The expression of STAT-1 and phosphorylated STAT-1 in conjunctival granulomas

Purpose: Sarcoidosis is a granulomatous inflammatory disease whose cause is unknown. Based on gene expression profiles of peripheral blood and on immunostaining of lymph nodes from sarcoidosis patients, the authors recently implicated the transcription factor STAT-1 in the pathogenesis. They explored the potential contribution of STAT-1 in an ocular manifestation of this disease. Methods: Conjunctival biopsies from 4 subjects with known sarcoidosis and from 8 subjects with conjunctival granulomas presumed from causes other than sarcoidosis were immunostained for STAT1. Results: STAT-1 was readily detectable in all biopsies from patients with sarcoidosis and in 3 controls. The activated form of STAT-1, phosphorylated STAT-1, was also more frequently detected in tissue from subjects with sarcoidosis relative to controls. Conclusions: The activities of STAT-1 in regulating the inflammatory response suggest that it contributes to the conjunctival granulomas characteristic of sarcoidosis, but its expression is not specific for either sarcoidosis or all granulomatous conjunctival disease.