T-lymphocyte subpopulations and B7-H1/PD-1 expression in nasal polyposis.

T-lymphocyte subpopulations and B7-H1/programmed death-1 (PD-1) positive lymphocytes infiltrating nasal polyps were evaluated in 17 patients with chronic sinusitis with nasal polyposis. Peripheral blood samples were also obtained from the patients and from 11 healthy controls. The CD4(+), CD8(+), CD3(+), CD19(+), B7-H1(+) and PD-1(+) lymphocyte populations were measured using flow cytometry. Lymphocytes from nasal polyps had significantly fewer CD4(+) but significantly more CD8(+) T-cells compared with lymphocytes from the peripheral blood of patients and controls. The percentages of CD19(+)/B7-H1(+) B-cells and of CD3(+)/PD-1(+) T-cells were significantly higher in the nasal polyp samples than in those from peripheral blood of patients and controls. Changes in the T-lymphocyte subpopulations and in the up-regulation of B7-H1 and PD-1 in lymphocytes infiltrating nasal polyps may be involved in the development of the chronic inflammation associated with nasal polyposis.