P. Gionchetti et al., MACROPHAGE SUBPOPULATIONS AND INTERLEUKIN-1-BETA TISSUE-LEVELS IN PELVIC ILEAL POUCHES, European journal of gastroenterology & hepatology, 6(3), 1994, pp. 217-222
Objective: To characterize macrophage subpopulations and to determine
interleukin 1beta mucosal levels in pelvic ileal pouches and without p
ouchitis. Design and methods: The study included 30 patients who had u
ndergone proctocolectomy with ileal pouch anastomosis; pouchitis was p
resent in 10. Macrophage subpopulations were characterized immunohisto
chemically in pouch biopsy specimens using a panel of monoclonal antib
odies. Concentration of interleukin-1beta was determined by a solid ph
ase enzyme-linked immunosorbent assay in tissue homogenates of mucosal
biopsy specimens. Normal ileal mucosa was used as a control. Results:
Studies in pouchitis tissue showed a significant increase in the numb
er of macrophages stained with the monoclonal antibody RFD9 (epithelio
id 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%) an
d normal ileal mucosa (median 0.4%, range 0-1.4%; P<0.001). There were
no significant differences between the three groups in the proportion
of positive cells for the other macrophage markers (RFD1, dendritic c
ells; RFD7, mature macrophages). Concentrations of interleukin-1beta w
ere significantly greater in pouchitis specimens compared with either
those from pouches without pouchitis or normal ileal mucosa (P<0.001).
In pouchitis, tissue levels of interleukin-1beta significantly correl
ated with the percentage of RFD9-positive macrophages (P<0.01). Conclu
sions: The significance of the increase in RFD9-positive macrophage le
vels is unknown. This histochemical pattern also occurs in inflammator
y bowel disease and cannot be attributed to non-specific mucosal damag
e. Its presence, together with the significant increase in interleukin
-1beta tissue levels, may suggest that there is a similar pathogenic m
echanism for pouchitis and ulcerative colitis.