Immune involvement in the pathogenesis of schizophrenia: a meta-analysis on postmortem brain studies.

Although the precise pathogenesis of schizophrenia is unknown, genetic, biomarker and imaging studies suggest involvement of the immune system. In this study, we performed a systematic review and meta-analysis of studies investigating factors related to the immune system in postmortem brains of schizophrenia patients and healthy controls. Forty-one studies were included, reporting on 783 patients and 762 controls. We divided these studies into those investigating histological alterations of cellular composition and those assessing molecular parameters; meta-analyses were performed on both categories. Our pooled estimate on cellular level showed a significant increase in the density of microglia (P=0.0028) in the brains of schizophrenia patients compared with controls, albeit with substantial heterogeneity between studies. Meta-regression on brain regions demonstrated this increase was most consistently observed in the temporal cortex. Densities of macroglia (astrocytes and oligodendrocytes) did not differ significantly between schizophrenia patients and healthy controls. The results of postmortem histology are paralleled on the molecular level, where we observed an overall increase in expression of proinflammatory genes on transcript and protein level (P=0.0052) in patients, while anti-inflammatory gene expression levels were not different between schizophrenia and controls. The results of this meta-analysis strengthen the hypothesis that components of the immune system are involved in the pathogenesis of schizophrenia.

Search for viral nucleic acid sequences in brain tissues of patients with schizophrenia using nested polymerase chain reaction.

BACKGROUND: We used polymerase chain reaction to search for nucleic acid sequences of several viruses in DNA and RNA extracted from brain tissues of schizophrenic and control subjects. METHODS: We extracted DNA and RNA templates from frozen brain specimens of 31 patients with schizophrenia and 23 nonschizophrenic control patients with other diseases. The extracts were subjected to polymerase chain reaction with oligonucleotide primers for 12 different viruses (cytomegalovirus, Epstein-Barr virus, herpes simplex virus type 1, human herpesvirus type 6, varicellazoster virus, measles virus, mumps virus, rubella virus, the picornavirus group, influenza A virus, human T-cell lymphotropic virus type I, and St Louis encephalitis virus), several of which have been suspected of involvement in schizophrenia. Nested primers were used to increase the sensitivity of the method. RESULTS: No amplified nucleic acid sequences encoded by the selected viral genomes were detected in extracts of any brain specimens from either schizophrenic or control patients. CONCLUSIONS: These data agree with previous studies that failed to find sequences of a number of viruses in the cerebrospinal fluid or selected areas of the brains of schizophrenic patients. Additional efforts should be undertaken to identify other known and unknown pathogens in schizophrenia, sampling more areas of the brain from subjects with a variety of clinical types of schizophrenia.

Visual hallucinations in the elderly associated with the use of levodopa.

Visual hallucinations are a well recognized unwanted effect of treatment with levodopa. Although many individual cases have been reported, there has only been one review previously published about this finding, and this did not discriminate age groups. We present five cases and briefly review the literature. It is important to enquire specifically about visual hallucinations in patients on levodopa therapy at follow up, as this otherwise potentially reversible side effect may be overlooked.