No broad PBMC cytokine-response fingerprint of endometriosis under PHA-stimulated culture conditions: A 27-plex case-control study.

Endometriosis is associated with immune dysregulation yet circulating cytokine measurements have shown limited discriminatory value. We investigated whether peripheral blood mononuclear cells (PBMCs) from women with endometriosis exhibit altered basal or phytohemagglutinin (PHA)-induced cytokine secretion. In this single-center case-control study, PBMCs from 36 women with laparoscopically and histopathologically confirmed endometriosis and 44 laparoscopy-confirmed controls without endometriosis were cultured for 24 h under unstimulated and PHA-stimulated conditions. Supernatant concentrations of 27 cytokines, chemokines and growth factors were measured using a Bio-Plex/Luminex assay. Cytokine concentrations were analyzed using linear mixed-effects models including group, condition, and group × condition interaction terms, with false-discovery-rate correction. PHA induced broad cytokine responses, with significant condition effects for 20 of 27 analytes in the full panel and 14 of 15 analytes in the robust quantifiable panel. A significant group × condition interaction was observed for IL-5; however, this result was based on very sparse PHA data and was not retained in a robust restricted panel of adequately quantified analytes. Exploratory multivariate analyses did not show clear group separation. Overall, these findings do not support the presence of a broad and reproducible endometriosis-associated cytokine-response profile in 24-h bulk-PBMC cultures stimulated with PHA-L at 5 µg/mL. Within this experimental framework, any between-group differences appeared subtle, analyte-specific, and sensitive to data completeness. These results are compatible with, but do not directly demonstrate, the concept that disease-related immune alterations may be more prominent in specific immune-cell subsets or local pelvic compartments than in non-specifically stimulated circulating PBMC cultures.