Phenotypic changes of peripheral blood mononuclear cells upon corticosteroid treatment in idiopathic intermediate uveitis

We analyzed phenotype and function of peripheral blood mononuclear cells in 9 patients with active idiopathic intermediate uveitis (IIU) before and after 6 and 12 weeks of systemic corticosteroid (CS) treatment and compared to 28 healthy individuals. Monocytes from IIU patients showed increased MHCII expression compared with controls (p = 0.09). Treatment reduced expression of MHCII, CD86, CD39 and CD124 (all p < 0.05), whereas the percentage of CD121b-expressing monocytes was increased by week 6 (p = 0.039). Patients showed alterations in T cell polarization (Th1/Th2 ratio: patients 5.2 versus controls 3.1, p = 0.054; Th17/Treg ratio: 3.0 versus 1.7, p = 0.027). S100A12 serum levels were higher in active IIU (p = 0.057). Phagocytosis, oxidative burst and serum cytokine levels did not differ between patients and controls, and were not altered by treatment. In conclusion, monocytes from patients with active IIU show increased co-stimulatory capacities, which are modulated by systemic CS treatment, whereas innate immune cell functions are not altered.