Heterogeneity of HLA‐DR2: definition of two subtypes by serological and cellular techniques

Abstract
The serological and cellular (PLT) techniques were used to investigate the heterogeneity of HLA-DR2. DR2 can be subdivided into 2 specificities based on the patterns of reactivity with the Ninth Workshop serum, 9w555. These 2 DR2 subtypes were also recognized by cellular assay using PLT generated between HLA-DR2, DQ-identical, DP-identical or incompatible individuals. The existence of 2 alleles of DR2, DR2.1 (long) and DR2.2 (short), is suggested.