A new study has reported that a large number of children with autism may have an elevated level of interleukin-17A. This isn't a new result but it is interesting because this time there appears to be an association between the level of IL-17A and the severity of autism - the more severe the case, the higher the level of IL-17A.
If you are interested in the subject I suggest you read the (open access) paper. It has some good background material about other immune system abnormalities that have been found in autism.
The one thing that I would like to point out is that this elevated level of IL-17A was seen in almost half of even a moderate sized group children with autism - 22 out of 45. Compare that size and number to what passes for significance on the genetics side of autism research where finding 3 or four children with similar mutations out of a group of thousands is considered significant.
The abstract is below.
Elevated serum levels of interleukin-17A in children with autism.
Al-Ayadhi LY, Mostafa GA.
The T-helper (Th)1/Th2 dichotomy dominated the field of immune regulation until interleukin (IL)-17-expressing T cells (Th17) were proposed to be a third lineage of helper T cells, the key players in the pathogenesis of autoimmune disorders. Autoimmunity to brain tissue may play a pathogenic role in autism. IL-17A is a pro-inflammatory cytokine that has been shown to play an important role in various autoimmune neuroinflammatory diseases. The aim of this study was to measure serum levels of IL-17A in relation to the degree of the severity of autism.
Serum IL-17A levels were measured by ELISA in 45 children with autism and 40 healthy matched healthy controls.
Children with autism had significantly higher serum IL-17A levels than healthy controls (P <0.001), with increased serum levels of IL-17A found in 48.9% of the autism group. Patients with severe autism had significantly higher serum IL-17A levels than those with mild to moderate autism (P = 0.01), and raised serum IL-17A levels were significantly more common in children with severe autism (67.9%) than in those with mild to moderate autism (17.6%), P = 0.001.
Serum IL-17A levels were raised in the group with autism, and the levels correlated significantly with the severity of autism. This is the first study to measure levels of IL-17A in relation to the severity of autism, to our knowledge. Further research, with a larger subject population, is warranted to determine whether the increase of serum IL-17A levels plasma has a pathogenic role in autism, and whether anti- IL-17A therapy could be useful.
Al-Ayadhi LY, Mostafa GA. Elevated serum levels of interleukin-17A in children with autism. J Neuroinflammation. 2012 Jul 2;9(1):158. [Epub ahead of print] PubMed PMID: 22748016.