Complement C3 cleavage and cytokines interleukin-1 beta and tumor necrosisfactor-alpha in otitis media with effusion

Objectives: To analyze whether complement C3a anaphylatoxin, other C3 fragm ents, interleukin-1 beta (IL-1 beta), or tumor necrosis factor-alpha (TNF-a lpha) contributes to inflammation in chronic otitis media with effusion (OM E). Methods: The amount of C3a was measured by enzyme-linked immunoassay, F urther breakdown of C3 was analyzed by Western blotting. IL-1 beta and TNF- alpha concentrations were measured by radioimmunoassay, Bacteria were analy zed by culture and polymerase chain reaction. Results: Highly elevated leve ls of C3a and other C3 cleavage fragments mere found in all middle ear effu sion (MEE) samples. The mean values (+/- SEM, n = 26) for C3a, IL-1 beta, a nd TNF-alpha were 5973 +/- 1124 ng/mL, 1043 +/- 490 pg/mL, and 79 +/- 14.3 pg/mL, respectively. Comparison to an average C3 level of 555 (+/-108) mu g /mL indicated that at least 40.5% +/- 6% of total C3 had become activated w ithin the MEE, C3a concentrations were higher in the group in which the eff usion had been present in the middle ear for a prolonged period (greater th an or equal to 4 mo) (P = .04). Children with multiple tube insertions had higher C3 (P = .006) and TNF-alpha (P = .04) concentrations in their MEE sa mples than those receiving their first tubes. C3 and C3a concentrations in MEE correlated to each other (correlation coefficient [r] = 0.513, P = .005 6), as did concentrations of IL-1 beta and TNF-alpha (r = 0.7016, P < .0001 ). No significant correlation was found between complement C3 or C3a levels and IL-1 beta, TNF-alpha, or bacterial growth. Conclusions: Highly elevate d levels of C3a in MEE indicate ongoing complement activation, which is str onger than in almost any other disease demonstrated previously. Elevated C3 a levels contribute to chemotactic and inflammatory potential in the MEE an d correlate with the chronicity of the disease.