IMPACT OF ANTI-MICA ANTIBODIES ON GRAFT FUNCTION, REJECTION, AND SURVIVAL IN LIVE-RELATED RENAL TRANSPLANT RECIPIENTS: A PROSPECTIVE CASE-CONTROL STUDY

Background: Non-HLA antibodies directed against major histocompatibility complex class I-related chain A (MICA) have been implicated in acute and chronic antibody-mediated rejection and in reduced graft survival after renal transplantation. Data on the clinical impact of anti-MICA antibodies, and of pre-transplant desensitisation in anti-MICA-positive recipients, remain limited, particularly from the Indian subcontinent. This study assessed the outcomes of anti-MICA antibody-positive live-related renal transplantation performed using a structured desensitisation protocol. Materials and Methods: This prospective case-control study was conducted at a tertiary-care transplant centre from March 2016 to March 2018 and included 50 live-related kidney transplant recipients who tested positive for anti-MICA antibodies, had a negative CDC crossmatch, and lacked donor-specific HLA class I/II antibodies (cases). These were compared to 50 recipients without anti-MICA antibodies (controls). All the Cases received desensitisation treatment with rituximab, plasma exchange (PLEX), and intravenous immunoglobulin (IVIg) before transplantation; controls did not undergo any desensitisation. Over a 6-month period, outcomes such as graft function (serum creatinine), biopsy-proven rejection, major infections, new-onset diabetes after transplantation (NODAT), graft failure, and mortality were evaluated. Results: The mean age of the study participants was comparable between anti-MICA-positive and -negative groups (45.06 ± 10.77 vs 39.62 ± 13.24 years; p = 0.12). Anti-MICA-positive recipients had a significantly longer pre-transplant dialysis duration (8.32 ± 5.49 vs 5.20 ± 4.58 months; p=0.001) and a higher rate of prior blood transfusion (34.0% vs 14.0%; p = 0.01) compared to controls. Serum creatinine at discharge and at 1, 3, and 6 months did not differ significantly between groups (p>0.05). Biopsy-proven rejection occurred in 2/50 (4.0%) cases and 2/50 (4.0%) controls (RR 1.00, 95% CI 0.36–2.71; p=1.00). The incidence of major infections, NODAT (8.0% vs 6.0%; RR 1.15, 95% CI 0.58–2.26; p=0.79), graft failure, and mortality (4.0% in each group) was comparable between groups. Conclusion: Pretransplant desensitisation with rituximab, PLEX, and IVIg yields comparable six-month results- such as renal graft function, rejection rates, infection risk, and patient and graft survival- in anti-MICA antibody-positive live-related transplant recipients versus those negative for anti-MICA. The study highlights that pre-transplant blood transfusions and prolonged dialysis significantly raise the odds of anti-MICA sensitisation. These findings emphasise the need for mandatory pre-transplant anti-MICA antibody screening and suggest that desensitisation should be considered for sensitised patients. Nonetheless, longer-term prospective studies are essential for further validation.