A prospective, double-blind, randomized, placebo-controlled study on the efficacy and safety of influenza vaccination in myasthenia gravis
OBJECTIVE:To investigate the efficacy and safety of an influenza vaccination in patients with myasthenia gravis with acetylcholine receptor antibodies (AChR MG). METHODS:An influenza vaccination or placebo was administered to 47 AChR MG patients. Before and 4 weeks after administration blood samples and clinical outcome scores were obtained. Antibodies to the vaccine strains A/California/7/2009 (H1N1)pdm09, A/Hong Kong/4801/14 (H3N2) and B/Brisbane/060/08 were measured using the hemagglutination-inhibition (HI) assay and disease-specific AChR antibody titers were measured with a radio-immunoprecipitation assay. Forty-seven healthy controls (HC) were vaccinated with the same influenza vaccine to compare antibody titers. RESULTS:A post-vaccination, seroprotective titer (HI ≥ 1:40) was achieved in 89.4% of MG patients vs. 93.6% in healthy controls for the H3N2 strain, 95.7% vs 97.9% for the H1N1 strain and 46.8 vs 51% for the B-strain. A seroprotective titer for all three strains of the seasonal influenza vaccine was reached in 40.4% (19/47) of the MG group and in 51% (24/47) of the HC group. Immunosuppressive medication did not significantly influence post geomean titers (GMT). The titers of disease-specific AChR antibodies were unchanged 4 weeks after vaccination. The clinical outcome scores showed no exacerbation of MG symptoms. CONCLUSION:The antibody response to an influenza vaccination in patients with AChR MG was not different from that in healthy subjects, even in AChR MG patients using immunosuppressive medication. Influenza vaccination does not induce an immunological or clinical exacerbation of AChR MG. CLINICAL TRIAL REGISTRY:The influenza trial is listed on clinicaltrialsregister.eu under 2016-003138-26.