At higher concentrations, exogenous retinoic acid such as that in Accutane has been found to induce programmed cell death or apoptosis in cranial neural crest cells. The separation of drug intolerance and immunological reactions is perhaps artificial since immunological reactions are also dependent on genes, but the separation does focus on a particular subgroup of drug intolerance. One of the most powerful mechanisms of the human immune system is the production of a group of immunoglobulins, the antibodies. Elicited by a foreign protein or antigen and produced by the B lymphocytes, they recognize and bind the specific antigen and help facilitate its removal from the body. Yet immunoglobulin E, or IgE, antibodies, which are responsible for most allergies, have other properties that may be harmful to the person.
Basophils are functionally similar to mast cells but appear to have a different cell lineage.
The B cell secretes IgE, which binds to mast cells or basophils through high-affinity receptors. The clinical and pathological manifestations of immediate hypersensitivity are due to the actions of released mediators. In the most extreme systemic form, called anaphylaxis, the mediators restrict airways to the point of asphyxiation and produce cardiovascular collapse leading to death. Certain drugs are often associated with undesirable side effects. The risk of a reaction to an antimicrobial drug may be increased at least threefold in patients with a history of reaction to antimicrobial agents of a different class.