Genetic Variations May Help Explain Racial/ethnic Differences in Immune Response
to Hepatitis C Virus It
is widely recognized that chronic hepatitis C patients
of various racial/ethnic groups have different outcomes, with people of African
descent generally exhibiting lower rates of spontaneous HCV clearance and poorer
response to interferon-based therapy. The
reasons underlying these differences are not well understood. However, some research
suggests that immune markers known as human leukocyte antigen (HLA) class II,
which influence CD4 T cell responses against HCV, may play a role, given that
the distribution of HLA genotypes differs among racial/ethnic groups. As
reported in the June 7, 2008 issue of Hepatology, Rebecca Harris from the
University of Pennsylvania and colleagues assessed whether HLA class II genotypes
associated with HCV clearance are similar between Caucasian and African American
patients, and whether they contribute to enhanced anti-HCV CD4 cell response.
The analysis included 93 HCV seropositive participants from the Northeast U.S.
Results
•
The investigators confirmed previously reported associations between HCV clearance
and 2 HLA types, DQB1*03 and DRB1*11.
•
They also identified a new association with HLA type DRB3*02.
•
These associations were seen only among Caucasian patients, not among African
Americans.
•
Although the HLA DQB1*03, DRB1*11, and DRB3*02 genotypes were associated with
increased HCV-specific CD4 cell response in univariate analyses, this associations
was lost after controlling for virological outcomes.
Based
on these findings, the study authors wrote, "We conclude that the immunogenetic
basis for HCV clearance differs between ethnic groups and that the association
between HLA class II and HCV clearance is not directly explained by antiviral
CD4 T cell response." This
lack of association between HLA genotypes and anti-HCV T cell response in this
study leaves open the search for a specific mechanism that can explain racial/difference
in hepatitis C outcomes.
Division of Gastroenterology, Department of
Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA; Philadelphia
Veterans Affairs Medical Center, Philadelphia, PA; Haverford College, Haverford,
PA; Department of Pathology and Laboratory Medicine, University of Pennsylvania
School of Medicine, Philadelphia, PA.
7/29/08
Reference
RA
Harris, K Sugimoto, DE Kaplan, and others. Human leukocyte antigen class II associations
with hepatitis C virus clearance and virus-specific CD4 T cell response among
Caucasians and African Americans. Hepatology 48(1): 70-79. June 7, 2008. (Abstract)
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