Clearance of low levels of HCV viremia in the absence of a strong adaptive immune response.
Spontaneous clearance of hepatitis C virus (HCV) has frequently been associated with the presence of HCV-specific cellular immunity. However, there had been also reports in chimpanzees demonstrating clearance of HCV-viremia in the absence of significant levels of detectable HCV-specific cellular immune responses. We here report seven asymptomatic acute hepatitis C cases with peak HCV-RNA levels between 300 and 100,000 copies/ml who all cleared HCV-RNA spontaneously. Patients were identified by a systematic screening of 1176 consecutive new incoming offenders in a German young offender institution. Four of the seven patients never developed anti-HCV antibodies and had normal ALT levels throughout follow-up. Transient weak HCV-specific CD4+ T cell responses were detectable in five individuals which did not differ in strength and breadth from age- and sex-matched patients with chronic hepatitis C and long-term recovered patients. In contrast, HCV-specific MHC-class-I-tetramer-positive cells were found in 3 of 4 HLA-A2-positive patients. Thus, these cases highlight that clearance of low levels of HCV viremia is possible in the absence of a strong adaptive immune response which might explain the low seroconversion rate after occupational exposure to HCV.
Meyer
Manuela F
MF
Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany. ManuelaF.Meyer@gmx.de
Lehmann
Marc
M
Cornberg
Markus
M
Wiegand
Johannes
J
Manns
Michael P
MP
Klade
Christoph
C
Wedemeyer
Heiner
H
D000293:Adolescent; D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016174:Hepacivirus / Q000276:immunology*; D006526:Hepatitis C / Q000276:immunology* / Q000821:virology*; D018937:Hepatitis C Antibodies / Q000097:blood; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D008297:Male; D012367:RNA, Viral / Q000097:blood; D016176:T-Lymphocyte Subsets / Q000276:immunology; D014766:Viremia / Q000276:immunology*
D018937:Hepatitis C Antibodies; D012367:RNA, Viral; D007371:Interferon-gamma; D000410:Alanine Transaminase