Friday, March 18, 2016
Unique Gene Expressions in ME/CFS and Lyme Disease
In the ME/CFS gene expression study, they used 88 subjects - 42 with a diagnosis of ME/CFS and 38 healthy controls - to conduct a comprehensive study of the entire known genome to look for differences and distinct markers in the ME/CFS patients. They found 442 SNPs (pieces of known genetic material) associated generally with the ME/CFS patients, 12 of which were significantly in the coding region of the genome, with 2 of these being especially significant. They also identified 5 SNPs specifically related to T-cell receptors (a part of the immune system known to be dysfunctional in ME/CFS).
This is a very significant study, as it is the first one applying the advanced genetic analysis currently available to ME/CFS, but it is not the first genetic study of ME/CFS. Two earlier researchers began this process about 10 years ago. Dr. Kerr of Scotland headed up a genetic ME/CFS study whose preliminary results were published in 2008 of 25 patients and 50 healthy controls. Then, those genes that were different in the ME/CFS patients in the first round were analyzed in another 55 patients and 75 healthy controls (my blood was a part of this study! I worked through Dr. Enlander in NYC to donate my blood and participate in the surveys). Their results showed 88 genes showing different expression in the ME/CFS patients, many of these related to immune function or infections, which suggested 7 sub-types of ME/CFS.
Dr. Gow, also of Scotland, published a follow-up paper in 2009, building on Kerr's earlier work. This was a smaller study - only 8 patients and 7 controls - but went into greater depth. It found 366 genes with different expressions in ME/CFS patients versus healthy controls. Unfortunately, all of that ground-breaking work in Scotland came to a halt when funding dried up...so seeing this new study is a reason for celebration and hope!
However, even before the technology existed to do this kind of genome analysis, researchers knew that ME/CFS had genetic roots, just from observations of how often ME/CFS occurred in family members. Back in 2006, the New Jersey CFS Association did a population study of ME/CFS incidence in families with some startling results, showing both genetic and infectious roots for ME/CFS. In their study of 219 patients and their families, blood-related family members not in the same household as an ME/CFS patient had a 3 times greater chance of getting ME/CFS, those in the same household but not blood-related (like spouses) had an 8 times greater chance of getting ME/CFS, and those both blood-related and in the same household, like children, had a 13 time greater chance of getting ME/CFS than the general population! Wow. Is it any surprise that both of my sons got ME/CFS a couple of years after I did?
Back to the present, another new study was just published analyzing the genes of Lyme disease patients (29 patients and 13 controls) at the time of diagnosis and six months later, after treatment. It showed a different gene expression in patients, both at the time of diagnosis and six months post-treatment, than the healthy controls. Interestingly, it did not show genetic differences between those patients who were fully recovered and those who had persistent symptoms. Those gene expressions specific to the Lyme patients showed some similarities to those of patients with three different chronic immune disorders, suggesting that Lyme causes similar immune dysfunction that stays on, even after the disease is resolved.
Why should we care about these complicated genetic studies that we can barely understand? Because this information on gene expression could form the basis for future biomarkers (providing a test for ME/CFS and more reliable testing for Lyme), modes of treatment, and perhaps even cures through genetic manipulation. The better the medical field understands what is behind our diseases, the better treatment that will be available to patients. These genetic studies help to form the basis for future research and improvements in patient care and are definitely a reason to celebrate!