[Is the target of anti-cardiolipin antibodies the same in Gougerot-Sjögren syndrome and lupus erythematosus disseminatus?].

Forty-seven patients were diagnosed as having systemic lupus erythematosus (SLE) and 34 patients primary Sjögren's syndrome (SS); 30 controls were also studied. Anti cardiolipin (CL), anti double-stranded DNA (ds DNA) and anti single-stranded DNA (ss DNA) antibodies were determined by the enzyme-linked immunosorbent assay. Elevated anti-CL antibody levels were detected in 47.8 p. 100 (n = 46) of patients with SLE and in 85.3 p. 100 (n = 34) of patients with SS, but only once in controls. Elevated ss DNA were detected in 91.5 p. 100 (n = 47) of patients with SLE and in 18.3 p. 100 of patients with SS but never in controls. Elevated anti-ss DNA were detected in 93.3 p. 100 and 97.1 p. 100 respectively of patients with SLE and SS and in 3.3 p. 100 of controls. There was no correlation between anti-CL and thrombosis, circulating lupus anti coagulant or VDRL. The most striking association, however, was between anti-CL and anti ss-DNA antibodies in SLE. There was no correlation between anti-CL and anti ds-DNA antibodies in SLE patients. Anti CL antibodies were correlated both to ss-DNA and anti ds-DNA in SS patients. Absorption of positive anti-CL antibodies sera were done on DNA (ss-DNA and ds-DNA) affinity column chromatography: anti-CL antibodies were absorbed only by ss DNA in SLE and by both ss DNA and ds DNA in SS.