Different circulating lymphocyte profiles in patients with different subtypes of juvenile idiopathic arthritis.

OBJECTIVE To determine the immunophenotypic profiles of circulating lymphocytes in patients with different disease types of Juvenile Idiopathic Arthritis (JIA). METHODS Peripheral blood lymphocyte subsets from 19 patients with oligoarticular JIA (o-JIA), 10 patients with polyarticular JIA (p-JIA), 12 patients with systemic JIA (s-JlA) andfrom 41 age-matched healthy controls were characterized by two color immunofluorescence flow cytometry analysis. RESULTS Patients with o-JIA and p-JIA had increased numbers of HLA-DR+ Tcells and Tcells co-expressing CD57 and CD16/56, indicating T cell activation and terminal differentiation of CD8+ T cells respectively. By contrast, in patients with s-JIA there was no increase in the activation or differentiation markers on T cells, but a profound decrease in circulating NK cells. All patients had hypergammaglobulinemia consistent with B cell hyperactivity, but increased numbers of CD5+ B cells were found only in o-JIA and p-JIA. CONCLUSION Distinct immunophenotypic lymphocyte profiles in patients with o-JIA and p-JIA compared to patients with s-JIA as demonstrated in this study, are consistent with afundamental heterogeneity of the disease.