Lymphocyte subsets in immune-mediated otitis media with effusion.

To examine the role of T-cell subsets in immune-mediated otitis media with effusion induced by keyhole limpet hemocyanin (KLH), we used immunohistochemical methods to investigate the kinetics of immunocytes of the middle ear (ME) and eustachian tube (ET) in healthy BALB/c mice. Antibodies against murine macrophages and granulocytes (anti-Mac-1), helper T cells (anti-Lyt-1), suppressor T cells (anti-Lyt-2), immunoglobulins (anti-IgG, -IgM, -IgA), secretory component (SC) and KLH were used. The ME exhibited a substantial immune response, whereas the response of the ET was minor and was associated with a secondary ME immune response. After KLH challenge, an effusion with an extensive infiltration of inflammatory cells (Mac-1, IgG+ and IgM+ cells) was observed at days 1 and 3 in the ME cavity and rapidly disappeared by day 7. Within the ME mucosa, a large number of cells was observed at days 1 and 3, peaking on day 7 when a submucosal lymphoid infiltration was detected. In the immune response of the ME mucosa, Mac-1 cells were the predominant cell type followed by helper T cells, IgG+ cells, IgA+ cells and then IgM+ cells. Suppressor T cells were rarely detected after KLH challenge. SC was present within ME epithelial cells from days 1 to 14.(ABSTRACT TRUNCATED AT 250 WORDS)