Immune Profile Analysis and Biomarker Identification in Women With Repeated Implantation Failure or Unexplained Recurrent Spontaneous Miscarriage

Implantation is a determining step in human reproduction which requires the transition from a pro-inflammatory state to an anti-inflammatory state allowing the implantation of a competent embryo within a receptive endometrium, and then the maternal immunotolerance towards the alloantigenic fetus. Repeat implantation failures (RIFs), that refers to the fail to achieve a clinical pregnancy after the transfer of at least 3-4 good quality embryos or two blastocysts, and unexplained recurrent spontaneous miscarriage (RM) (≥2-3) could be related in some patients to immune imbalances characterized by an excessive and prolonged inflammatory response and/or a defect of anti-inflammatory regulation. In this context, several therapies have been evaluated in patients with RIFs or RMs in order to restore the immune balance, with heterogeneous results. No serum biomarker assay has been routinely approved to identify patients with immune imbalances that may explain repeated pregnancy failures and to predict the success of the subsequent IVF/ICSI cycle. The immunological analysis on peripheral blood will be based on the determination of the proportions of immune subpopulations (e.g. CD4+ et CD8+, TH1, TH2, TH17, Treg, ILC 1, ILC2, and ILC3) on the one hand and the circulating level of plasma cytokines on the other hand.