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Archive - Jan 8, 2014

Scientists Identify Possible Key to Drug Resistance in Crohn’s Disease

Two-thirds to three-quarters of the estimated 700,000 Americans living with Crohn’s disease, an autoimmune condition that can disrupt the entire gastrointestinal tract, will require surgery at some point during their lives. Patients and physicians often turn to this surgical intervention after a patient develops resistance to current treatments, such as steroids. Now scientists from the Florida campus of The Scripps Research Institute (TSRI) have identified a normally small subset of immune cells that may play a major role in the development of Crohn’s disease generally and in disease-associated steroid resistance specifically. The study, published online January 6, 2014 in the Journal of Experimental Medicine, focused on Th17 cells, part of a family of white blood cells that have been implicated in numerous autoimmune diseases, including Crohn’s disease. In the new study, the researchers found that a subset of TH17 cells in humans expresses the multidrug transporter MDR1 and that these cells are linked to inflammation in Crohn’s patients. MDR1—a protein famous for promoting drug-resistance in tumors—may also act as a survival and steroid resistance factor in T cells, particularly in harsh environments such as the inflamed gut mucosa of Crohn’s disease patients. “Our study is the first to identify and characterize this uniquely pro-inflammatory T-cell subset,” said biologist Dr. Mark Sundrud, a TSRI assistant professor who led the study. “We were able to sort these cells directly out of damaged tissue resected from Crohn’s patients and found that these pro-inflammatory cells are over-expressing genes that contribute to disease.” Within healthy individuals, only approximately 5 to 10 percent of CD4+ T cells are MDR1-expressing TH17 cells.

Zone in with Zon—Nucleic Acid Chemist Tackles Direct-to-Consumer Genetic Testing

Dr. Gerald Zon’s latest blog post, dated January 6, 2014, and published by TriLink BioTechnologies of San Diego, focuses on the controversial subject of direct-to-consumer (DTC) genetic testing. Dr. Zon shares some personal history, beginning in 2009, of dealing with Navigenics, the first provider of direct-to-consumer (DTC) SNP-based genetic testing and medical counseling. He then discusses 23andMe, a company that has been a lightning rod of controversy in the area of DTC genetic testing and received a “bombshell” November 2013 letter from the FDA calling on the company to stop marketing its testing kit until it received proper authorization. D. Zon also noted the FDA’s November issuance of marketing authorization for the first high-throughput (next-generation) genomic sequencer (Illumina’s MiSeqDx), which will allow development and use of innumerable new genome-based tests, as described in a December 19, 2013 New England Journal of Medicine Perspective piece by Francis Collins, M.D., Ph.D., and Margaret Hamburg, M.D. Dr. Zon further mentioned the “upbeat “Consumer Genetics Conference,” held in September 2013 to emphasize the swirl of developments and debate in this key arena. According to Dr. Zon, Navigenics began selling its genetic testing services in 2008 based on SNP analysis to assess risk for a variety of common health conditions. In July 2008, California health regulators sent cease-and-desist letters to Navigenics and 12 other genetic testing firms, including 23andMe. The state regulators asked the companies to prove a physician was involved in the ordering of each test and that state clinical laboratory licensing requirements were being fulfilled. Two months later, Navigenics and 23andMe received state licenses allowing the companies to continue to do business in California. Dr.