Detection of Antibodies Against Major Histocompatibility Complex Class I-Related Chain A in Long-term Renal Graft Recipients

Abstract

Objectives: To determine the prevalence, allele specificity, and intensity of anti-MICA antibodies in long-term renal graft recipients and to investigate their association with impaired renal function.

Materials and Methods: Sixty-eight long-term (> 10 y) renal graft recipients were divided into 2 groups: (1) patients with impaired renal function (serum creatinine ≥ 2 mg/dL, n=6); (2) patients with normal renal function (serum creatinine < 176.8 µmol/L, n=62). Anti-MICA antibodies were tested using Luminex single antigen beads assays and the frequency, specificity, and intensity of these antibodies were compared between 2 patient groups.

Results: MICA antibodies were detected in 33% of impaired renal function patients and 15% of normal renal function patients (P > .05). Anti-MICA*027 antibodies were found in 11.76% of patients, whereas antibody to MICA*012 was found in 2.94% of patients. Interestingly, among all antibody specificities, MICA*001,*004, *007, *009, *012, and *018 were found more frequently in impaired renal function patients than in normal renal function patients. The peak mean fluorescence intensity levels of MICA antibodies in impaired renal function patients were significantly higher than those in normal renal function patients (P < .05).

Conclusions: Our data suggest that increased prevalence and intensity of anti-MICA antibodies are associated with impaired renal graft function in long-term renal graft recipients and some MICA antibodies might be more important than others in mediating graft rejection.