New HLA‐D Alleles Associated with DRI and DR2

Abstract

Two new [human] HLA-D specificities are described: LD13, associated with DR1, and LD14 associated with DR2. LD13 is defined by an HTC [histocompatibility typing candidate] who is the bc offspring of an a: A25, B18, DR7, Dw7/b: A33, B14, DR1, Dx father and of a c: A24, B14, DR1, Dx/d: A26, B41, DR5, Dw5 mother. This HTC was included both as a responder and as a stimulator in cross-reference [mixed lymphocyte culture] studies of 8W HTC. While failing to cluster with any other 8W HTC, it typed 2 of 64 panel members carrying a blank HLA-D, linked to DR1. To exclude the possibility that HTC-LD13 might be a split of Dwl, the entire family was tested with the family set of 8W HTC. No typing responses to any 8W Dw1 HTC were observed. Checkerboard experiments between HTC-LD13 and 8W Dw1 HTC showed strong reciprocal stimulation. The LD13 specificity was only found in Ashkenazi Jews, and may be in linkage disequilibrium with HLA-B14. LD14 is defined by 3, SD [serologically defined, a histocompatibility complex determinant] different, HTC deriving from the same family of Sicilian descent. The family was included in the 8th Workshop and each HTC had inherited DR2, MT1 from both parents. When tested as stimulators, on the HLA-D reference panel, these cells were clustered in a distinct group, LD14, associated with DR2. None of the 8W HTC appeared to belong to this cluster. The antigen frequency of LD14 is 0.03.