Lack of association of Borna disease virus and human T-cell leukemia virus type 1 infections with psychiatric disorders among Japanese patients.

Borna disease virus (BDV) infection has been suspected to be a possible etiological factor in human psychiatric disorders and recently in chronic fatigue syndrome. Evidence of the correlation of BDV infection with these disorders remained unclear. Kagoshima is known to be one of the major areas in which human T-cell leukemia virus type 1 (HTLV-1) is endemic; this is the first isolated human retrovirus that causes adult T-cell leukemia with neurological symptoms. The present study aimed to clarify whether BDV and HTLV-1 infections are associated with psychiatric disorders among Japanese patients. Subjects were 346 patients with psychiatric disorders (schizophrenia, 179; mood disorder, 123; and others, 44) and 70 healthy controls. Anti-BDV antibodies from plasma samples were screened by the indirect immunofluorescence (IF) method using BDV-infected MDCK cells. Results revealed that only three samples were found to be weakly positive for BDV in the IF assay and seronegative by Western blot (immunoblot) assay. Furthermore, BDV-p24 related RNA in peripheral blood mononuclear cells from 106 of 346 psychiatric patients and 12 or 70 healthy controls by p24-reverse transcription PCR was examined. Two mood disorder patients were positive for BDV-p24 RNA but seronegative. To detect anti-HTLV-1 antibodies the plasma samples were screened by the particle agglutination method and no significant difference in seropositivity for anti-HTLV-1 antibody was found between the patients and healthy controls. These results also suggested that there is a lack of association between BDV and HTLV-1 infections with psychiatric disorders among Japanese patients.