The pregnancy hormone human chorionic gonadotropin differentially regulates plasmacytoid and myeloid blood dendritic cell subsets.

PROBLEM: Dendritic cells (DCs) are critically involved in fetal fate due to their capability to promote either immunity or tolerance to foreign fetal antigens. Our study aimed to investigate whether the hormone human chorionic gonadotropin (hCG) affects different peripheral blood DC (PBDCs) subsets.

METHOD OF STUDY: PBDCs were isolated from non-pregnant women, stimulated and co-cultured with hCG-producing JEG-3 or non hCG-producing SWAN-71 trophoblasts as well as with two different hCG preparations. The total and mature number of each PBDC subset were assessed. Additionally, the secretion of cytokines was determined in the presence or absence of hCG.

RESULTS: We found no significant effects; neither from trophoblasts nor from the hCG preparations on PBDC cellularity. JEG-3 cells and both hCG preparations significantly hampered the maturation of MDC1, while SWAN-71 cells did not provoke any changes on this regard. We observed an altered ability of PBDCs to secrete cytokines in the presence of both trophoblasts and both hCG preparations.

CONCLUSION: Our data propose that hCG is not a key regulator of cellular alterations within PBDCs. However, under inflammatory conditions, hCG seems to keep the delicate balance between PDC and MDC and retains a tolerogenic MDC1 profile and this may contribute to tolerance maintenance.