Sensitized infants who tolerate peanut have more dendritic cells and HLA-DR+ memory CD4 T cells

Abstract

Some infants with peanut-specific IgE tolerate peanut, but the cellular features that distinguish this sensitized tolerance from peanut allergy are poorly defined. Here we reanalyze mass cytometry data from unstimulated peripheral blood mononuclear cells of 36 one-year-old infants with challenge-confirmed peanut allergy, sensitized tolerance or neither. Clustering all 3,560,317 cells into 19 curated cell types, we find that sensitized-tolerant infants have more HLA-DR+ memory CD4 T cells (1.97-fold, q = 0.033) and lineage-negative CD38+ cells (2.26-fold, q = 0.006) than allergic infants, and a trend toward more conventional dendritic cells (2.55-fold, q = 0.069). The dendritic-cell difference persists in samples from the bright-staining batch, whereas the T-cell difference weakens. Of the published signatures, the expansion of plasmacytoid dendritic cells in sensitized-tolerant infants is reproduced, whereas the naive CD4 T-cell and B-cell differences track a staining batch that includes half of the sensitized-tolerant samples, in the published values as in ours. Activation markers and cytokines do not differ between groups, and spillover of CD20 signal into the TNF channel differs between staining runs. These results link sensitized tolerance to an expanded dendritic-cell compartment and show that staining batches must be controlled in mass cytometry studies of food allergy.