We found that in the presence of FcɛRI engagement MC-TNFRSF14:TNFSF14 interactions enhanced: (1) MC surface expression of the granule-associated marker LAMP-1 (ref. 29) (Fig. 1g); (2) MC release of pre-stored mediators (pre-synthesized histamine and TNF-α, Fig. 1h,i); and (3) MC production of several other mediators which could contribute to the development of asthma pathology: LTC4, LTE4, TNF-α, IL-6 and IL-13 (Fig. 1j–n). The gene discussed is IL13; the disease is asthma.