Treatment of life-threatening viral infections with interferon alpha: pharmacokinetic studies in a clinical trial.

The effectiveness of human leukocyte interferon (IFN alpha) therapy was studied in 15 patients with acute life-threatening viral illnesses. All patients were critically ill, many close to death, when IFN therapy was begun. Included were six patients with acute fulminant hepatitis, four immunosuppressed patients with spreading herpes simplex, three severely ill patients with encephalitis, one case of severe fulminant juvenile laryngeal papillomatosis, and one of postmeasles dermatitis. Twelve of the 15 patients recovered, some dramatically, including 3 of the 6 fulminant hepatitis patients. Pharmacokinetic studies showed defective antiviral IFN responses in most of the patients--in particular, absence of in vivo IFN production. Because the patients were not producing IFN in response to the viral infection, the peripheral blood mononuclear cells were not primed into an antiviral state. Treatment with IFN alpha led to the rapid development of an antiviral state of the cells, which paralleled clinical recovery. In our opinion, IFN is the treatment of choice in acute viral infections, often lifesaving, provided it is given early in the infection before irreversible cell and tissue damage has taken place. Its use is most effective in those seriously ill patients with defective antiviral IFN responses.