van der Ploeg EK, Hermans MAW, van der Velden VHJ, et al. - Researchers examined a clinically diverse cohort comprising mastocytosis patients in order to characterize circulating ILC2s (group 2 innate lymphoid cells) in these cases. They analyzed 21 adults with systemic mastocytosis as well as 18 healthy controls. Using flow cytometry, peripheral blood ILC2 abundance as well as phenotype were examined. Findings indicated that ILC2s and pathogenic ILC2-mast cell crosstalk have a role in mastocytosis. Experts hypothesized that the skin microenvironment is altered by a high cutaneous D816V ⁺ mast cell burden, resulting in chronic local ILC2 activation as well as their dissemination into the circulation. By generating inflammatory mediators and by further augmenting mast cell mediator release, activated ILC2s could act as a contributor to skin symptoms.