Complement activation in Brazilian patients with preeclampsia.

The aim of this study was to evaluate the complement activation in Brazilian patients with preeclampsia and to correlate it with the severity and clinical outcome of the disease. Plasma levels of C3d, SC5b-9, C3 and C4 were measured in 16 patients with preeclampsia and in 17 normotensive pregnant women. Ten patients developed severe and six mild disease. C3 and C4 levels were determined by turbidimetry using polyclonal specific antisera. C3d concentrations were evaluated through double-decker rocket immunoelectrophoresis and SC5b-9 was assayed by a double-antibody enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody against a neoantigen expressed in the formed complex. The mean levels of all variables were significantly higher in the preeclamptic group (before the delivery) when compared to the normal pregnancies. The complex SC5b-9 followed by C3d showed the most significant results for those comparisons (p < or = 0.00001). The levels of all parameters in the preeclampsia patients decreased significantly after the delivery. Again, the complex SC5b-9 and C3d showed the most significant results (p < or = 0.0004). None of the studied variables showed statistically significant differences regarding the severity of preeclampsia. These results confirm the activation of complement in preeclampsia, suggesting that this activation is related to the disease manifestation. Our findings further emphasize the involvement of complement activation in the pathological manifestations of preeclampsia.