Existence of c-kit receptor-positive, tryptase-negative, IgE-negative cells in human allergic nasal mucosa: a candidate for mast cell progenitor.

The accumulation of mast cells in the allergic nasal epithelium is well known, yet the mechanism remains unclear. We studied whether there is a candidate for mast cell progenitors in the allergic nasal mucosa tissue removed at the time of surgery. We first confirmed that most mast cells in nasal mucosae of 10 nasal allergic patients had c-kit receptor by immunohistochemistry using the mirror sectioning technique. We then investigated whether c-kit receptor+, tryptase-, IgE- cells existed in nasal mucosae of 15 nasal allergic patients and 15 nonallergic ones using sequential triple immunohistochemistry. We observed the area in which 1,000 to 1,100 tryptase-positive cells (mast cells) existed in both the subepithelial layer and the deep layer of each nasal lamina propria. The epithelial layer above this area was also examined. Some c-kit receptor+, tryptase- cells existed in the nasal mucosae of 11 patients with nasal allergy and of 5 patients with nonallergic rhinitis. From one to four of these cells in the nasal epithelium and subepithelial layer of the 4 allergic patients were IgE-negative. In contrast, no IgE-negative cells existed in the deep layer of allergic nasal mucosae or in any nonallergic nasal mucosae. Our results suggest that mast cell progenitors, hematopoietic progenitor cells or multipotential blood cells exist in the allergic nasal mucosa, and may contribute to the increase of mast cells in the epithelium and subepithelial layer of allergic nasal mucosa.