Impact of obesity on LAG-3 and CTLA-4 expression in CD4+ T cells from lymph nodes of sarcoidosis patients.

Obesity is increasingly recognized as a metabolic factor influencing immune regulation in sarcoidosis (SA). This study examined whether obesity alters immune-checkpoint expression on lymph-node-resident T cells in newly diagnosed, treatment-naïve SA patients. Sixty-three individuals underwent EBUS-TBNA with flow-cytometric analysis of lymph node (LN) aspirates and peripheral blood (PB), and were stratified into obese (n = 18) and non-obese (n = 45) groups. Obesity was associated with distinct LN-specific immunophenotypic changes, including markedly higher LAG-3 and CTLA-4 expression on CD4+ T cells and lower TIM-3 expression on CD8+ T cells. Obese patients also showed reduced high-fluorescent cell counts and lower lymphocyte fluorescence intensity, suggesting altered activation states. These differences were absent in PB, underscoring tissue-specific immune modulation. Pulmonary function was lower in obese patients but served mainly as a clinical correlate. Overall, obesity emerges as a relevant modifier of local T-cell regulation in SA, highlighting the value of LN-based immunophenotyping.