Natural Killer Cells and the Search for Biomarkers for Autism
Wednesday, January 30, 2008 (10:30:04)

Posted by lightfoot

by Kristina Chew, PhD

Researchers at the M.I.N.D. Institute at the University of California at Davis are the first to use genomic profiling of blood to note differences in autistic children, the January 25th Health News Digest reports. Their hope is that such “gene expression analyses can provide biological evidence of autism, currently diagnosed only through behavioral assessments, in some children.”

“What we found were 11 specific genes with expression levels that were significantly higher in the blood of children with autism when compared to the blood of typically developing children,” said Frank Sharp, senior author of the study and professor of neurology with the M.I.N.D. Institute. “Those 11 genes are all known to be expressed by natural-killer cells, which are cells in the immune system necessary for mounting a defense against infected cells. We were surprised by our results because we were not looking for these particular genes. And while a number of studies have shown immune system dysregulation to be an important factor in autism, ours is one of the first to implicate these particular cells.”

In conducting the study, Sharp, molecular pathologist Jeff Gregg and their M.I.N.D. Institute colleagues used blood samples from 35 children diagnosed with autism, 14 with development delay but not autism and 12 typically developing children. The samples were subjected to gene expression analysis using microarrays and compared for common patterns. In addition to finding the 11 genes with natural-killer cell connections shared by all of the children with autism, they identified a pattern of 140 genes differentially expressed in children with the early onset form of the disorder and a pattern of 20 genes differentially expressed in children with the regressive form of the disorder. The team is the first to use genomic profiling of blood to observe differences in children with autism.

Might this study point towards the development of a blood test for autism, of a biomarker for diagnosing autism? The study is published in the January issue of Genomics.

Dr. Sharp further notes that the current study also does not “identify whether or not the natural-killer cells are functioning abnormally,” which further work by M.I.N.D. Institute immunologists will consider reveal. He continues:

“If the natural-killer cells are dysfunctional, this might mean that they cannot rid a pregnant mother, fetus or newborn of an infection, which could contribute to autism.”

The image of some “natural killer” cells that ward off tumors and affect cells, and so play a role in the genes of autistic children stands out. One can imagine proponents of theories that something in the environment “triggers” autism making something of this research about something like stealth autism getting into the genes of some children and causing an “infection” in a pregnant mother or fetus.

A life less ordinary by Emily goes into much more detail about this study and about autoimmunity and autism (and I’ll note here that, between Jim’s family and mine, there is a history of autoimmune disorders: multiple sclerosis and allergies on his side, and asthma, which I used to have a severe case of).

from: AutismVox