Circovirus Hepatitis Infection in Heart-Lung Transplant Patient, France

Abstract

In March 2022, a 61-year-old woman in France who had received a heart-lung transplant sought treatment with chronic hepatitis mainly characterized by increased liver enzymes. After ruling out common etiologies, we used metagenomic next-generation sequencing to analyze a liver biopsy sample and identified an unknown species of circovirus, tentatively named human circovirus 1 (HCirV-1). We found no other viral or bacterial sequences. HCirV-1 shared 70% amino acid identity with the closest known viral sequences. The viral genome was undetectable in blood samples from 2017-2019, then became detectable at low levels in September 2020 and peaked at very high titers (10¹⁰ genome copies/mL) in January 2022. In March 2022, we found >10⁸ genome copies/g or mL in the liver and blood, concomitant with hepatic cytolysis. We detected HCirV-1 transcripts in 2% of hepatocytes, demonstrating viral replication and supporting the role of HCirV-1 in liver damage.

Keywords: France; circoviruses; hepatitis; mNGS; metagenomic next-generation sequencing; solid organ transplants; viruses; zoonoses.

Figure 1

Clinical and laboratory data over time for a heart-lung transplant patient in France who had cytolytic hepatitis caused by HCirV-1 develop. A–C) Monitoring of patient over time: A) viral loads; B) liver cytolysis markers; C) blood cell counts. D) Patient’s treatment history; red indicates timing of liver biopsy (March 21, 2022). Average values are depicted for HCirV-1 and TTV viral loads in plasma and blood on June 8 and August 3, 2022. *Dose 5mg/day; †solumedrol dose 500 mg/day. ALT, alanine transaminase; AST, aspartate aminotransferase; CMV, cytomegalovirus; EBV, Epstein-Barr virus; GGT, gamma-glutamyl transferase; HCirV-1, human circovirus type 1; IV, intravenous; TTV, Torque teno virus.

Figure 2

Lobular hepatitis in a heart-lung transplant patient in France. Apoptotic bodies, hepatocyte swelling and ballooning were present surrounded by a slight inflammatory infiltrate made of lymphocytes and histiocytes. Hematoxylin and eosin stain; original magnification ×40.

Figure 3

Phylogenetic analysis of capsid protein sequences of human circovirus type 1 (HCirV-1) from a heart-lung transplant patient in France (red) and representative circovirus strains. Sequences were aligned with Multiple Alignment using Fast Fourier Transform (https://www.ebi.ac.uk/Tools/msa/mafft) under the L-INS-I parameter, and maximum-likelihood phylogenetic reconstruction was performed with PhyML implemented through the NGPhylogeny portal (https://ngphylogeny.fr). GenBank accession numbers for reference sequences are indicated, along with graphic representations of the animal of origin. Scale bar indicates the number of amino acid substitutions per site.

Figure 4

In situ hybridization in liver section from a heart-lung transplant patient in France. Chromogenic in situ hybridization detected human circovirus type 1 mRNA (red staining) in hepatocytes nuclei and cytoplasm. Nuclei were counterstained with Harris hematoxylin and eosin stain; original magnification ×40.