The immune system: we hear about it all the time, especially this time of year as cold and flu season is in full swing. But there’s a lot more to it than just your susceptibility to a runny nose. 50 million people suffer from immunologic diseases, ranging from an overactive immune system (autoimmunity) to an underactive one (immunodeficiency), and many stages in between. The field of immunology is much more expansive than you might think, spreading into neurology, gastroenterology, epigenetics, psychosocial health, and even mindfulness and gratitude.My guest on this week’s episode of The Doctor’s Farmacy, Dr. Leonard Calabrese, is an expert in immunology and rheumatology. In fact, he is a Professor of Medicine at the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University and Vice Chair of the Department of Rheumatic and Immunologic Diseases. Dr. Calabrese is the director of the RJ Fasenmyer Center for Clinical Immunology at the Cleveland Clinic and holds joint appointments in the Department of Infectious Diseases and the Wellness Institute.