Immunocompetent cells in human nasal polyps and normal mucosa.

The distribution of T- and B-lymphocytes, HLA-DR-expressing cells, and macrophages was determined using monoclonal antibodies in frozen biopsy sections of nasal polyps from 12 patients, and of nasal mucosa from five disease-free controls. The relative proportion and spatial distribution of different lymphoid cells was similar with regards to both nasal polyps and normal mucosa. Numerous scattered T lymphocytes (Leu4-positive) and HLA-DR-expressing macrophage/dendritic-like cells were shown and tended to accumulate in the subepithelial areas. Aggregates of T lymphocytes and HLA-DR-positive cells were also found close to deeper glands. In the submucosal clusters, the Leu3a-positive ("helper/inducer") cells were more common than the Leu2a-positive ("suppressor/cytotoxic") cells. Furthermore, a number of epithelial, non-lymphoid cells were found to express the HLA-DR antigen, which suggests an active role for the epithelium in the immunological response of the normal mucosa as well as that of the nasal polyp.