THE SURFACE EPITHELIUM OF RECURRENT INFECTED PALATINE TONSILS IS RICHIN GAMMA-DELTA T-CELLS

Using a large panel of MoAbs in quantitative morphometric analysis of immunohistochemically stained tissue sections, we compared the frequen cy and distribution of immune cells in palatine tonsils from patients with recurrent tonsillitis (RT) and patients with idiopathic tonsillar hypertrophy (ITH). We found that differences between the two patient groups in leucocyte populations were limited to the surface epithelium , whereas the cellular composition of interfollicular and follicular a reas was similar. Most intraepithelial lymphocytes were CD8(+) T cells in both groups. However, the number of intraepithelial T cells was si gnificantly higher in RT compared with ITH. This was due to a selectiv e increase in the number of intraepithelial CD8(+) gamma delta T cells utilizing V delta 1 and V gamma 9. In both patient groups the majorit y of the intraepithelial gamma delta T cells expressed V delta 1 and V gamma 9. Subepithelially, gamma delta T cells utilizing V gamma 9 dom inated over cells utilizing V gamma 8, while equal proportions express ed V delta 1 and V delta 2. These results suggest that cells utilizing the otherwise rare combination V delta 1/V gamma 9 in their T cell re ceptors (TCR) may constitute a major gamma delta T cell population in palatine tonsils and are probably reactive to antigens specific to the tonsillar milieu. Furthermore, they indicate that preferentially this gamma delta T cell subpopulation is involved in immune reactions with in the surface epithelium in RT. We speculate that gamma delta T cells are involved in clearing infectious bacteria at the tonsillar surface and in limiting inflammatory responses in the tonsils. Both local exp ansion and infiltration of blood cells probably contribute to the high numbers of gamma delta T cells in RT patients.