[Nasal polyps: comparative immunological study of polyps with different histopathologic types]

Cellular Infiltrate as well as class I and II HLA molecule expression, on 22 nasal polyps and on 12 samples of corresponding hypsilateral mucous membrane were studied by means of immuno-histological methods. These nasal polyps were classified according to their histopathological structure. Five polyps, with a fibrous connective core infiltrated by cells of the monocyte-macrophage lineage, were classified mixed. The remaining seventeen polyps were characterized by the presence of central oedematous connective tissue infiltrated almost exclusively by eosinophils and either contained (glandular type) or did not contain (oedematous type) glands. A comparative study of different types of nasal polyps and corresponding hypsilateral nasal mucous membranes was carried out on atopic and non-atopic patients. No correlation between atopic status and polyp presence or polyp typology was found. On the other hand, different polyp types appear to have a structural correlation with the corresponding hypsilateral mucous membrane regarding infiltrate cell type, oedematous or fibrous connective tissue presence and expression of on HLA antigen positivity pattern. The characteristic histological structure of hypsilateral mucous membranes in patients with different types of polyps appeared to be brought about by a multifactorial etiology involving mucosal hyperreactivity. Lastly, both polyps and parapolypal nasal mucous membranes were found to be infiltrated mainly in the peripheral subepithelial connective tissue by lymphocytes (55%) as well as by other leukocyte types. The presence of growth factors capable of enhancing an increase of fibroblasts, endothelial cells, together with focal distrupture on the basal membrane, might well be a general mechanism responsible for polyp sprouting.