Long-term outcomes of milk oral immunotherapy and food allergy spesific health related quality of life

Around two percent of young children are allergic to cow’s milk proteins. Usually, cow’s milk allergy is outgrown by school age, but severe milk allergy tends to persist. In severe milk allergy, the Finnish guideline of children’s food allergy treatment advises avoiding milk proteins and being prepared for accidental exposures. In experimental settings, oral immunotherapy toward cow’s milk proteins appears to increase the amount of protein that may be ingested without triggering an allergic reaction. Oral immunotherapy to milk is associated with adverse events, and not all patients benefit from it. This study aimed to define the long-term outcomes of milk oral immunotherapy. Between 2005 and 2015, a total of 296 patients began milk oral immunotherapy at the Skin and Allergy Hospital, Helsinki, and University Hospital of Tampere. The patients had immunoglobulin E (IgE)-mediated milk allergy, they were at least five years of age, and their milk allergy diagnosis was confirmed before they started the treatment. The therapy started with 0.5 µg of milk protein, and the milk dose was increased to a 200-mL (6.4 g) maintenance dose, and the patients were advised to continue the daily maintenance dose. During 2016 and 2017, the patients were recruited for a long-term follow-up study of clinic outcomes associated with treatment success, side effects, immunoglobulin profiles, and health-related quality of life (HRQL). Long-term follow-up data on milk consumption were available from 244/296 (83%) patients. Among these patients, 136/244 (56%) consumed at least 200 mL of milk daily, 44/244 (18%) consumed 10–199 mL of milk, and 64/244 (26%) discontinued the treatment. Patients who were able to consume 200 mL of daily milk had lower milk specific sIgE levels before they started the treatment. There were also differences in the immunoglobin profiles associated with long-term outcomes of the milk oral immunotherapy. The overall HRQL among patients who participated in milk oral immunotherapy was at the same level as the general population, but the capability to consume 200 mL of daily milk was associated with better allergy specific HRQL among children and adolescents. The Finnish food allergy quality of life questionnaire was validated as part of the thesis.