Recurrent meningococcal infections as a sign of inborn error immunity.

Invasive meningococcal diseases (IMD) caused by Neisseria meningitidis are generally rare. They affect mostly selected age categories and risk groups of patients (in terms of age, comorbidities, or applied therapy), and the immune system and its defects may play an important modifying role. Meningococcal infections could be the first and only clinical sign of unrecognised immunodeficiency. IMD are a typical clinical presentation of inborn errors of immunity with low concentrations or dysfunction of the terminal components of complement cascade. Meningitis is present in approximately 40% of the patients with terminal complement components deficiencies and in 6% of the patients with properdin deficiency. Despite evident advances in the understanding of the pathogenesis of meningococcal infections and the mechanisms of immune defence against this pathogen, patients with defects in the alternative or terminal complement pathway are highly predisposed to invasive and recurrent meningococcal infections, usually with a mild course. Therefore, it is recommended that each patient with IMD, especially recurrent, should undergo an immunological examination to rule out complement deficiencies.