The role of B cells in immune cell activation in polycystic ovary syndrome

Angelo Ascani; Sara Torstensson; Sanjiv Risal; Haojiang Lu; Sabrina Teschl; Gustaw Eriksson; Congru Li; Joana Menezes; Katalin Sandor; Camilla Svensson; Martin Stradner; Barbara Obermayer-Pietsch; Elisabet Stener-Victorin

doi:10.1530/endoabs.81.P190

Objective: Age-associated double negative (DN) B memory cells lacking surface expression of CD27 and immunoglobulin D (IgD) are associated with proinflammatory characteristics and higher disease activity in autoimmune diseases. We first characterized B cells phenotypes in women with and without polycystic ovary syndrome (PCOS). We then took an in vivo approach, transferring purified IgG extracted from serum of hyperandrogenic women with PCOS to mice to establish whether self-reactive B cells have a causal effect on the development of a PCOS-like phenotype.

Methods: We initially characterized major B cell lineages in serum of hyperandrogenic women with PCOS and of women without PCOS (controls). We purified IgG from the serum of women with PCOS (PCOS IgG) and controls which was injected intraperitoneally into immunocompetent wild type (WT) female mice and thereafter into age paired mice lacking both B and T cells (RAG1-/-). Reproductive function was tested by measuring anogenital distance and estrous cyclicity. Body composition and metabolic functions were assessed combining EchoMRI, metabolic cages and oral glucose tolerance test. Serum was collected for analysis of sex steroids by liquid chromatography mass spectrometry. Comprehensive flow cytometric analysis of lymphocytes and myeloid cells was applied in whole blood, spleen, lymph node, ovary, endometrium, visceral adipose tissue.

Results: Immunophenotypic analyses showed a significant remodeling of B cell repertoire in women with PCOS compared with controls: higher frequencies of DN B memory cells were found in PCOS patients (P=0.002), with declined IgD⁺ B memory cells (P=0.011). Total testosterone was an independent predicting variable for IgM variability (P=0.01). Transfer of human PCOS IgG into female WT mice resulted in PCOS-like phenotype with higher circulating estrogens and trend of increased androgens, as well as higher body weight (P<0.05). Preliminary results from immune profiling showed an overall increase of DN B cells in mice receiving PCOS IgG, particularly DN2 subsets with a CD21^- phenotype, with increased frequencies of active naïve cells and neutrophils in ovary.

Conclsions: Women with PCOS display an increased peripheral expansion of DN B cells. Exposing mice with IgG from women with PCOS rapidly induced an altered immune cell profile with increased body weight and circulating sex steroids. PCOS may represent a state of inflammatory-cell hypersensitivity and chronic inflammation, resulting in remodeling of the lymphocytes. The ongoing transfer of purified B cells from prepubertal hyperandrogenic mouse model into mice B cell deficient mice (muMt-) will define the overall impact of androgen exposure on B cell phenotypes.

Endocrine Abstracts

P190