Isotype analysis of human anti-Borna disease virus antibodies in Japanese psychiatric and general population

Abstract

Background Borna disease virus (BDV) infection of humans has not been widely accepted due to the low titer of the antibody and lack of reliable diagnostic tools. Objectives To examine exposure to BDV or a related virus in Japanese psychiatric and general population by detecting the specific IgG, IgM, and IgA. Study design Sera from 304 psychiatric and 378 control subjects were examined for IgG, IgM, and IgA against BDV nucleoprotein (N) and phosphoprotein (P) using highly specific and sensitive radioligand assay. The avidity was also examined. Results The specific IgG, IgM, and IgA against both BDV-N and -P were detected and the seropositivity was not significantly different between patients and controls. The avidity of the specific IgG was low to moderate, and the specific IgM did not disappear for several years. Conclusions Our results suggested common exposure to BDV or a related virus in the general Japanese population. Low avidity IgG and persistent IgM suggested delayed immune response against BDV or a related virus. The specific IgA indicated mucosal involvement.