Immunogenicity of meningococcus C vaccination in a patient with atypical hemolytic uremic syndrome (aHUS) on eculizumab therapy

We report successful kidney transplantation in a 10-yr-old boy with aHUS and heterozygous factor H mutation using the terminal complement inhibitor eculizumab to avoid recurrence of aHUS in the renal graft. Vaccination against meningococcus C (Men C) is essential in patients with dysfunction of the complement system, as induced by eculizumab. In our patient, we report waning SBA titers but maintenance of protective SBA titers (≥1:8) after kidney transplantation under immunosuppressive therapy with mycophenolate mofetil, tacrolimus, steroids, and eculizumab over a 27-month observational period. Our case illustrates that a humoral immune response to conjugate Men C vaccination may be mounted and maintained despite chronic renal disease, kidney transplantation, immunosuppressive drugs, and immunomodulatory therapy with eculizumab. However, it remains unclear whether serologically defined protective SBA titers mediate true protection from invasive meningococcal disease in an immunocompromised patient, particularly under treatment with a complement inhibitor. Thus, close monitoring of SBA titers seems mandatory in this patient.