RESUMO
INTRODUCTION: The MIC (MHC class I chain-related) genes are a group of nonclassical MHC genes, located in the MHC class 1 region of chromosome 6. The aim of the present study was to find the prevalence of MHC class 1 chain-related (MICA) alloantibodies in patients undergoing live-related donor renal transplantation and its role in short-term graft survival. The role of blood transfusion in the formation of these antibodies was also studied. MATERIALS AND METHODS: Pretransplant samples of patients undergoing renal allograft transplantation were tested for anti-MICA antibodies. Association of various demographics, HLA-A + B + DRB1 mismatches, anti-HLA antibody screen, and anti-MICA antibodies was assessed using Pearson's chi-square test. RESULTS: Out of 646 serum samples, 94 (14.6%) were positive and 552 (85.4%) were negative for anti-MICA antibodies. Patients with anti-MICA antibody had a graft survival 89.3% as compared to 94.7% in patients without anti-MICA antibody (P < 0.05). The hazard ratio for all patients was 3.0701 (P < 0.05). Out of the 340 patients with no HLA antibodies, the presence of anti-MICA antibodies without any HLA antibodies (n = 43) was associated with poor outcome in the patients (hazard ratio of 2.768, P < 0.05). The presence of MICA antibodies with HLA antibodies did not decrease the graft survival (hazards ratio of 1.3750, P > 0.05). CONCLUSION: Preformed MICA antibodies independently increase the risk of kidney rejection and therefore recommend that guidelines should be formed for mandatory testing of these antibodies prior to renal transplant.
Assuntos
Epitopos/imunologia , Sobrevivência de Enxerto/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Isoanticorpos/metabolismo , Transplante de Rim , Estudos de Coortes , Epitopos/genética , Feminino , Rejeição de Enxerto , Antígenos HLA-A/genética , Antígenos HLA-A/imunologia , Antígenos HLA-B/genética , Antígenos HLA-B/imunologia , Cadeias HLA-DRB1/genética , Cadeias HLA-DRB1/imunologia , Antígenos de Histocompatibilidade Classe I/genética , Teste de Histocompatibilidade , Humanos , Imunidade Humoral , Índia , Masculino , Transplantados , Transplante HomólogoRESUMO
Transplant recipients are always at a risk of developing anti-human leukocyte antigen (HLA) antibodies due to prior sensitizing events such as blood transfusions, multiple pregnancies, or transplantation. Unexpected positive outcomes can be seen in complement dependent cytotoxicity (CDC) based assays due to underlying autoimmune disorders or pharmacological treatment (rituximab/intravenous immunoglobulin/anti-thymocyte globulin administration), therefore, limiting its value. CDC based assay results strongly depend on the vitality of the donor lymphocytes, highlighting another major limitation of this assay. Thus, as an alternative approach, solid phase based crossmatch assays were introduced which function independently of the cell quality and have higher sensitivity and specificity in detecting anti-HLA antibodies. We describe a case where the patient awaiting renal transplantation from living related donor was evaluated by pretransplant histocompatibility testing for the detection of anti-HLA antibodies. The histocompatibility testing revealed positive CDC anti-human globulin and flow crossmatch along with negative Luminex based assays (HLA antibody screen, luminex crossmatch, and luminex single bead assay). Detailed histocompatibility workup revealed immunoglobulin G autoantibodies which were complement activating and lympocytoxic in nature.
