CD4+Foxp3+ T-regulatory cells in noninfectious uveitis.

OBJECTIVE: To evaluate CD4(+)Foxp3(+) (forkhead box P3) T-regulatory cell populations in patients with uveitis and to determine if T-regulatory cell populations are associated with disease features.
METHODS: Patients with uveitis were evaluated for CD4(+)Foxp3(+) T-regulatory cells by flow cytometry. Systemic and ocular diagnoses, disease activity, and the presence of cystoid macular edema were reviewed. Percentages of CD4(+)Foxp3(+) lymphocytes were compared for patients with inactive vs active disease, systemic vs ocular diagnoses, and the presence or absence of cystoid macular edema. Real-time polymerase chain reaction testing was performed on 2 patients with extremely low CD4(+)Foxp3(+) cell populations to assess Foxp3 mRNA.
RESULTS: A total of 20 patients with intermediate uveitis, posterior uveitis, and panuveitis were evaluated. The mean age was 40.6 years and the mean visual acuity was 20/57. Percentages of CD4(+)Foxp3(+) cells were lower in patients with active compared with inactive uveitis (P< .05). No differences in T-regulatory cells were observed between the other subgroups. Two patients with recalcitrant uveitis who demonstrated less than 1% CD4(+)Foxp3(+) lymphocytes showed extremely low or absent Foxp3 mRNA.
CONCLUSION: T-regulatory cells are reduced in patients with active compared with inactive disease. Severe depletion of CD4(+)Foxp3(+) T cells and Foxp3 mRNA in 2 patients with severe uveitis suggests that loss of the T-regulatory cells of uveitis may be a salient feature in certain patients.