Serum sickness-like reactions in patients receiving intravenous infliximab.

Infliximab, a monoclonal antibody against tumor necrosis factor (TNF) has been used successfully for the treatment of certain forms of Crohn's disease and rheumatoid arthritis. Both acute and delayed hypersensitivity reactions have been associated with the intravenous use of this drug. The delayed forms may present as a serum sickness-like illness and recognition of the clinical manifestations becomes crucial for early diagnosis and treatment. With the dramatic increase in the use of infliximab, there will likely be increased numbers of patients with this type of reaction. These patients may have received this drug days or even weeks before the clinical presentation. These types of reactions also have been reported with the use of other monoclonal antibodies.