Mass Cytometry_Pediatric Food Allergy

To conduct a comprehensive phenotypic and functional investigation of immune parameters in a group of well-characterized 1-year-old infants with clinical peanut allergy (as defined by positive food challenge), infants with peanut-sensitized tolerance (as defined by negative food challenge but the presence of peanut sIgE), and non-sensitized non-allergic healthy control infants following in-vitro antigen-specific (peanut) and nonspecific (Phorbal myristate acetate (PMA)/ionomycin) stimulation.
Conclusion:
This study performed high-dimensional mass cytometry-based single-cell profiling of resting and stimulated PBMCs to identify the circulating immune cell signatures associated with peanut sensitization with tolerance (PST) vs. clinical peanut allergy (PA). Unsupervised clustering and mixed-effects model analysis of cell frequency revealed that PA is associated with increased frequency of CD19++HLADR++ B cells compared with PST infants. In comparison, PST was associated with reduced frequency of CD45RA+CCR7+ naive CD4 T cells and increased frequency of plasmacytoid DCs compared with healthy infants. Functional analysis of intracellular cytokine production following PMA/ionomycin stimulation revealed increased global expression of TNFα across all single cells in PA infants and increased IL-2 expression in the naive CD4 T-cell cluster in PST infants. In addition, investigation of the peanut-specific T-cell response by expression of CD40L and CD69 on CD4 T cells following peanut stimulation revealed that PA, but not PST, is characterized by increases in peanut-activated CD4 T cells that display a memory phenotype.