Detection of Borna disease virus-reactive antibodies from patients with psychiatric disorders and from horses by electrochemiluminescence immunoassay

The prevalence of Borna disease virus (BDV)-specific antibodies among patie nts with psychiatric disorders and healthy individuals has varied in severa l reports using several different serological assay methods. A reliable and specific method for anti-BDV antibodies needs to be developed to clarify t he pathological significance of BDV infections in humans. We developed a ne w electrochemiluminescence immunoassay (ECLIA) for the antibody to BDV that uses two recombinant proteins of BDV, p40 and p24 (full length). Using thi s ECLIA, we examined 3,476 serum samples from humans with various diseases and 917 sera from blood donors in Japan for the presence of anti-BDV antibo dies. By ECLIA, 26 (3.08%) of 845 schizophrenia patients and 9 (3.59%) of 2 51 patients with mood disorders were seropositive for BDV. Among 323 patien ts with other psychiatric diseases, 114 with neurological diseases, 75 with chronic fatigue syndrome, 85 human immunodeficiency virus-infected patient s, 50 with autoimmune diseases including rheumatoid arthritis and systemic lupus erythematosis and 17 with leprosy, there was no positive case except one case each with alcohol addiction, AIDS, and dementia. Although 19 (1.36 %) of 1,393 patients with various ocular diseases, 10 (1.09%) of 917 blood donors, and 3 (4.55%) of 66 multitransfused patients were seropositive for BDV-specific antigen, high levels of seroprevalence in schizophrenia patien ts and young patients (16 to 59 years old) with mood disorders were statist ically significant. The immunoreactivity of seropositive sera could be veri fied for specificity by blocking with soluble p40 and/or p24 recombinant pr otein. Anti-p24 antibody was more frequent than p40 antibody in most cases, and in some psychotic patients antibody profiles showed only p40 antibody. Although serum positive for both p40 and p24 antibodies was not found in t his study, the p40 ECLIA count in schizophrenia patients was higher than th at of blood donors. Furthermore, we examined 90 sera from Japanese feral ho rses. Antibody profiles of control human samples are similar to that of nat urally BDV-infected feral horses. We concluded that BDV infection was assoc iated in some way with psychiatric disorders.