Exposure to hepatitis C virus induces cellular immune responses without detectable viremia or seroconversion.
Sporadic cases of cell-mediated immunity (CMI) in persons exposed to hepatitis C (HCV) but evidently uninfected have been reported. To further define this, we measured CMI in individuals without evidence of HCV infection, that is, negative for HCV-antibodies (anti-HCV) and RNA, residing in a rural Egyptian community where prevalence of anti-HCV was 24%. Cell-mediated immunity (CMI) measured by interferon-gamma (IFN-gamma) enzyme-linked immunospot (ELISPOT) assay, confirmed by intracellular staining using flow cytometry, against HCV peptides was measured in seronegative individuals with high-risk (HR) and low-risk (LR) exposures to HCV. Thirteen of 71 (18.3%) HR subjects but only 1 of 35 (2.9%) LR subjects had detectable CMI (P = 0.032). These data are compatible with the hypothesis that exposures to HCV may lead to development of HCV-specific CMI without anti-HCV and ongoing viral replication. We speculate induced CMI clears HCV sometimes when anti-HCV is not detectable, and HCV-specific CMI is a useful surrogate marker for exposure to HCV.
Al-Sherbiny
Maged
M
Egyptian Reference Diagnostic Center, VACSERA, Cairo, Egypt.
Osman
Ahmed
A
Mohamed
Nahla
N
Shata
Mohamed Tarek
MT
Abdel-Aziz
Fatma
F
Abdel-Hamid
Mohamed
M
Abdelwahab
Sayed F
SF
Mikhail
Nabiel
N
Stoszek
Sonia
S
Ruggeri
Lionello
L
Folgori
Antonella
A
Nicosia
Alfredo
A
Prince
Alfred M
AM
Strickland
G Thomas
GT
D000328:Adult; D002648:Child; D003430:Cross-Sectional Studies; D004534:Egypt / Q000453:epidemiology; D004781:Environmental Exposure; D005260:Female; D005434:Flow Cytometry; D016174:Hepacivirus / Q000302:isolation & purification*; D006526:Hepatitis C / Q000453:epidemiology / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D015994:Incidence; D007371:Interferon-gamma / Q000097:blood / Q000378:metabolism; D008297:Male; D009679:Nuclear Family; D012307:Risk Factors; D013601:T-Lymphocytes / Q000276:immunology / Q000821:virology; D014766:Viremia / Q000175:diagnosis
D007371:Interferon-gamma