Aims-- To evaluate the involvement of multipotential stem and progenitor cells in the pathogenesis of pterygium.
Methods-- Paraffin-embedded and snap-frozen primary pterygium (n=10) were serially sectioned and analyzed immunohistochemically to determine the expression level of AC133 (marker for the primitive hematopoietic progenitors), CD34 (marker for the hematopoietic progenitor cells and endothelium), c-Kit (marker for hematopoietic and stromal progenitor cells) and STRO-1 (a differentiation antigen present on bone marrow fibroblast cells and on various nonhematopoietic progenitor cells),
Results-- In all the primary pterygium, immunoreactivity of AC133 and STRO-1 was found in some of the epithelial and stromal cells, CD34 was observed in the vascular endothelium, and some scattered ovoidal cells were found in subepithelial connective tissue. C-Kit was expressed mainly in the basal epithelium of the head portions, and some spindle-shaped stromal cells. There is no immunoreactivity of AC133, c-Kit, and STRO-1 in normal conjunctiva, whereas CD34 was mildly stained with vessel wall.
Conclusion-- Multipotential stem and progenitor cells may be involved in the pathogenesis of pterygium through its differentiation into fibroblasts and vascular endothelial cells.
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