[Show abstract][Hide abstract]ABSTRACT: It has been widely believed that it is critical to remove as much anti A/B blood group antibody as possible before ABO incompatible renal transplantation (ABOI-RTx) for renal graft survival. We, however, report a rare case that implied a presence of hyperacute rejection in ABOI-RTx leading to graft loss, in a way, regardless of titers of blood group antibody before transplantation.We newly developed a method for measuring a complement-fixing ability of anti A/B blood group IgG antibody to elucidate an immunological mechanism of how anti A/B blood group antibody works in ABOI-RTx. Results of such measurements revealed that a high positive rate of complement-fixing ability of anti A/B IgG antibody was predictive of poor graft survival or graft loss. This method, therefore, might turn out to be an important laboratory test before ABOI-RTx.
[Show abstract][Hide abstract]ABSTRACT: Various methods have been proposed for the detection of HLA antibodies in organ transplantation. However, the discrepancies in the results between LCT (CDC)-XM and the other methods, FCXM, LABScreen etc. are observed. We investigated the cause of these discrepancies using the LABScreen Single Antigen Test (LABScreen) and LABScreen Single C1q (C1qScreen). C1qScreen is detected the complement-binding HLA antibody. As a result, in 37 patients whose HLA antibodies positive by using LABScreen test, 28 patients (76%) and 25 patients (68%) whose HLA Class I and Class II antibodies positive, respectively. Moreover, it was only 11 patients (30%) that C1qScreen was positive in the patients whose Class I antibodies were positive. And it was 14 patients (40%) that C1qScreen was positive in the patients whose Class II was positive. Furthermore C1qScreen positive was 176 (31%) among 567 specificity of detected Class I antibodies, and C1qScreen positive was 171 (44%) among 392 specificity of Class II. Therefore, many HLA antibodies are not detected by LCT-XM. It is because these antibodies do not have complement-binding nature. And such antibodies could be detected by AHG-LCT, and it is supposed that these are not related to kidney-allograft failure.
[Show abstract][Hide abstract]ABSTRACT: The effect of a humanized anti-human leukocyte antigen-DR monoclonal antibody, IMMU-114, on the allogeneic immune response was investigated in vitro.
Responder peripheral blood mononuclear cells were cocultured with inactivated self or allogeneic stimulator peripheral blood mononuclear cells in the presence of control antibody or IMMU-114. Thymidine incorporation rates were then measured. Phenotypic changes in peripheral blood mononuclear cells and the intracellular Th1-type cytokines interleukin-2, interferon-γ, and tumor necrosis factor-α were analyzed using flow cytometry. The concentrations of interleukin-2, interferon-γ, and tumor necrosis factor-α in the mixed lymphocyte reaction culture medium were measured.
Thymidine incorporation rates at a 1:1 responder/stimulator ratio of allogeneic, allogeneic + IMMU-114, self, and self + IMMU-114 were 22,080.7 ± 602.4, 2,254.5 ± 118.1, 1,284.0 ± 227.8, and 494.5 ± 27.5 cpm, respectively (P = .038). IMMU-114 decreased the frequencies of human leukocyte antigen-DR-expressing CD16+56+ NK cells, CD19+ B cells, and CD3+25+ activated T cells.
Intracellular cytokine assay and measurement of Th1-type cytokines in the mixed lymphocyte reaction culture medium revealed that IMMU-114 significantly decreased the titers of interleukin-2, interferon-γ, and tumor necrosis factor-α. IMMU-114 significantly suppresses the allogeneic immune response in vitro, partly through inhibition of the Th1 response.
[Show abstract][Hide abstract]ABSTRACT: The effect of an anti-human leukocyte antigen-DR (MHC class II) humanized monoclonal antibody, IMMU-114, against the human to bovine cellular response was investigated.
Human peripheral mononuclear cells (PBMCs) were cocultured with inactivated self-PBMCs (Self), bovine PBMCs with control antibody (Xeno), or bovine PBMCs with IMMU-114 (IMMU-114). Cellular responses were investigated by thymidine incorporation assay, CFSE (carboxyfluorescein diacetate succinimidyl ester)-mixed lymphocyte reaction, and cytokine production in culture medium.
Thymidine incorporation rates at a 1:1 responder to stimulator ratio for Xeno + control antibody, Xeno + IMMU-114, Self + control antibody, and Self + IMMU-114 were 14201.3 ± 1968.4, 513.0 ± 49.5, 952.7 ± 128.7, and 423.3 ± 138.8 cpm, respectively (P = 0.032). Those at a 1:2 ratio were 6518.0 ± 690.1, 896.6 ± 92.9, 1051.0 ± 123.6, and 736.0 ± 35.6 cpm, respectively (P = 0.036). CFSE-mixed lymphocyte reaction demonstrated that the frequencies of CFSE-low, CD4(+), and CD25(+) activating T cells in Self, Xeno, and IMMU-114 were 0.27 ± 0.04%, 3.65 ± 0.53%, and 1.23 ± 0.15%, respectively (P = 0.027). Cytokine production in culture medium indicated that IMMU-114 decreased Th1-type cytokines, including interleukin-2, interferon-γ, and tumor necrosis factor-α.
IMMU-114 effectively suppresses human to bovine cellular responses. The mechanism involves direct inhibition of the interaction between class II human leukocyte antigen-DR-positive cells and CD4(+) T cells, and indirect suppression of Th1 cytokine production.