HL-A Typing in Families of Potential Kidney Recipients

Abstract

HL-A typing was performed in 22 potential kidney recipients, 35 parents and 87 siblings. Homozygosity for one or two HL-A antigens was present in about half of the patients with a phenotypic incomplete HL-A pattern. In 12 patients 23 HL-A identical siblings were found. In one patient recombination of the paternal first and second locus of the HL-A system was observed. Mixed lymphocyte reactions (MLR) were carried out with 3 sibs and an unrelated donor. A difference at the first HL-A locus was accompanied by a weak mixed lymphocyte reactivity, while a difference at the second HL-A locus gave rise to a strong MLR. Our findings support the hypothesis of two MLR loci localized closely to the HL-A loci.