Objective: The aim of this study was to characterize patient antibodies before and after cadaver and/or living-donor kidney transplantation and to correlate these data with the clinical course after transplantation. Methods: Sera from 69 cadaver, -9 living-related and 2 patients waiting for living-donor kidney transplantation were analyzed by the complement dependent cytotoxicity (CDq test, flow cytometry (FCXM) and ELISA. Results: FCXM revealed that 15.0% of patients before transplantation and 16.7% after transplantation had antibodies to donor cells. 10.3% patients were positive before and after transplantation (+/ +), while 6.8% developed antibodies early after transplantation (-/ +). Analysis of the specificity of those antibodies by ELISAshowed that it was directed to: I) mismatched donor HLAantigens 2) antigens belonging to the same cross-reacting group (CREG) as the mismatched donor antigens 3) HLAantigens not expressed by donor cells or, probably, to non-HLA antigens. Conclusion:Anti-HLA antibodies were detected in patients before and after transplantation and in most cases their anti-HLA specificity could be determined. Fast and precise characterization of antibodies in patients before and after transplantation can be performed by both sensitive methods - FCXM and ELISA - which may help predict the onset of immunological complications and, consequently, improve the prognosis after organ transplantation.

Keywords: Antibodies, Crossmatch, HLA