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As many as 50-90% of the U.S. general population experiences a traumatic event that has the potential to result in Post-Traumatic Stress Disorder (PTSD) 1-2. The discovery of a clear biomarker for PTSD is urgently needed, as this disorder affects 7-8% of the general population and as many as 20% of returning combat veterans 3.  The economic impact of PTSD related to military personnel deployed to Iraq and Afghanistan is estimated at $2-3 billion per year.  According to the Sidran Institute PTSD statistics, people with PTSD have among the highest rates of healthcare service use. Individuals with PTSD have symptoms such as chronic hyperarousal, heightened startle reactions, depression, numbed emotions, anxiety, and social withdrawal 4. Furthermore, they are also considerably more likely to have health problems related to inflammation and autoimmune disease 5-6. Given that the chronic stress typical of this condition affects the immune system, individual genetic biomarkers that indicate risk and resilience to PTSD may exist 7,8. With this view, past studies have examined PTSD in relation to altered gene expression 9-11, the stress-response hormone system12, gene networks underlying the innate immune system 13, and the adaptive immune system’s T cell number and ratio 14. Taken together, these studies suggest that the comorbid health problems observed in individuals with PTSD are moderated by dysregulated immune function. 


iXpressGenes has conducted preliminary studies of T cell receptor transcriptome sequences that offer an unprecedented analysis of linking an immune repertoire to sensitivity or resilience to PTSD.  The T-cell receptor is a protein molecule found on the surface of T cell lymphocytes, a type of white blood cell that forms part of a body’s defense system against pathogens.  Any individual will have hundreds of thousands of different shape T-cell receptors based on environmental exposure.  The transcriptome sequences refer to the collection of all the gene readouts corresponding to different T-cell receptor shapes.  Thus the unique library collection of an individual’s transcriptome sequences is referred to as the immune repertoire.   


Our preliminary data suggest there may be distinguishing immune repertoire associated with those who have PTSD.  Further study of our preliminary finding, that people with PTSD have unique immune repertoire sequences, is critical to the understanding of why certain immune problems are more common in people with PTSD, how these differences can serve as biomarkers, and what may serve as targeted therapy for this condition. While our preliminary study findings are encouraging and provide strong support for the proposed study, they cannot stand alone due to the size of the participant pool. We seek funding to expand our preliminary findings by collecting immune repertoire data for a thousand or more soldiers who have been trauma exposed with and without PTSD symptoms.  Our goal is to establish a secure and intelligent database for analyses and data mining in the search for predictive markers.  Once the markers have been identified and verified, intervention strategies can be recommended. 


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Other references

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