The immunolocalization of bcl-2 at the maternal-fetal interface in healthy and failing pregnancies

Programmed cell death by apoptosis occurs in both fetal and maternaltissues during early pregnancy. To investigate a role for apoptosis at thematernal-fetal interface, we have immunolocalized the bcl-2 protein informalin-fixed decidual and placental tissue collected from womenundergoing surgical termination of pregnancy (n = 22), from womenundergoing a sporadic miscarriage (n = 16) and from women with a history ofrecurrent pregnancy loss (more than three consecutive pregnancy losses; n =22) undergoing a further miscarriage. In all three groups, bcl-2+ cellswere found in aggregates and dispersed in the stroma, and immunoreactivitywas observed in glandular epithelium. Double immunostaining revealed that amajority of stromal bcl-2+ cells were CD56+ large granular lymphocytes. Acomputerized image analysis revealed no significant differences inpercentage area of bcl-2 or CD56+ immunostaining. Significantly morebiopsies from the surgical termination group (4/10) had > 20% positiveimmunostaining for CD56 compared with 0% in the other two groups combined(0/20; P < 0.05). Bcl- 2 immunoreactivity was observed in the villisyncytiotrophoblast, and staining intensity was consistently greater in thesurgical termination group. The possible roles of bcl-2 at thematernal-fetal interface are discussed.