Immunological studies of human placentae: complement components in pre-eclamptic chorionic villi.

Forty human placentae were studied by immunofluorescence for the presence of complement (C) components C1q, C4, C3d, C6 and C9 with the use of characterized antisera. The tissues were grouped as control placentae from 20 normal pregnancies and 20 from cases of pre-eclampsia (PE): the PE samples were sub-grouped as being obtained from patients with mild or severe PE. All of the C components studied were found in the same distribution for test and control samples, but statistical analysis of each pattern of distribution revealed that the deposition of C1q, C3d and C9 were increased in PE as compared to normal tissues. This impression was strengthened by the finding that the deposition of these C components was further increased when chorionic villus immunopathology was compared between mild and severe PE. These data indicate that immunological mechanisms are operating in PE chorionic villi, and they suggest that, among other mechanisms, immune processes may be operative in the pathophysiology of this clinical disease, and that more studies along these lines are in order to rule either in or out this possibility.