The greatest differences in cellular composition between PB and SF were within CD3+ T lymphocytes, which made up the majority of mononuclear cells (69.6 ± 1.9% HC PB, 67.7 ± 1.2% JIA PB, 77.5 ± 1.6% JIA SF, Fig. 4A) but with differing distribution of CD4+ and CD4− T cells. The gene discussed is CD4; the disease is juvenile idiopathic arthritis.