Short Communication Failure to demonstrate Borna disease virus genome in peripheral blood mononuclear cells from psychiatric patients in Korea Yong Ku Kim 1 , Sang Hyun Kim 2,3 , So-Hyun Choi 4 , Young-Hoon Ko 1 , Leen Kim 1 , Min Soo Lee 1 , Kwang Yoon Suh 1 , Dong-Il Kwak 1 , Ki-Joon Song 2,3 , Yong Ju Lee 2,3 , Richard Yanagihara 5 and Jin-Won Song 2,3 1 Department of Psychiatry and 2 Department of Microbiology, College of Medicine; 3 Institute for Viral Diseases, Korea University, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-705; 4 YongIn Mental Hospital, 4 Sanghari, Kusungmyun, YongIn-Kun, Kyungki-Do, 449 ± 910, Korea; 5 Retrovirology Research Laboratory, Paci®c Biomedical Research Center, University of Hawaii at Manoa, Honolulu, Hawaii 96816, USA RNA, extracted from peripheral blood mononuclear cells (PBMC) obtained from 81 Korean psychiatric patients (39 with schizophrenia, 33 with bipolar affective disorders and nine with major depression), was analyzed for a 391- nucleotide, highly conserved region of the p24 protein-encoding ORF II of Borna disease virus (BDV), using nested reverse transcription-polymerase chain reaction (RT ± PCR). BDV genomic RNA was not detected in PBMC from any of the 81 Korean psychiatric patients. These data do not support an etiologic association between BDV infection and neuropsychiatric disorders in humans. Keywords: Borna disease virus; RT ± PCR; PBMC; psychiatric disorders Aberrations in interleukin 2 (IL-2) regulation, including elevated soluble IL-2 receptor in sera of Caucasian and Korean schizophrenic patients (Rapaport et al, 1994) and decreased IL-2 produc- tion after mitogen stimulation (Kim et al, 1998), have been regarded as indirect evidence that schizophrenia may have an infectious or autoim- mune basis. That viruses (or autoimmunity stimu- lated by viruses) may be involved in the pathogenesis of major psychiatric disorders, such as schizophrenia, bipolar disorder and major depression (Kirch and Alexander, 1992), is a concept which is gaining increasing support. Recent interest in the potential role of viruses in the pathogenesis of major psychiatric disorders has focused on speci®c candidate viruses. Originally isolated from horses with behavioral abnormalities and since detected in sheep, cats, ostriches and cattle, Borna disease virus (BDV), a member of the Bornaviridae family, possessing a non-segmented, negative-sense, single-stranded RNA genome with ®ve open reading frames (ORF), is one such candidate. Although BDV has not been de®nitively shown to cause any human disease, an etiologic association between BDV infection and major psychiatric disorders is tantalizing. Striking clinical similarities have been found between particular animal models of BDV infection and patients with affective disorders or schizophrenia. For example, behavior- al disturbances in experimentally infected rats are reminiscent of affective disorders, such as bipolar and monopolar depression, in humans (Lipkin et al, 1995). In particular, the observations that BDV- infected rats have high levels of viral nucleic acid in prefrontal cortex, as well as abnormal mesocortical dopamine activity and abnormal nucleus accum- bens dopamine system, suggest the potential for BDV being pathogenetically linked to psychiatric conditions having a dopaminergic substrate, such as schizophrenia and affective disorders (Solbrig et al, 1996a, b). As determined by the indirect immuno¯uores- cence test (Amsterdam et al, 1985; Rott and Becht, 1995; Bode et al, 1993) and Western blot analysis Correspondence: J-W Song, Department of Microbiology, College of Medicine, Korea University, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-705, Korea This work was presented in part at the 151st annual meeting of American Psychiatric Association in Toronto, Canada, May 30± June 4, 1998 Received 10 July 1998; revised 25 August 1998; accepted 26 August 1998 Journal of NeuroVirology (1999) 5, 196 ± 199 ã http://www.jneurovirology.com 1999 Journal of NeuroVirology, Inc.