Macrophage subpopulations and interleukin-1 β tissue levels in pelvic ileal pouches

OBJECTIVETo characterize macrophage subpopulations and to determine interleukin 1β mucosal levels in pelvic ileal pouches with and without pouchitis. DESIGN AND METHODSThe study included 30 patients who had undergone proctocolectomy with ileal pouch anastomosis; pouchitis was present in 10. Macrophage subpopulations were characterized immunohistochemically in pouch biopsy specimens using a panel of monoclonal antibodies. Concentration of interleukin-1 β was determined by a solid phase enzyme-linked immunosorbent assay in tissue homogenates of mucosal biopsy specimens. Normal ileal mucosa was used as a control. RESULTSStudies in pouchitis tissue showed a significant increase in the number of macrophages stained with the monoclonal antibody RFD9 (epithelioid cells and tingible body macrophages; median 8.7%, range 4.2–12.7%) compared with pouches without pouchitis (median 0.8%, range 0–2.4%) and normal ileal mucosa (median 0.4%, range 0–1.4%; P