Meningococcal Vaccination in Patients on Complement Inhibitors

The Serum Bactericidal Assay (SBA) will be used for the analysis of the antibody titer, which represents a valid surrogate for the efficacy of the tetravalent vaccine. Subjects' sera will be serially diluted and incubated with a solution containing a certain strain of meningococcus. At this point, an exogenous source of rabbit complement will be added. Bactericidal activity will be assessed against controls. Neutralizing antibody titers will be defined as the highest dilution of sera at which at least 50% of bacteria death occurs. Antibody titers will be considered protective with a cut-off greater than or equal to 1:8.