Impact of pre-transplant anti-MICA sensitization in graft rejection and survival

• Main Author: Costa,Rui
• Publication Date: 2015
• Other Authors: Malheiro,Jorge, Tafulo,Sandra, Santos,Clara, Almeida,Manuela, Pedroso,Sofia, Martins,La Salete, Dias,Leonídio, Castro-Henriques,António
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://scielo.pt/scielo.php?script=sci_arttext&pid=S0872-01692015000200005
• topic: HLA; kidney; MICA; rejection; survival; transplant

Background: Evidence supporting deleterious effect of preformed major histocompatibility class I chain-related A (MICA) antibodies in rejection incidence and graft survival is still unclear. Methods: Retrospective analysis of 554 kidney transplanted patients. Comparison between positive or negative for MICA antibodies patients was performed to characterize sensitizing triggers. Further classification according to pre-transplant flow cytometry-recorded anti-MICA and/or anti-human leukocyte antigen (HLA) antibodies was made to determine first year rejection incidence and graft survival. Multivariate analysis was applied to determine predictors for acute rejection. Results: Pre-formed anti-MICA antibodies were detected in 41 patients (7.4%). HLA sensitization, blood transfusions and pregnancies were frequently found in anti-MICA+ patients but only pre-formed anti-HLA class I antibodies showed independent association (OR 2.67, p = 0.02). Comparing to MICA-/HLA-, MICA-/HLA+ group presented significantly lower first year rejection-free survival (78.6% vs. 89.3%, p < 0.01), mostly occurred in the first six months, while no difference was found in MICA+/HLA- (88.9% vs. 89.3%, p = ns). MICA-/HLA+ showed independent impact in rejection (OR 2.09, p = 0.03), while no evidence was found in MICA+/HLA- (OR 1.08, p = ns). At 4 years, MICA-/HLA+ group presented lower graft survival (85.8% vs. 95.3%, p = 0.03). Again, no difference was found in MICA+/HLA- group (95.1% vs. 95.3%, p = ns). Conclusion: Our results do not support HLA-independent deleterious pathogenic role of pre-formed MICA antibodies on first year rejection incidence and graft survival