Infliximab is a monoclonal antibody that binds and blocks the effects of TNF-α. It is used to treat several inflammatory diseases including Crohn disease, ulcerative colitis, ankylosing spondylitis, and psoriasis; it is also used as an adjunct in rheumatoid arthritis and immunotherapy-related colitis. Immediate transfusion reactions to infliximab can happen within 1-2 hours of infusion and can include symptoms of pruritus, flushing, dyspnea, chest discomfort, hypertension, myalgia, nausea, headache, rash, and dizziness; they are estimated to occur in 5-23% of patients receiving this drug. In particular, people with inflammatory bowel disease treated with infliximab who develop antibodies toward infliximab have a 2-fold risk of acute infusion reactions (and 6x risk of serious acute infusion reactions). Delayed transfusion reactions occur at > 24 hours post-transfusion and mimic serum sickness with symptoms of pruritus, fever, malaise, and polyarthralgia; they are less common than acute reactions, occurring in approximately 1-3% of patients receiving this drug.
References: Infliximab-Related Infusion Reactions: Systematic Review