High percentage of immune Th1 and Tc1 cells infiltrating visceral adipose tissue in people with obesity

Subcutaneous (SAT) and visceral (VAT) adipose tissue dysfunction during the obesity onset can lead to increased expression of inflammatory molecules, and consequently to immune cell infiltration. The aim was to deeply characterize the T cells, those infiltrating SAT and VAT, compared to peripheral blood (PB), in individuals undergoing bariatric surgery. Forty-two adult individuals were recruited, SAT and VAT samples were collected. T cell characterization was performed by flow cytometry. Results show that T cells infiltrating VAT from people with obesity display higher polarization towards Th1, Tc1 and T1-like CD4⁺CD8⁺ T cells, compared to SAT. These cells also display higher percentage of activated cells, and a higher percentage of PD-1-expressing cells. Furthermore, the percentage of Th1/17 and Tc1/17 cells was increased 7-18 months post-surgery. In summary, the phenotype of T cells and their expression of PD-1 within SAT and VAT appear different, especially compared to PB.