Levels of CD5+ B cells are not increased in probands or relatives in a family study of primary Sjögren's syndrome.

Levels of CD5+ B lymphocytes were assayed in a large family study of Primary Sjögren's syndrome. There was no significant difference in CD5 expression by index cases or their relatives when compared to controls. No association between CD5 expression, serological abnormalities or HLA haplotype was found and, furthermore, no evidence of linkage with HLA was observed. There was, however, variation in the expression of CD5+ B cells between the families. Levels in spouses were lower and reached statistical significance. The role for genetic and environmental factors influencing CD5 expression is discussed. Any genetic influence does not appear to involve the HLA region or genes in linkage disequilibrium.