Drug allergy pathophysiology
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Charmaine Patel, M.D. [2]
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Drug Allergy |
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Overview
Medications can cause allergic reactions through various mechanisms. The drug can either act as a direct antigenic particle, or it can cause activation of immune cells by the direct interaction with immune cell receptors.
Pathophysiology
Drugs Acting as Antigens
Most drugs do not act as antigenic particles in their mature form. This is because they are usually small, and therefore not recognized by immune receptors enough to actually activate T cells or B cells. However, drugs can act as antigens if they are presented to lymphocytes by antigen presenting cells such as dendrites. This response specific to the drug can be solely T-cell mediated, antibody mediated, or can have components of both.
- Stimulation of the antibody response- In general, antigens are processed by antigen presenting cells and presented to T-cells. This leads to t-cell activation and produces cytokines which then activate B cells. B cells then recognize the antigen through its IgG receptor, and becomes activated subsequently producing antigen-specific immunoglobulins. Modern pharmaceuticals that are proteins or resemble proteins, can stimulate antibody and T cell responses similar to other protein antigens. Examples of drugs that cause this type of reaction are:
- insulin
- enzymes
- antisera
- recombinant proteins (monoclonal antibodies)
- vaccines
Some of these compounds can induce antibody formation without any T cell interaction.