Role of de novo HLA-DQ antibodies in renal transplantation: analysis of a single center data

Abstract

To explore the generation pattern and clinical relevance of de novo HLA-DQ antibodies in renal transplantation. A total of 175 primary renal transplant recipients without pre-transplant HLA antibodies were recruited from January 2012 to December 2013. The average follow-up period was 10 (6-18) years. They were divided into control group (n = 94) with normal renal graft function (serum creatinine <120 µmol/L); dysfunction group (n = 54) with continued serum creatinine >150 µmol/L over 6 months; and graft loss group (n = 27) with resumed hemodialysis. The sera were collected and screened for de novo HLA antibodies by flow PRA or Luminex mixed beads. And HLA-A, -B, -DR and -DQ specific antibodies were identified by HLA single antigen beads. Positive de novo HLA antibodies were detected in 48% (26/54) of patients from dysfunction group and in 52% (14/27) from graft loss group, but only in 17% (16/94) from control group (P < 0.01). The frequency of de novo DQ antibodies among patients with any positive HLA antibody was the highest in all three groups (14/16, 24/26 and 14/14). Additionally, the average mean peak fluorescence intensity of DQ antibodies was almost the highest when compared to other antibodies. Moreover, when those with positive HLA antibodies in each group were analyzed, 10/16 in control group were detected to have DQ antibodies alone. However, 17/26 of patients in dysfunction group and 14/14 in graft loss group were detected to have DQ antibodies plus HLA-DR and/or -A, -B antibodies. It indicated that the combined presence of DQ-and non-DQ- antibodies was associated with chronic renal graft failure. The presence of de novo HLA-DQ antibodies is frequent after renal transplantation. And it is associated with chronic graft failure when co-displaying with other HLA antibodies. The screening and detection of HLA-DQ antibodies after kidney transplantation may aid early warning of donor antigen-specific activation of immune system and subsequent graft dysfunction. Thus it serves as an indication for early treatment.