Expression of the high affinity IgE receptor by neutrophils of individuals with allergic asthma is both minimal and insensitive to regulation by serum IgE

We evaluated the hypothesis that serum IgE regulates neutrophil FcεRI expression in the same manner as described for other FcεRI+ cells. FcεRI expression by neutrophils of 40 asthma subjects and 20 control subjects did not correlate with serum IgE levels, whereas FcεRI expression by basophils of the same subjects showed a highly significant correlation. The level of FcεRI expression by neutrophils of both asthma and control subjects was approximately 1% of that for basophil FcεRI expression. IgE+ neutrophils were minimally detectable, and FcεRI α-subunit was not detected in Western blots of neutrophil membranes and cytosol. The neutrophil FcεRI did not support anti-IgE stimulated superoxide release or IgE-induced increase in neutrophil survival. We conclude that FcεRI expression by neutrophils of both asthma patients and control individuals is minimal at best and that, if present, neutrophil FcεRI expression, unlike that of other human FcεRI+ cells, is not regulated by serum IgE.