Definition of a new supertypic HLA class II determinant (LAR) associated with HLA-DR2 and -DR7

A Serum from a patient (LAR), immunized by pregnancies and blood transfusions, reacted with cells Carrying HLA-DR2 and/or -DR7 specificities (titer 1:200 1:1000) Absorption-elution experiments showed that the allo-serum recognized a determinant shared by DR2 and DR7 cells. The high correlation coefficients (0.90–1) with these specificities suggested that the supertypic specificity LAR was carried by the first DR molecule encoded by DRB1 gene. IAR is another example of new supertypic specificities, reflecting structural homologies between alleles at HLA class II loci.