Involvement of transporter associated with antigen processing 2 (TAP2) gene polymorphisms in hepatitis C virus infection.
OBJECTIVE
Transporter associated with antigen processing (TAP) has essential roles in the antigen-presenting systems, translocating antigenic peptides from the cytosol into the endoplasmic reticulum. The aim of this study was to clarify whether TAP polymorphisms are involved in hepatitis C virus (HCV) infection.


METHODS
The 145 HCV-infected Japanese patients examined in this study were categorized into two groups: 36 carriers with persistently normal alanine transaminase (ALT) values and 109 patients with chronic liver disease (CLD). TAP2 gene phenotypes were determined by means of polymerase chain reaction-restriction fragment length polymorphism, and their frequencies were compared between the two groups.


RESULTS
Frequencies of TAP2*0101, *0102, and *0201 were not different between the two groups. However, TAP2*0103 frequency in carriers with normal ALT levels was significantly higher than that in patients with CLD (44% vs. 16%; P = 0.00064, Pc < 0.005). Although the TAP2*0103 allele was tightly linked with class II DRB1*1302-DQB1*0604 haplotype in this study, the TAP2*0103 frequency in the normal ALT group was also significantly higher than that in the CLD group even in DRB1*1302-DQB1*0604-negative patients (31% vs. 10%; P = 0.0076, Pc < 0.05).


CONCLUSIONS
These findings suggest that TAP2*0103 may be closely associated with low serum ALT activity in HCV-infected Japanese patients.
Kuzushita
N
N
Department of Internal Medicine and Therapeutics, Osaka University School of Medicine, Osaka, Japan.
Hayashi
N
N
Kanto
T
T
Takehara
T
T
Tatsumi
T
T
Katayama
K
K
Ohkawa
K
K
Ito
A
A
Kasahara
A
A
Moribe
T
T
Sasaki
Y
Y
Hori
M
M
D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000410:Alanine Transaminase / Q000097:blood; D000483:Alleles; D005260:Female; D005787:Gene Frequency; D008040:Genetic Linkage; D006683:HLA-DQ Antigens / Q000235:genetics; D059866:HLA-DQ beta-Chains; D006684:HLA-DR Antigens / Q000235:genetics; D059811:HLA-DRB1 Chains; D016174:Hepacivirus / Q000235:genetics; D019698:Hepatitis C, Chronic / Q000201:enzymology / Q000235:genetics*; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length
D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; C071692:TAP2 protein, human; D000410:Alanine Transaminase