Down-regulation of intra-hepatic T-cell signaling associated with GB virus C in a HCV/HIV co-infected group with reduced liver disease.
OBJECTIVE
Studies have shown that GB virus C (GBV-C) infection leads to reduced liver disease in hepatitis C virus (HCV)/human immunodeficiency virus (HIV) co-infection. Considering that the underlying mechanism(s) are unknown, we aim to identify differential gene and protein expression associated with GBV-C in HCV/HIV co-infection that may be responsible for reduced liver disease.


METHODS
Liver, peripheral blood mononuclear cells (PBMCs), and plasma samples were collected from 43 HCV/HIV patients. Plasma was tested for GBV-C RNA by RT-PCR with NS5B gene primers. A microarray was performed on the liver and RT-qPCRs on the liver/PBMC samples. Hepatic protein expression was measured by immunohistochemistry.


RESULTS
Sixteen out of 43 patients had GBV-C RNA. GBV-C was associated with reduced hepatic fibrosis (p=0.005) and inflammation (p=0.007). The microarray analysis of the liver samples (n=10) showed down-regulation of genes critical to intra-hepatic T-cell signaling associated with GBV-C. Quantitative RT-PCR of the liver samples (n=13) confirmed the down-regulation of lymphocyte-specific protein tyrosine kinase (LCK) (p=0.02) and docking protein 2 (DOK2) (p=0.04). No differences in the expression levels of these genes were observed in PBMCs (n=22) according to the GBV-C status. The hepatic expression of the LCK protein, measured by immunohistochemistry (n=36), was decreased in CD3-positive T-cells within portal tracts associated with GBV-C (p=0.003). This remained significant in multivariate analysis controlling for hepatic fibrosis and inflammation (p=0.027). No differences were observed in plasma cytokine concentrations (n=25) or ex-vivo peripheral T-cell responses (n=13) versus GBV-C status.


CONCLUSIONS
GBV-C infection is associated with down-regulation of critical genes involved in intra-hepatic T-cell signaling in HCV/HIV co-infection. This may be relevant to the pathogenesis of reduced HCV-related liver disease in HIV co-infection.
Department of Gastroenterology, Alfred Hospital, Commercial Road, Prahran, 3181 Victoria, Australia. Electronic address: M.Berzsenyi@alfred.org.au.
Mark D
MD
Berzsenyi
Burnet Institute for Medical Research and Public Health, Commercial Road, Melbourne, 3004 Victoria, Australia.
David J
DJ
Woollard
Department of Pathology, Alfred Hospital, Commercial Road, Prahran, 3181 Victoria, Australia.
Catriona A
CA
McLean
Victorian Infectious Diseases Reference Laboratory, 10 Wreckyn St., North Melbourne, 3051 Victoria, Australia.
Scott
S
Preiss
Neuroproteomics and Neurogenomics Platform and Centre for Neuroscience, University of Melbourne, Melbourne, 3010 Victoria, Australia.
Victoria M
VM
Perreau
Center for Cancer Biology, Hanson Institute and School of Molecular and Biomedical Science, The University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.
Michael R
MR
Beard
Victorian Infectious Diseases Reference Laboratory, 10 Wreckyn St., North Melbourne, 3051 Victoria, Australia.
D
D
Scott Bowden
Victorian Infectious Diseases Reference Laboratory, 10 Wreckyn St., North Melbourne, 3051 Victoria, Australia.
Benjamin C
BC
Cowie
Burnet Institute for Medical Research and Public Health, Commercial Road, Melbourne, 3004 Victoria, Australia.
Shuo
S
Li
Infectious Diseases Unit and Victorian HIV Service, Alfred Hospital, Macfarlane Burnet Institute for Medical Research and Public Health, Commercial Road, Melbourne, 3004 Victoria, Australia.
Anne M
AM
Mijch
Department of Gastroenterology, Alfred Hospital, Commercial Road, Prahran, 3181 Victoria, Australia.
Stuart K
SK
Roberts
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000328:Adult; D017252:CD3 Complex / Q000235:genetics / Q000378:metabolism; D060085:Coinfection; D016207:Cytokines / Q000097:blood; D015536:Down-Regulation / Q000235:genetics* / Q000276:immunology; D005260:Female; D018178:Flaviviridae Infections / Q000097:blood / Q000150:complications / Q000235:genetics* / Q000378:metabolism*; D029407:GB virus C / Q000276:immunology / Q000378:metabolism*; D015658:HIV Infections / Q000150:complications* / Q000276:immunology; D006526:Hepatitis C / Q000150:complications / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D006525:Hepatitis, Viral, Human / Q000097:blood / Q000150:complications / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008103:Liver Cirrhosis / Q000209:etiology / Q000473:pathology; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000235:genetics / Q000378:metabolism; D008297:Male; D046228:Microarray Analysis; D008875:Middle Aged; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D012367:RNA, Viral / Q000097:blood; D012720:Severity of Illness Index; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D018417:Th1 Cells / Q000378:metabolism; D018418:Th2 Cells / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D017252:CD3 Complex; C472562:CD3delta antigen; D016207:Cytokines; C115089:DOK2 protein, human; D010750:Phosphoproteins; D012367:RNA, Viral; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck)