(a) Estrous cycles in mice receiving control IgG. (b) Estrous cycles in mice receiving polycystic ovary syndrome (PCOS) IgG. (c) Weekly body weight (BW) recordings. (d) EcoMRI results for body fat and lean mass composition. (e) Double-negative (DN) B cells in blood. (f) Naive B cells in blood. (g) DN CD21+ B cells in blood. (h) Unswitched B cells in visceral adipose tissue (VAT). (i) Switched B cells in ovary. (j) Testosterone. (k) Androstenedione. (l) Estradiol. (m) Estron. (n) Progesterone. (a–n) IgG donors; controls n = 4, PCOS n = 4 (see Table 2). Mice receiving control IgG (n = 6), mice receiving PCOS IgG (n = 6). All bars indicate means, circles represent individual mice. In the case of missing values due to lack of measurement, mice were excluded from the analysis report for that variable. Unpaired Student’s t-test for analysis of EchoMRI results and all B cell frequencies except DN CD21+ and switched; two-way ANOVA with Sidak’s post hoc test for analysis of weekly BW recordings; Mann–Whitney test for analysis of DN CD21+, switched, estron, testosterone, and androstenedione, Welch´s t-test for analysis of estradiol and progesterone. *p<0.05, **p<0.01, ***p<0.001.