Carla J Greenbaum

Benaroya Research Institute, Seattle, Washington, United States

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Publications (150)1135.07 Total impact

  • Sandra Lord, Carla J. Greenbaum
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    ABSTRACT: With more than four decades of clinical research and 25 years of clinical trials, much is known about the natural history of T1D before and after clinical diagnosis. We know that autoimmunity occurs early in life, that islet autoimmunity inevitably leads to clinically overt disease, and that some immune therapies can alter the disease course. In the future, we will likely conduct trials to more deeply explore mechanisms of disease and response to therapy, employ combinations of agents including those aimed at supporting beta cells, consider the use of chronic, intermittent therapy, focus studies on preventing progression from islet autoimmunity, and consider the potential benefits of studying children independently from adults. Much of this work will depend upon clinical trial networks such as Diabetes TrialNet. Such networks not only have the expertise to conduct studies; sharing of data and samples allow for discovery work by multiple investigators laying the groundwork for the future. Working with patients, families, funders and industry, such collaborative networks can accelerate the translation of science to clinical practice to improve the lives of those living with T1D. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Pharmacological Research 03/2015; DOI:10.1016/j.phrs.2015.02.002 · 3.98 Impact Factor
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    ABSTRACT: We developed a scale to serve as a potential end point for 6-month glycemic progression (PS6M) toward type 1 diabetes (T1D) in autoantibody-positive relatives of individuals with T1D. The PS6M was developed from Diabetes Prevention Trial-Type 1 (DPT-1) data and tested in the TrialNet Pathway to Prevention Study (PTP). It is the difference between 6-month glucose sum values (30-120 min oral glucose tolerance test values) and values predicted for nonprogressors. The PS6M predicted T1D in the PTP (P < 0.001). The area under the receiver operating chacteristic curve was greater (P < 0.001) for the PS6M than for the baseline-to-6-month difference. PS6M values were higher in those with two or more autoantibodies, 30-0 min C-peptide values <2.00 ng/mL, or DPT-1 Risk Scores >7.00 (P < 0.001 for all). The PS6M is an indicator of short-term glycemic progression to T1D that could be a useful tool for assessing preventive treatments and biomarkers. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.
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    ABSTRACT: This study investigated the effect of parenteral insulin therapy on endogenous insulin secretion in the Diabetes Prevention Trial of Type 1 Diabetes (DPT-1). In the parenteral insulin arm of DPT-1, subjects without diabetes at high risk of future type 1 diabetes randomized to active treatment received a yearly 4-day intravenous insulin infusion (IV-I) and daily subcutaneous insulin (SC-I). To examine the effects of these insulin therapies on endogenous insulin secretion, C-peptide and glucose concentrations were compared during oral glucose tolerance tests (OGTTs) performed on and off IV-I and SC-I. Forty-six paired OGTTs were performed in 30 subjects from DPT-1 to determine the effect of IV-I. Twenty paired OGTTs were performed in 15 subjects from DPT-1 to determine the effect of SC-I. IV-I suppressed fasting and OGTT-stimulated C-peptide (62% and 40%, respectively), and it significantly lowered fasting glucose (67.4 ± 4.5 mg/dL during IV-I vs. 90.9 ± 1.8 mg/dL off insulin; P < 0.05). By contrast, post-OGTT glucose levels were significantly higher during IV-I: Glucose during IV-I versus off insulin at 120 minutes was 203.9 ± 15.1 vs. 151.8 ± 10.2 mg/dL, respectively (P < 0.05). Of OGTTs, 49% became transiently diabetic (>200 mg/dL at 120 minutes) when receiving IV-I. Fasting glucose was significantly lower when receiving SC-I versus when off insulin (85 ± 3 vs. 94 ± 2 mg/dL, respectively; P < 0.05), but SC-I did not significantly alter fasting or OGTT-stimulated C-peptide compared with being off insulin. These data demonstrate that the IV-I used in the DPT-1 markedly suppressed endogenous insulin secretion, which was frequently associated with postprandial glucose intolerance. SC-I, however, did not. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.
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    ABSTRACT: Background Type 1 Diabetes TrialNet is an NIH-sponsored clinical trial network aimed at altering the disease course of type 1 diabetes. The purpose of this study is to evaluate age-dependent heterogeneity in clinical, metabolic, and immunologic characteristics of individuals with recent-onset type 1 diabetes (T1D), to identify cohorts of interest and to aid in planning of future studies.Methods883 individuals with recent onset T1D involved in five TrialNet studies were categorized by age as: ≥ 18, age 12-17, ages 8-12, and age <8. Data was compared with healthy age-matched subjects in the National Health and Nutrition Examination Survey.ResultsWhile only 2.0 % of individuals overall were excluded due to insufficient C-peptide values (<0.2 pmol/ml), 9.0% of those < age 8 did not meet this entry criteria. Leukopenia was present in 21.2% of individuals and lymphopenia in 11.6%; these frequencies were markedly different than age-matched healthy population. 24.5% of the cohort was overweight or obese. 31.1% of adults and 21.1% of children had neither HLA DR3 nor DR4.Conclusions The ability of recent onset T1D patients to meet key entry criteria for TrialNet studies, including C-peptide >0.2 pmol/ml, varies by age. Lower C-peptide level requirements for younger participants should be considered in the design of future trials. These data also highlight subgroups of type 1 diabetes patients, such as those with abnormal WBC or who are overweight, which allow for targeted studies of etiopathology and interventions. This article is protected by copyright. All rights reserved.
    Diabetes/Metabolism Research and Reviews 02/2015; DOI:10.1002/dmrr.2643 · 3.59 Impact Factor
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    ABSTRACT: We assessed whether type 1 diabetes (T1D) can be diagnosed earlier using a new approach based on prediction and natural history in autoantibody-positive individuals. Diabetes Prevention Trial-Type 1 (DPT-1) and TrialNet Natural History Study (TNNHS) participants were studied. A metabolic index, the T1D Diagnostic Index60 (Index60), was developed from 2-h oral glucose tolerance tests (OGTTs) using the log fasting C-peptide, 60-min C-peptide, and 60-min glucose. OGTTs with Index60 ≥2.00 and 2-h glucose <200 mg/dL (Ind60+Only) were compared with Index60 <2.00 and 2-h glucose ≥200 mg/dL (2hglu+Only) OGTTs as criteria for T1D. Individuals were assessed for C-peptide loss from the first Ind60+Only OGTT to diagnosis. Areas under receiver operating characteristic curves were significantly higher for Index60 than for the 2-h glucose (P < 0.001 for both DPT-1 and the TNNHS). As a diagnostic criterion, sensitivity was higher for Ind60+Only than for 2hglu+Only (0.44 vs. 0.15 in DPT-1; 0.26 vs. 0.17 in the TNNHS) OGTTs. Specificity was somewhat higher for 2hglu+Only OGTTs in DPT-1 (0.97 vs. 0.91) but equivalent in the TNNHS (0.98 for both). Positive and negative predictive values were higher for Ind60+Only OGTTs in both studies. Postchallenge C-peptide levels declined significantly at each OGTT time point from the first Ind60+Only OGTT to the time of standard diagnosis (range -22 to -34% in DPT-1 and -14 to -27% in the TNNHS). C-peptide and glucose patterns differed markedly between Ind60+Only and 2hglu+Only OGTTs. An approach based on prediction and natural history appears to have utility for diagnosing T1D. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.
    Diabetes Care 12/2014; DOI:10.2337/dc14-1813 · 8.57 Impact Factor
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    ABSTRACT: It is generally accepted that complete β-cell destruction eventually occurs in individuals with type 1 diabetes, which has implications for treatment approaches and insurance coverage. The frequency of residual insulin secretion in a large cohort of individuals at varying ages of diagnosis and type 1 diabetes duration is unknown. The frequency of residual insulin secretion was determined by measurement of nonfasting serum C-peptide concentration in 919 individuals with type 1 diabetes according to prespecified groups based on age at diagnosis and duration of disease (from 3 to 81 years duration). Stimulated C-peptide was measured in those with detectable nonfasting values and a group of those with undetectable values as control. The overall frequency of detectable nonfasting C-peptide was 29%, decreasing with time from diagnosis regardless of age at diagnosis. In all duration groups, the frequency of C-peptide was higher with diagnosis age >18 years compared with ≤18 years. Nineteen percent of those with undetectable nonfasting C-peptide were C-peptide positive upon stimulation testing. The American Diabetes Association's definition of type 1 diabetes as "usually leading to absolute insulin deficiency" results in clinicians often considering the presence of residual insulin secretion as unexpected in this population. However, our data suggest that residual secretion is present in almost one out of three individuals 3 or more years from type 1 diabetes diagnosis. The frequency of residual C-peptide decreases with time from diagnosis regardless of age at diagnosis, yet at all durations of disease, diagnosis during adulthood is associated with greater frequency and higher values of C-peptide. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.
    Diabetes Care 12/2014; DOI:10.2337/dc14-1952 · 8.57 Impact Factor
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    ABSTRACT: Susceptibility to type 1 diabetes (T1D) is strongly associated with MHC class II molecules, particularly HLA-DQ8 (DQ8: DQA1*03:01/DQB1*03:02). Monitoring T1D-specific T cell responses to DQ8-restricted epitopes may be key to understanding the immunopathology of the disease. In this study, we examined DQ8-restricted T cell responses to glutamic acid decarboxylase 65 (GAD65) using DQ8 tetramers. We demonstrated that GAD65121-140 and GAD65250-266 elicited responses from DQ8+ subjects. Circulating CD4+ T cells specific for these epitopes were detected significantly more often in T1D patients than in healthy individuals after in vitro expansion. T cell clones specific for GAD65121-140 and GAD65250-266 carried a Th1-dominant phenotype, with some of the GAD65121-140-specific T cell clones producing IL-17. GAD65250-266-specific CD4+ T cells could also be detected by direct ex vivo staining. Analysis of unmanipulated peripheral blood mononuclear cells (PBMCs) revealed that GAD65250-266-specific T cells could be found in both healthy and diabetic individuals but the frequencies of specific T cells were higher in subjects with type 1 diabetes. Taken together, our results suggest a proinflammatory role for T cells specific for DQ8-restricted GAD65121-140 and GAD65250-266 epitopes and implicate their possible contribution to the progression of T1D.
    PLoS ONE 11/2014; 9(11):e112882. DOI:10.1371/journal.pone.0112882 · 3.53 Impact Factor
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    ABSTRACT: Previous studies in type 1 diabetes (T1D) in the nonobese diabetic mouse demonstrated that a crucial insulin epitope (B:9-23) is presented to diabetogenic CD4 T cells by IA(g7) in a weakly bound register. The importance of antigenic peptides with low-affinity HLA binding in human autoimmune disease remains less clear. The objective of this study was to investigate T-cell responses to a low-affinity self-epitope in subjects with T1D. HLA-DQ8 tetramers loaded with a modified insulin peptide designed to improve binding the low-affinity register were used to visualize T-cell responses following in vitro stimulation. Positive responses were only detectable in T1D patients. Because the immunogenic register of B:9-23 presented by DQ8 has not been conclusively demonstrated, T-cell assays using substituted peptides and DQ8 constructs engineered to express and present B:9-23 in fixed binding registers were used to determine the immunogenic register of this peptide. Tetramer-positive T-cell clones isolated from T1D subjects that responded to stimulation by B:11-23 peptide and denatured insulin protein were conclusively shown to recognize B:11-23 bound to HLA-DQ8 in the low-affinity register 3. These T cells also responded to homologous peptides derived from microbial antigens, suggesting that their initial priming could occur via molecular mimicry. These results are in accord with prior observations from the nonobese diabetic mouse model, suggesting a mechanism shared by mouse and man through which T cells that recognize a weakly bound peptide can circumvent tolerance mechanisms and play a role in the initiation of autoimmune diseases, such as T1D.
    Proceedings of the National Academy of Sciences 09/2014; 111(41). DOI:10.1073/pnas.1416864111 · 9.81 Impact Factor
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    ABSTRACT: Fate determination for autoreactive T cells relies on a series of avidity-dependent interactions during T cell selection, represented by two general types of signals, one based on antigen expression and density during T cell development, and one based on genes that interpret the avidity of TCR interaction to guide developmental outcome. We used proinsulin-specific HLA class II tetramers to purify and determine transcriptional signatures for autoreactive T cells under differential selection in type 1 diabetes (T1D), in which insulin (INS) genotypes consist of protective and susceptible alleles that regulate the level of proinsulin expression in the thymus. Upregulation of steroid nuclear receptor family 4A (NR4A) and early growth response family genes in proinsulin-specific T cells was observed in individuals with susceptible INS-VNTR genotypes, suggesting a mechanism for avidity-dependent fate determination of the T cell repertoire in T1D. The NR4A genes act as translators of TCR signal strength that guide central and peripheral T cell fate decisions through transcriptional modification. We propose that maintenance of an NR4A-guided program in low avidity autoreactive T cells in T1D reflects their prior developmental experience influenced by proinsulin expression, identifying a pathway permissive for autoimmunity.
    PLoS ONE 05/2014; 9(5):e98074. DOI:10.1371/journal.pone.0098074 · 3.53 Impact Factor
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    ABSTRACT: The renin–angiotensin system (RAS), bone morphogenetic protein (BMP), and WNT pathways are involved in pathogenesis of diabetic kidney disease (DKD). This study characterized assays for urinary angiotensinogen (AGT), gremlin-1, and matrix metalloproteinase 7 (MMP-7), components of the RAS, BMP, and WNT pathways and examined their excretion in DKD. We measured urine AGT, gremlin-1, and MMP-7 in individuals with type 1 diabetes and prevalent DKD (n = 20) or longstanding (n = 61) or new-onset (n = 10) type 1 diabetes without DKD. These urine proteins were also quantified in type 2 DKD (n = 11) before and after treatment with candesartan. The utilized immunoassays had comparable inter- and intra-assay and intraindividual variation to assays used for urine albumin. Median (IQR) urine AGT concentrations were 226.0 (82.1, 550.3) and 13.0 (7.8, 20.0) μg/g creatinine in type 1 diabetes with and without DKD, respectively (P < 0.001). Median (IQR) urine gremlin-1 concentrations were 48.6 (14.2, 254.1) and 3.6 (1.7, 5.5) μg/g, respectively (P < 0.001). Median (IQR) urine MMP-7 concentrations were 6.0 (3.8, 10.5) and 1.0 (0.4, 2.9) μg/g creatinine, respectively (P < 0.001). Treatment with candesartan was associated with a reduction in median (IQR) urine AGT/creatinine from 23.5 (1.6, 105.1) to 2.0 (1.4, 13.7) μg/g, which did not reach statistical significance. Urine gremlin-1 and MMP-7 excretion did not decrease with candesartan. In conclusion, DKD is characterized by markedly elevated urine AGT, MMP-7, and gremlin-1. AGT decreased in response to RAS inhibition, suggesting that this marker reflects therapeutic response. Urinary components of the RAS, BMP, and WNT pathways may identify risk of DKD and aid development of novel therapeutics.
    05/2014; 2(5). DOI:10.14814/phy2.12010
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    ABSTRACT: Mechanisms associated with Type 1 diabetes (T1D) development remain incompletely defined. Employing a sensitive array-based bioassay where patient plasma is used to induce transcriptional responses in healthy leukocytes, we previously reported disease-specific, partially IL-1 dependent, signatures associated with pre and recent onset (RO) T1D relative to unrelated healthy controls (uHC). To better understand inherited susceptibility in T1D families, we conducted cross-sectional and longitudinal analyses of healthy auto-antibody-negative (AA-) high HLA risk siblings (HRS, DR3 and/or DR4) and AA- low HLA risk siblings (LRS, non-DR3/non-DR4). Signatures, scored with a novel ontology-based algorithm, and confirmatory studies differentiated the RO T1D, uHC, HRS, and LRS plasma milieus. Relative to uHC, T1D family members exhibited an elevated inflammatory state, consistent with innate receptor ligation that was independent of HLA, AA, or disease status and included elevated plasma IL-1α, IL-12p40, CCL2, CCL3, and CCL4 levels. Longitudinally, signatures of T1D progressors exhibited increasing inflammatory bias. Conversely HRS possessing decreasing AA titers revealed emergence of an IL-10/TGF-β mediated regulatory state that paralleled temporal increases in peripheral activated CD4+/CD45RA-/FoxP3(high) regulatory T-cell frequencies. In AA- HRS, the familial innate inflammatory state was also temporally supplanted by immunoregulatory processes, suggesting a mechanism underlying the decline in T1D susceptibility with age.
    Diabetes 04/2014; 63(11). DOI:10.2337/db14-0214 · 8.47 Impact Factor
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    ABSTRACT: Post-translational modification of self-proteins has been shown to elicit clinically relevant immune responses in rheumatoid arthritis and celiac disease. Accumulating evidence suggests that recognition of modified self-proteins may also be important in type 1 diabetes. Our objective was to identify post-translationally modified GAD65 peptides which are recognized by subjects with type 1 diabetes and to assess their disease relevance. We show that citrullination and transglutamination of peptides can enhance their binding to DRB1*04:01, a diabetes susceptible HLA allele. These and corresponding modifications to amino acids at T cell contact positions modulated the recognition of multiple GAD65 peptides by self-reactive T cells. Using class II tetramers, we verified that memory T cells specific for these modified epitopes were detectable directly ex vivo in the peripheral blood of subjects with type 1 diabetes at significantly higher frequencies than healthy controls. Furthermore, T cells that recognize these modified epitopes were either less responsive or non-responsive to their unmodified counterparts. Our findings suggest that post-translational modification contributes to the progression of autoimmune diabetes by eliciting T cell responses to new epitope specificities that are present primarily in the periphery, thereby circumventing tolerance mechanisms.
    Diabetes 04/2014; 63(9). DOI:10.2337/db13-1952 · 8.47 Impact Factor
  • Dana E. VanBuecken, Carla J. Greenbaum
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    ABSTRACT: Connecting peptide, or C-peptide, is a protein that joins insulin's α and B chains in the proinsulin molecule. During insulin synthesis, C-peptide is cleaved from proinsulin and secreted in an equimolar concentration to insulin from the β cells. Because C-peptide experiences little first-pass clearance by the liver, and because levels are not affected by exogenous insulin administration, it may be used as a marker of endogenous insulin production and a reflection of β-cell function. Residual β-cell function, as measured by C-peptide in those with type 1 diabetes (T1D), has repeatedly been demonstrated to be clinically important. The Eisenbarth model of type 1 diabetes postulated immune-mediated linear loss of β cells, with clinical diagnosis occurring when there was insufficient insulin secretion to meet glycemic demand. Moreover, the model also implied that all individuals with T1D rapidly and inevitably progressed to absolute insulin deficiency. Correspondingly, it was assumed that most people with longstanding T1D would show little to no residual C-peptide secretion. While more than a quarter century of data confirms that this model remains largely true and appropriately serves as the basis for prevention studies, accumulating evidence suggests that the natural history of β-cell function before, during and after diagnosis is more complex. In this review, we discuss the clinical benefits of residual insulin secretion and present recent data about the natural history of insulin secretion in those with, or at risk for T1D.
    Pediatric Diabetes 03/2014; 15(2). DOI:10.1111/pedi.12135 · 2.13 Impact Factor
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    ABSTRACT: OBJECTIVE We studied the utility of the Diabetes Prevention Trial-Type 1 Risk Score (DPTRS) for improving the accuracy of type 1 diabetes (T1D) risk classification in TrialNet Natural History Study (TNNHS) participants.RESEARCH DESIGN AND METHODS The cumulative incidence of T1D was compared between normoglycemic individuals with DPTRS values >7.00 and dysglycemic individuals in the TNNHS (n = 991). The cumulative incidence was compared between individuals with DPTRS values <7.00 and >7.00 among those with dysglycemia and those with multiple autoantibodies in the TNNHS. DPTRS values >7.00 were compared with dysglycemia for characterizing risk in Diabetes Prevention Trial-Type 1 (DPT-1) (n = 670) and TNNHS participants. The reliability of DPTRS values >7.00 was compared with dysglycemia in the TNNHS.RESULTSThe cumulative incidence of T1D for normoglycemic TNNHS participants with DPTRS values >7.00 was comparable to those with dysglycemia. Among those with dysglycemia, the cumulative incidence was much higher (P < 0.001) for those with DPTRS values >7.00 than for those with values <7.00 (3-year risks: 0.16 for <7.00 and 0.46 for >7.00). Dysglycemic individuals in DPT-1 were at much higher risk for T1D than those with dysglycemia in the TNNHS (P < 0.001); there was no significant difference in risk between the studies among those with DPTRS values >7.00. The proportion in the TNNHS reverting from dysglycemia to normoglycemia at the next visit was higher than the proportion reverting from DPTRS values >7.00 to values <7.00 (36 vs. 23%).CONCLUSIONSDPTRS thresholds can improve T1D risk classification accuracy by identifying high-risk normoglycemic and low-risk dysglycemic individuals. The 7.00 DPTRS threshold characterizes risk more consistently between populations and has greater reliability than dysglycemia.
    Diabetes care 02/2014; 37(4). DOI:10.2337/dc13-2359 · 8.57 Impact Factor
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    ABSTRACT: Complement component C4 (C4) is a highly variable complement pathway gene situated approximately 500kb from DRB1 and DQB1, the genes most strongly associated with many autoimmune diseases. Variations in C4 copy number, length, and isotype create a highly diverse gene cluster, in which insertion of an endogenous retrovirus in the 9(th) intron of C4, termed HERV-K(C4), is a notable component. Here we investigate the relationship between C4 variation/copy number and type 1 diabetes. We find that individuals with type 1 diabetes have significantly fewer copies of HERV-K(C4), and that this effect is not solely due to linkage with known MHC class II susceptibility alleles. We show that HERV-K(C4) is a novel type 1 diabetes marker that accounts for the disease association previously attributed to some key HLA-DQB1 alleles raising the possibility that this retroviral insertion element contributes to functional protection against type 1 diabetes.
    Diabetes 01/2014; 63(5). DOI:10.2337/db13-1382 · 8.47 Impact Factor
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    ABSTRACT: IL-2 receptor (IL-2R) signaling is essential for optimal stability and function of CD4(+)CD25(hi)FOXP3(+) regulatory T cells (Treg); a cell type that plays an integral role in maintaining tolerance. Thus, we hypothesized that decreased response to IL-2 may be a common phenotype of subjects who have autoimmune diseases associated with variants in the IL2RA locus, including T1D and MS, particularly in cells expressing the high affinity IL-2R alpha chain (IL-2RA or CD25). To examine this question we used phosphorylation of STAT5 (pSTAT5) as a downstream measure of IL-2R signaling, and found a decreased response to IL-2 in CD4(+)CD25(hi) T cells of T1D and MS, but not SLE patients. Since the IL2RArs2104286 haplotype is associated with T1D and MS, we measured pSTAT5 in controls carrying the rs2104286 risk haplotype to test whether this variant contributed to reduced IL-2 responsiveness. Consistent with this, we found decreased pSTAT5 in subjects carrying the rs2104286 risk haplotype. Reduced IL-2R signaling did not result from lower CD25 expression on CD25(hi) cells; instead we detected increased CD25 expression on naive Treg from controls carrying the rs2104286 risk haplotype, and subjects with T1D and MS. However the rs2104286 risk haplotype correlated with increased soluble IL-2RA levels, suggesting that shedding of the IL-2R may account in part for the reduced IL-2R signaling associated with the rs2104286 risk haplotype. In addition to risk variants in IL2RA, we found that the T1D-associated risk variant of PTPN2rs1893217 independently contributed to diminished IL-2R signaling. However, even when holding genotype constant at IL2RA and PTPN2, we still observed a significant signaling defect in T1D and MS patients. Together, these data suggest that multiple mechanisms converge in disease leading to decreased response to IL-2, a phenotype that may eventually lead to loss of tolerance and autoimmunity.
    PLoS ONE 12/2013; 8(12):e83811. DOI:10.1371/journal.pone.0083811 · 3.53 Impact Factor
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    ABSTRACT: Objective We previously reported that two years of co-stimulation modulation with abatacept slowed decline of beta-cell function in recent-onset type 1 diabetes mellitus (T1DM). Subsequently, abatacept was discontinued, and subjects followed to determine whether there was persistence of effect.Research Design and Methods In 112 subjects (ages 6-36) with T1DM, 77 received abatacept and 35 received placebo infusions intravenously for 27 infusions over two years. The primary outcome - baseline-adjusted geometric mean 2-hour area under the curve (AUC) serum C-peptide during a mixed meal tolerance test (MMTT) at two years - showed higher C-peptide with abatacept versus placebo. Subjects were followed an additional year, off treatment, with MMTTs performed at 30 and 36 months.ResultsC-peptide AUC means, adjusted for age and baseline C-peptide, at 36 months were 0.217 (95% CI: 0.168, 0.268) and 0.141 (95% CI: 0.071, 0.215) nmol/L for abatacept and placebo groups, respectively (p=0.046). The C-peptide decline from baseline remained parallel with an estimated 9.5 months' delay with abatacept. Moreover, HbA1c levels remainded lower in the abatacept group than in the placebo group. The slightly lower (non-significant) mean total insulin dose among the abatacept group reported at 2 years was the same as the placebo group by 3 years.Conclusions Co-stimulation modulation with abatacept slowed decline of beta-cell function and improved HbA1c in recent-onset T1DM. The beneficial effect was sustained for at least one year after cessation of abatacept infusions, or three years from T1DM diagnosis.
    Diabetes care 12/2013; 37(4). DOI:10.2337/dc13-0604 · 8.57 Impact Factor
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    ABSTRACT: Background Type 1 diabetes results from autoimmune targeting of the pancreatic β cells, likely mediated by effector memory T (Tem) cells. CD2, a T cell surface protein highly expressed on Tem cells, is targeted by the fusion protein alefacept, depleting Tem cells and central memory T (Tcm) cells. We postulated that alefacept would arrest autoimmunity and preserve residual β cells in patients newly diagnosed with type 1 diabetes. Methods The T1DAL study is a phase 2, double-blind, placebo-controlled trial in patients with type 1 diabetes, aged 12–35 years who, within 100 days of diagnosis, were enrolled at 14 US sites. Patients were randomly assigned (2:1) to receive alefacept (two 12-week courses of 15 mg intramuscularly per week, separated by a 12-week pause) or a placebo. Randomisation was stratified by site, and was computer-generated with permuted blocks of three patients per block. All participants and site personnel were masked to treatment assignment. The primary endpoint was the change from baseline in mean 2 h C-peptide area under the curve (AUC) at 12 months. Secondary endpoints at 12 months were the change from baseline in the 4 h C-peptide AUC, insulin use, major hypoglycaemic events, and HbA1c concentrations. This trial is registered with ClinicalTrials.gov, number NCT00965458. Findings Of 73 patients assessed for eligibility, 33 were randomly assigned to receive alefacept and 16 to receive placebo. The mean 2 h C-peptide AUC at 12 months increased by 0·015 nmol/L (95% CI −0·080 to 0·110) in the alefacept group and decreased by 0·115 nmol/L (–0·278 to 0·047) in the placebo group, and the difference between groups was not significant (p=0·065). However, key secondary endpoints were met: the mean 4 h C-peptide AUC was significantly higher (mean increase of 0·015 nmol/L [95% CI −0·076 to 0·106] vs decrease of −0·156 nmol/L [–0·305 to −0·006]; p=0·019), and daily insulin use (0·48 units per kg per day for placebo vs 0·36 units per kg per day for alefacept; p=0·02) and the rate of hypoglycaemic events (mean of 10·9 events per person per year for alefacept vs 17·3 events for placebo; p<0·0001) was significantly lower at 12 months in the alefacept group than in the placebo group. Mean HbA1c concentrations at week 52 were not different between treatment groups (p=0·75). So far, no serious adverse events were reported and all patients had at least one adverse event. In the alefacept group, 29 (88%) participants had an adverse event related to study drug versus 15 (94%) participants in the placebo group. In the alefacept group, 14 (42%) participants had grade 3 or 4 adverse events compared with nine (56%) participants in the placebo group; no deaths occurred. Interpretation Although the primary outcome was not met, at 12 months, alefacept preserved the 4 h C-peptide AUC, lowered insulin use, and reduced hypoglycaemic events, suggesting efficacy. Safety and tolerability were similar in the alefacept and placebo groups. Alefacept could be useful to preserve β-cell function in patients with new-onset type 1 diabetes. Funding US National Institutes of Health and the Juvenile Diabetes Research Foundation.
    12/2013; 1(4):284–294. DOI:10.1016/S2213-8587(13)70111-6
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    ABSTRACT: To clarify whether the rate of decline in stimulated C-peptide (SCP) from 2 to 15 months after diagnosis has changed over an interval of 27 yr. The rate of decline in SCP levels at 1, 2, 3, 6, 9, 12, and 15 months after diagnosis was compared in four paediatric cohorts from Scandinavian and European countries including 446 children with new onset type 1 diabetes (T1D, 1982-2004). Findings were evaluated against 78 children (2004-2009) from the TrialNet studies. The mean rate of decline [%/month (±SEM)] in SCP for a 10-yr-old child was 7.7%/month (±1.5) in the 1982-1985 Cohort, 6.3%/month (±1.7) in the 1995-1998 Cohort, 7.8%/month (±0.7) in the 1999-2000 Cohort, and 10.7%/month (±0.9) in the latest 2004-2005 Cohort (p = 0.05). Including the TrialNet Cohort with a rate of decline in SCP of 10.0%/month (±0.9) the differences between the cohorts are still significant (p = 0.039). The rate of decline in SCP was negatively associated with age (p < 0.0001), insulin antibodies (IA) (p = 0.003), and glutamic acid decarboxylase-65 (GAD65A) (p = 0.03) initially with no statistically significant effect of body mass index (BMI) Z-score at 3 months. Also, at 3 months the time around partial remission, the effect of age on SCP was significantly greater in children ≤5 yr compared with older children (p ≤ 0.0001). During the past 27 yr, initial C-peptide as well as the rate of C-peptide decline seem to have increased. The rate of decline was affected significantly by age, GAD65A, and IA, but not BMI Z-score or initial C-peptide.
    Pediatric Diabetes 11/2013; 15(5). DOI:10.1111/pedi.12098 · 2.13 Impact Factor

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  • 2002–2015
    • Benaroya Research Institute
      • Diabetes Research Program
      Seattle, Washington, United States
  • 1990–2014
    • University of Washington Seattle
      • • Department of Medicine
      • • Department of Pediatrics
      • • Division of Metabolism, Endocrinology and Nutrition
      Seattle, Washington, United States
  • 2002–2013
    • Virginia Mason Medical Center
      Seattle, Washington, United States
  • 2011
    • University of Florida
      Gainesville, Florida, United States
  • 2008–2011
    • University of Miami
      • Diabetes Research Institute
      كورال غيبلز، فلوريدا, Florida, United States
  • 2010
    • University of Colorado
      • Barbara Davis Center for Childhood Diabetes
      Denver, CO, United States
  • 2006–2007
    • Columbia University
      New York, New York, United States
  • 2004
    • University of South Florida
      • Pediatrics Epidemiology Center
      Tampa, Florida, United States
  • 2003
    • Clinical Immunology Society
      Society Hill, New Jersey, United States
  • 2001–2002
    • VA Puget Sound Health Care System
      Washington, Washington, D.C., United States
  • 2000
    • University of Southern California
      Los Angeles, California, United States