IGHE and Increased total eosinophil count: On the other hand, loss-of-function mutations that affect IL-6 signaling, including mutations in IL6R [5], GP130 [6, 7], and STAT3 [8–11], lead to increased T helper 2 (Th2) bias and manifestation of hallmarks of Th2-mediated immune responses, such as high serum allergen-specific and total IgE concentrations and eosinophilia [12].