HLA-A region in highly sensitized patients: another immune response gene region

HLA haplotypes were assigned by family typing in 94 prospective kidney transplant recipients. An HLA-A region of the HLA-A, B, DR haplotypes was found in association with high levels of antibodies against lymphocytes. There was a significant difference in the frequency of HLA-B8-positive haplotypes among the patients with regard to the distribution of HLA-A alleles (p = 0.0028); on the same haplotype the A1 and B8 alleles were found in moderately and weakly sensitized patients and HLA-A alleles other than A1 were present with B8 in highly sensitized patients. A significantly higher number of highly sensitized patients when compared with moderately sensitized patients had haplotypes with HLA-A alleles in negative linkage disequilibrium with HLA-B alleles (77 vs. 10%, p = 0.014). The results are in good agreement with a previous suggestion that the interaction between the HLA-A class I and class II regions regulates the immune response. Determination of HLA haplotypes might identify patients at high risk for broad and persisting sensitization.