Is hepatitis C virus infection a trigger of porphyria cutanea tarda?

The causes of liver disease, ranging from fatty changes to cirrhosis and hepatocellular carcinoma, in porphyria cutanea tarda (PCT) remain unclear. We tested 100 consecutive PCT patients for antibodies to hepatitis C virus (HCV) by enzyme-linked immunosorbent assay and a recombinant immunoblot assay. 75 (79%) patients with sporadic PCT but none of 5 with familial PCT were positive. HCV RNA was found in serum of all 18 anti-HCV-positive patients tested. There were no significant differences in the prevalence of anti-HCV between treated and untreated patients or between those with and without various HCV risk factors. The frequency of anti-HCV increased with the severity of liver histology. These findings implicate HCV in the aetiology of PCT-associated liver disease.