The influence of Duffy blood group on renal allograft outcome in African Americans

Background. African American patients demonstrate higher rates of acute allograft rejection and lower kidney-graft survival compared with white patients. Duffy antigen receptor for chemokines (DARC) on red blood cells has been suggested to have an anti-inflammatory role by acting as a "chemokine sink." We investigated the relationship of Duffy blood group type to renal allograft outcome in African American patient population. Methods. A total of 163 African American kidney-transplant recipients were studied for Duffy blood group status. Patient outcomes were assessed at 6 to 42 months after transplantation and monitored for acute rejection episodes, graft function, and graft survival. Results. A total of 117 (71.8%) patients were Duffy (a-b-), 14 (8.6%) Duffy (a+b-), 21 (12.9%) Duffy (a-b+), and 11 (6.8%) Duffy (a+b+). No significant differences were observed among the groups with respect to median serum-creatinine values or the incidence of biopsy-confirmed acute-rejection episodes. Although only 15.4% of the patients had Duffy (a+) antigen, none lost their allograft during the study period, and Kaplan-Meier graft survival was not significantly different compared to Duffy (a-) group (log-rank test, P=0.12). Duffy (a-b-) patients demonstrated lower allograft survival compared with the other three groups, although statistical significance was not reached (log-rank test P=0.15). Delayed graft function (DGF) was strongly associated with graft failure for only Duffy (a-b-) patients (log-rank test P=0.003). Conclusions. Duffy (a-b-) patients have lower allograft survival in the presence of DGF. DARC may attenuate the inflammatory effects of DGF by acting as a "chemokine sink," and DARC-negative patients may be more vulnerable to DGF.