The role of the adenoid in allergic sensitisation.

Allergic sensitisation of the airways occurs in the mucosa of the shock organ, or in the lymphatic stations draining these structures. The lymphatic structure closest to the nasal mucosa in humans is the adenoid and in mice the nasal mucosa associated lymphoid tissue (NALT). In this study we tried to find evidence for our hypothesis that allergic sensitisation can occur in the adenoid (NALT). The first part of the investigation was set up to determine possible cellular changes in the adenoid of allergic children compared to non-allergic controls using immunohistochemical staining techniques. We found CD1a (Langerhans cells) and eosinophils to be more numerous in the adenoid of allergic children. In the second part of this study we used a murine model to determine if an intranasally applied 'allergen' is processed in the NALT and/or cervical lymph nodes (CLN). An auto fluorescent dye (Di I) was applied into the nasal cavity of mice. At subsequent time intervals mice were terminated. NALT and CLN tissue sections were placed under fluorescent microscopy. We found that Di I transported to both the NALT and CLN. However, the dye remained in the NALT at least 2 days longer than in the CLN. In these studies we found evidence that the lymphoid compartment in the upper respiratory tract (adenoid and NALT) are involved in the processes of allergic diseases.