Background: The aim of this study was investigation of the HLA-I cross-reactive group (CREG)-specific antibodies (Abs) in sera from patients with a failed renal transplant and from nontransplanted patients.
Methods: A total of 5292 sera from 570 patients awaiting kidney transplantation were screened for the presence of HLA-I CREG-specific Abs. Patients who had never received a transplant (group A), and those with a previous transplant and Abs either not related (group B) or related to donor specificities (group C) were studied. A further division was made for Abs directed against specificities either included in (intra-CREG) or not included in patients' HLA-CREG (extra-CREG).
Results: Twelve of 24 (50%) Abs produced in response to mismatched donor HLA specificities after a failed graft were intra-CREG Abs, compared to 7 of 39 (18%) Abs that were not transplant-related.
Conclusions: Renal grafts showed a stronger immunogenicity than other sources of allosensitization. Our data also suggest that CREG matching may not be useful for renal allocation.