Sarcoidosis (SA) is a systemic disease that affects different organs including lymph nodes (LNs). Lymphocytes play an important role in the formation of granulomas in SA. Enhanced expression of inhibitory molecules has been described in lung cancer. However, their expression in SA remains unknown.

The aim of the study was to investigate the expression of immunomodulatory molecules: CD28, Tim3, PD-1, CTLA-4, Lag3 on CD4 and CD8 T cells from EBUS/TBNA and peripheral blood (PB)  samples in patients with SA. Patients with cancer were excluded from the study. T cells characteristics were determined by multiparameter flow cytometry.

In patients with confirmed granulomas in LNs CD4 T cells from EBUS/TBNA samples expressed more CD28, but had a lower expression of PD-1 and CTLA-4. Contrariwise, in patients with granulomas in lungs, but not in LNs CD4 T cells had higher expression of PD-1 and CTLA-4 and had lower expression of CD28. Such differences were not observed in CD8 T cells from LNs and in PB samples.

Recent study confirmed the advantage of flow cytometric analysis of immune cells in EBUS/TBNA samples. We demonstrated the CD4 T cells dysfunction among SA patients. Finally, our results suggest the potential role of CD28, PD-1 and CTLA-4 pathways in development of SA.