title: Exposure to hepatitis C virus induces cellular immune responses without detectable viremia or seroconversion.
abstract: 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.
authors: Egyptian Reference Diagnostic Center, VACSERA, Cairo, Egypt.
authors: Maged
authors: M
authors: Al-Sherbiny
authors: Ahmed
authors: A
authors: Osman
authors: Nahla
authors: N
authors: Mohamed
authors: Mohamed Tarek
authors: MT
authors: Shata
authors: Fatma
authors: F
authors: Abdel-Aziz
authors: Mohamed
authors: M
authors: Abdel-Hamid
authors: Sayed F
authors: SF
authors: Abdelwahab
authors: Nabiel
authors: N
authors: Mikhail
authors: Sonia
authors: S
authors: Stoszek
authors: Lionello
authors: L
authors: Ruggeri
authors: Antonella
authors: A
authors: Folgori
authors: Alfredo
authors: A
authors: Nicosia
authors: Alfred M
authors: AM
authors: Prince
authors: G Thomas
authors: GT
authors: Strickland
mesh_terms: 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
chemical_list: D007371:Interferon-gamma