Serum bactericidal activity against meningococcus in patients with systemic lupus erythematosus.

Background: Patients with systemic lupus erythematosus (SLE) are susceptible to infectious diseases owing to various immunosuppressive treatments and disease characteristics. Meningococcal infections progress rapidly with a high incidence of severe complications and mortality; therefore, meningococcal vaccination is needed. However, there is limited evidence regarding the immunity and immunogenicity of patients with SLE.

Purpose: This study aimed to analyze the serum bactericidal activity against meningococci in patients with SLE in two domestic institutions in Korea.

Methods: Serum samples were collected from patients diagnosed with SLE (age < 19 years) at Seoul National University Children's Hospital and Ewha Womans University Mokdong Hospital in 2016-2018. Serum bactericidal activity against the four meningococcal serogroups was analyzed using a serum bactericidal assay with rabbit serum. The patients' demographic information, diagnostic history, and disease activity status were obtained from electronic medical records.

Results: The mean age of the 41 included patients was 20.3±5.4 (range, 10-35) years. All but one patient received steroids. The sera of most of the patients (34/41 [82.9%]) lacked bactericidal activity against serogroup A. Some patients showed bactericidal activity against serogroups C, W-135, and Y (63.4%, 56.1%, and 61.0%, respectively). There were no significant differences in the geometric mean indices based on complement consumption state or anti-double-stranded DNA antibody positivity.

Conclusion: Although the sera of some patients exhibited serum bactericidal activity against meningococci, most remained seronegative. It is important that patients with SLE at risk of meningococcal infection receive appropriate vaccinations. Our findings serve as baseline serological data for meningococcal vaccination policies for patients with SLE.