A comparative histo- and immunopathological study of the placenta in diabetes mellitus and in erythroblastosis fetalis

Abstract

A study has been carried out comparing the normal placenta with that in diabetes and erythroblastosis. A proliferative vascular lesion has been demonstrated, which binds fluorescent insulin specifically in the diabetic placenta and fluorescent anti-Rh serum in the erythroblastotic placenta. In both diseases there is an increase in the syncytial knot/villus ratio. Neither the vascular endothelium nor the syncytial knots bind the fluorescent reagents; the antigen-antibody complex evidently diffuses through these cells and is trapped in basement membrane structures.Serological studies indicate that in both disease states maternal antibodies cross the placental barrier and enter the fetal circulation. However, the binding of fluorescent reagent by placental tissue in cases with negative titers indicates the presence of fixed tissue antibody. Pathological and clinical evidence suggests that the latter is more directly related to the occurrence of placental lesions than is circulation antibody. In the case of diabetic subjects who have never received insulin, the binding of fluorescent insulin may be indicative of an autoimmune phenomenon.