The investigation of IL-2 in experimental models of otitis media showed the involvement of IL-2 in regulation of acute inflammation because: (1) the IL-2 producing cells were predominant in acute OME compared with chronic OME, 93 and (2) recombinant IL-2 trans-tympanically injected into the middle ear of normal guinea pigs caused the inflammatory middle ear effusion within 24 h, which cleared by 72 h after inoculation. 94 However, differing degrees of responsiveness of effusion production were observed following the instillation of IL-2 in the middle ear, 95 varying from pronounced middle ear effusion causing rather severe mixed hearing loss to complete lack of effusion, and IL-2 was detected in all the middle ear effusions in experimental OME with signs of sensorineural hearing loss. 96 By analysis of clinical and experimental data we can propose the following conclusions about the role of IL-2 in OME: