CYTOKINE PRIMING OF HUMAN BASOPHILS - DESCRIPTION OF ALLERGEN NONRELEASERS

Interleukins 3 and 5 and GM-CSF enhance histamine release from basophi ls triggered by various stimuli. In this report, we describe a subset of allergic patients whose basophils release histamine in response to allergen only when primed with cytokine. In the absence of cytokine: t here is no detectable response to allergen. These patients, who repres ent 4-13% of the allergic population, cannot be distinguished by skill test reactivity or severity of allergic symptoms. Allergen nonrelease rs tend to have lower titers of allergen-specific IgE than the majorit y of atopic subjects, but this difference is not significant (average titer of 29.8 for nonreleasers vs. 188 for typical allergies; p = 0.15 ). They release histamine normally with anti-lgE and with fMLP, indica ting that basophils are responsive to signalling through the IgE recep tor, and there is no intrinsic defect in degranulation, Thus, in these patents, the IgE-mediated release of inflammatory mediators from baso phils is dependent on, rather than merely enhanced by, T cell cytokine s. The relationship between these patients and die previously describe d anti-IgE 'nonreleasers' is discussed.