The nucleotide at position 1858 of hepatitis B virus has importance in chronic hepatitis B (HB) because a cytosine at nt 1858 effectively prevents virus escape through the precore TAG stop codon mutation. The relatedness between nt 1858 and genotypes was analyzed using a new genotyping method based on restriction fragment length polymorphism (RFLP) analysis of an S gene amplicon. Seventy-three gene bank sequences were analyzed by phylogenetic tree construction and RFLP prediction. A tree supporting the existence of 6 genotypes (A-F) was obtained, with C-1858 found in 9 of 9 A genotypes, 0 of 7 B, 0 of 19 C, 1 of 10 D, 0 of 2 E, and 3 of 3 F. Serum samples from 187 HB e antigen-positive chronic carriers were analyzed: Genotypes in northern Europeans were 60% A, 31% D; in southern Europeans and Middle Easterners 96% D; in Africans 53% A, 27% D, 20% E; and in East Asians 14% A, 43% B, 43% C. Cytosine at nt 1858 was found in 36 of 44 A, 0 of 32 B, 8 of 34 C, 0 of 59 D, 0 of 3 E, and 1 of 1 F genotype samples.

Objective:To test the hypothesis that COVID-19 has an impact on the CNS by measuring plasma biomarkers of CNS injury.Methods:We recruited 47 patients with mild (n=20), moderate (n=9) or severe (n=18) COVID-19 and measured two plasma biomarkers of CNS injury by Single molecule array (Simoa): neurofilament light chain protein (NfL) (a marker of intra-axonal neuronal injury) and glial fibrillary acidic protein (GFAp) (a marker of astrocytic activation/injury) in samples collected at presentation and again in a subset after a mean of 11.4 days. Cross-sectional results were compared with 33 age-matched controls derived from an independent cohort.Results:The patients with severe COVID-19 had higher plasma concentrations of GFAp (p=0.001) and NfL (p<0.001) than controls, while GFAp was also increased in patients with moderate disease (p=0.03). In severe patients an early peak in plasma GFAp decreased upon follow-up (p<0.01) while NfL showed a sustained increase from first to last follow-up (p<0.01), perhaps reflecting a sequence of early astrocytic response and more delayed axonal injury.Conclusion:We show neurochemical evidence of neuronal injury and glial activation in patients with moderate and severe COVID-19. Further studies are needed to clarify the frequency and nature of COVID-19-related CNS damage, and its relation to both clinically-defined CNS events such as hypoxic and ischemic events and to mechanisms more closely linked to systemic SARS-CoV-2 infection and consequent immune activation, and also to evaluate the clinical utility of monitoring plasma NfL and GFAp in management of this group of patients.