Different types of immunoglobulins, namely IgM, IgG, IgA, secretory IgA and IgE, have been identified in effusions and middle ear fluid of chronic OME. 120 Á 123 The effusion level of IgM in some patients with chronic otitis media was markedly elevated. 120 The mucoid type of effusions contained a high level of IgG, IgA 121 and IgE. 124 Comparison of the immunoglobulin levels measured in effusions and in sera showed that, in many cases, the effusion level of secretory IgA 122 and IgE 125 was significantly higher than the corresponding serum level, and this was the evidence of local overproduction of immunoglobulins in the middle ear.