Progesterone directly and indirectly affects perforin expression in cytolytic cells

PROBLEM: Decidual lymphocytes (DL) expressing the cytolytic molecule perfor in represent approximately 55% of Db in the first trimester of human pregna ncy. Progesterone dominates this phase of pregnancy and controls the produc tion of uterine cytokines and growth factors. The aim of this study was to investigate the role of progesterone and progesterone-induced blocking fact or (PIBF) on perforin expression in Db and peripheral blood lymphocytes (PB L). METHOD OF STUDY: Perforin expression was analyzed in PBL and DL incubated e ither in culture medium or with decidual adherent cells (DAC) and periphera l blood adherent cells (PBAC) and their supernatants with or without proges terone or PIBF. Perforin was detected by how cytometry in PB and in decidua l first trimester pregnancy lymphocytes. RESULTS: Progesterone in high concentrations directly affects perforin expr ession in Db, but not in PDL. Progesterone in a concentration dependent man ner indirectly blocks perforin expression in DL and PBL cultured with adher ent cells or their supernatants. PIBF blocked upregulation of perforin expr ession of DL cultured with DAC, but none of those cultured with PBAC. Simil arly, PIBF was inefficient when PBL or DL were cultured with PBAC. CONCLUSION: Progesterone present in a high concentration locally at the mat ernal-fetal interface modulates perforin expression in the first trimester pregnancy DL.