The immunoregulatory cytokines IL-2, IL-10, TGF-b and their cellular and molecular networks in OME IL-2 in otitis media IL-2 has been detected in middle ear effusions from children with chronic OME at high concentration (greater than 300 pg/ml). 88 The analysis of peripheral blood immunologic pattern in patients with persistent middle ear effusions 89,90 showed the following: (1) the number of CD4 ' and CD8 ' T lymphocytes was decreased and the T-cell subset ratio (CD4 ' / CD8 ' ) was reduced; (2) proliferative responses of blood T cells were diminished; and (3) generation of IL-2 by peripheral blood lymphocytes was decreased. Another immunologic investigation of children with recurrent otitis media revealed a consistent inability of adenoidal T cells to turn on B cells to mature into immunoglobulin-secreting plasma cells that has been explained by defective production of IL-2 in adenoids. 91 This assumption was confirmed by cytokine assay of IL-2, which has been done simultaneously in nasopharyngeal lymphoid tissues and in peripheral blood of children with recurrent otitis. The adenoidal lymphocytes produced significantly less IL-2 compared with the patient's peripheral blood lymphocytes. 92 It has been assumed that poor production of IL-2 in adenoidal tissues is probably linked to a deficiency of IL-2 production in the middle ear tissues, and that could be associated with the persistence of OME. Thus, general and/or local deficiency of the IL-2 production could induce defective immunoregulation of the middle ear inflammation and promote the persistence of OME.