Identification and characterization of circulating and adipose tissue infiltrated CD20T cells from subjects with obesity that undergo bariatric surgery.

T cells play critical roles in adipose tissue (AT) inflammation. The role of CD20T cell in AT dysfunction and their contributing to insulin resistance (IR) and type 2 diabetes progression, is not known. The aim was to characterize CD20T cells in omental (OAT), subcutaneous (SAT) and peripheral blood (PB) from subjects with obesity (OB, n = 42), by flow cytometry. Eight subjects were evaluated before (T1) and 12 months post (T2) bariatric/metabolic surgery (BMS). PB from subjects without obesity (nOB, n = 12) was also collected. Higher percentage of CD20T cells was observed in OAT, compared to PB or SAT, in OB-T1. CD20 expression by PB CD4T cells was inversely correlated with adiposity markers, while follicular-like CD20T cells were positively correlated with impaired glucose tolerance (increased HbA1c). Notably, among OB-T1, IR establishment was marked by a lower percentage and absolute number of PB CD20T cells, compared nOB. Obesity was associated with higher percentage of activated CD20T cells; however, OAT-infiltrated CD20T cells from OB-T1 with diabetes displayed the lowest activation. CD20T cells infiltrating OAT from OB-T1 displayed a phenotype towards IFN-γ-producing Th1 and Tc1 cells. After BMS, the percentage of PB CD4CD20T cells increased, with reduced Th1 and increased Th17 phenotype. Whereas in OAT the percentage of CD20T cells with Th1/17 and Tc1/17 phenotypes increased. Interestingly, OAT from OB pre/post BMS maintained higher frequency of effector memory CD20T cells. In conclusion, CD20T cells may play a prominent role in obesity-related AT inflammation.