Tehran University Medical Journal

Background: Schizophrenia (SC) and bipolar disorder (BD) are two chronic psychiatric illnesses with worldwide distribution. People could be involved at any age, particularly in early adolescence. Main symptoms of SC are non- affective symptoms such as auditory hallucination and illogical thinking. In contrast, BD represents affective symptoms such as depression and mania. Although the main cause of these mood disorders has been remained elusive, there are some potential contributing factors that could be considered in the pathogenesis of mentioned illnesses including, genetic and environmental factors. Cytomegalovirus (CMV) is one of the probable contributing factors in SC and BD. CMV is a prototype of herpesviridae family which may infect different cell types such as endothelial and differentiated hematopoietic cells. CMV infections in immunocompromised patients as well as congenitally infected children represent CNS complication such as microcephaly and hearing loss. This virus has capability to impair the limbic structures in brain.

Methods: This descriptive study was designed to evaluate the role of CMV in these illnesses. We investigated the level of serum IgG antibody and the presence of CMV DNA in serum and peripheral blood mononuclear cells (PBMCs) samples of 46 SC and BD patients admitted to Iran Psychiatry Hospital Tehran, Iran from 2014 to 2015 as well as 46 healthy control groups at Tehran University of Medical Sciences.  First, the level of CMV IgG antibody was evaluated in serum samples, by enzyme-linked immunosorbent assay (ELISA). Then, DNA extraction conducted by using the high pure viral nucleic acid kit (Roche, Germany). Serologically positive sera along with PBMC samples were tested by Real-time PCR, to investigate the presence of CMV DNA.

Results: Results indicated higher levels of CMV IgG antibody in psychiatric patients, compared with a healthy control group. Afterward, we did not observe the presence of CMV DNA in either case or control groups.

Conclusion: According to the CNS impairment mediated by CMV infection, this virus has been supposed to play an important role in pathogenesis of mental disorders such as SC and BD. We suggest further investigation to be conducted, particularly on other samples such as cerebrospinal fluid.