Development of host immune response to bacteriophage in a lung transplant recipient on adjunctive phage therapy for a multidrug resistant pneumonia.

Bacteriophage therapy is the use of viruses to kill bacteria for the treatment of antibiotic-resistant infections. Little is known about the human immune response following phage therapy. We report the development of phage-specific CD4+ T cells alongside rising phage-specific IgG and neutralizing antibodies in response to adjunctive bacteriophage therapy used to treat a multidrug resistant Pseudomonas aeruginosa pneumonia in a lung transplant recipient. Clinically, treatment was considered a success despite the development phage-specific immune responses.