Human neutrophils express the high-affinity receptor for immunoglobulin E (Fc«RI): role in asthma

Polymorphonuclear neutrophils (PMNs) are important effector cells in host defense and the inflammatory response to antigen. The involvement of PMNs in inflammation is mediated mainly by the Fc receptor family, including IgE receptors. Recently, PMNs were shown to express two IgE receptors (CD23/Fc«RII and galectin-3). In allergic diseases, the dominant role of IgE has been mainly ascribed to its high-affinity receptor, Fc«RI. We have examined the expression of Fc«RI by PMNs. mRNA and cell surface expression of Fc«RIa chain was identified on PMNs from asthmatic subjects. Furthermore, preincubation with human IgE Fc fragment blocks completely the binding of anti-Fc«RIa chain (mAb15–1) to human PMNs. Conversely, preincubation of PMNs with mAb15–1 inhibits significantly the binding of IgE Fc fragment to PMNs, indicating that IgE bound to the cell surface of PMNs mainly via the Fc«RI. Peripheral blood and bronchoalveolar lavage (BAL) PMNs from asthmatic subjects also express intracellular Fc«RIa and b chain immunoreactivity. Engagement of Fc«RI induces the release of IL-8 by PMNs. Collectively, these observations provide new evidence that PMNs express the Fc«RI and suggest that these cells may play a role in allergic inflammation through an IgE-dependent activation mechanism.—Gounni, A. S., Lamkhioued, B., Koussih, L., Ra, C., Renzi, P. M, Hamid, Q. Human neutrophils express the high-affinity receptor for immunoglobulin E (Fc«RI): role in asthma. FASEB J. 15, 940–949 (2001)