Abstract: Objective To evaluate the association of major histocompatibility complex class I chain related gene A (MICA)
antibodies with acute rejection (AR), chronic rejection (CR) and renal function after renal transplantation. Methods Serum
MICA antibodies were detected with ELISA before and after transplantation with also examinations of panel reactive
antibodies (PRA), serum creatinine, urine, graft ultrasound, lymphocyte subsets and the pathology of graft biopsy. The study
was carried out in two parts to monitor MICA antibodies in acute and chronic rejections after renal transplantation. Results In
the first part of the study 18 of the 41 recipients experienced episodes of acute rejection, and the incidence rate was markedly
higher in MICA+ group than in MICA- group (P<0.05). Compared with the recipients with stable renal functions, the patients
with acute graft rejection showed a significantly higher positivity rate of MICA antibodies. Postoperative MICA antibody
monitoring showed that MICA antibody level increased gradually 2-3 days after the occurrence of acute rejection;
anti-rejection treatment lowered serum creatinine to a normal level but MICA antibodies remained positive. In the second part,
21 of 40 patients had chronic graft rejection and showed significantly higher positivity rate of MICA than the patients with
stable renal functions (P<0.05). In patients with chronic rejections, the serum creatinine levels were significantly higher in
MICA+ than in MICA- cases (P<0.05). Graft biopsy of all MICA+ cases showed C4d deposition. Conclusion The status of MICA
antibodies can predict the occurrence and treatment outcomes of acute rejection, and also as one of the major causes of chronic
graft rejection, they affect the long-term survival of the renal grafts.