Humoral immune reactivity against human leukocyte antigen (HLA)-DQ graft molecules in the early posttransplantation period.

Humoral graft-specific alloreactivity was investigated in 110 renal transplant (RTx) recipients (group A) starting immediately postTx and in 32 RTx candidates sensitized against a failed graft (group B) using an enzyme-linked immunosorbent assay (ELISA) assay. All patients received a human leukocyte antigen (HLA) class I and II incompatible graft. Donor-specific (DS) antibodies were detected in 11 of 110 (90.9%) group-A patients, predominately during the first 6 months postTx. In all 11 cases, only HLA class II antibodies were detected. Ten of 11 antibody-positive patients received an HLA-DR, HLA-DQ incompatible graft, and all patients had HLA-DQ DS antibodies, either alone (n=8) or with HLA-DR antibodies (n=2). HLA-DQ antibodies were also detected in 80.9% of group-B patients. The presence of HLA-DQ DS antibodies in the early postTx period does not identify patients with rejection or deterioration of graft function. Whether these patients are at high risk for graft loss remains to be clarified.