Detailed endometrial immune assessment of both normal and adverse reproductive outcome populations

Abstract

Flow cytometric endometrial evaluation has the ability to provide a rapid and objective analysis of lymphocyte subpopulations. The findings show significant variations in cellular proportions of immune cells across the patient categories relative to control tissue. The cell types involved suggest that a potential differential pro-inflammatory bias may exist in patients with a history of adverse reproductive outcomes. Immunological assessment in appropriate populations may provide insight into the underlying aetiology of some cases of reproductive failure.

Endometrial Immune Profiling: A Method to Design Personalized Care in Assisted Reproductive Medicine

“…Previous authors documented by flow cytometry or immunohistochemistry abnormal immune cell mobilization or expression in patients with either RIF or RM history (13,(16)(17)(18) suggesting that endometrial immune local imbalance may contribute to implantation failures.…”

“…Result(s): After testing, 16.5% of the patients showed no endometrial immune dysregulation, 28% had a local immune under-activation, 45% had a local immune over-activation, and 10.5% had a mixed endometrial immune profile. In patients with a history of repeated implantation failures (RIF) or recurrent miscarriages (RM), the pregnancy rate was significantly higher if an endometrial dysregulation was found and the personalized plan applied, compared to the patients with an apparent balanced immune profile (respectively 37.7 and 56% vs. 26.9 and 24%, p < 0.001).…”

Endometrial lymphocyte concentrations in adverse reproductive outcome populations

“…These latter cells are mainly CD56 dim with strong expression of the CD16 transmembrane receptor, while uNK cells are exclusively CD56 bright and lack CD16 [31,32]. CD56 dim cells are also more mature with a higher cytotoxic potential than CD56 bright [33] The immunoregulatory potential of uterine NK cells is thought to be different to that of peripheral type NKs [34]; however, under the influence of pro-inflammatory cytokines, or other agents, a phenotypic switch to a more aggressive profile is hypothesised [24]. It is likely that pNKs, in particular, are recruited from the peripheral blood as opposed to resident in endometrial tissue.…”

“…The endometrial preparation and flow cytometric processes were first tested by a pilot study, followed by expansion of the antibody panel for CD markers to provide a comprehensive immunophenotype using proportions as previously described in detail [24]. The addition of 100 μL flowcount™ beads (Beckman Coulter UK Ltd.) were added, of a consistent nature and at a defined concentration, allowed for the addition of volumetric counts of the cellular populations ( Fig.…”

“…Co-localisation of selected antibodies was employed across individual tubes using flow cytometry (Navios™, Beckman Coulter UK LTD) for cellular evaluation, with a 10-colour flow panel and appropriate compensation matrices as previously described [24] and Supplementary Figs. 3, 4 and 5. Cell types were defined according to accepted conventions.…”