Autism and Immune Dysfunction

Overview and Implications

40 years ago, scientists were first able to recognize that there is a complex relationship between Autism Spectrum Disorder (ASD) and altered immune responses. Prior general research showed that ASD can impact a great number of processes related to neurology, such as cognition and theory of mind. However, more recently, evidence for this sophisticated link between behaviors associated with ASD and immune dysfunction has arisen; changes in the immune system (including, but not limited to, high pro-inflammatory cytokine levels in the blood and cerebrospinal fluid) have shown to be present in individuals with ASD.

More importantly, bodily responses related to the immune system, such as that of the cytokine levels, seem to be associated with hallmark aspects of ASD, such as impairment in communication. Abnormal cytokine levels are found in many neuropsychiatric conditions including lupus. Therefore, scientists suggest that the immune system, and its processes, is likely quite important to the overall pathophysiology of ASD. Based on current research, the relationship between ASD and the immune system seems evidently powered by the different interactions of unique cell types. A conclusion that has been derived in some novel research is that immune factors, such as an increase in the production of cytokine (like TNF-α and IL-1β) can affect the Central Nervous System (CNS), made up of the brain and spinal cord, and can then cause for actions such as neuron death or even a decrease in the production of new neurons in the brain.

Furthermore, along with an increase in the production of cytokine, an increase in different complement proteins can cause for the presence of many opsonizing synapses; these then become subject for being removed by a type of specialized microglia called phagocytic microglia (cells that act as the immune system in the CNS). In regards to microglia, the activation of it is often associated with a cellular process called synaptic pruning, which is when the brain undergoes several processes to remove synapses it deems to be extra or not used. Much of this has been known for a while; however, scientists are now realizing that all of these neurological reactions and processes, as a whole, can cause many adverse effects on one’s cognition and behavior in ways that are often found in those who suffer from ASD.

Future Directions

The aforementioned pieces of information are findings that resulted from several different research studies and are not tabulated in just one study; rather, they come from a literature review per se. However, findings on the relationship between ASD and the immune system (through neurological processes) can allow for an increase in curiosity and subsequent studies targeted on learning about the link between immune dysfunction and other behavior-related conditions that are similar to ASD, such as Rett Syndrome. Additionally, research in neuro-immune reactions specifically can provide a great amount of insight in regards to how different immune responses can be artificially altered to affect the behaviors and possibly even immunity of those battling ASD.

Article Reviewed

Onore, Charity et al. “The role of immune dysfunction in the pathophysiology of autism.” Brain, behavior, and immunity vol. 26,3 (2012): 383-92. doi:10.1016/j.bbi.2011.08.007

References

Santos E., Noggle C.A. (2011) Synaptic Pruning. In: Goldstein S., Naglieri J.A. (eds) Encyclopedia of Child Behavior and Development. Springer, Boston, MA