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T-cell
Response to Genotype and Ethnicity during Therapy for Chronic
Hepatitis C
Viral
genotype and
host
ethnicity
are important predictors of viral clearance during antiviral
therapy for chronic hepatitis C virus (HCV) infection. Based
on the role of T cells in natural HCV clearance, researchers
hypothesized that T cells may contribute to the genotypic
and ethnic difference in treatment outcome.
To
test this hypothesis, T-cell response to HCV antigens (core,
nonstructural NS3/4 and NS5) and control phytohemagglutinin
(PHA) was monitored prospectively and was correlated with
virological outcome in 41 patients chronically infected with
HCV (27 genotype
1, 14 genotype
2 or 3; 19 black
persons, 22 white persons)
undergoing combined
interferon alfa and ribavirin therapy.
Results
· Interestingly,
in patients with genotype 2 or 3 infection, enhanced virological
response coincided with a greater T-cell response to HCV NS3/4
antigen at baseline (50% vs. 15%; P = .026) that augmented
further during therapy (29% vs. 4%; P = .035) compared with
genotype 1-infected patients.
· However,
HCV-specific T-cell response remained weak in genotype 1-infected
patients regardless of virological outcome or ethnicity.
· Furthermore, virological
outcome was associated with a suppressed baseline proliferative
response to phytohemagglutinin (P < .03) that increased
during therapy (P < .003) independent of ethnicity or genotype.
In
conclusion, “HCV-specific T-cell response was associated with
HCV genotype but not with therapeutic clearance of HCV infection,
according to the investigators.
“The
association between treatment outcome and phytohemagglutinin
response suggests more global and antigen-nonspecific mechanisms
for therapeutic
HCV clearance,” note the authors.
Division of Gastroenterology, Department of Medicine, University of Pennsylvania,
Philadelphia 19104, USA.
06/13/05
Reference
D E Kaplan. T-cell response relative to genotype and ethnicity
during antiviral therapy for chronic hepatitis C.
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