Screening for antibodies to hepatitis C virus (HCV) has substantially
reduced the risk of HCV infection from transfusion of blood and blood
products. Nevertheless, new infections may continue to occur. These in
fections may be caused by donor infections that escape detection or by
insufficient decontamination of blood products during preparation. Fr
equently, HCV infection becomes chronic, is clinically silent, and can
be associated with extrahepatic illnesses and liver cancer. A recent
outbreak of HCV infection in patients who received intravenous immunog
lobulin has permitted study of this infection in immunocompromised hos
ts. Some evidence indicates that this infection is more virulent in th
ese patients, and our experience at Children's Hospital, Boston, Massa
chusetts, substantiates this finding. In this article, epidemiology an
d modes of transmission of HCV, pathogenesis of HCV infections, differ
ential diagnosis, and clinical features of HCV infection in both child
ren and adults are discussed. Particular attention is given to the ser
ologic findings seen in the spectrum of diseases associated with chron
ic HCV infection. The mechanisms of action of interferon alfa treatmen
t of HCV infections are discussed. However, results of interferon alfa
treatment of patients with HCV infection at Children's Hospital are p
reliminary.