Faecal lactoferrin and calprotectin in patients with Clostridium difficile infection: a case-control study.

Calprotectin and lactoferrin are released by the gastrointestinal tract in response to infection and mucosal inflammation. Our objective was to assess the usefulness of quantifying faecal lactoferrin and calprotectin concentrations in Clostridium difficile infection (CDI) patients with or without free toxins in the stools. We conducted a single-centre 22-month case-control study. Patients with a positive CDI diagnosis were compared to two control groups: group 1 = diarrhoeic patients negative for C. difficile and matched (1:1) to CDI cases on the ward location and age, and group 2 = diarrhoeic patients colonised with a non-toxigenic strain of C. difficile. Faecal lactoferrin and calprotectin concentrations in faeces were determined for patients with CDI and controls. Of 135 patients with CDI, 87 (64.4%) had a positive stool cytotoxicity assay (free toxin) and 48 (35.6%) had a positive toxigenic culture without detectable toxins in the stools. The median lactoferrin values were 26.8 µg/g, 8.0 µg/g and 15.8 µg/g in CDI patients and groups 1 and 2, respectively. The median calprotectin values were 218.0 µg/g, 111.5 µg/g and 111.3 µg/g, respectively. Among patients with CDI, faecal lactoferrin and calprotectin levels were higher in those with free toxins in their stools (39.2 vs. 10.2 µg/g, p = 0.003 and 274.0 vs. 166.0 µg/g, p = 0.051, respectively). Both faecal calprotectin and lactoferrin were higher in patients with CDI, especially in those with detectable toxin in faeces, suggesting a correlation between intestinal inflammation and toxins in stools.