Cd4+ Foxp3+ Cd25Bright T Regulatory Cells Population In Ocular Sarcoidosis

Abstract

Purpose: : CD4+ FOXP3 CD25bright T regulatory cells (Treg) are expanded in systemic sarcoidosis wich is a chronic inflammatory disorder characterized by noncaseating granulomas. The effector Treg expansion is already described in pulmonary and renal sarcoidosis. The main objective of this study is to describe the circulating Treg population (naive and effector Treg) in uveitis and in particular in ocular sarcoidosis.

Methods: : Patients followed for uveitis were included. Clinical, biological and pathological features were analyzed. The patients were divided in 4 groups : definite ocular sarcoidosis among the international criteria for the diagnosis of ocular sarcoidosis from the International Workshop on Ocular Sarcoidosis (IWOS), suspected ocular sarcoidosis but not biopsy proved, idiopathic uveitis and uveitis of other origin. Treg populations were measured in blood using fluocytometry analysis.

Results: : 103 patients were included with 19 definite ocular sarcoidosis, 12 suspected sarcoidosis, 41 idiopathic uveitis and 31 uveitis of other diagnosis. In the definite ocular sarcoidosis and the suspected sarcoidoisis groups, the median effector Treg rate was 2,54 and 2,7 which was significantly higher than in the control group (p<0,0001). There were no statistical difference between the Treg effector rate of idiopathic uveitis (0,86), uveitis of other diagnosis (0,73) and the control group. In the definite ocular sarcoidosis group, the Treg was significantly higher compared to idiopathic uveitis (p=0,046) and to uveitis of other origin (p=0,009). The naive Treg population showed no statistical difference between the 4 groups.

Conclusions: : Definite ocular sarcoidosis and suspected ocular sarcoidosis are associated with peripheral effector Treg expansion. There is no alteration of Treg population in idiopathic uveitis and uveitis of other origin. The naive Treg population is not expanded in the 4 groups. This test could be used as a new diagnostic tool in uveitis in particular when sarcoidosis is suspected.

Keywords: inflammation • uveitis-clinical/animal model