Diminished frequency of hepatitis C virus specific interferon gamma secreting CD4+ T cells in human immunodeficiency virus/hepatitis C virus coinfected patients.
BACKGROUND
Human immunodeficiency virus/hepatitis C virus (HIV/HCV) coinfection is a common and complex clinical problem in which loss of immunological control of HCV occurs, with increased HCV viral load and more aggressive liver disease. Cellular immune responses, particularly secretion of interferon gamma (IFN-gamma) appear to be important in the control of HCV, and a detectable HCV specific CD4 response is associated with clearance of the virus. HCV specific CD8+ T cell responses, weak in chronic HCV infection, have been shown to be further impaired in HIV coinfection and this CD8+ T cell deficiency is related to the decline in CD4 T cell count.


OBJECTIVE
To compare the CD4 T cell response to HCV in HIV/HCV coinfected and HCV monoinfected individuals and to determine the relationship of responses with declining CD4 count.


METHODS
The study subjects were a cohort of 68 HCV monoinfected and 67 HCV/HIV coinfected haemophiliac children and adolescents (the Hemophilia Growth and Development Study) who were followed for a seven year period.


METHODS
We analysed IFN-gamma secreting CD4+ responses to HCV proteins and peptides and HIV p24 antigen using an ELISpot assay.


RESULTS
We found a significant decrease in HCV specific responses among those who were HIV coinfected (10/67 v 36/68; p<0.0001) both in numbers of responders and frequency of specific cells. This did not appear to be closely related to CD4 count.


CONCLUSIONS
The reduction in HCV specific CD4 T cells in coinfection provide a cellular mechanism for the loss of control of HCV in coinfected individuals, even in those with relatively preserved CD4+ T cell counts and CD4+ T cell responses to HIV.
Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, South Parks Road, Oxford OX1 3SY, UK.
G
G
Harcourt
E
E
Gomperts
S
S
Donfield
P
P
Klenerman
D000293:Adolescent; D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D002648:Child; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy / Q000276:immunology*; D016174:Hepacivirus / Q000276:immunology; D019698:Hepatitis C, Chronic / Q000150:complications / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D007371:Interferon-gamma / Q000378:metabolism*
D007371:Interferon-gamma