Background: Interferons (IFNs) are functional proteins of vertebrate cells that have been
conserved throughout evolution. Antiviral response in cells and uncontrolled cell proliferation of lymphocytes
and macrophages are influenced by IFNs. B and T cell functions are influenced by these molecules
in vitro and in vivo. These facts are confirmed by the effects on different conditions: antibodies
production, T cells' cytotoxicity, allograft survival, delayed-type hypersensitivity reactions. Some IFNs
are produced as a result of antigen recognition by T cells, and in turn, they modulate Natural Killer
(NK) cell and phagocyte activities and functions. On the other hand, there are viral infections without
immunological specificity, which involve IFNs and interfere in immune reactions. Some clinical applications
of IFNs have been implemented in the recent years, for example for hepatitis B and C treatment.
Conclusion: However, in this review, emphasis will be placed on the use of IFNs for the possible
treatment of seasonal influenza viruses that have specificity with the upper respiratory tract. IFNs prevent
highly pathogenic influenza viruses to disseminate to the lung, assuming their use as an emergency
drug against pandemic forms of influenza.