Lupus erythematosus.

Lupus erythematosus represents a wide spectrum of diseases. Within this heterogeneity, however, several clinically relevant subsets have been found that may unite differing aspects of the disease and that may have pathogenic implications for the problem as a whole. Exciting links between genetic phenotypes, certain immune responses, and related cutaneous findings in neonatal, complement-deficient, subacute cutaneous, and ANA-negative lupus erythematosus and Sjögren's syndrome have been found. The increased frequency of the anti-Ro(SSA) antibody in these groups is notable. The ultraviolet light-altered immune system found in vivo and in vitro may also be relevant to disease pathogenesis. Even if the mechanisms elaborated are not the precise aberrations in lupus erythematosus, they may serve as an operational model for further research. Continued investigations into mechanisms of photoexacerbations in lupus erythematosus, as well as into genetically mediated immune response, may further our understanding of these disorders.