Elevated CD1c+ Myeloid Dendritic Cell Proportions Associate With Clinical Activity and Predict Disease Reactivation in Noninfectious Uveitis

PURPOSE To test the association between elevated proportions of CD1c+ myeloid dendritic cells (mDCs) and disease activation/reactivation in noninfectious uveitis. METHODS Noninfectious uveitis patients (n = 89) and healthy controls (n = 111) were recruited. The proportion of CD1c+ mDCs in the total dendritic cell (DC) population of peripheral blood was measured by flow cytometry (CD1c+ mDCs gated on Lineage 1+HLADR+ DCs). Disease activity was assessed per Standardization of Uveitis Nomenclature criteria. Uveitis reactivation was ascribed to clinically quiescent patients who developed reactivation of intraocular inflammation within 6 months. RESULTS The proportions of CD1c+ mDCs were increased in noninfectious uveitis patients, especially in active disease, compared to healthy controls. This CD1c+ mDC elevation was not associated with underlying systemic diseases, anatomic locations of uveitis, medications, or demographic factors. Longitudinal data showed that the dynamics of CD1c+ mDC levels were correlated with disease activity. The average proportion of CD1c+ mDCs in active uveitis patients was 60% so we set this as the cutoff between high and low CD1c+ mDC levels. Although 74% of quiescent patients had low proportions of CD1c+ mDCs, 26% still had high proportions. Quiescent patients with high CD1c+ mDC proportions showed increased risk of disease reactivation, compared to quiescent patients with low CD1c+ mDC proportions. CONCLUSIONS Increased proportions of CD1c+ mDCs were associated with clinical activity, and quiescent patients with elevated CD1c+ mDCs were more likely to undergo reactivation. This suggests that CD1c+ mDC proportion may be a potential biomarker for assessing clinical activation and reactivation in noninfectious uveitis.