Circulating immune complexes in pregnancy, preeclampsia, and autoimmune diseases: evaluation of Raji cell enzyme-linked immunosorbent assay and polyethylene glycol precipitation methods.

Sera from 86 individuals were tested for circulating immune complexes by the polyethylene glycol precipitation method and a Raji cell enzyme immunoassay (Raji-ELISA). These included normal nonpregnant control subjects, nonpregnant patients with autoimmune diseases, healthy women in the second and third trimesters of pregnancy, patients with preeclampsia, and women with pregnancies complicated by preexisting autoimmune diseases. Diseases such as systemic lupus erythematosus and rheumatoid arthritis were associated with increased levels of immune complexes in both pregnant and nonpregnant individuals. Circulating immune complexes were not observed in normal pregnancies or in preeclampsia. Although pregnancy itself is not an immune complex-associated state, the presence of immune complexes in autoimmune diseases may explain some of the complications observed during pregnancy in these patients.