Absolute number of circulating CD3+ T cells, CD4+ T cells, CD8+ T cells, percentage ofactivated CD4+ T cells, regulatory CD4+ T cells (Treg) and percentage of cells expressing intracellular CTLA-4 in healthy controls, patients with Spondylarthropathies and rheumatoid arthritis. The gene discussed is CD4; the disease is rheumatoid arthritis.