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Interferons (IFNs) are types of cytokines, natural cell-signaling proteins produced by the cells of the immune system, in response to challenges from pathogens and tumor cells. Interferon therapy is immunosuppressive, reducing in number both Th1 cytokines and immune cells.1)
Interferons are used in a variety of diseases including cancer, hepatitis C infections, rheumatoid arthritis, osteoporosis, and Crohn's disease for these immunomodulatory effects. In the absence of a robust immune response to bacterial pathogens and the accompanying immunopathological reaction, patients feel temporarily better, however:
The immune system is activated by a delicate balance of many, many hormones, cytokines, proteins and steroids. To affect any one of these will suppress proper action of the immune system. If you give somebody exogenous interferon then their endogenous production will be cut back.
Trevor Marshall, PhD
The immunosuppression brought about by interferon therapy contributes to leads to numerous side effects and poor long-term outcome. It is not uncommon for the efficacy of interferon treatment to disappear within six months following discontinuation of therapy.2)
The most common side effects of interferon are: alopecia (hair loss), insomnia and sleep disturbances, psychiatric symptoms including suicidal ideation, and flu-like symptoms.