Summary
We have undertaken a comprehensive study of hepatitis C virus (HCV) genotype and its
clinical significance in haemophilic patients. 189 HCV RNA positive patients were
typed, using the Simmonds classification scheme, by restriction fragment length polymorphism
(RFLP) in an amplified segment of the 5 non-coding region of the HCV genome. Type
1 was found in 121 (64.0%), type 2 in 23 (12.2%), type 3 in 36 (19.0%), type 4 in
3 (1.6%), type 5 in 2 (1.1%) and mixed infection in 3 (1.6%). There were no type 6
infections and one patient (0.5%) could not be typed. Genotype was not associated
with diagnosis, age, or with HIV infection. Type I was associated with higher serum
HCV RNA levels, and with a poor response to interferon. Progression to hepatic decompensation
has been seen less frequently in those with type 3 compared to type 1 infection (p
= 0.07). Three out of eleven patients studied over a longer time course showed a change
in genotype, the remainder were persistently infected with HCV type 1. In conclusion,
HCV genotype has clinical relevance in the management of haemophilic patients. Those
with type 1 are probably more likely to develop serious liver disease and since they
respond poorly to inter- feron-α, should be considered for new treatment strategies
aimed at sustained clearance of HCV RNA.
