Buon giorno Professor Ideo, ho letto questo articolo
Heterogeneity of hepatitis B virus (HBV) core gene in a patient with HBV-associated cirrhosis and serum negativity for anti-HBc.
Zoulim F, Zhang X, Pichoud C, Trepo C.
Hepatitis and AIDS Research Unit, Lyon, France.
AIMS: We describe here the case of a patient suffering from severe chronic hepatitis B associated with an unusual hepatitis B virus serology: HBsAg and HBeAg were both positive while anti-HBc was negative by radioimmunoassay.
METHODS: A very sensitive anti-HBc ELISA (IMx CORE) was performed and was able to detect anti-HBc sporadically throughout the clinical course. Molecular characterization of hepatitis B virus strains in this patient enabled us to explain this particular serological and clinical pattern of hepatitis B virus infection.
RESULTS: Hepatitis B virus genotype determined by size polymorphism of the core gene and the pre-S region was found to be D/E and consistent with the results of serological subtyping (HBV ayw2-4). DNA sequence analysis of the pre-C/C region showed the presence of significant nucleotide changes. In association with a wild type hepatitis B virus strain, we could detect at least four hepatitis B virus variants with nucleotide deletions leading to a frameshift in the core gene. According to the position of the mutations, these hepatitis B virus core variants are expected to be defective for B-cell epitopes and TH-cell epitopes.
CONCLUSIONS: These mutations explain the low level production of anti-HBc antibody. It is noteworthy that the absence of detectable anti-HBc in serum was associated with severe liver damage, suggesting that the deficient humoral response to HBcAg was not accompanied by a cellular immune tolerance to HBc/eAg, the supposed target for cytotoxic T-cell lysis.
Le chiedo per favore quale è la prevalenza di questa mutazione che comporta un'espressione di HBcAb "sporadica"? Quando un ammalato di questo tipo guarisce, invece di avere HBcAb permanente lo avrà sporadico? Ma cosa si intende per sporadico? Che se si fa l'analisi lo si trova una volta su quante? E' vero che la prevalenza tra la popolazione generale italiana (escludendo i giovani che sotto i 30 anni sono tutti vaccinati)di marcatori di pregressa infezione (HBcAb e HBsAb)è circa il 10%?