Interferon alfa-2a for cryoglobulinemia associated with hepatitis C virus

To the Editor: Misiani and colleagues (March 17 issue)¹ conclude that the therapeutic efficacy of interferon alfa-2a in cryoglobulinemia associated with hepatitis C virus (HCV) is closely related to the drug's antiviral activity. However, the authors do not present sufficient data to justify this conclusion. The demonstration that HCV is specifically concentrated in type II cryoglobulins suggests that the virus may be involved in the development of the disease and that the effect of interferon alfa may be due to its antiviral activity²; however, it has also been demonstrated that mixed cryoglobulins diminish immune-complex clearance mechanisms³. In view.