TITLE: HEPATITIS C: THE MOST COMMON GENOTYPES ARE
ALSO THE HARDEST TO TREAT
The most common hepatitis C virus (HCV) genotypes in the U.S.
are 1a and 1b, according to the authors of this study. These two
genotypes cause more severe liver disease and are associated with
poorer rates of response to interferon therapy than genotypes 2a
and 2b.
The authors studied serum samples obtained from 179 patients
(mean age: 42; 74% men) who had chronic HCV infection and who were
treated at tertiary referral centers in the Midwest, Northeast,
Southeast, and West.
DISTRIBUTION. Infection rates by genotype:
- genotype 1a: 58%
- genotype 1b: 21%
- genotype 2b: 13%
- genotype 3a: 5%
- genotype 2a: 2%
- genotype 4a: 1%
The distribution of genotypes did not vary by geographic region,
nor was it associated with gender, the route of acquisition (ie,
blood transfusion, IV drug abuse, accidental needle-stick) or the
histologic appearance of the liver at presentation (ie, mild
hepatitis, moderate hepatitis, or cirrhosis). Severe hepatitis was
seen in 68% of patients infected with HCV genotype la and in 80 to
87% of those infected with genotypes 1b, 3a, 3b, or 4a. In
contrast, only 37% of patients infected with genotypes 2a or 2b had
severe hepatitis.
RESPONSE TO INTERFERON. Among patients who received interferon
therapy for 6 months, neither age nor gender was associated with
their response. Overall response rates:
- in patients infected with HCV genotype 2a or 2b: 71%
- in patients without cirrhosis: 46%
- in patients infected with genotype 1a, 1b, or 3a: 25 to
28%
- in patients who had cirrhosis: 14%
Only 12% of patients who received inter-feron had normal
biochemical findings 6 months after treatment was stopped. A
sustained response was not associated with age, sex, the presence
of cirrhosis, or the genotype.
AUTHOR: Zein NN, Rakela J, Krawitt EL, et al. Hepatitis C
virus genotypes in the United States: Epidemiology, pathogenicity,
and response to interferon therapy. Ann Intern Med (Oct. 15) 1996;
125:634-9.
SOURCE: MODERN MEDICINE; FEBRUARY 01, 1997 Section: INFECTIOUS
DISEASE
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