FOXP3 and synovial sarcoma: More of the lymphocytes were FoxP3+ in the SS/HTLV-1 patients compared with chronic duodenitis and healthy controls (Fig 4A, SS/HTLV-1: 1.5 [IQR: 0.7–2.3]; chronic duodenitis: 0 [range 0–0.7]; healthy controls: 0; Mann-Whitney p = 0.03 comparing the proportion of lymphocystes that were FoxP3 positive in co-infected patients to controls, Fig 4B).