Oral immunotherapy in hen’s egg‐allergic children increases a hypo‐proliferative subset of CD4+ T cells that could constitute a marker of tolerance achievement

Background: Food allergy affects a significant number of children and its prevalence, and persistence is undergoing an important increase in the last years. Specific oral tolerance induction (SOTI) is a promising therapy for food allergy. However, little is known about the immune mechanisms implicated in the desensitization to allergens. Our purpose was to study which immune parameters are modified during the process of tolerance achievement with the goal of identifying markers of tolerance induction. Methods: We performed an extensive immune analysis in 19 allergic children following SOTI with hen’s egg before and after the immunotherapy. Changes in lymphocyte subpopulations and serum cytokines were identified in children with desensitization achievement. Results: Sixteen children achieved complete tolerance to egg, and the immune analysis reveals that desensitization was accompanied in all the cases by a significant decrease in the percentage and absolute counts of effector‐memory CD4+ T cells (T_EM) and a marked increase in the absolute counts of a subset of CD4⁺CD38⁺CD45RO^? cells. Additionally, we also observed a marked reduction in the plasma levels of different Th1 and Th2 cytokines after tolerance achievement. Conclusions: Acquisition of tolerance in children after oral immunotherapy is accompanied by a decrease in the T_EM population and the increase in a particular subset of CD4+ T cells with a hypo‐proliferative and non‐reactive phenotype. This hypo‐proliferative subset of cells could constitute a marker of the development of oral tolerance, and the study of this subset could contribute to the better understanding of the immune responses in allergic subjects.     

Measles vaccine in egg allergic children: poor immunogenicity of the Edmoston-Zagreb strain

Despite the fact that a number of recent studies have shown that measles/ mumps/rubella vaccine is safe for egg allergic children, many pediatricians are still concerned about immunization in egg allergic children. In Europe, a measles vaccine with the Edmoston-Zagreb strain (EZMV) grown in human fibroblast culture has been developed and recommended for children with egg allergy. However, some doubt arises on the efficacy of this strain due to its weak immunogenicity. The aim of this study was to investigate the immunogenicity of the EZMV in comparison to the measles vaccine with the Schwarz strain (SWMV) grown in a chick embryo fibroblast culture.
Thirty-nine children affected by severe immediate manifestations due to IgE mediated egg allergy were enrolled. The children received at random the SWMV (Morupar, Sclavo) or the EZMV (Triviraten, Berna) in one 0. 5 ml subcutaneous injection, and were checked for any immediate allergic reactions in the following 4 hours. Blood samples were taken for the detection of specific antibody response 5 months after the immunization. In SWMV seroconverted children (18/19) the geometric mean antibody liter was 3 times higher than that observed in EZMV seroconverted children (17/20) (p < 0.01). No allergic reactions occurred following the immunization with the two different vaccines. This data confirms the safety of SWMV in egg allergic children. In addition, the present study provides further data on the lower immunogenicity of the EZMV in comparison to the SWMV.