[Biological diagnosis of systemic lupus erythematosus]

Systemic lupus erythematosus (SLE) is a polymorphic disease of unknown origin, characterized by many stigmata of autoimmunization which allow a biological diagnosis. Besides non-specific inflammatory disorders, considerable alterations of humoral and cellular immunity are found. The hallmark of the disease is the presence of anti-double-stranded-desoxyribonucleic acid (anti-ds DNA) antibodies, detected by the Farr radioimmunologic method or the crithidia luciliae immunofluorescence technique, both of which are nearly specific for SLE. The clinical significance of other types of anti-nuclear antibodies is unclear. Serial evaluations of antinuclear antibodies, complement fractions, circulating immune complexes, and, above all, immune complexes bound to target organs (kidneys, skin, synovial membranes) are needed to follow the course of the disease. The demonstration of abnormal suppressor T-cell activity has led to current pathogenic hypotheses and ongoing therapeutic trials with immunoregulating drugs.