Relative importance of enterochromaffin cell hyperplasia, anxiety, and depression in postinfectious IBS

Background & Aims: Both psychological and mucosal changes (increased enterochromaffin [EC] cells and T lymphocytes) have been associated with postinfectious irritable bowel syndrome (PI-IBS). However, previous studies have been underpowered to determine the relative importance of these changes in predicting the development of PI-IBS. Our aim was to prospectively determine the relative importance of both psychological and histologic factors in the development of PI-IBS after Campylobacter infection. Methods: Questionnaires detailing psychological and bowel symptoms were sent to 1977 patients 3 months after infection. Twenty-eight patients with new-onset PI-IBS, 28 age- and sex-matched patient controls who were asymptomatic after infection, and 34 healthy volunteers underwent rectal biopsy, which was assessed for serotonin-containing EC cells, mast cells, and lamina propria T lymphocytes. Results: PI-IBS, predominantly of the diarrhea-predominant subtype, occurred in 103 of 747 (13.8%) of those infected. EC cell counts per high-power field (hpf) were higher in patients with PI-IBS (35.8 +/- 1.2) compared with patient controls (30.6 +/- 1.9; P = 0.022) and volunteers (29.1 +/- 1.8; P = 0.006). Lamina propria T lymphocytes per hpf were higher in patients with PI-IBS (127.1 +/- 8.7) and patient controls (113.4 +/- 6.2) in contrast to healthy volunteers (97.1 +/- 5.7) (P = 0.006 and P = 0.058, respectively). Anxiety, depression, and fatigue were significantly increased in patients with PI-IBS compared with patient controls. Multivariate analysis indicated that increased EC cell counts and depression were equally important predictors of developing PI-IBS (relative risk, 3.8 and 3.2 for each standard deviation increase in respective values). Conclusions: Both increased EC cells and depression are important independent predictors of developing PI-IBS.