The molecular genetics of systemic lupus erythematosus and Sjögren's syndrome.

Refinements in molecular genetic technology as well as in the organization of the major histocompatibility complex and the genes contained therein continue to lead the way to elucidation of the immunogenetics of systemic lupus erythematosus and Sjögren's syndrome. In this article, recent advances in these areas are reviewed, and major histocompatibility complex associations with systemic lupus erythematosus and Sjögren's syndrome will be explored with particular emphasis on autoantibody subsets of these diseases. Data thus far support the hypothesis that systemic lupus erythematosus and Sjögren's syndrome are clinically and serologically heterogeneous disorders of major histocompatibility complex class II allele-associated autoantibody subsets, to which other major histocompatibility complex genes (C4 null alleles) and non-major histocompatibility complex genes (such as T-cell receptor genes) may contribute in susceptibility.