Serum major-histocompatibility-complex class Ⅰ-related chain A antibody detection for the evaluation of graft dysfunction in renal allograft recipients

Background In addition to the well-known antibodies against human leukocyte antigens （HLA）-induced kidney-graft rejection, polymorphic major-histocompatibility-complex （MHC） class Ⅰ-related chain A （MICA） antigens can elicit antibodies and have been suggested to play a role in the antibody-mediated allograft rejection （AMR）. We carded out a prospective study of MICA antibodies in post-renal transplant patients to determine the association between MICA antibodies, C4d staining, histological features, and graft outcome.Methods We tested 52 patients who had biopsy results due to graft dysfunction. The MICA antibodies in concurrent sera were determined by Luminex. All patients were followed up for one year after renal biopsy. The influence of antibody production on the function of graft was analyzed.Results Antibodies against MICA were positive in 15 out of the 52 patients （28.9%）. The presence of MICA antibodies was associated with renal-allograft deterioration. During one-year follow-up, the estimated glomerular filtration rate （eGFR） decreased （24.0±3.4）% among recipients with anti-MICA antibodies. However, among recipients without anti-MICA antibodies, the eGFR has declined only （8.4＋3.0）% （P=0.017）. The association between C4d staining,histological features and MICA antibody production was found no significant difference.Conclusion Besides anti-HLA antibodies, the presence of post-transplant MICA antibody is associated with poor graft outcome and increases the risk of graft failure.

Assessment of 188Re marked anti MHC class II antibody by peripheral blood mononuclear cells stimulated by donor alloantigen

Background Previous studies showed that anti MHC-II monoclone antibody （MAb） only had partial inhibiting effect of alloreactive mixed lymphocyte reaction （MLR） in vitro and it was unsteady and non-persistent. The aim of this research was to determine whether radioactive isotope 188Re marked MHC-II antibody could benefit the allograft acceptance in transplantation as compared to normal MHC-II antibody. Methods 188Re was incorporated to 2E9/13F（ab＇）2 which is against swine MHC class II antigen （MAb-~88Re）. Porcine peripheral blood mononuclear （PBMC） cells were examined for proliferation and cytokine mRNA expression after stimulation with MHC-II MAb or MAb-188Re. Results The proliferative response of recipient PBMCs in mixed lymphocyte reaction （MLR） to donor alloantigen showed that the stimulation index of MAb-188Re group was significantly lower than the MHC-II MAb group and control （P 〈0.05）. mRNA expression of interleukin 2, interferon y and tumor necrosis factor a （type 1 cytokines） was lower in MAb-188Re group than the MHC-II MAb group, while interleukin 10 （type 2 cytokines） was higher in MAb-~aSRe group in the first 24 hours. Conclusion MAb-188Re could help the graft acceptance by inhibiting T cell proliferation, lowering the expression of type 1 cytokines and elevating the type 2 cytokines produced by PBMC.