title: Acute infection by hepatitis E virus with a slight immunoglobulin M antibody response.
abstract: The anti-hepatitis E virus (HEV) immunoglobulin (Ig) M antibody response is generally regarded as a useful marker for diagnosing primary infection. However, in some cases, this antibody is not detected during the acute phase of infection. An 81-year-old man with stable membranous nephropathy who presented with asymptomatic acute liver dysfunction came to our hospital. HEV RNA of genotype 3 was detected in his serum, and he was diagnosed with acute hepatitis E. According to an enzyme-linked immunosorbent assay, high-level positivity for anti-HEV IgG and IgA antibodies was observed, but the assay was negative for IgM antibody throughout the clinical course of infection. The patient was not immunosuppressed. We further investigated the presence of IgM antibody using two other polyclonal antibodies against human IgM as secondary antibodies and another recombinant ORF2 protein of genotype 3 as an immobilized antigen. IgM was weakly detected in the serum during the acute phase only by the test with the antigen of genotype 3. Multi-genotype antigens can detect a slight IgM antibody response; however, anti-HEV IgA is more useful in diagnosing primary HEV infection, particularly in cases with a low IgM antibody response.
authors.affiliation: Division of Gastroenterological and Hepatobiliary Surgery, and Organ Transplantation, Department of Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Inagaki
authors.forename: Yukio
authors.initials: Y
authors.lastname: Oshiro
authors.forename: Mamiko
authors.initials: M
authors.lastname: Imanishi
authors.forename: Kazunori
authors.initials: K
authors.lastname: Ishige
authors.forename: Masaharu
authors.initials: M
authors.lastname: Takahashi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Okamoto
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Ohkohchi
mesh_terms: D000369:Aged, 80 and over; D004797:Enzyme-Linked Immunosorbent Assay; D005838:Genotype; D006508:Hepatitis Antibodies / Q000097:blood*; D016751:Hepatitis E / Q000175:diagnosis* / Q000821:virology*; D016752:Hepatitis E virus / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood*; D008297:Male; D012367:RNA, Viral / Q000097:blood
chemical_list: D006508:Hepatitis Antibodies; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D012367:RNA, Viral