Cellular-mediated and humoral immunity in children with autism

Abstract

Background: Autism spectrum disorder (ASD) is a spectrum of behavioral anomalies characterized by impaired social interaction and communication, often accompanied by repetitive and stereotyped behavior. The condition manifests within the first 3 years of life and persists into adulthood. There are numerous hypotheses regarding the etiology and pathology of ASD, including a suggested role for immune dysfunction. While immune system abnormalities have been reported in children with autistic disorder, there is little consensus regarding the nature of these differences which include both enhanced autoimmunity and reduced immune function. It has long been known that extensive interactions occur between the immune system and neuronal system/brain, and that normal neurodevelopment is contingent upon an appropriate interaction with the immune system. Objectives: the aim of the present study was to evaluate the cell mediated and humoral immunity of children with autism through evaluation of the serum antibody levels of immunoglobulin (IgG, IgM, IgA), also we evaluated the T helper and T suppressor cells (CD4 and CD8 T cell subpopulations) and CD4/CD8 ratio in children with autism and compared with the healthy control children. Methods: This study was carried out in the Psychiatry Unit, Department of Pediatrics, Tanta University Hospital. Thirty children with autism (24 males, 6 females) newly diagnosed were included in the study, their age range was (3-9 years) with the mean age of 51.8 years. Childhood Autism Rating Scale (CARS) was used for the diagnosis of autism. Diagnosis of autism was based also, on the criteria for the diagnosis of autism that are set out in the Diagnostic and Statistical Manual of Mental Disorders DSM-IVTR (Fourth Edition, Text Revision). The intial Childhood Autism Rating Scale (CARS) score for these children was ≥30, as children with a CARS score ≥30 were considered to have autism. Intial CARS score range for children with autism was (31-60). The control group consisted of thirty healthy children (10 females, 20 males). Their age range was (2-10 years) and the mean age was 5.3 ± 2.4 years. Results: Children with autism had significantly lower serum levels of IgG, IgA and IgM compared to the control children p < 0.001. Also children with autism had significantly lower numbers of CD4 cells with increased CD8+ T cell subpopulations and decreased CD4+/CD8+ ratio. Conclusion: Children with autism have significantly reduced levels of serum IgG, IgA and IgM compared to the control children, suggesting an underlying defect in the immune function, also the cell-mediated immunity is impaired as evidenced by low numbers of CD4+ cells and increased CD8+ T cell subpopulations and decreased CD4+/CD8+ ratio.

Keywords: autism spectrum disorder (ASD), neurodevelopment, immunity

Egypt J Pediatr Allergy Immunol 2012;10(1):25-32.