Twins — Double the Hope
Twins are an incredible asset for researchers, helping to determine whether genetics or the environment are involved in a particular trait or disease. The Sean N. Parker Center for Allergy and Asthma Research is looking to twins – fraternal and identical, with and without allergies or asthma — to help investigate why the incidences of food allergy and asthma are increasing across the globe. Specifically, we look to answer if the increases are caused by pollution, the modern diet, the daily chemicals we are exposed to in our modern households, or other environmental factors. It is also likely that some genes make us more susceptible to allergies and asthma than others. We are lucky to have a number of twins, both identical and fraternal, who have enrolled in clinical research studies at the Center.
Meet our fraternal twins – Josh and Sam
Josh and Sam are six-year-old fraternal twins in kindergarten. As babies, they both simultaneously reacted with hives to egg white in the frosting on their first birthday cake. Although only genetically as similar as any siblings, blood tests showed that both had almost identical high levels of IgE antibodies to egg and peanut. Their food allergy diagnosis wasn’t a big surprise to their parents who already had an older child with a food allergy to sesame. The egg allergy for both boys resolved by the time they were 3 years old. But, Sam had a series of increasingly severe reactions to peanut cross-contamination, prompting additional testing. While the twins still shared most things at this age – pacifiers, toys, food, friends, school — interestingly, their allergies were no longer the same. Along with his increasing sensitivity to cross-contamination, Sam now had higher IgE levels, and more severe symptoms of asthma than Josh. Their mother, Debbie, prompted by their allergist, inquired at this point about the food allergy studies at Stanford. During the boys’ comprehensive screening process, the family ultimately learned that both boys had also developed tree nut allergies. Josh specifically — as his allergies diverged from Sam’s — had become severely allergic to cashew and hazelnut.
Some patients and families are anxious about the screening process, which entails eating the very foods that one is allergic to either as an open food challenge or a double-blind placebo-controlled food challenge. At the Center, food challenges are done in a very controlled setting and start with very small incrementally increased amounts. “The Center makes certain that you are well supported during your clinical trials. They put you in touch with other parents who have been through the trials and the experienced staff clearly explain what to expect at every stage. This really helped reduce my anxiety during the first screening visit. My attempts to stay calm helped keep my kids calm and relaxed,” said Debbie. The Center also has a psychologist on staff to counsel parents and children who are enrolled in the trials.
Josh and Sam are currently enrolled in a multi-allergen open-label Xolair trial. Although Sam has been tolerating the doses relatively better than Josh, the boys feel that they are partners in a project. “Having them participate together in the study has been great. They are their own support system. They sit together each afternoon and eat their doses, and then relax together watching TV or playing legos or video games for their calm post-dose time. Having them go through this together is now part of the rhythm in our house,” says Debbie.
Meet our identical twins – Anjali and Anushka
Anjali and Anushka are identical twins and juniors in high school. As infants, they both got rashes after ingesting milk. When she was 1-year-old, Anushka had an anaphylactic reaction to cashew. As identical twins, they share the same genes, but, as they grew, it became evident that their allergies were diverging. Anushka developed an allergy to cats and had mild asthma, but Anjali did not. While both were allergic to garbanzo beans, Anjali reacted more severely than Anushka. By the age of 5, blood tests showed that both girls had outgrown their milk allergy, but were allergic to tree nuts and many types of lentils. At the time, their only hope was full elimination of these foods from their diets to stay as safe as possible – excluding many of their family’s traditional Indian fare.
In 2013, as soon as their parents read about Dr. Kari Nadeau’s pioneering work on food allergies in the New York Times, the family contacted the Center to be considered for a trial. The teens have now completed a multi-allergen open-label Xolair trial. Altogether, both girls underwent immunotherapy for several allergens — including cashew, garbanzo, peas, ginger and another less common seed often found in Indian food.
“I wasn’t that anxious about the trial, since I knew it was in a controlled medical setting, but Anjali was. Having each other definitely decreased both our anxieties. We do everything together, and it was great having someone going through the same experience,” Anushka shared. “Before I completed the clinical trial, every time I ate out, I used to ask the chef so many questions about the ingredients. It was hard to enjoy eating out. I am now so much calmer when eating out and this has made a huge difference in my life,” said Anjali. “Being through the trials, we feel so much more in control and are no longer afraid to try new foods.” said Anushka.
As trial graduates, both girls are now on a daily maintenance dose, and will return once or twice a year to the Center for follow-up. They have both developed a deep appreciation for scientific research. Anushka specifically envisions pursuing a PhD in immunology. This interest has already led both girls to take advanced chemistry and biochemistry courses at local colleges and participate in research internships at UC Berkeley and the Children’s Hospital Oakland Research Institute.
Twin studies at the Center
Examining changes that occur in immune cells before and after immunotherapy in twin trial participants, like Josh and Sam and Anushka and Anjali, has the potential to propel our understanding of what changes are occurring in allergic individuals at a very fundamental level.
Written by Vanitha Sampath
Vanitha Sampath received her PhD in Nutrition from the University of California at Davis. At the Sean N. Parker Center for Allergy and Asthma Research, as a medical writer and content manager, she enjoys being in the midst of groundbreaking research in asthma and allergy and is committed to communicating the scientific advances of the Center and spreading awareness of its mission and vision.