Biochemical and cytological studies of immune-complex-induced otitis media in the chinchilla

The pathogenesis of immune complex (IC)-induced otitis media in the chinchilla was studied through cytological and biochemical analyses of middle ear fluid (MEF) recovered after instillation of premade IC. The number to total leukocytes was 3.03 +/- 2.13 X 10(6)/cm3, and mainly involved neutrophils (72.3%) and macrophages (22.7%). The mean value of total protein, alpha 1-antitrypsin (alpha 1-AT) and alpha 2-macroglobulin (alpha 2-M) was 27.1 mg/ml, 189.5 and 75.2 mg/dl. The number of leukocytes had a significant correlation with the levels of total protein, alpha 1-AT and alpha 2-M (P less than 0.01). The inflammatory reaction induced by premade IC is characterized by an increased vascular leakage and an infiltration of leukocytes into the locus. The percentage of macrophages in the total leukocytes was larger in IC-induced otitis media than that in antigen-induced otitis media. These findings suggest that cellular events in the early stage of IC-induced otitis media may be different from antigen-induced otitis media.