Host and Viral Factors Associated with Hepatitis B Clinical Outcomes in Chronic Infection
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Date
2019
Journal Title
Journal ISSN
Volume Title
Publisher
International Journal of Pure Medical Research
Abstract
Viral and host factors have been implicated in persistence of HBV
infection to chronicity and perhaps to liver cancer. Fortunately 90-
95% of those who get infected in adult hood clear the virus and
remain with antibodies suggesting previous exposure to HBV. The
underlying reasons as to why majority of the patients with acute
infection clear the virus while a small proportion progress to chronic
infection lies in the difference in host immunological and genetic
factors. The immune determinants of complete clearance are not
fully understood but both innate and adaptive are paramount in this
response. Similarly, the role of the host genes in the pathogenesis of
the virus are not fully elucidated but polymorphisms in genes
encoding for the HLA, cytokine and vitamin D receptor (VDR) have
been highlighted in inuencing both disease clearance and
progression to chronicity. In this review, the host and viral factors
responsible for differential clinical presentation of hepatitis B are
discussed.
Introduction
Hepatitis B virus (HBV) is the causative agent for liver diseases,
including chronic hepatitis, liver cirrhosis, and hepatocellular
carcinoma (Matsuura, K., Tanaka, Y., Hige, S. et al., 2009).
Hepatocellular carcinoma is one of the most common cancers
globally with high incidents in Eastern Asia and Sub-Saharan Africa
(Jemal, Bray, Center, Ferlay, & Ward, 2011). Most patients who get
infected with hepatitis B virus go into an acute phase during when
the virus is cleared. None the less, in some patients the virus persists
resulting into chronic hepatitis B infection which may later progress
to liver cancer. Immune responses and genetic factors of the host
along with the viral characteristics remain pivotal in determining
the course of the disease
Hepatitis B genotypes and subtypes
The HBV genome is composed of approximately 3,200 nucleotides
(Matsuura et al., 2009). Arauz-Ruiz, Norder, Robertson, & Magnius,
(2002) previously classied HBV into 8 genotype identied as A-H
based on an intergroup divergence of 8% or more in complete
nucleotide sequence whose geographical distributions was
previously extensively studied by Sanchez-Tapias, Costa, Mas,
Bruguera, & Rodes, (2002) who documented that genotype A is
pandemic, B and C are predominant in Asia, D in southern Europe, E
in Africa, F in United States of America, G in France while H in Central
America. However recent studies by McMahon (2009), Cao (2009),
Kurbanov, Tanaka, & Mizokami, (2010) have introduced two new
genotypes designated as I and J giving a total of 10 genotypes
together with several sub-genotypes. With the exception of the
newly identied genotypes, the other genotypes and subgenotypes
have well characterized ethnic and geographical
distribution
Description
Keywords
hepatitis B, Vitamin D receptor, Hepatitis B virus
Citation
Kafeero, M. H., Sendagire, H., Ocama, P., & Ndagire, D. (2019). Host and viral factors associated with hepatitis B clinical outcomes in chronic infection-review article. International Journal of Pure Medical Research