Serologic response to meningococcal vaccination in patients with cold agglutinin disease (CAD) in the novel era of complement inhibition.

Cold agglutinin disease (CAD) is a rare, potentially life-threatening acquired autoimmune hemolytic anemia characterized by hemagglutination and hemolysis due to immunoglobulin-mediated (usually IgMκ) classic complement pathway activation. Complement inhibition (CI) represents a novel treatment option to control hemolysis. Due to CI patients (pts) are susceptible to encapsulated bacteria e.g. N. meningitidis. Therefore, meningococcal vaccination on CI is mandatory. In this study serologic response to the tetravalent conjugate vaccine Menveo® was analyzed in CAD pts on eculizumab treatment (DECADE trial) using rabbit serum as complement source (rSBA). Protective rSBA titers varied for meningococcal serogroups and over time reflecting an early decline to even non-protective rSBA titers. These data highlight the importance of serologic analyses under chronic CI. Currently, re-vaccination with a tetravalent meningococcal conjugate vaccine every 3 years is recommended on chronic CI. However, re-vaccination on CI might further rely on serologic analyses, implying even early booster vaccinations similar to adults with (functional) asplenia.