HIGH-RESOLUTION HISTOCOMPATIBILITY TESTING OF A GROUP OF 16 B44-POSITIVE, ABDR SEROLOGICALLY MATCHED UNRELATED DONOR-RECIPIENT PAIRS - ANALYSIS OF SEROLOGICALLY UNDISCLOSED INCOMPATIBILITIES BY CELLULAR TECHNIQUES, ISOELECTROFOCUSING, AND HLA OLIGOTYPING

We have characterized HLA incompatibilities in a group of 16 B44-posit ive patients who were serologically ABDR matched with their 23 (unrela ted) potential bone marrow donors. After analysis with a combination o f cellular techniques, IEF for HLA-A/B and oligotyping for class II an d HLA-B44, 44% of the patients revealed one or more HLA incompatibilit y with at least one of their potential donors. CTL activity was detect ed in 12 of the 22 combinations tested. CTL incompatibility occurred m ore frequently in DR subtype-mismatched combinations, but CTL reactivi ty was always directed against class I. To characterize these incompat ibilities between matched unrelated individuals, we analyzed the speci ficity of T-cell clones from seven primary CTL cultures. In three comb inations, CTL reactivity was directed against a subtype of B44. In two combinations, the CTL reactivity was directed against a non-B44 class I subtype. In two of seven combinations, the CTLs recognized an antig en that, though unconditionally associated with B4403, was expressed b y 60% of the B4403+ cells only. Because all 12 of these B4403+ targets recognized could be typed for one HLA-C allele only (Cw1-Cw8), we bel ieve that this alloreactivity might be directed against a serologicall y undefined Cw antigen.