ABSTRACT: Allogeneic bone marrow transplantation (BMT) has been shown to provide effective therapy for chronic myelogenous leukemia (CML), but previous reports have also demonstrated the persistence of bcr-abl-positive cells for months to years after BMT in the majority of patients. To evaluate the biologic significance of persistent bcr-abl-positive cells, we examined the relationship between clinical parameters known to affect the risk of relapse and the ability to detect bcr-abl-positive cells post-BMT.
We analyzed 480 samples from 92 patients at two transplant centers for the presence of bcr-abl-positive cells by polymerase chain reaction (PCR). Two different BMT preparative regimens and protocols for prevention of graft-versus-host disease (GVHD) were used. One center used cyclophosphamide plus total-body irradiation (CY/TBI) and T-cell-depleted marrow; the second center used busulfan plus cyclophosphamide (Bu/CY) and untreated marrow with cyclosporine and methotrexate (Csp/MTX) as GVHD prophylaxis.
We first determined the percent of patients at each center with > or = one PCR-positive (PCR+) result at defined intervals post-BMT. Between 0 and 6 months post-BMT, the majority of patients (80% to 83%) in both populations had PCR-detectable bcr-abl-positive cells. Between 6 and 24 months post-BMT, 80% to 88% of patients who received T-cell-depleted marrow remained PCR+, as compared with 26% to 30% of patients who received unmodified marrow. After 24 months post-BMT, the percentage of PCR+ patients was not significantly different in the two populations. This pattern of detection of bcr-abl-positive cells post-BMT followed the development of chronic GVHD in patients who received unmodified marrow. All patients were also divided into three groups based on post-BMT PCR results as follows: (1) persistent PCR+ (n = 29), (2) intermittent PCR-negative ([PCR-] n = 40), and (3) persistent PCR- (n = 23). These three groups were found to have a low, intermediate, and high probability of maintaining remission and disease-free survival, respectively (P = .0001). Intermittent or persistent PCR- results, which reflect levels of minimal residual disease < or = the limit of detection by PCR, were clearly associated with both acute (P = .004) and chronic (P = .000005) GVHD. Nevertheless, 44% of patients without GVHD also had intermittent or persistent PCR- assays.
The persistence of PCR-detectable bcr-abl-positive cells early post-BMT in more than 80% of patients suggests that neither BMT preparative regimen effectively eradicates CML cells in most patients. Subsequently, acute and/or chronic GVHD are associated with a decreased ability to detect residual bcr-abl-positive cells, which suggests that immunologic mechanisms mediated by donor cells are important for inducing long-term remissions after BMT. The demonstration that 44% of patients without GVHD had either low or undetectable levels of residual leukemia suggests the presence of mechanisms capable of suppression or eradication of CML independent of GVHD.
No preview · Article · Aug 1995 · Journal of Clinical Oncology
[Show abstract][Hide abstract] ABSTRACT: The administration of low doses of recombinant interleukin-2 (rIL-2) in vivo to patients with malignant neoplasms has been demonstrated to selectively increase the number of circulating natural killer (NK) cells in these patients. Recent evidence from SCID mouse models suggests that IgG subclass levels can be influenced by the presence and activity of NK cells. Therefore, we sought to examine the effect of rIL-2 infusions on human serum IgG subclass concentrations. We determined serum IgG subclass concentrations in 27 cancer patients receiving low-dose rIL-2 by daily continuous intravenous infusion. Eleven of these patients had active, metastatic, nonhematologic tumors; 16 patients had received IL-2 when they were in a minimal residual disease state after autologous or allogeneic bone marrow transplantation. Samples obtained before beginning IL-2 therapy and 8 to 10 weeks into therapy were tested. Treatment with IL-2 resulted in an increase in the percentage of CD56+ NK cells from 18% to 54% (P = .0001). A significant decrease in geometric mean IgG2 concentration from 2,017 micrograms/mL to 1,655 micrograms/mL was noted over this time interval (P = .03). Furthermore, the geometric mean IgG2 concentration after treatment was significantly lower than that of healthy controls (P = .026). In contrast, no significant changes in serum IgG1, IgG3, or IgG4 were noted during r-IL2 infusions. Our data suggest that rIL-2 treatment selectively decreases serum IgG2 concentrations. We speculate that increased NK cells mediate downregulation of human serum IgG2.
[Show abstract][Hide abstract] ABSTRACT: One of the major obstacles in allogeneic bone marrow transplantation (allo-BMT) is prolonged T cell dysfunction resulting in a variety of infectious complications in the months to years after hematologic engraftment. We previously showed that immobilized extracellular matrix (ECM) proteins such as fibronectin (FN), the CS-1 domain of FN, or collagen (CO) acted synergistically with immobilized anti-CD3 to induce T cell proliferation. In addition, the comitogenic effect of ECMs could be mimicked by immobilized mAb reactive with a common beta 1 chain (CD29) of very late activating (VLA) antigens which include ECM receptors. Since the interaction of T cells with ECMs appears to play an important role in the process of T cell reconstitution following allo-BMT, we examined the expression of VLA antigens (alpha 1-alpha 6, beta 1) and their functional roles in CD3-mediated T cell proliferation at various times after T cell depleted allo-BMT. VLA beta 1 as well as VLA alpha 4, alpha 5, and alpha 6 expression was lower than normal controls during the first 3 mo after allo-BMT and auto-BMT, whereas these expressions returned to normal levels by 4 mo after allo-BMT and auto-BMT. Although alpha 1 and alpha 2 were not expressed on lymphocytes from normal controls, these antigens were expressed on lymphocytes at the detectable levels (5-15%) from patients after allo-BMT and auto-BMT. Both CD29 and CD3 were expressed at normal levels on lymphocytes from patients > 3 mo after allo-BMT, whereas T cell interaction with ECM through VLA proteins or crosslinking of VLA beta 1 expressed by T cells with anti-CD29 mAb results in poor induction of CD3-mediated T cell proliferation for a prolonged period (> 1 yr) after allo-BMT. In contrast, T cell proliferation induced by crosslinking of anti-CD2 or anti-CD26 with anti-CD3 was almost fully recovered by 1 yr post-allo-BMT. After autologous BMT, impaired VLA-mediated T cell proliferation via the CD3 pathway after auto-BMT returned to normal levels within 1 yr despite no significant difference in CD3 and CD29 expression following either allo- or auto-BMT. The adhesion of T cells from post-allo-BMT patients to FN-coated plate was normal or increased compared to that of normal controls. Moreover, the induction of the tyrosine phosphorylation of pp105 protein by the ligation of VLA molecules was not impaired in allo-BMT patients. These results suggest that there are some other defects in the process of VLA-mediated signal transduction in such patients. Our results imply that disturbance of VLA function could explain, at least in part, the persistent immunoincompetent state after allo-BMT and may be involved in susceptibility to opportunistic infections after allo-BMT.
Full-text · Article · Aug 1994 · Journal of Clinical Investigation
[Show abstract][Hide abstract] ABSTRACT: Interleukin-12 (IL-12) is a heterodimeric 70-kD cytokine that can enhance the activity of cytotoxic effector cells. Although IL-12 shares some functional properties with interleukin-2 (IL-2), it appears to act via a distinct mechanism. In this report, we examined the effects of IL-12 on the cytolytic activity and proliferation of peripheral blood mononuclear cells (PBMC) obtained from patients with malignant disease. PBMC from two groups of patients were evaluated. The first group consisted of 12 individuals with metastatic solid tumors. PBMC from these patients demonstrated a marked defect in their ability to lyse natural killer (NK)-sensitive targets (K562) compared with normal volunteers. Overnight incubation with IL-12 (35 pmol/L) corrected this defect. The effect of 35 pmol/L of IL-12 on cytotoxicity was similar to that of 3 nmol/L of IL-2. In contrast, this concentration of IL-12 had little effect on cytolytic activity against an NK-resistant cell line (COLO 205). When IL-12 was added to PBMC obtained from cancer patients who were being treated with low-dose IL-2 in vivo, a dramatic increase in cytolytic activity against both NK-sensitive and -resistant tumor targets was observed. Unlike IL-2, IL-12 failed to stimulate proliferation of resting PBMC from cancer patients significantly. The second group of patients we studied comprised 13 patients who had recently undergone allogeneic bone marrow transplantation (BMT) for hematologic malignancy. In resting PBMC from these transplant recipients, IL-12 was capable of enhancing cytotoxicity against both NK-sensitive and -resistant tumor targets. Our findings indicate that IL-12 can restore defective NK activity of PBMC from patients with metastatic cancer, as well as enhance cytolytic function of PBMC from patients after allogeneic BMT. The clinical use of IL-12 as an immunomodulator in patients with malignancy merits further consideration.
[Show abstract][Hide abstract] ABSTRACT: Forty patients with plasma cell dyscrasias underwent high-dose chemoradiotherapy and either anti-B-cell monoclonal antibody (MoAb)-treated autologous, anti-T-cell MoAb-treated HLA-matched sibling allogeneic or syngeneic bone marrow transplantation (BMT). The majority of patients had advanced Durie-Salmon stage myeloma at diagnosis, all were pretreated with chemotherapy, and 17 had received prior radiotherapy. At the time of BMT, all patients demonstrated good performance status with Karnofsky score of 80% or greater and had less than 10% marrow tumor cells; 34 patients had residual monoclonal marrow plasma cells and 38 patients had paraprotein. Following high-dose chemoradiotherapy, there were 18 complete responses (CR), 18 partial responses, one non-responder, and three toxic deaths. Granulocytes greater than 500/microL and untransfused platelets greater than 20,000/microL were noted at a median of 23 (range, 12 to 46) and 25 (range, 10 to 175) days posttransplant (PT), respectively, in 24 of the 26 patients who underwent autografting. In the 14 patients who received allogeneic or syngeneic grafts, granulocytes greater than 500/microL and untransfused platelets greater than 20,000/microL were noted at a median of 19 (range, 12 to 24) and 16 (range, 5 to 32) days PT, respectively. With 24 months median follow-up for survival after autologous BMT, 16 of 26 patients are alive free from progression at 2+ to 55+ months PT; of these, 5 patients remain in CR at 6+ to 55+ months PT. With 24 months median follow-up for survival after allogeneic and syngeneic BMT, 8 of 14 patients are alive free from progression at 8+ to 34+ months PT; of these, 5 patients remain in CR at 8+ to 34+ months PT. This therapy has achieved high response rates and prolonged progression-free survival in some patients and proven to have acceptable toxicity. However, relapses post-BMT, coupled with slow engraftment post-BMT in heavily pretreated patients, suggest that such treatment strategies should be used earlier in the disease course. To define the role of BMT in the treatment of myeloma, its efficacy should be compared with that of conventional chemotherapy in a randomized trial.
[Show abstract][Hide abstract] ABSTRACT: The prognosis for adults with B lineage ALL who have relapsed after an initial remission is poor. High-dose chemoradiotherapy followed by autologous BMT can induce prolonged clinical remissions in some children with recurrent ALL. In this study, we evaluated the efficacy of autologous BMT in adults. Autologous marrow was treated in vitro with J5 and J2 monoclonal antibodies (CD10/CD9) plus rabbit complement to purge residual ALL cells. Twenty-two adults with B lineage ALL were treated with high-dose chemoradiotherapy followed by infusion of J2/J5 purged autologous BM. The median age was 28 years (range 18-54 years). Twenty-one of 22 patients had experienced at least one relapse prior to BMT. All patients achieved complete hematologic engraftment. Disease-free survival (DFS) in this cohort of patients was 20%, with all survivors alive and free of disease between 2.5 and 7.5 years post-BMT. Age at the time of BMT was an important prognostic factor, with patients < 28 years old faring much better than older individuals (DFS, 45% vs 0%, p = 0.01). Our experience suggests that high-dose chemoradiotherapy followed by infusion of J2/J5 purged autologous marrow is as efficacious in young adults as it is in children and is a reasonable alternative for patients who lack HLA-matched donors. Results in older adults are poor, however, and demonstrate the need for more effective transplant strategies in these individuals.
No preview · Article · Oct 1993 · Bone Marrow Transplantation
[Show abstract][Hide abstract] ABSTRACT: Graft-versus-host disease (GVHD) is a major cause of morbidity and mortality following allogeneic bone marrow transplantation (BMT). Because GVHD is frequently refractory to treatment, the early identification of high-risk patients could have significant clinical value. To identify such patients, we examined early immunologic recovery in 136 patients with hematologic malignancies who received anti-T12 (CD6)-purged allogeneic bone marrow over a 9-year period. The majority of patients received marrow from HLA-matched sibling donors after ablation with cyclophosphamide and total body irradiation. No patients received any immune suppressive medications for GVHD prophylaxis. The fraction and absolute numbers of peripheral blood lymphocytes (PBL) expressing the CD3, CD4, CD8, and CD56 surface antigens were determined weekly by immunofluorescence analysis in patients beginning 8 to 14 days (week 2) after marrow infusion. Results in patients who did or did not subsequently develop GVHD post-BMT were compared. Within 2 weeks of marrow infusion, patients who developed grades 2-4 GVHD had significantly higher percentages and absolute numbers of CD8+ T cells and a lower fraction of CD56+ natural killer (NK) cells than individuals who remained free of GVHD. Thirty-five percent of patients whose PBL were greater than 25% CD8+ in the second posttransplant week developed GVHD, compared with only 3% of patients who had < or = 25% CD8+ cells (odds ratio 37.8; 95% confidence interval [CI] 4.1 to 397). A subgroup of patients at very high risk for GVHD could be identified based on the combined frequency of CD8+ T cells and NK cells in blood. Seventy-five percent of patients with greater than 25% CD8+ cells and < or = 45% CD56+ cells during week 2 post-BMT developed GVHD, compared with only 11% of the remaining patients (odds ratio 24.9; 95% CI, 5.3 to 117.0). None of the 23 patients with both less than 25% CD8+ cells and greater than 45% CD56+ cells in the second posttransplant week developed grades 2-4 GVHD. Our findings indicate that CD8+ T cells play an important role in the pathogenesis of GVHD in humans. Analysis of immune reconstitution early after BMT is useful in predicting the onset of GVHD and can help direct the implementation of treatment strategies before the appearance of clinical manifestations. Such interventions may decrease the morbidity and mortality associated with allogeneic BMT and ultimately improve overall survival.
[Show abstract][Hide abstract] ABSTRACT: The immunologic consequences of prolonged infusions of rIL-2 in doses that produce physiologic serum concentrations of this cytokine were investigated. rIL-2 in doses of 0.5-6.0 x 10(6) U/m2 per d (3.3-40 micrograms/m2 per d) was administered by continuous intravenous infusion for 90 consecutive days to patients with advanced cancer. IL-2 concentrations (25 +/- 25 and 77 +/- 64 pM, respectively) that selectively saturate high-affinity IL-2 receptors (IL-2R) were achieved in the serum of patients receiving rIL-2 infusions of 10 micrograms/m2 per d and 30 micrograms/m2 per d. A gradual, progressive expansion of natural killer (NK) cells was seen in the peripheral blood of these patients with no evidence of a plateau effect during the 3 mo of therapy. A preferential expansion of CD56bright NK cells was consistently evident. NK cytotoxicity against tumor targets was only slightly enhanced at these dose levels. However, brief incubation of these expanded NK cells with IL-2 in vitro induced potent lysis of NK-sensitive, NK-resistant, and antibody-coated targets. Infusions of rIL-2 at 40 micrograms/m2 per d produced serum IL-2 levels (345 +/- 381 pM) sufficient to engage intermediate affinity IL-2R p75, which is constitutively expressed by human NK cells. This did not result in greater NK cell expansion compared to the lower dose levels, but did produce in vivo activation of NK cytotoxicity, as evidenced by lysis of NK-resistant targets. There was no consistent change in the numbers of CD56- CD3+ T cells, CD56+ CD3+ MHC-unrestricted T cells, or B cells during infusions of rIL-2 at any of the dosages used. This study demonstrates that prolonged infusions of rIL-2 in doses that saturate only high affinity IL-2R can selectively expand human NK cells for an extended period of time with only minimal toxicity. Further activation of NK cytolytic activity can also be achieved in vivo, but it requires concentrations of IL-2 that bind intermediate affinity IL-2R p75. Clinical trials are underway attempting to exploit the differing effects of various concentrations of IL-2 on human NK cells in vivo.
Full-text · Article · Feb 1993 · Journal of Clinical Investigation
[Show abstract][Hide abstract] ABSTRACT: Acute and chronic graft-versus-host disease (GVHD) continues to be the major causes of morbidity and mortality after allogeneic bone marrow transplantation (BMT). In this study, we have evaluated the clinical effects of selective in vitro T-cell depletion of donor allogeneic bone marrow by using a single monoclonal antibody ([MoAb] anti-T12, CD6) and rabbit complement. This antibody recognizes mature T cells, but not other cellular elements such as natural-killer (NK) cells, B cells, and myeloid precursors.
From August 1983 to April 1991, 112 consecutive adult patients with hematologic malignancies underwent BMT with bone marrow from HLA-identical sibling donors. Marrow was harvested and depleted of mature T lymphocytes ex vivo by the use of three rounds of incubation with an anti-T12 antibody and rabbit complement. The preparative regimen consisted of cyclophosphamide and fractionated total body irradiation (TBI) in 108 patients. No patients received prophylactic immune suppression post-BMT. Purgation by anti-T12 was used as the only method for the prevention of GVHD.
Twenty patients (18%) developed acute GVHD (grade 2 to 4); only eight patients developed chronic GVHD. The incidence of GVHD did not increase significantly with age. Only three of 112 patients (2.7%) exhibited acute graft failure. One patient developed late graft failure that was associated with cytomegalovirus (CMV) infection. Within the subset of 50 patients who had not previously undergone unsuccessful conventional therapy (acute leukemia in first remission or chronic myelogenous leukemia [CML] in stable phase), we estimated by the Kaplan-Meier method that the probability of disease-free survival was 50% at 3 years post-BMT, with a median follow-up of 44 months. The treatment-related mortality rate in this group was only 14% and was independent of patient age.
We conclude that selective in vitro T-cell depletion with an anti-T12 monoclonal antibody effectively reduces the incidence of both acute and chronic GVHD after allogeneic BMT without compromising engraftment. Moreover, depletion of CD6-positive cells from donor marrow obviates the need to administer immune suppressive medications to the majority of patients. This approach reduces the morbidity and mortality of allogeneic BMT and permits the BMT of older patients.
No preview · Article · Aug 1992 · Journal of Clinical Oncology
[Show abstract][Hide abstract] ABSTRACT: The CD33 antigen, identified by murine monoclonal antibody anti-MY9, is expressed by clonogenic leukemic cells from almost all patients with acute myeloid leukemia; it is also expressed by normal myeloid progenitor cells. Twelve consecutive patients with de novo acute myeloid leukemia received myeloablative therapy followed by infusion of autologous marrow previously treated in vitro with anti-MY9 and complement. Anti-MY9 and complement treatment eliminated virtually all committed myeloid progenitors (colony-forming unit granulocyte-macrophage) from the autografts. Nevertheless, in the absence of early relapse of leukemia, all patients showed durable trilineage engraftment. The median interval post bone marrow transplantation (BMT) required to achieve an absolute neutrophil count greater than 500/microL was 43 days (range, 16 to 75), to achieve a platelet count greater than 20,000/microL without transfusion was 92 days (range, 35 to 679), and to achieve red blood cell transfusion independence was 105 days (range, 37 to 670). At the time of BM harvest, 10 patients were in second remission, one patient was in first remission, and one patient was in third remission. Eight patients relapsed 3 to 18 months after BMT. Four patients transplanted in second remission remain disease-free 34+, 37+, 52+, and 57+ months after BMT. There was no treatment-related mortality. Early engraftment was significantly delayed in patients receiving CD33-purged autografts compared with concurrently treated patients receiving CD9/CD10-purged autografts for acute lymphoblastic leukemia or patients receiving CD6-purged allografts from HLA-compatible sibling donors. In contrast, both groups of autograft patients required a significantly longer time to achieve neutrophil counts greater than 500/microL and greater than 1,000/microL than did patients receiving normal allogeneic marrow. CD33(+)-committed myeloid progenitor cells thus appear to play an important role in the early phase of hematopoietic reconstitution after BMT. However, our results also show that human marrow depleted of CD33+ cells can sustain durable engraftment after myeloablative therapy, and provide further evidence that the CD33 antigen is absent from the human pluripotent hematopoietic stem cell.
[Show abstract][Hide abstract] ABSTRACT: In previous clinical trials, recombinant interleukin-2 (rIL-2) has been infused at high doses over short periods of time to generate lymphokine-activated killer (LAK) cells in vivo. These trials have been limited by severe toxicities, and the immunologic effects of rIL-2 have been transient. The present study was designed to assess the toxicity and immunologic effects of prolonged administration of low doses of rIL-2. In this phase I study, patients with advanced cancer were scheduled to receive intravenous (IV) infusion of rIL-2 without interruption for 3 months in an outpatient setting. Twenty-one patients received rIL-2 at doses ranging from 0.5 x 10(5) to 6.0 x 10(5) U/m2/d. Treatment was extremely well tolerated, and no patient experienced grade 3 or grade 4 toxicity. The lowest dose level (0.5 x 10(5) U/m2/d) did not have demonstrable immunologic activity. At doses of 1.5 x 10(5) and 4.5 x 10(5) U/m2/d, rIL-2 infusion resulted in the specific expansion of natural-killer (NK) cells (sixfold and ninefold increases, respectively, at these two dose levels) without any changes in B cells, T cells, neutrophils, or monocytes. Grade 2 toxicity was observed at the dose of 6.0 x 10(5) U/m2/d, as three patients required interruption of therapy and two patients who completed therapy developed transient hypothyroidism. In patients with increased NK cells, enhancement of non-major histocompatibility complex (MHC)-restricted cytotoxicity and increased generation of LAK cells in vitro were also demonstrated. Therapy with low-dose rIL-2 can be given safely in an uninterrupted fashion for prolonged periods of time in an outpatient setting. This results in selective expansion of NK cells in vivo with minimal toxicity. Further investigation of this schedule for immunomodulation in vivo should be pursued in phase II studies of both malignant and immunodeficient disease states.
No preview · Article · Jan 1992 · Journal of Clinical Oncology
[Show abstract][Hide abstract] ABSTRACT: A 47-year-old female developed autoimmune hemolytic anemia, autoimmune neutropenia, and autoimmune thrombocytopenia 19 months following allogeneic bone marrow transplantation for chronic myelogenous leukemia. Treatment with high-dose corticosteroids resulted in marked improvement in all three cell lines.
No preview · Article · Jan 1991 · Bone Marrow Transplantation
[Show abstract][Hide abstract] ABSTRACT: Patients who undergo allogeneic bone marrow transplantation (BMT) are clinically immunodeficient for a prolonged period after engraftment. In the present study, we examined immune function after BMT in a series of patients who had received HLA compatible sibling marrow grafts purged of T cells with anti-CD6 monoclonal antibody and complement. None of the patients in this analysis received immunomodulating agents and none had developed graft-versus-host disease (GVHD). Initially after BMT, natural killer (NK) cells are the predominant cell type, giving way to CD3+, CD5+ T cells after 4 to 8 weeks. Despite the return of normal numbers of T lymphocytes post-BMT phenotypic analysis reveals several long-term abnormalities, including an inverted T4:T8 ratio and a significant fraction of CD3+ T cells that do not co-express CD6. In mitogenic assays, stimulation by either nonspecific lectin (phytohemagglutinin; PHA) or antibodies to the CD2 surface structure (anti-T11(2) + anti-T11(3)) results in decreased levels of T-cell proliferation compared with controls for over 18 months post-BMT. In contrast, the ability of unstimulated peripheral blood mononuclear cells (PBMC) to respond to recombinant interleukin-2 (rIL-2) is relatively intact, most likely reflecting early functional reconstitution of the NK cell population. To further characterize the prolonged abnormalities in T-cell proliferation after PHA or CD2 stimulation, we examined more proximal events in T-cell activation such as induction of IL-2 receptor expression and stimulus-induced intracellular calcium flux. We found that the induction of IL-2 receptor (p55) after in vitro activation, although initially abnormal, recovers completely by 6 months post-BMT. We also found that, after CD2 stimulation, calcium flux in T cells was normal immediately after engraftment. In contrast, after stimulation with anti-CD3 antibodies, a large population of T cells do not develop intracellular calcium flux compared with controls. We conclude that despite the recovery of normal numbers of T lymphocytes early after engraftment of CD6-depleted marrow, these T cells exhibit several physiologic and functional abnormalities that persist for varying intervals post-BMT. At present, it is unclear which of these specific defects is most closely associated with increased susceptibility to infectious agents after BMT.
[Show abstract][Hide abstract] ABSTRACT: Mixed hematopoietic chimerism (MC) is a common finding after allogeneic bone marrow transplantation (BMT), but the natural history of this phenomenon remains unclear. To understand the evolution and the implications of this finding, we performed a prospective analysis of the development of mixed chimerism in 43 patients with hematologic malignancies who received bone marrow (BM) from human leukocyte antigen (HLA)-identical sibling donors. T-cell depletion in vitro with anti-T12 (CD6) monoclonal antibody and rabbit complement was used as the only method of graft-versus-host disease (GVHD) prophylaxis. Overall, MC was identified in peripheral blood (PB) and BM in 22 of 43 (51%) patients evaluated. MC was found by restriction fragment length polymorphism (RFLP) analysis in 21 of 40 (53%) patients, by cytogenetic analysis in 6 of 29 (21%) patients, and by red blood cell phenotyping in 4 of 9 (44%) patients. RFLP studies were performed at 0.5, 1, 3, 6, 9, and 12 months post-BMT and then every 6 months, and showed a high probability of developing MC in the first 6 months after BMT followed by stabilization after 12 months. Cytogenetic analysis was less sensitive in detecting MC. Once MC was detected after BMT, the percentage of recipient cells increased very slowly over more than 3 years of follow-up, and no patient reverted to complete donor hematopoiesis (CDH). Thus, recipient and donor cells remained in a relative state of equilibrium for prolonged periods that seemed to favor recipient cells over donor cells. Patient's disease, remission status, or intensity of the transplant preparative regimen did not influence the subsequent development of mixed chimerism. Early immunologic reconstitution was the only factor that correlated with the subsequent chimeric status of the patients. The percentage and absolute number of T3 (CD3) and T4 (CD4) positive cells at day 14 after BMT were significantly higher in the patients who maintained CDH but NK cell reconstitution was similar in both groups, suggesting that early reconstitution with T cells may play a role in preventing recovery of recipient cells after BMT. GVHD was also associated with maintenance of CDH, but the probability of relapse, survival, and disease-free survival was identical in patients with MC and CDH.
[Show abstract][Hide abstract] ABSTRACT: This report characterizes the mechanism of graft failure in five patients who received allogeneic marrow depleted of T cells in vitro using anti-T12 (CD6) monoclonal antibody and rabbit complement. This group of five patients represents all patients who experienced early graft failure in a larger group of 59 consecutive patients given T12 depleted marrow over a 5-year period. Although all patients received ablative pre-transplant conditioning including total body irradiation (12-14 Gy) graft failure was more frequent in patients without genetically HLA-identical donors (four of 11 patients) than in patients with HLA identical sibling donors (one of 48 patients). In patients without genotypically identical donors, graft failure was observed with variable degrees of genetic disparity including two patients with HLA haplotype-mismatched sibling donors, one patient with a phenotypically HLA-matched parental donor, and one patient with an HLA-matched unrelated donor. In patients with both HLA identical and non-identical donors, results of immunophenotypic analysis demonstrated that early graft failure was associated with peripheral lymphocytosis with T cells expressing CD2, CD3, CD5, CD6, CD8 and Ia antigens. Direct cytotoxicity studies demonstrated specific lysis of donor cells by circulating lymphocytes and further analysis indicated that effector cells were derived from the recipients and not donors. Taken together, these results suggest that these allogeneic grafts did not 'fail', but rather that residual host cytotoxic T cells were responsible for active rejection of donor marrow.(ABSTRACT TRUNCATED AT 250 WORDS)
No preview · Article · Jun 1989 · Bone Marrow Transplantation