We have investigated the association between the presence of antibodies to HLA class II antigens and the development of acute and chronic rejection after kidney transplantation. Sera from seventy-one patients before, shortly (2 weeks), and in the period between 8 and 22 months after transplantation were analyzed by the standard complement-dependent cytotoxicity (CDC) test, ELISA-LATM, and LAT tests. Absence of antibodies to HLA class II antigens before and shortly after transplantation was associated with a lower incidence of rejection episodes in the first post-transplant year. Donor-specific class II antibodies could not be detected by the ELISA-LAT test and there was no statistically significant difference in serum creatinine levels between the antibody-positive and antibody-negative patient groups two years after transplantation. Our study suggests that anti- HLA class II antibodies represent a risk factor for the development of acute immunological complications during the first year after transplantation.

Keywords: Antibodies - blood, Enzyme-Linked Immunosorbent Assay - methods, Graft Rejection - epidemiology, Graft Rejection - etiology, Graft Survival, Histocompatibility Antigens Class II - immunology, Incidence, Incidence, Kidney Transplantation, Predictive Value of Tests, Risk Factors, Risk Factors, Transplantation, Homologous