Hypersensitivity reactions to biological agents with special emphasis on tumor necrosis factor-α antagonists

Purpose of reviewSeveral biological agents have been introduced into the drug market and more are emerging. Adverse reactions to these agents have recently been classified into five different subtypes. Some of these reactions are frequent but without consequences for the patients. Others are less frequent but potentially life-threatening, and they include allergic reactions. Recent findingsHypersensitivity reactions are well described adverse drug reactions, corresponding to the ß-type of the newly proposed classification of adverse reactions induced by biological agents. We focus our search on tumor necrosis factor-α antagonists, as they represent a dramatic improvement in the therapy of both rheumatic and inflammatory bowel diseases and because adverse reactions have been closely scrutinized. We also add cases from our own experience. We found very few properly documented allergic reactions. SummaryHypersensitivity reactions to tumor necrosis factor-α antagonists are not rare. Whether these manifestations have to be considered type β or type γ reactions is still a matter of debate. There is a need for allergological tests in vivo and in vitro.