Combined T regulatory cell and Th2 expression profile identifies children with cow's milk allergy

The role of T regulatory cells in spontaneous recovery from cow's milk allergy (CMA) is unclear. We investigated the mRNA expression of 12 T-cell markers and the protein expression of CD4, CD25, CD127, FoxP3 after in vitro β-lactoglobulin stimulation of peripheral blood mononuclear cells from children with persisting CMA (n = 16), early recovery (n = 20) or no atopy (n = 21). Artificial neural networks with exhaustive search for all marker combinations revealed that markers FoxP3, Nfat-C2, IL-16 and GATA-3 distinguished patients with persisting CMA most accurately from other study groups. FoxP3 mRNA expression following β-lactoglobulin stimulation was highest in children with persisting CMA. Also the FoxP3 intensity in CD4⁺ CD25^highCD127^low cells was higher in children with CMA compared with non-atopic children. The expression profile of both Th2- and T regulatory cell-related genes thus reflects the clinical activity of CMA. Tolerance, in contrast, is not characterized by activation of circulating T regulatory cells.