Trichuris suis seems to be safe and possibly effective in the treatment of inflammatory bowel disease.

OBJECTIVES: Inflammatory bowel disease (IBD), especially Crohn's disease (CD), probably results from failure to downregulate a chronic Th1 intestinal inflammatory process. Induction of a Th2 immune response by intestinal helminths diminishes Th1 responsiveness. This study evaluates the safety and effectiveness of helminthic ova in the treatment of active IBD.

METHODS: We studied four patients with active CD and three with ulcerative colitis (UC). In an initial treatment and observation period, a single dose of 2500 live Trichuris suis eggs was given orally, and patients were followed every 2 wk for 12 wk. Baseline medications were continued at the same dose throughout the study. Safety was monitored by following the patients' clinical status and laboratory studies at regular intervals. Patients also were monitored regularly using the Crohn's Disease Activity Index, Simple Clinical Colitis Activity Index (SCCAI), and the Inflammatory Bowel Disease Quality of Life Index (IBDQ). To assess safety and efficacy with repetitive doses, two patients with CD and two with UC were given 2500 ova at 3-wk intervals as maintenance treatment using the same evaluation parameters.

RESULTS: During the treatment and observation period, all patients improved clinically without any adverse clinical events or laboratory abnormalities. Three of the four patients with CD entered remission according to the Crohn's Disease Activity Index; the fourth patient experienced a clinical response (reduction of 151) but did not achieve remission. Patients with UC experienced a reduction of the Clinical Colitis Activity Index to 57% of baseline. According to the IBD Quality of Life Index, six of seven patients (86%) achieved remission. The benefit derived from the initial dose was temporary. In the maintenance period, multiple doses again caused no adverse effects and sustained clinical improvement in all patients treated every 3 wk for >28 wk.

CONCLUSIONS: This open trial demonstrates that it is safe to administer eggs from the porcine whipworm, Trichuris suis, to patients with CD and UC. It also demonstrates improvement in the common clinical indices used to describe disease activity. The benefit was temporary in some patients with a single dose, but it could be prolonged with maintenance therapy every 3 wk. The study suggests that it is possible to downregulate aberrant intestinal inflammation in humans with helminths.