Quantitative aspects of IgD and secretory immunoglobulins in middle ear effusions

Levels of the true secretory immunoglobulins, secretory IgA (SIgA) and secretory IgM (SIgM) were determined in middle ear effusions (MEEs) from children with secretory otitis media (SOM) and correlated to the MEE levels of IgD. Double sandwich enzyme-linked immunosorbent assays (ELISA) were used for the quantitative determinations. The levels of SIgM were expressed arbitrarily in units using a nasopharyngeal secretion pool as a standard. The quantitative data substantiated a local synthesis of IgD to the middle ear cavity. In 8/45 MEEs more than 600 mg/l of IgD could be calculated and between 70% and 98% could be considered to be locally produced. A statistically significant correlation was observed between SIgA and SIgM. The results are discussed in the context of the possibility that IgD plasma cells located in the middle ear cavity may primarily originate from the nasopharyngeal tonsils.