Characterization of HBV2‐like infections in Spain

Abstract

Hepatitis B viral serum markers suggestive of infection by hepatitis B virus type 2 were found in 354 patients tested in the laboratory during a 2.5 year period of study. Confirmation of the HBsAg reactivity by neutralization and subtyping analysis and determination of serum HBV-DNA by molecular hybridization were carried out on selected samples from these patients. Clinical and epidemiological data were obtained from 234 patients and serological follow-up was done in 70 cases. The results obtained from the confirmatory tests and DNA assays indicated that HBsAg reactivities were specific, being frequently associated to low levels of HBV-DNA. The incidence rates obtained for HBV2 serological patterns among patients at different level of risk for HBV infection, as well as the finding of a high rate of coinfection with hepatitis A virus among those showing acute hepatitis, suggested that the HBV2 agent could be transmitted by the oral route. An hypothesis considering the so called HBV2 infections as resulting from infections by an HBV variant strain which has an improved ability for non-sexual, non-parenteral transmission is suggested. Specific recommendations for detection and confirmation of such cases in blood banks are also outlined.

Hepatitis B virus genotype E surface antigen detection with different immunoassays and diagnostic impact of mutations in the preS/S gene

“…Alternatively, samples may have been drawn before anti-HBc seroconversion at the end of the incubation period. Decreased sensitivity for anti-HBc detection in genotype E infected patients, in-frame deletions or other mutations in the precore/core gene may also (partially) account for the isolated HBsAg reactivity [4,21]. In a recent study, the isolated HBsAg positive result was described in 24 patients [5] and seems more frequent during pregnancy and in spring [Echevarria JM, personal communication].…”

Nucleotide Sequence of the Precore/Core Gene and X Gene of Hepatitis B Virus DNA in Asymptomatic Hepatitis B Virus Carriers Who Are Negative for Serum Hepatitis B Core Antibody

“…In the majority of patients with continuous HBV infection in Africa, Spain and Taiwan, the serum markers of HBV infection are positivity for HBs antigen and strong positivity for HBc antibody [9,10]. However, there are rare cases of HBV carriers who are negative for HBc antibody with the exception of patients in the terminal stage, irrespective of the presence of hepatitis; this is Terada/Moriyama/Uchida/Arakawa called HBV2 and results in mild hepatitis [8][9][10]. Kaneko et al [11] found that silent HBV infection with negative serum HBV markers is due to an 8-nucleotide deletion in the X gene coding region and a point mutation in DR2 of HBV DNA.…”

“…tis, and is not commonly reported [8][9][10]. We have recently clarified that the so-called silent HBV infection with negative serum markers is caused by the deletion of an 8-nucleotide (nt) sequence in the X gene coding region and a point mutation in DR2 [11].…”

Variants of Hepatitis B Virus

“…Despite the fact that some investigators continue to believe that so-called HB V-2-like infections are caused by a distinct strain or variant of HBV [46], a recent report [47] confirms that the core gene sequences of viruses in fecting individuals who fail to make an anti-HBc response are not aberrant. Nonetheless, reported low or negative reactivity for HBsAg from these and other [37] HBV in fections raises the spectre of posttransfusion hepatitis B should individuals so infected become donors.…”