Meet our Providers
Amy L. Darter, M.D., FACAAI, FAAAAI
Dr. Darter received her medical degree from the University of Oklahoma College of Medicine where she was an Alpha Omega Alpha honor graduate. She completed an Internal Medicine residency and chief residency at OUHSC as well. She holds the honor of being board certified in both adult and pediatric allergy, asthma and immunology. She trained at the University of Texas Southwestern in Dallas at Children’s Medical Center of Dallas, and at Parkland Memorial Hospital; one of the most elite training programs for clinical allergy, asthma, immunology and clinical research.
Dr. Darter remains cutting-edge and up-to-date in her sub-specialty by holding professional memberships in a host of professional organizations. Dr. Darter has numerous scientific publications and frequently lectures to other physicians around the world regarding various allergy, asthma, and immunology topics. Dr. Darter also has the honor and distinction of being a Fellow in the American Academy of Allergy, Asthma and Immunology and the American College of Allergy, Asthma and Immunology.
Dr. Darter has resided in the Oklahoma City/Edmond community since 1993. She and her husband have three daughters and enjoy spending quality time as a family. Dr. Darter also enjoys exercising, especially running, and numerous other outdoor activities.
Jason M. Bellak, M.D.
Dr. Bellak is board certified in pediatric and adult allergy and immunology as well as internal medicine. He knows what allergy sufferers face having eczema, allergies and asthma himself. He is passionate about teaching his patients how to live with allergies and asthma without limitations.
Dr. Bellak is a native of Las Vegas, Nevada. He graduated with honors from UCLA before returning to Nevada for medical school. After medical school, Dr. Bellak completed his internship and residency in internal medicine at the Mayo Clinic in Arizona. He moved to Wisconsin to complete allergy, asthma and immunology training at one of the best training programs in the country at the University of Wisconsin (UW). While at UW, Dr. Bellak trained under Dr. William Busse, chair of the National Heart, Lung, and Blood Institute expert panel on asthma diagnosis and management, and Dr. Robert Lemanske, immediate-past president of the American Academy of Allergy, Asthma and Immunology (AAAAI). During his education and training, Dr. Bellak participated in multiple laboratory and clinical research studies. Dr. Bellak is a fellow of the American College of Physicians, and a member of the AAAAI and American College of Allergy, Asthma and Immunology.
Prior to moving to Oklahoma, Dr. Bellak had a State of Wisconsin grant to provide primary care and specialty allergy and immunology care to an underserved community in rural Wisconsin. During his tenure there, Dr. Bellak served as medical director of the family clinic and chief of staff while being active in the community providing free asthma and allergy screenings and serving on a community task force to limit prescription drug abuse.
Dr. Bellak, his wife, Jennifer, and his three children, Isabelle, Hunter and Tyson, look forward to establishing strong roots in Oklahoma. They enjoy spending time as a family outdoors and being active.
Andrea L. Sestak, MD, PhD
Dr. Sestak grew up in Edmond, where she graduated valedictorian of the EMHS class of ’85. After college at Trinity University, she obtained an MD and PhD from UT Southwestern inDallas. She did her pediatrics residency in St. Louis, and then completed a fellowship in pediatric rheumatology in a joint program between UTSW and OMRF. Initially focusing on research, she stayed here and continued work on the genetics of lupus in children until 2010, at which point she turned to the clinical side of her training and joined the staff at OU Childrens Physicians. She is board certified in Pediatrics and a fellow of the American College of Rheumatology. She looks forward to continuing to care for children with arthritis, lupus, and other autoimmune diseases here at OIAAI.
Andrea loves spending time with her daughter, Mikaela, and singing with the Windsong chamber choir.
Katie Ellis, PA-C
Katie Ellis, PA-C was born and raised in the Oklahoma City area. She graduated Magna Cum Laude from the University of Central Oklahoma with a Bachelor of Science degree in Biology. She then continued her education at the University of Oklahoma Health Sciences Center graduating in 2012 from the Physician Associate Program.
She began her search for a career in respiratory medicine when she discovered the Oklahoma Institute of Allergy and Asthma. She immediately fell in love with the specialty and the patients and knew it was the perfect fit. She worked with Dr. Darter for 2 years prior to taking some time off due to the birth of her son. She then eagerly returned to OIAAI to resume her life’s passion as a PA, taking care of patients with allergies, asthma and immunologic conditions, building lasting relationships with them, and helping them achieve a better quality of life. She is certified by the National Allergy Bureau and the American Academy of Allergy, Asthma and Immunology as an aeroallergen analyst and performs the daily pollen count for the clinic.
Katie resides in Edmond with her husband and son. She enjoys an active lifestyle, including running half marathons, swimming, biking and golf. She also enjoys volunteer work with the Ministries of Jesus Clinic in Edmond.
Leslie Jump, APRN-CNP
Leslie Jump graduated from the University of Oklahoma with a bachelor of science in Nursing in 2004. She worked as an RN in the ICU for 6 years prior to becoming a Nurse Practitioner. She attended Graceland University obtaining her Family Nurse Practitioner degree in 2010 and after passing board exams in 2010, she started her Nurse Practitioner practice in family medicine. She then gained experience in pediatric medicine for a few years. Leslie has particular interest in asthma and was attracted to asthma and allergy medicine. When she had the opportunity to specialize, she transitioned to Oklahoma Institute of Allergy and Asthma. She brings valued experience to our team, having worked with both children and adults.
In Leslie’s free time, she enjoys camping, mountain biking, crossfit, and training her dog.
Rebekah Green, PA-C
Rebekah Green, PA-C was raised in Mustang, Oklahoma and lived in Edmond and Norman before finally settling in Moore, OK. Rebekah discovered her combined passions for patient care and medical research while working in clinical research and as a phlebotomist as she pursued her Bachelor‘s degree from the University of Oklahoma. She completed an undergraduate research internship through OUHSC and coauthored the article, Role of the Skp1 prolyl-hydroxylation/glycosylation pathway in oxygen dependent submerged development of Dictyostelium during her sophomore year of college. After completing a B.S. in Biomedical Sciences with a minor in Chemistry, she spent a year researching cellular neurobiology at OU, coauthoring the paper, AP180 couples protein retrieval to clathrin-mediated endocytosis of synaptic vesicles. She then continued her education, attaining her Master’s degree from University of Oklahoma Health Sciences Center graduating in 2014 from the Physician Associate Program. After graduation, Rebekah worked in urgent care in the OKC metro before transitioning to allergy and asthma so she could spend more time caring for her patients and working to get to the root of what is keeping them from living life to the fullest. Rebekah is thrilled to be at the Oklahoma Institute of Allergy and Asthma where she is able to simultaneously pursue her passion in continuing clinical research while providing the utmost care and compassion for her patients every day.
Rebekah enjoys swimming, sunshine, cooking, traveling, and spending time with family and friends.