Basophils and eosinophils account for fewer than 1% and 5% of white blood cells, respectively. Their significance in asthma and allergic inflammation is yet unknown. For a current review, researchers discussed recent discoveries in the biology and genetic roles of these two cell types in allergic inflammation and asthma. The involvement of interleukin(IL)-25, IL-33, and thymic stromal lymphopoietin (TSLP) in eosinophils was demonstrated, and activation states of eosinophil 1 and 2 integrins was found to correlate with the assessment of eosinophil recruitment and pulmonary function in asthma. Basophils’ involvement as regulators of Th2 cell response via IL-4 production or the differentiation of monocytes to macrophages, as well as their population variability in humans, had yielded new insights into their biology. The transcription factor PU.1 was linked to the regulation of particular gene transcription in both eosinophils and basophils. Genes implicated in intracellular calcium influx and apoptosis were investigated in candidate genetic research on eosinophils. Studies at the genome-wide level discovered genetic polymorphisms in IL1RL1, TSLP, and IL-33, as well as four loci with pleiotropic effects on eosinophil and basophil, counted [GATA2 (3q21), MHC (6p21), HBS1L-MYB (6q23), and ERG (21q22)].

Recent discoveries from eosinophil and basophil biology and genetic research indicate the importance of epithelial cell-derived cytokines such as TSLP and IL-33 in asthma and allergy disorders.