In a 4-year follow-up study, patients with acute sporadic non-A, non-B (NAN
B) hepatitis were evaluated to determine the etiology and natural history o
f the disease. Acute hepatitis C virus (HCV) was detected in 13 of 43 (30%)
of patients, anti-hepatitis E virus (HEV) IgG in 5 (12%), and 25 (58%) wer
e considered non-A-E. The HCV RNA was detected in all HCV patients but none
of the non-A-E cases. The initial clinical and biochemical presentation of
the HCV and non-A-E cases was quite similar, although 2 of the non-A-E pat
ients had severe disease. The 5 patients who were found to be anti-HEV IgG-
reactive recovered within 6 months of follow-up. Of the 13 HCV cases, alani
ne transaminase (ALT) levels returned to normal in 7 (53.8%), while 6 (46.2
%) continued to show abnormal ALT after 6 months of follow-up. However, 9 (
69.2%) of them remained HCV-RNA-positive, denoting virological/biochemical
dissociation. Longterm follow-up showed a reappearance of HCV RNA in 2 of t
he 4 patients who were in virological remission performing 84% of chronicit
y rate. Acute non-A-E hepatitis patients were less likely to evolve toward
chronicity, as compared with acute HCV cases (16% vs. 84%; P = .0001). Only
4 (16%) of the non-A-E patients were hepatitis G virus (HGV)-RNA-positive.
Concerning risk factors for acquiring parenterally transmitted viruses, ta
ttooing was the only one that could be associated with HCV transmission (P
= .002). No risk factors could be identified for putative non-A-E virus tra
nsmission. Liver biopsies performed for chronic HCV patients showed a varia
ble degree of inflammation, while the non-A-E patients presented less sever
e histological disease.