Decreased measles virus-neutralizing activity in sera from otosclerotic patients.

Hypothesis: Any kind of depressed systemic anti-measles reaction can lead to the induction of a local immune response in the inner ear and possibly to reactivation of bone turnover in this region.

Methods: Different dilutions of sera were tested for neutralizing activity against a constant viral concentration. The ability of measles virus to infect and replicate in the cell monolayer was detected by enumeration of living and growing cells with a colored reaction.

Results: Virus-neutralizing activity in the sera of patients with confirmed otosclerosis was significantly weaker than in that of healthy controls. When age- and sex-matched pairs were compared, the neutralizing activity in the healthy counterpart was higher in 5 cases. Nearly complete viral neutralization was achieved with samples containing inactivated complement and in IgG-containing fractions, but not in immunoglobulin-depleted samples.

Conclusion: The present study is consistent with measles virus participation at least in the initiation of some cases of otosclerosis.