Meet Our Team

Dr. Walter is the division chief of the University of South Florida (USF) and Johns Hopkins All Children’s Pediatric Allergy & Immunology Programs. She is the Robert A. Good Endowed Chair of the USF Division of Pediatric Allergy & Immunology, and an associate professor of pediatrics, medicine and molecular biology in the USF Morsani College of Medicine. She serves as director of the Jeffrey Modell Diagnostic and Research Center for Primary Immunodeficiencies at Johns Hopkins All Children’s. Her research interests include understanding the (severe) combined immunodeficiencies, and breech in tolerance in primary immune disorders leading to autoimmunity and inflammation. Dr. Walter has specific clinical expertise in the diagnosis and treatment of patients with (severe) combined immunodeficiencies, in particular those with recombination activating gene (RAG) variants. She is focusing on genetic evaluation, mechanism-based treatment therapies for non-infectious complications and involved in the care of patients with definitive therapies such as hematopoietic stem cell transplantation (HSCT) and gene therapy protocols.

Dr. Sriaroon is the medical director of the outpatient USF Allergy/Immunology clinic at Johns Hopkins All Children’s Hospital and the director of the USF Pediatric Allergy/Immunology fellowship training program. She is also the medical director of the Johns Hopkins All Children's Food Allergy Clinic. She is an associate professor of internal medicine and pediatrics at the University of South Florida (USF) Morsani College of Medicine.

Dr. Leiding is an immunologist and allergy specialist for the USF Pediatric Allergy/Immunology Program at Johns Hopkins All Children's Hospital and the University of South Florida (USF) Morsani College of Medicine, where she is an associate professor of pediatrics. Dr. Leiding's research interests include understanding the etiology of auto-inflammation in chronic granulomatous disease and primary immunodysregulatory disorders. Dr. Leiding has specific clinical expertise in the diagnosis and treatment of patients with chronic granumolmatous disease and primary immunodeficiencies associated with immunodysregulation particularly patients signal transducer and activator of transcription (STAT)–gain of function (GOF) mutations.

Dr. Sher is an allergy and immunology specialist for the USF Pediatric Allergy/Immunology Program at Johns Hopkins All Children's Hospital and the University of South Florida Morsani College of Medicine, where he is a professor of pediatrics and internal medicine.

Dr. Tang is an immunologist and allergy specialist in the USF Pediatric Allergy/Immunology Program at Johns Hopkins All Children's Hospital. He is an associate professor in pediatrics and medicine in the University of South Florida Morsani College of Medicine.

Dr. Ballow is physician in the USF Allergy/Immunology program at Johns Hopkins All Children’s Hospital. He is a professor in the Department of Pediatrics in the USF Morsani College of Medicine. From 1988 to 2012, Dr. Ballow was chief of the Division of Allergy, Immunology and Pediatric Rheumatology at Women and Children’s Hospital of Buffalo, an affiliate hospital of the SUNY Buffalo School of Medicine and Biomedical Sciences; training program director of the allergy/immunology fellowship program, and director of the Immunobiology Laboratory. He earned his medical degree from the University of Chicago School of Medicine. He completed his internship and residency in pediatrics at Yale New Haven Hospital in Connecticut, and then completed a fellowship in clinical immunology at University of Minnesota Hospitals.

Carla Duff is a nurse practitioner in the USF Pediatric Allergy/Immunology Program at Johns Hopkins All Children's Hospital. She joined the hospital staff in 2019. In her role, Duff provides comprehensive care for children and adolescents with a wide range of allergies and immune disorders. Duff earned her Bachelor of Science in Nursing from the University of South Florida in Orlando, followed by a Master of Science in Nursing from the University of South Florida in Tampa.

Daime Nieves is a nurse practitioner in the USF Pediatric Allergy/Immunology Program at Johns Hopkins All Children's Hospital. She joined the hospital staff in 2020. In her role, Nieves provides comprehensive care for children and adolescents with a wide range of allergies and immune disorders. Nieves earned her Bachelor of Science in Nursing from St. Petersburg College in Florida, followed by a Master of Science in Nursing from the University of South Florida.