Prospective evaluation of the adaptive immune response to SlpA in Clostridium difficile infection.

Clostridium difficile is a major cause of healthcare-associated diarrhea. SlpA is the precursor of the S-layer of C. difficile. The aim of this work was to evaluate the humoral immune response of hospitalized patients to SlpA and its potential role on CDI outcome. Sera of 87 included patients were collected the day of CDI diagnosis as well as at early and late periods after infection. SlpA appeared to be immunogenic with a heterogeneous response between patients after a CDI. Patients with a single episode had a significantly higher anti-SlpA IgG antibody level than patients with recurrent CDI (p = 0.0197). These preliminary results will be useful to understand better the inter-individual variability of immune responses to C. difficile as well as for the development of new therapeutics.