• affective disorders;
  • antibodies;
  • Borna disease virus;
  • indirect immunofluorescence;
  • schizophrenia

Aim:  Data suggesting a pathogenetic role for Borna disease virus (BDV) in neuropsychiatric diseases are still inconclusive and it is unknown whether humans become persistently infected or clear the virus infection. The aim of the present study was therefore to investigate long-term BDV-specific antibody responses in psychiatric patients in order to gain new insights into human BDV infection and its pathogenicity.

Methods:  BDV-specific antibody titers and associations with clinical conditions were studied retrospectively in 94 seropositive patients with schizophrenia (n = 46), affective disorders (n = 19) and other psychiatric disorders (n = 29) who had been repeatedly tested for the presence of BDV-specific antibodies on indirect immunofluorescence assay between 1985 and 2006. Long-term titer dynamics were studied in 46 patients followed up for a period of >36 months.

Results:  A total of 25 of these 46 patients (54.3%) had persistent seropositivity, whereas seroreversion from positive to negative was observed in 21 (45.7%). Patients in the early course of schizophrenia had lower antibody titers compared to patients in the advanced course (P = 0.017), while a higher proportion of patients in the early course had titer increases (P < 0.05). There were no significant differences in antibody titers between patient subgroups with clinically stable and acute psychiatric disorders.

Conclusion:  Persistent seropositivity in a subgroup of psychiatric patients in the long-term analysis suggests chronic BDV infection in humans.