Successful oral desensitization in children with cow's milk anaphylaxis: Clinical and laboratory evaluation up to nine-years follow-up

Introduction: Cow's milk protein allergy (CMPA) is the most common food allergy in children worldwide. Some children have severe and persistent CMPA, with near-fatal reactions after exposure to trace amounts of cow's milk-proteins (CMP). Strict avoidance diet is difficult, negatively affects quality of life and represents a conservative approach. Therefore, different therapeutic strategies are necessary. Objective: We aimed to assess long-term efficacy and safety of oral immunotherapy (OIT) in children with severe and long-lasting IgE-mediated CMPA. Materials and methods: The authors present four case reports of patients with CMPA who underwent CMP-OIT, that have been under long-term follow-up up to nine years. We provide information about the clinical and laboratory evaluation. Skin prick tests (SPT), specific IgE and IgG4 were performed before, during, and after OIT. Immune profile after OIT was assessed by flow cytometry (lymphocyte subsets, regulatory T and B cells). Results: The success rate was 100%, and all patients currently have a free diet with minimal diary ingestion of 200 mL CMP or equivalent. Specific IgE levels and SPT to CMP have progressively decreased, and specific IgG4 levels have increased. CD4⁺CD25⁺CD127^−/dim regulatory T cells were increased after OIT. Conclusions: OIT ensured a clinical tolerance state after up to nine years, confirmed by both clinical and immune profile, allowing a diet without restrictions, with high satisfaction from patients and caregivers. We emphasize that OIT should be performed only by allergy experts in the hospital setting, and that only motivated families should be enrolled, since it is essential to ensure CMP daily intake at home.