Interferons (IFNs) are a subclass of lymphocyte-released cytokines that interfere with intracellular viral
replication. These drugs are classified into three groups: IFN type 1 (IFN-α, IFN-β, and IFN-ω), IFN type 2 (IFN-γ), and
IFN type 3 (IFN-λ). Despite numerous trials, IFN therapy has yet to conclusively demonstrate superiority in the treatment
of various pulmonary diseases. In addition to the FDA-approved and ongoing investigational uses for IFN therapy, there is
a debate regarding the appropriate dosage of these agents. A retrospective literature review is moving experts towards
low-dose therapies in nearly every application of IFN therapy. It is speculated that known and unknown toxicity may limit
the beneficial effects of IFN therapy.