Distinct T-cell immunophenotypic signature in a subset of sarcoidosis patients with arthritis

Background: The objective of the study was to assess T-cell subsets in sarcoidosis patients with or without articular involvement. Methods: Treatment-naive patients were divided into Group A (articular) and Group B (non-articular) based on joint involvement. Flow cytometric analysis of T-cell subsets and pro-inflammatory cytokines were carried out in the peripheral blood. Results: Patients in group A (n = 29, mean age 40 +/- 10.1 years) were compared with group B (n = 18, 43 +/- 12.2 years). T-cell subsets: the CD4/CD8 ratio was abnormal in two groups but had no significant difference (p = 0.63). Ratios of Th1/Treg, Th2/Treg and Th17/Treg were significantly increased in group A as compared to group B [p < 0.001] indicating polarisation of T-cell subsets. CD8 T-cells in group A had higher granzyme B expression (p = 0.03). B cells were increased in group A [p = 0.04]. Ratio of IFN-gamma/IL10, IL-4/IL10, IL-17/IL10 in sera as well as culture supernatant were significantly higher in group A as compared to group B. Conclusion: The T-cell axis was skewed towards Th1, Th2 and Th17 in sarcoid arthritis when compared to non-articular patients.