Purpose: To review the available data on the association between hepatitis C virus (HCV) infection and conditions reportedly related to infection with the virus and to assess the clinical implications of these associations.
Data sources: Pertinent articles were identified using the Paperchase database, which simultaneously searches the MEDLINE (1966 to present), Health (1975 to present), AIDSLINE (1980 to present), and Cancerlit databases.
Study selection: All studies for a given association were reviewed, but special attention was paid to randomized controlled trials where applicable.
Results: According to the available data, HCV infection appears to be strongly associated with essential mixed cryoglobulinemia, membranoproliferative glomerulonephritis, and porphyria cutanea tarda. Evidence strongly suggests that HCV has a direct pathogenetic role in some patients with the first two conditions. The association with Mooren corneal ulcers and autoimmune thyroiditis is suggested, but more data are needed to confirm it. The data for the association between HCV infection and the Sjögren syndrome, lichen planus, and idiopathic pulmonary fibrosis remain weak. Although interferon therapy has been effective in patients with both essential mixed cryoglobulinemia and membranoproliferative glomerulonephritis, a high relapse rate has been noted in the latter condition.
Conclusions: Patients with essential mixed cryoglobulinemia, membranoproliferative glomerulonephritis, and porphyria cutanea tarda should be tested for HCV infection. Conversely, signs and symptoms of these conditions should be sought in patients with chronic HCV infection. Interferon therapy is currently recommended only for patients with symptomatic essential mixed cryoglobulinemia.