SERUM INTERLEUKIN-8 IN INFLAMMATORY BOWEL-DISEASE

To investigate the relationship between serum concentrations of interl eukin-8 (IL-8) and disease activity in inflammatory bowel disease, ser um IL-8 concentrations were measured by enzyme-linked immunosorbent as say (ELISA) in 93 patients. Interleukin-8 levels were compared with pl asma interleukin-6 (IL-6) levels in 80 of these patients. Interleukin- 8 levels were also measured in ten patients with active Crohn's diseas e, before and after treatment with a defined formula polymeric diet. O f these patients, 70 out of 93 IL-8 concentrations were below the dete ction limit of the assay. Levels were higher in patients with active u lcerative colitis (median < 20 pg/mL, 75th centile value = 190) compar ed with inactive disease (median and 75th centile value < 20; P < 0.05 ). Interleukin-8 concentrations correlated with a combined score for d isease severity and extent (P = 0.01). Thirty-eight per cent (8/20) of patients with active Crohn's disease also had high levels of IL-8 but there was no significant difference between active and inactive disea se. There was no correlation between serum IL-8 and plasma IL-6; on th e contrary, very few patients had raised blood levels of both cytokine s. In the diet treated group, serum IL-8 fell significantly after trea tment (median = 37 pg/mL, range < 20-4615 before treatment, median < 2 0, range < 20-104 after treatment; P = 0.03). The results suggest that although IL-8 may be involved in the inflammatory process in inflamma tory bowel disease, it is a poor marker of disease activity.