Interferon-α therapy in noninfectious uveitis

Interferon (IFN)-α and IFN-β are naturally occurring cytokines which seem to have similar effects on the immune system. One of the effects of IFN seems to increase regulatory T cells. There are numerous case reports and studies reporting about the effect of IFN-α against Behçet's disease (BD), but also against chronic uveitic macular edema and a few other types of uveitis. Within 2-4 weeks, approximately 94% of patients reach complete or partial remission in the case of BD-associated uveitis. So far, IFN-α is the only drug that leads to stable remission even after discontinuation of the treatment. It is recommended to start treatment with 3-6 million IU per day. Administering less than daily dosages seems to increase the recurrence rate for BD-associated uveitis. Flu-like symptoms are expected in all patients as a sign of nonexisting anti-IFN antibodies. They are treated with nonsteroidal anti-inflammatory drugs like paracetamol and disappear normally after some days. Depression(8%) and mild leukopenia (30%) are additional side effects of concern; all other side effects are reported to appear in ≤1% of cases. This chapter updates the mechanisms and pharmacology of IFN and its effects in experimental studies. This is followed by a summary of clinical studies in intraocular inflammation and the spectrum of side effects.