Family studies of B lymphocyte alloantigens in systemic lupus erythematosus.

In Caucasians with systemic lupus erythematosus (SLE), we have identified 3 risk markers in the HLA-D region -- HLA-DR2, HLA-DR3, and la-715 -- and have used these markers to probe 7 families in which more than 1 case of lupus had occurred. In 6 of the 7 families studied, persons with SLE were either homozygous for HLA-DR2, had 2 haplotypes carrying reactivity with la-715, or had at least 2 of the 3 risk markers HLA-DR2, HLA-DR3, and la-715. Several normal individuals in these kindreds also had these multiple risk markers but had no signs or symptoms of lupus. This limited study of lupus families suggests a role for coinheritance of HLA-D region genes as a factor in the development of SLE.