Associations of Anti-MHC Class I-related Chain A (MICA) Antibodies with Renal Allograft Outcomes

The association of anti-MHC class I-related chain A (MICA) and kidney allograft rejection has been reported. However, the associations of antibodies specific to donor MICA (dsMICA) and dsMICA levels with allograft outcome have not been elucidated. From November 2009 to June 2017, 125 sera samples from renal transplantation recipients with no HLA antibodies were screened for MICA antibodies. Patients with positive MICA antibody screening results and available residual donor DNA for MICA geno-typing underwent dsMICA analysis. Among these 125 sera samples, 19 were positive for MICA antibodies. dsMICA was positive in 5 out of the 12 analyzed sera samples. Neither MICA antibodies nor dsMICA were associated with acute rejection. However, interstitial fibrosis and tubular atrophy (IFTA) was significantly associated with MICA antibody positivity (OR=3.84, =0.009). In addition, the MFI value of dsMICA was significantly higher in patients with IFTA II or III than in patients without IFTA II or III ( =0.009). The association of MICA antibodies and dsMICA with high grade IFTA (grade II or III) was suggested. The MICA antibody and dsMICA might be useful indicators of chronic renal damage.