Int. J Sci. Emerging Tech Vol-4 No 3 September 2012
153
Mutations in ISDR may be linked to High
VIREMIA and Virus Resistance to
IFN-Alpha-2b But Responsive
to PEG-IFN-Alpha-2a
Abida Raza
1
*, Nasib Zaman
2
, Binish Gull Arshad
3
, Muhammad Javed Asad
2
,
Hafsa Aziz
1
, Samina N. Qureshi
3
, Javaid Irfan
1
1
Postdoc School of Pharmacy, University of London,
Senior Scientist, Nuclear Medicine,
Oncology and Radiotherapy Institute (NORI), Islamabad, Pakistan
Email: abida_rao@yahoo.com
2
PMAS, Arid Agriculture University, Rawalpindi
3
Quaid-i-Azam University, Islamabad
Abstract: Mutation in interferon sensitivity determining
region may play role in virus resistance. Genotype 3a
patient was subjected to 48 weeks combination therapy
of IFN-alpha-2b plus ribavirin but he showed high
levels of viremia before, during and after treatment
although his ALT level became normal. His IL-8 and
TNF-alpha levels werefound quite high before and after
IFN-alpha-2 combination therapy. While comparing its
ISDR-NS5A with end of treatment responder patient,
eight mutations were observed in a 52 amino acid
protein residue. Patient was advised for PEG-IFN-
alpha-2a combination therapy for 24 weeks, to which he
responded well after 4 week and showed sustained
virologic response after 06 months of completion of
therapy. His IL-8 and TNF-alpha levels also came to
lower levels after treatment with PEG-IFN-alpha 2a
combination therapy. In phylogenetic tree its genome
(NZ1) along with another nonresponder case (NZ2) was
placed close to Brazilian isolates. NZI and NZ2 showed
87 % sequence homology with each other while NZ1
had 89% sequence homology with EF208017 and 87%
with EF20995. NZ2 showed 91% homology with
EF208017 and 98% with EF207995 which is quite
interesting. Mutations in ISDR sequence may be the
reason for non response to IFN combination therapy of
this HCV genotype 3 patient. ISDR of genotype 3 along
with IL-8 and TNF-alpha may be screened on larger
scale in Pakistani population which may help in
deciding a cost effective treatment plan.
Key words: NS5A-ISDR mutations; IFN-alpha-2b; PEG-
IFN; HCV; IL-8; Pakistan
1. Introduction
Mutations in interferon sensitivity
determining region (ISDR) has been linked to
Hepatitis C virus resistance in some studies from
Japan in genotype 1 [1]-[3] but contradictory reports
have been submitted from other parts of the world
including Pakistan [4]-[8]. If three or more than three
mutations are observed in ISDR region, it is declared
as mutant ISDR strain, while intermediate mutant
type has one to three amino acid mutations 4. The
number of amino acid substitutions in ISDR in the
non-structural 5A (NS5A) gene of hepatitis C virus
(HCV) is closely associated with the interferon (IFN)
response and viral load [9]. Mutations in ISDR may
play role in virus replication and in some cases
increase the replication many folds. Most of the data
available is on viral genotype 1b. In Pakistan most
common genotype is 3a and fortunately above 70
percent response to 24 week treatment plan of non
pegylated interferon (non PEG-IFN) combination
therapy has been observed [10]. Pegylated interferon
combination therapy (PEG-IFN) being quite
expensive is not affordable so usually it is not first
choice for poor patients. There is need to
individualize the treatment plan. For the current case
we have tried to explore the NS5A-ISDR amino acid
sequence with viral load, virus genotype, ALT, IL-8
protein, TNF-alpha levels with response to interferon
therapy with change in treatment plan.
2. Methods
Study involves the human subjects; it was
approved by the ethical review committee of the
Institute. Moreover written consent forms dually
signed by the patients were also taken before the start
of the study.
3. Patient Clinical Details
A 50-year-old male patient body mass index
20.8 belonging to district Mandibahauddin in upper
Punjab, Pakistan was diagnosed Hepatitis C in 1995.
He was admitted with general fatigue, high-grade
fever, and liver dysfunction. No evidence of prior
liver disease was found, and the patient had no
history of drug or alcohol consumption. The infection
route of HCV was obscure. In the last 6 months, he
had not received any blood transfusions, taken any
drugs intravenously, undergone acupuncture, nor had
sexual contact with a known hepatitis virus carrier
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