Infectious Colitis Associated With Ipilimumab Therapy

Ipilimumab is a monoclonal antibody against cytotoxic T lymphocyte-associated molecule-4 and is thought to promote anti-tumor activity by enhancing cell mediated immunity. It is one of the few therapies shown to improve overall survival in metastatic melanoma. Given its mechanism of action, the drug is associated with significant immune-related adverse events with the gastrointestinal system being commonly involved. Our patient is a 22-year-old female with stage IVA melanoma on ipilimumab therapy who presented with fever, diarrhea and abdominal pain. She gave a history of recent travel to a wedding where several other guests in attendance had also developed diarrheal illnesses. Her colonoscopy and pathology were consistent with ipilimumab-induced colitis. Her stool culture returned positive for Salmonella enteritides. She was treated with prednisone and ciprofloxacin with resolution of her symptoms. In our case, we describe ipilimumab-induced colitis where an infectious pathogen was identified with temporal relationship to symptoms and could be suggestive of a causal relationship.