Metachromatic Cell Progenitors and Specific Growth and Differentiation Factors in Human Nasal Mucosa and Polyps

We previously demonstrated that fluctuations in circulating metachromatic cell progenitors were inversely related to nasal metachromatic cell (NMC) counts and nasal symptoms in allergic rhinitis. Now, we have quantitated NMC progenitors and lineage-specific growth factors using a hemopoietic colony assay. Cell suspensions from excised collagenase-treated nasal polyps (n = 7) contained 3.8 +/- 1.1 granulocyte colony-forming cells per 10(6) cells plated, compared to less than or equal to 0.5 in human tonsil suspensions, less than or equal to 0.5 in nasal mucosal epithelial scrapings, and 33 +/- 8 in peripheral blood of patients with ragweed allergic rhinitis (p less than 0.01). The percentage of metachromatic cells in nasal-polyp-derived colonies was 47 +/- 10 compared with 3.0 +/- 0.7 in peripheral blood colonies (p less than 0.005). Highly potent metachromatic cell colony-stimulating activity (CSA) was detected in supernatants from cultured human nasal epithelial scrapings from both polyps and atopic nasal mucosa, but not from nonatopic nasal mucosa. Supernatants from polyp mononuclear cells stimulated with phytohemagglutinin also contained metachromatic cell-CSA, which had an approximate molecular size of 25 to 70,000 daltons on column chromatography. An IL-3-like activity was also detected in these supernatants. These observations provide further evidence for in situ hemopoietic mechanisms in human nasal mucosa, involving epithelium-derived stimulation of local metachromatic cell progenitor growth and differentiation in allergic rhinitis.