case_images: PMC9581728_01
case_images: Clinical course of HEV infection prior to and after ribavirin. (A) Light red legend indicating ALT (circles) and light blue legend indicating AST (circles). The y-axis on the left represents levels of ALT (U/L) and the right represents levels of AST (U/L). (B) The light red legend indicates HEV RNA of stool (circles) and serum (squares). The light blue legend indicates HEV antigen of stool (circles), serum (squares), and urine (triangles). The y-axis on the left represents viral load of HEV (Log10 copies/mL) and the right represents levels of HEV Ag (Log10 S/CO). The x-axis of (A) and (B) are scaled to illustrate time intervals in relation to oral ribavirin. The presence and absence of anti-HEV IgM and anti-HEV IgG in serum are indicated by "+" and "-", respectively. AA, aplastic anemia; Ag, antigen; ALT, Abnormal alanine aminotransferase; AST, aspartate aminotransferase; antigen; IgM, immunoglobulin M; IgG, immunoglobulin G.
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case_images: Abnormal alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were observed after 21 days of HSCT with 85 U/L and 53 U/L in Mar 13rd 2017 (day -765), which persisted for twenty-nine months until Jul 29th 2019 (day +103) ( Figure 1A ). Upon admission to our hospital in Jul 31st 2018 (day -260), abnormal liver enzymes were persistent, ALT 314 U/L, and AST 193 U/L ( Figure 1A ). Follow-up samples in serum and stool revealed HEV RNA and Ag positive in Dec 12nd 2018 (day -126), ALT 160 U/L, and AST 68 U/L ( Figures 1A, B ). Serological testing revealed anti-HEV IgM and IgG to be persistent ( Figure 1B ). Samples did not detect HEV RNA in stool and serum specimens at day +17 and +36 and HEV Ag was undetectable in urine and stool specimens on Nov 30th 2019 (day +227) ( Figure 1B ). The case was found with a normal ALT and AST at 12 U/L and 20 U/L on Jul 29th 2020 (day +103) ( Figure 1A ).
case_images: Phylogenetic tree analysis of HEV full-genome sequence in the case. The phylogenetic analysis was based on HEV full-genome. Viral genotype, GenBank accession number, virus host, country of origin, and year of detection are indicated for the reference sequences. The sequence obtained from the case is highlighted with a red triangle. The bootstrap values > 70 were shown.
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case_images: The sequence analysis based on a full-length genome revealed that the patient was infected with HEV G4, subtype 4a ( Figure 2 ).
case_images: Immunohistochemical detection of HEV antigen and pathological analysis of bone marrow and liver biopsy samples. (A, B) HEV antigen (HEV Ag) detection of bone marrow (BM) biopsy (x400) and smears (x200). BM biopsy and smears (Jan 10th 2019, day -97) collected from the case were shown. (C) H&E of the liver biopsy (x100). (D, E) Masson trichrome and reticular fiber staining of liver biopsy (x40). (F) HEV Ag detection of liver biopsy (x100). Liver biopsy samples prior to and after oral ribavirin (Apr 17th 2019, day 0) were shown above (Apr 10th 2019, day -7) and below (Jul 21st 2020, day +461), respectively. The time of sample was designated on the left side of each row of pictures. HEV-specific anti-ORF3 1E6 antibodies (Millipore, Temecula, CA) were used in IHC of HEV Ag.
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case_images: Bone marrow (BM) biopsy was performed for the case in Jan 10th 2019 (day -97) and moderate positive stains of HEV Ag were found in BM cells detected by immunohistochemistry (IHC) ( Figure 3A ). HEV in BM, IHC of HEV Ag was performed in BM smears, and positive stains were detected ( Figure 3B ). HEV RNA (6.72x102 copies/mL) and HEV Ag (S/CO 11919.4) was detected in BM fluid. Apr 10th 2019 (day -7) showed a large number of focal lymphocytes aggregates, severe interface hepatitis, and lobular architectural disruption ( Figure 3C ). A biliary pattern was shown in the liver biopsy, and increased fibrosis was present in the portal area, with a medium amount of lymphocytes infiltrate ( Figure 3D ). Collapsed reticular fibers scaffold was shown in hepatic lobule ( Figure 3E ). The histopathological findings and the presence of HEV Ag in liver tissue were compatible with chronic HE ( Figure 3F ). On Jul 21st 2020 (day +461), a liver biopsy showed mild interface hepatitis, reduced portal and lobular inflammation, with few lymphocytes infiltrate and regression of cirrhosis and architectural disruption ( Figures 3C-E ). The absence of HEV Ag in liver tissue was detected by IHC ( Figure 3F ).
case_images: Overview of the case's diagnosis, management, and follow-up process and timelines of major clinical events.
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case_images: The overview of the case's diagnosis, treatment, and follow-up process and timelines of major clinical events are summarized in  Figure 4 .