However, the involvement of IL-5 in regulation of the non-allergic inflammatory response in the middle ear should not be ignored. The production of IL-5 was detected in effusions of non-atopic patients with OME, 110, 117 although it was significantly less compared with atopic patients. Analysis of immunoregulatory cytokines in experimental models of OME 93 demonstrated the absence of IL-5 in acute otitis media and significant up-regulation of IL-5 production in chronic otitis media, where IL-5 ' cells were numerous. Thus, the presence of IL-5 in OME of nonallergic patients shows the involvement of IL-5 in regulation of non-allergic chronic inflammatory reactions in the middle ear, where IL-5 can support humoral processes such as increased production and secretion of immunoglobulins, IgA in particular (Fig. 6) .