Aim of study: We investigated to which degree IgG, IgA and IgM anti-cardiolipin antibodies (aCL) are associated in recurrent abortion or late fetal death with other signs of autoimmune disease and in particular SLE.
Material and methods: Serological variables typical of SLE and of the anti-phospholipid antibody syndrome were measured once eight to 16 weeks after the last fetal loss in 158 women with recurrent abortion or late fetal death; women with manifest autoimmune rheumatic disease were excluded.
Results: (1) Positive values, i.e. above the 99th percentile of reference material, of IgG aCL and IgA aCL were observed in 4% and 7%, respectively, whereas 26% had positive values of IgM aCL. (2) IgG aCL and IgA aCL but not IgM aCL correlated to anti-nuclear antibodies and to anti-double stranded DNA. (3) Anti-double stranded DNA, IgG aCL and IgA aCL but not IgM aCL correlated to previous occurrence of thrombosis. (4) ANA correlated to lower blood platelet concentrations and higher erythrocyte sedimentation rates.
Conclusions: Women with recurrent abortion or late fetal death who have higher but not necessarily abnormally high levels of IgG aCL or IgA aCL constitute a group with increased occurrence of clinical and serological characteristics of SLE. We suggest that these women be kept under surveillance for future development of autoimmune disease especially SLE. The women with high IgM aCL constitute another group without these characteristics.