Table 2. Summary of factors in the case of an adult presenting with an acute biochemical hepatitis favouring either AHB or CHB-AR.
| Evidence in support of AHB | Evidence in support of CHB-AR | |
|---|---|---|
| Patient history | • Recent travel to Malaysia as a possible
risk factor for HBV acquisition (prevalence estimated to be up to 9% 47). • No household members are HBsAg positive, and no (known) history of HBV infection in parents or siblings. • No precipitating factors identified for CHB-AR |
• Patient’s own description of previous similar events, possibly
representing previous episodes of CHB-AR. • Origin in Pakistan where HBV prevalence is estimated to be up to 4% 48, 49, with a history of infection in extended family members. |
| Routine clinical
laboratory data |
• Relatively high peak bilirubin level
20
(227 mol/L at highest). |
• Some studies indicate an anti-HBc-IgM S/CO >10 is indicative
of AHB 17. In this case, the S/CO level of 7.43 does not meet this threshold, suggesting CHB-AR may be more likely. • High HBV DNA level at diagnosis (5.5 log10 IU/ml). Studies have indicated this level of HBV DNA fits more with CHB-AR 7, 16, 50. • Relatively low rise in ALT (486 IU/ml at peak). • Patient remains HBsAg-positive six months after initial presentation. Since >90% of adults clear AHB infection, remaining HBsAg-positive is more in keeping with pre-existing CHB. |
| Deep sequencing
data |
• No polymorphisms associated with
CHB-AR identified at consensus level |
• Viral sub-genotype is D1, known to circulate in Pakistan
51,
suggesting infection early in life, and supported by 6/7 of the other sequences from Pakistan being D1. • Presence of several minority variant mutations associated with CHB-AR and lack of mutations described to be associated with AHB. |
| • Relative lack of nucleotide diversity in the HBV genome could be a feature of AHB due to a small number of
HBV variants establishing new infection. Could also represent high viral load CHB where there is reduced immune selection and unregulated replication of conserved viral populations. | ||
| • The pattern of deletions seen here has not been reported as typical of association with either AHB or CHB-AR. | ||
AHB – acute hepatitis b virus infection; CHB-AR – acute reactivation of chronic hepatitis b virus infection; S/CO – sample to cut off ratio.