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.