Human Nasal Polyp Epithelial Basophil/Mast Cell and Eosinophil Colony-stimulating Activity: The Effect is T-Cell-dependent

We have previously reported highly potent basophil/mast cell (BMC) and basophil/eosinophil (Eo) colony-stimulating activities (CSA) in conditioned medium derived from cultured human nasal polyp epithelial scrapings (NP-CM). We now have examined the involvement of peripheral blood T-cells in the NP-CM stimulation of colony-forming units (cfu) from the blood of atopic and nonatopic subjects. Because the number of BMC- and Eo-cfu was significantly higher in cultures of peripheral blood from subjects with out-of-season ragweed allergic rhinitis than from control subjects (23.8 +/- 4.1 versus 9.0 +/- 2.4, p less than 0.01), we asked whether the observed colony stimulation could be a T-cell-dependent effect. Indeed, peripheral blood target cells consisting of a reconstituted mixture of T-cells and T-cell-depleted peripheral blood mononuclear cells (non-T-cells) yielded a significantly higher number of colonies in the presence of NP-CM than the non-T-cells alone. NP-CM did not stimulate colony formation by isolated T-cells. These observations point to interactions among nasal epithelial growth and differentiation factors, blood-borne progenitors and T-cells in the local accumulation of basophils, mast cells, and eosinophils in nasal polyps.