Infectious Agents are Associated with Psychiatric Diseases.

There are several infectious agents in the environment that can cause persistent infections in the host. They usually cause their symptoms shortly after first infection and later persist as silent viruses and bacteria within the body. However, these chronic infections may play an important role in the pathogenesis of schizophrenia and Tourette's syndrome (TS).

Altered monocyte activation markers in Tourette's syndrome: a case-control study.

Background: Infections and immunological processes are likely to be involved in the pathogenesis of Tourette's syndrome (TS). To determine possible common underlying immunological mechanisms, we focused on innate immunity and studied markers of inflammation, monocytes, and monocyte-derived cytokines.

Methods: In a cross-sectional study, we used current methods to determine the number of monocytes and levels of C-reactive protein (CRP) in 46 children, adolescents, and adult patients suffering from TS and in 43 healthy controls matched for age and sex.

Intracellular monocytic cytokine levels in schizophrenia show an alteration of IL-6.

Several studies have shown an involvement of the immune system, in particular the monocytic system, in the pathophysiology of schizophrenia. Beside others, the monocyte-derived cytokines TNF-α, IL-6 and IL-10 were found to be affected. Since cytokines are secreted by several different cell types, the cellular source is only clear if intracellular levels are measured.

Monocytic HLA DR antigens in schizophrenic patients.

A genetic association of specific human leukocyte antigens (HLA) DR genes and schizophrenia has recently been shown. These HLA play a fundamental role in the control of immune responses. Furthermore infectious agents have been proposed to be involved in the pathogenesis of schizophrenia.

The association of infectious agents and schizophrenia.

Objectives: The influence of infectious agents on the pathogenesis of psychiatric disorders has been discussed for decades. Pre- and postnatal infections are risk factors for schizophrenia. This may be explained by chronic infections or an altered immune status.

A genetic variant of HTR2C may play a role in the manifestation of Tourette syndrome.

Gilles de la Tourette syndrome (GTS) (MIM 137580) is a complex neuropsychiatric disorder probably originating from a disturbed interplay of several neurotransmitter systems in the prefrontal-limbic-basal ganglia loop. Polygenetic multifactorial inheritance has been postulated; nevertheless, no confirmed susceptible genes have been identified yet. As neuroimaging studies allude to dopaminergic and serotonergic dysfunction in GTS and serotonin as an important factor for dopamine release, genotyping of common polymorphisms in the serotonergic receptor (HTR1A: C-1019G; HTR2A: T102C, His452Tyr, A-1438G; HTR2C: C-759T, G-697C) and transporter genes (SLC6A4) was carried out in 87 patients with GTS, compared with 311 matched controls.

Association between intracellular infectious agents and Tourette's syndrome.

The underlying pathophysiological mechanisms in Tourette's syndrome (TS) are still unclear. Increasing evidence supports the involvement of infections, possibly on the basis of an altered immune status. Not only streptococci but also other infectious agents may be involved.