Lack of circulating toxoplasma gondii DNA in seropositive patients with bipolar or schizophrenia spectrum disorders

• Published in: Psychiatry research Vol. 273; pp. 706 - 711
• Main Authors: Galli, L., Del Grande, C., Rindi, L., Mangia, C., Mangano, V., Schiavi, E., Masci, I., Pinto, B., Kramer, L., Dell'Osso, L., Bruschi, F.
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01-03-2019
• Subjects: Adult; Bipolar disorder; Bipolar Disorder - blood; Bipolar Disorder - parasitology; Case-Control Studies; Circulating parasite DNA; Cross-Sectional Studies; DNA, Protozoan - blood; Female; Humans; Male; Middle Aged; Nested-PCR; PCR; Polymerase Chain Reaction; Rt-PCR; Schizoaffective disorder; Schizophrenia - blood; Schizophrenia - parasitology; Seroepidemiologic Studies; Seroprevalence; Toxoplasma - genetics; Toxoplasma gondii; Toxoplasmosis - blood; Toxoplasmosis - parasitology; Toxoplasmosis - psychology; Circulating parasite DNA; Rt-PCR; Toxoplasma gondii; Nested-PCR; Bipolar disorder; Schizoaffective disorder; PCR; Seroprevalence
• ISSN: 0165-1781; 1872-7123
• DOI: 10.1016/j.psychres.2019.01.104

•T. gondii was associated with increased risk of schizophrenia or bipolar disorder.•We analyzed circulating T. gondii DNA in a cohort of Italian psychiatric inpatients.•Seropositive status for IgG anti-T. gondii was found in 28,6% of patients.•PCR, nested-PCR and real-time PCR revealed no positive samples for T. gondii.•No significant association between the seropositive status and a diagnostic category.
Toxoplasmosis has been previously associated with an increased risk of having Schizophrenia or Bipolar disorder in several epidemiological studies. The aim of this observational, cross-sectional study was to examine the seroprevalence of Toxoplasma infection in a cohort of Italian psychiatric inpatients and to verify the presence of circulating Toxoplasma gondii DNA in the seropositive subjects. Sixty-three patients affected by bipolar or schizoaffective disorders according to DSM-5 criteria were enrolled. The presence of Toxoplasma infection was firstly examined using an indirect serological method (ELFA), and three different direct PCR-based methods were performed to detect circulating DNA in the seropositive patients. The seroprevalence of infection was 28.6%, with a significant association between higher age and the infection status. PCR, nested-PCR and Real-Time PCR revealed no positive samples for Toxoplasma gondii. This result is in contrast with recent data from case-control studies that detected parasite genome in patients with different neuropsychiatric diagnosis without clinical evidence of acute toxoplasmosis. Our findings are to be interpreted with caution, because of the small sample size, the heterogeneity of enrolled patients and the observational nature of the study. Further studies are needed to better define the clinical features correlated to the seropositive status in neuropsychiatric patients.