Nasal Mast Cells in Perennial Allergic Rhinitics Exhibit Increased Expression of the Fc e RI, CD40L, IL-4, and IL-13, and Can Induce IgE Synthesis in B Cells

Cross-linking of allergen specific IgE bound to the high affinity IgE receptor (Fc e RI) on the surface of mast cells with multivalent allergens results in the release of both preformed and newly generated mediators, and in the manifestation of allergic symptoms. The expression of Fc e RI, and the synthesis of IgE are therefore critical for the development of allergic diseases. In this study, we report that nasal mast cells (NMC) from patients with perennial allergic rhinitis (PAR) expressed significantly greater levels of the Fc e RI, CD40L, IL-4, and IL-13 as compared to NMC from patients with chronic infective rhinitis (CIR). The level of Fc e RI expression in NMC of PAR patients strongly correlated with the levels of serum total ( r 5 0.8, P , 0.003) and specific IgE ( r 5 0.89, P , 0.0004) antibodies. In addition, stimulation of NMC with IL-4, upregulated the Fc e RI a chain expression both at the protein and mRNA levels, as detected by flow cytometry and reverse transcriptase-polymerase chain reaction. Furthermore, NMC from PAR, but not CIR, patients induced IgE synthesis by purified B cells in the presence of Der fII (mite antigen). These results suggest novel and critical roles for mast cells in promoting the allergic reaction through the increased expression of Fc e RI and by enhancing and amplifying the IgE production, within the local microenvironment. ( J. Clin. Invest. 1997. 99:1492–1499.)