A comparative study of the characteristics of intraepithelial and lamina propria lymphocytes of the human nasal mucosa.

The phenotypes and receptors of the intraepithelial lymphocytes which are a major component of the mucosal immune system are of considerable interest. Intraepithelial lymphocytes, especially those of the intestines, are well documented. The nasal intraepithelial lymphocytes probably play a key role in the immune defense of the entire respiratory tract. However, documentation of these lymphocytes is limited to only a few nondescriptive studies by immunohistological methods. In our previous paper, we examined the subsets of the nasal intraepithelial lymphocytes by two-color flow cytometry after culture with monoclonal antibody against CD3 and PMA. The mucosal immune system, which comprises the lymphoid tissue associated with the mucosal surface, consists of lymphocyte populations from both the epithelium and the lamina propria. In this paper (a sequel to our previous study), we have carried out a comparative study of the intraepithelial lymphocytes and lamina propria lymphocytes of the human nasal mucosa. In the 42 patients (with allergic rhinitis/infectious hypertrophic rhinitis) whom we examined, T lymphocytes were predominant in the epithelium as well as the lamina propria. B lymphocytes were detected only in the lamina propria. CD8+ T cells (suppressor/cytotoxic) and CD4-8- (double-negative) (DN) comprised the major population of the intraepithelial lymphocytes. The CD4+/CD8+ ratio was 0.5 +/- 0.1. In contrast, the lamina propria showed a predominance of CD4+ T cells (helper/inducer), with a CD4+/CD8+ ratio of 1.3 +/- 0.2. CD3 + 4-8- (double-negative T cells) were comparable in number in the epithelium and the lamina propria. CD8+ T cells of the epithelium were predominantly cytotoxic T cells, and CD4+ T cells were predominantly helper T cells. In the lamina propria, CD8+ T cells were predominantly of the suppressor type.(ABSTRACT TRUNCATED AT 250 WORDS)