Allelic subdivisions of the HLA-B12-Bw21 complex: association with Bw4 and Bw6.

Allelic subdeterminants (or splits) of the B12-Bw21 complex were characterized by the use of highly selected antisera and cell donors. The B12 antigen was separated into two major components, Bw44 and Bw45; and possibly a third. It was shown that Bw44 is primarily an antigen of whites, and Bw45 of blacks. Of the 68 persons who had B12, 49 were white and 19 were black. Among whites, 47 (96%) had Bw44 split, and only one (2%) had Bw45. Among blacks, however, 10 (53%) had Bw44, and 9 (47%) had Bw45. Thus, of the 57 persons who had Bw44, a majority (82%) were white, while of 10 persons who had Bw45, a majority (90%) were black. The broad specificity Bw4 was strongly associated with the presence of Bw44, and Bw6 with the presence of Bw45 (coefficient of correlationequa tol0.81). The Bw21 antigen was similarly separated into two major components, Bw49 and Bw50; and possibly a third. Among the 23 Bw21-positive persons, Bw49 was present in 68% of whites and 75% of blacks, while Bw50 was present in 26% of whites, and in 50% of blacks. The broad Bw4 was clearly associated with the presence of Bw49, and Bw6 with the presence of Bw50 (coefficient of correlation equal to 1.00).