Morphological and immunological evidence of coagulopathy in renal complications of pregnancy.

Renal biopsies in 14 patients with P.E.T. or eclampsia showed constant I.F. reactions for IgM and fibrin, with frequent reactions for C1q and C3. The glomeruli showed reversible mesangial proliferation and swelling, with characterictic E.M. deposits, and segmental lesions were present in seven patients. Similar I.F. reactions occurred in three other patients with clinical diagnoses of P.E.T. whose biopsies demonstrated coexistent glomerular disease. Serum complement studies showed a significant rise in C3 in the third trimester of normal pregnancies and a further significant elevation in C1q and C3 in the third trimester of a series of unselected P.E.T. patients. In contrast, four patients from the biopsy series with eclampsia or severe P.E.T. showed profound depression of serum C3 and C4, at the time of maximum clinical severity, which was shown to return to normal in two patients. The I.F. findings confirm those of Petrucco et al (6), and, with the other data, suggest that immune-complex deposition and activation of the classical complement pathway could interrect with intravascular coagulation to produce the glomerular lesions of P.E.T. and eclampsia.