The human leukocyte antigens (HLA) function as transplantation antigens and as markers in disease association. Disparity at the HLA A, B, Cw, and DR loci in allogeneic stem cell transplants results in an increased incidence of graft-versus-host disease, graft rejection, and decreased survival. HLA class I loci A, B, and Cw also function as ligands for natural killer (NK) cell receptors in an interaction that predominantly inhibits cytolysis of target antigens. This HLA-NK cell inhibitory function is required for protection against auto-aggression, and is of unclear significance in other clinical settings. Furthermore, the prevention of auto-aggression is HLA molecule specific as demonstrated by the association of specific HLA types with autoimmune diseases. It is not known whether the HLA molecules might serve as markers for outcome in autologous transplants. We investigated an association of HLA class I molecules and early transplant outcome in a cohort of patients who underwent autologous transplantation for the treatment of lymphoma. In this retrospective study, HLA class I molecules were analyzed to determine whether they affect transplant outcome. HLA typing was performed by microlymphocytotoxicity assays. Factors such as age, sex, disease type, lactate dehydrogenase (LDH), cell dose, type of graft, and transfusion events were reviewed. Outcome was defined as death (or survival) at 6 months from the date of transplant. HLA-Cw8 was significantly associated with poor outcome (odds ratio = 18 and 9.3, p = 0.01 and 0.02 in homozygous and all patients, respectively). The HLA-A and B locus molecules were not associated with outcome. Age, sex, elevated LDH, and cell dose were not associated with outcome. A blood progenitor cell dose of greater than 6 x 10(8) nucleated cells/kg was favorably associated with outcome (p = 0.08). The number of transfusions received was not associated with outcome. In the multivariate analysis of HLAs and factors associated with outcome, HLA-Cw8 emerged as an independent risk factor for poor outcome (p = 0.03) following autologous transplantation in lymphoma patients. The association of HLA-Cw molecules with outcome in this study group indicates a need for further investigation of the HLA-mediated interactions that affect antitumor cytotoxicity, cytokine release, and regimen related toxicity.