Oral Immunotherapy With Human Secretory Immunoglobulin A Improves Survival in the Hamster Model of Clostridioides difficile Infection

Coadministration of human secretory IgA (sIgA) together with subtherapeutic vancomycin enhanced survival in the Clostridioides difficile infection (CDI) hamster model. Vancomycin (5 or 10 mg/kg x 5 days) plus healthy donor plasma sIgA/monomeric IgA (TID x 21 days) or hyperimmune sIgA/monomeric IgA (BID x 13 days) enhanced survival. Survival was improved compared to vancomycin alone, P = .018 and .039 by log-rank Mantel-Cox, for healthy and hyperimmune sIgA, respectively. Passive immunization with sIgA (recombinant human secretory component plus IgA dimer/polymer from pooled human plasma) can be administered orally and prevents death in a partially treated CDI hamster model.