[Porphyria cutanea tarda and hepatitis C virus infection. Clinical and virological study]

The role of hepatitis C virus (HCV) infection in porphyria cutanea tarda (PCT) is probable since the global antibody prevalence among PCT patients is about 70 p. 100. The purpose of this study was to evaluate the virological characteristics in 12 patients with sporadic PCT and one with familial PCT.

Anti-HCV antibodies were detected by enzyme-linked immunosorbent assay and confirmed by recombinant immunoblot assay. Hepatitis B virus (HBV) and anti-human immunodeficiency virus (HIV) markers were also determined. The polymerase chain reaction (PCR) was performed in order to detect: 1) both positive and minus HCV strands, 2) HCV RNA titer and 3) HCV RNA genotype.

Seven of the 12 patients with sporadic PCT were HCV positive and the patient with familial PCT was HCV negative. The age of onset of PCT was significantly lower in HCV positive patients than in HCV negative patients (p < 0.02). The HCV RNA was detected in all patients who had HCV antibodies, and the replicative intermediate of HCV was detected in 3 of them. The positive RNA titer ranged from 1/10 to 1/10(6). Four patients were infected by HCV genotype I, 2 by genotype II and 1 patient was coinfected by type I and type II. Three of the 7 HCV positive patients also had HBV antibodies, but HBV DNA was never detected. All patients were HIV negative.

The HCV infection rate was high in this series (58 p. 100), and all HCV infected patients had HCV RNA, reflecting an active replication of the virus. The young age of onset of PCT suggests that HCV is a major triggering factor of PCT. Nevertheless, the clinical changes of PCT were not related to the virological findings, suggesting an indirect role of HCV.