CD69 expression on peripheral CD4(+) T cells parallels disease activity and is reduced by mycophenolate mofetil therapy in uveitis

PURPOSE. To assess the effects of mycophenolate mofetil (MMF) therapy on T helper cell activation status, using CD69 expression and cytokine profile w ith flow cytometry in relation to clinical activity in uveitis. METHODS. Patients with posterior or intermediate uveitis treated with MMF ( n = 10), patients with active uveitis not treated with MMF and receiving no or minimal therapy (n = 10), and healthy volunteers (n = 21) had periphera l blood lymphocyte immunofluorescence analysis for T helper cell (CD4, CD3) markers, activation status (CD69), and intracellular cytokine (interleukin [IL]-2, interferon [IFN]-gamma, and IL-4) levels. Patients were compared b efore and during MMF therapy in relation to T helper cell activation and cl inical activity. RESULTS. Patients with active uveitis not treated with MMF and receiving no or minimal therapy had increased frequency of CD69-positive CD4 T cells (1 0.5% +/- 4.6%, P = 0.0007) compared with healthy volunteers (3.3% +/- 2.7%) . Of all patients receiving MMF therapy, only patients with moderate to sev ere uveitis activity in the pre-MMF treatment group (n = 5; 15.5% +/- 5.0%, P = 0.004) had increased frequency of CD69-positive CD4 T cells compared w ith healthy volunteers. During MMF therapy, a significant reduction in freq uency of CD69-positive CD4 T cells occurred in patients with prior moderate to severe uveitis activity (to 8.9% +/- 3.8%, P = 0.04). Levels of GD69-po sitive CD4 T cells in patients who had had inactive or mildly active diseas e (n = 5) before and during MMF therapy were comparable with levels in heal thy volunteers. No significant changes in cytokine levels were found betwee n the patient and control groups. A significant association between changes in frequency of CD69-positive CD4 T cells and changes in visual acuity (P = 0.008) and changes in vitreal haze (binocular indirect ophthalmoscopy sco re; P = 0.01) was observed in MMF-treated patients with prior moderate to s evere uveitis activity. CONCLUSIONS. Reduction in uveitis activity during MMF therapy correlates wi th reduction in frequency of peripheral blood CD69-positive CD4 cells. The frequency of CD69-positive CD4 T cells is a measure of activity in posterio r uveitis and may guide adequate immunosuppression.