BACKGROUNDHumoral immunity is an important factor for long-term survival of renal allograft. Here we performed a four-year follow-up to explore the clinical significance of monitoring anti-human leukocyte antigens (HLA) and anti-major histocompatibility complex class I-related chain A (MICA) antibody expression after kidney transplantation.

METHODSWe obtained serial serum samples from 84 kidney transplant patients over a four-year period. All patients were followed up at least 6 months after transplantation and had at least two follow-up points. Anti-HLA and anti-MICA antibody titres and serum creatinine (SCr) levels were evaluated at each follow-up. Patients were divided into 4 groups: HLA(+) MICA(-), HLA(-)MICA(+), HLA(+)MICA(+) and HLA(-)MICA(-). The impact of post-transplant antibody level on kidney allograft function was evaluated.

RESULTSAntibodies were detected in 38.1% (32/84) of the renal allograft recipients. HLA, MICA and HLA+MICA expression was observed in 18.89%, 14.44% and 5.93% of the recipients respectively. The most frequent anti-HLA and anti-MICA specific antibodies identified were A11, A24, A29, A32, A33, A80; B7, B13, B37; DR17, DR12, DR18, DR52, DR53, DR1, DR4, DR9, DR51; DQ7, DQ4, DQ8, DQ2, DQ9, DQ5, DQ6 and MICA02, MICA18, MICA19, MICA07, MICA27. As the time after transplantation elapsed, more recipients developed de novo antibody expression. Total 11.91% (10/84) of the recipients had de novo antibody expression during the follow up. The average level of SCr and the percentage of recipients with abnormal allograft function were significantly higher in recipients with anti-HLA and/or anti-MICA antibody expression than those without. The appearance of anti-HLA and anti-MICA antibody expression always preceded the increase in SCr value.

CONCLUSIONSAnti-HLA and anti-MICA antibody expression has predictive value for early and late allograft dysfunction. The presence of donor specific antibody is detrimental to graft function and graft survival.