According to a study in the April 2012 International Journal of Developmental Neuroscience, the plasma of children with autism disorder (AD) had significantly lower levels of various cytokines, compared with that of unrelated healthy siblings from other families, who had family members with autism spectrum disorders (ASD). Cytokines are small proteins released by cells of the immune system that act as intercellular mediators and communicators between cells.
Researchers of the University of Kansas Medical Center analyzed 29 cytokine levels and discovered abnormal cytokine levels in five cells related to the T-helper cell immune system. They found three abnormal levels in the production of blood cells (hematopoiesis), which could potentially affect the production of antibodies that are needed in order to have a normally functioning immune system.
Merlin G. Butler, a professor of psychiatry at the KU Medical Center, said that the immune system and genetic factors are both affected in the biological basis for autism.
"Our study further supports a disturbed immune system in children with classic autism that may be related to genetic factors as cytokine proteins are coded by genes distributed among the human chromosomes."
He adds that studies in families with autism have discovered that in specific genes, involved with brain development and function, scientists found a significant contribution of genetics that included deletions and duplications of chromosomes and mutations or variants.
"The importance of identifying early immunological disturbances that may contribute to autism has implications for identifying risk factors, diagnosis and possibly intervention as cytokines may play a role in the function of the developing brain."
In one of the largest studies of its type to-date, the researchers examined the plasma of 99 AD children, aged between 5 and 10 years, and the plasma of 40 unrelated healthy siblings without AD, under the same clinical assessments, specimen processing and laboratory conditions. The healthy siblings were matched in terms of age and gender. According to the researchers, the male-to-female ratio was closely matched to that of the ASD population, and they note that five cytokines had gender-based differences.
Given that the study is one of only a few that utilizes nanoparticle technology to analyze cytokine patterns from peripheral blood in ASD children, which only needs very small quantities of plasma for analysis and uses standardized kits for cytokine assay, Butler underlines that this approach should also enable other scientists to examine findings of disturbed cytokines in ASD.
He concludes that this research is moving towards linking the genes encoding immune-related proteins and cytokines to ASD, along with identifying the sequence of the events during critical periods of brain and neurological development, which could mean an early recognition, diagnosis and potential therapy for ASD.
Written By Petra Rattue