Thomas A. Platts-Mills, PhD, FRS
Professor of Medicine and Microbiology
Chief, Division of Asthma, Allergy & Immunology
University of Virginia School of Medicine
Sensitization to Alpha-gal as a Consequence of Lone Star Tick Bites
Thomas Platts-Mills is Professor of Medicine and Microbiology at the UVA School of Medicine. The son of a British member of parliament, he was educated at Balliol College, Oxford, and received his medical training at St. Thomas’ Hospital Medical School in London. He earned a PhD from London University and completed a fellowship at Johns Hopkins University under the tutelage of Kimishige Ishizaka. He has been a member of Britain’s Royal College of Physicians since 1971.
Dr. Platts-Mills joined UVA’s faculty in 1982, and has served as chief of the Allergy division since 1993. He has also served a term as president of the American Academy of Allergy, Asthma, and Immunology (AAAAI).
In 2010, Dr. Platts-Mills was elected a Fellow of the Royal Society for his research into the causes of asthma and allergic disease. The Royal Society is the United Kingdom’s national academy of science and the oldest scientific academy in the world. Only a small number of fellows are physicians, and Platts-Mills is the first allergist ever elected. His election was based on more than 30 years of research on the role that dust mite, cat and cockroach allergens play in the development of allergic disease and asthma.
Conference Lecture Summary
In large areas of the United States, the lone star tick Amblyomma americanum has increased dramatically because of the increase in the deer population which is the primary breeding host for this tick. The lone stars are known vectors for several diseases, but recently it has been shown that bites from larval or adult ticks can induce sensitization to an important oligosaccharide of the non-primate mammals. This sensitization can be
identified by an in vitro assay for IgE to galactose alpha-1, 3-galactose (alpha-gal.) The presence of this antibody was first recognized because of severe reactions to the monoclonal antibody cetuximab. However, equally significant, it is now clear that sensitized subjects can experience delayed anaphylaxis 2-5 hours after eating red meat. This form of delayed reactivity was initially difficult to diagnose. It is now clear that the combination of reactions starting in adult life, the characteristic delay after eating red meat and a positive blood test, is sufficient to diagnose the condition. Furthermore, in these cases a diet avoiding red meat is effective in 90% of cases in preventing further severe attacks. Strikingly, bites of these ticks that are related to sensitization produce severe and prolonged itching at the site, which is very different from the experience with bites from Ixodes scapularis. Although the lone star tick routinely carries Rickettsia amblyomii, there is very little evidence that the sensitization to the oligosaccharide is caused by symbionts.