Low-CD25(High+)CD4(+), a subset of regulatory CD25(+)CD4(+) T cells and high-inflammatory CD28(-)CD4(+) T cells can exacerbate ulcerative colitis (UC). This study sought to investigate the frequency of CD25(High+)CD4(+) and CD28(-)CD4(+) T cells in patients with UC and the changes in these cells during Adacolumn granulocyte and monocyte adsorption apheresis (GMA). Subjects were 12 patients with active UC, 11 with quiescent UC, and 14 healthy volunteers (HVs). The mean clinical activity index was 15.7 +/- 2.2 in active UC and 4.5 +/- 1.1 in quiescent UC. Peripheral blood samples were stained with CD4, CD25, and CD28 antibodies for flow cytometry. Patients with active UC received GMA and blood samples were examined before and after the first GMA session. Patients with active UC (P < 0.04) or quiescent UC (P < 0.02) had a higher percentage of CD28(-)D4(+)T cells compared with HVs, while the percentage of CD28(+)CD4(+) T cells was lower in both UC groups compared with HVs (P = 0.03 and P < 0.02). Patients with active UC had a lower percentage of CD25(High+)CD4(+)T cells compared with quiescent UC patients (P < 0.001). A significant increase in CD25(High+)CD4(+) T cells was associated with GMA (P < 0.03). Low CD25(High+)CD4(+) and high CD28(-)CD4(+) are prominent features in UC. The increase in CD25(High+)CD4(+) T cells induced by GMA should contribute to improved immune function. Additional studies are warranted, since a low frequency of CD25(High+)CD4(+) (-) and a high frequency of CD28(-)CD4(+) (-) expressing T cells might be a predictor of clinical response to GMA.