Identification of dendritic cells in the blood and synovial fluid of children with Juvenile Idiopathic Arthritis

Abstract

Childhood chronic arthritis of unknown etiology is known collectively as juvenile idiopathic arthritis (JIA) and consists of heterogeneous subtypes with unique clinical patterns of disease. JIA is the commonest rheumatic disease in children and may still result in significant disability, with joint deformity, growth impairment, and persistence of active arthritis into adulthood. Basic research is rather focused on rheumatoid arthritis, and this lead to small number of publications considering JIA. In this study we examine, by flow cytometry, the expression of dendritic cells (DCs) in the peripheral blood and synovial fluid of children with active JIA in a group of 220 patients. We reveal a significant decrease in the percentage of immature DCs in the blood of patients compared to control children. Surprisingly, we found higher percentages of mature circulating dendritic cells. Both populations of DCs, immature and mature, were accumulated in patients’ synovial fluid. We also confirmed the presence of CD206+/CD209+ in JIA samples, which can represent a population of macrophages with dendritic cells morphology. Our results support the thesis that dendritic cells are crucial in the induction and maintenance of autoimmune response and local inflammation during juvenile idiopathic arthritis. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 1, pp. 188–199)