Systemic meningococcal infections in patients with acquired complement deficiency

Area of Science:

• Immunology
• Infectious Diseases

Background:

• Congenital deficiencies in late complement components are known risk factors for meningococcal infections.
• The risk associated with acquired complement deficiencies remains less understood.

Purpose of the Study:

• To investigate the association between acquired complement deficiencies and the risk of systemic meningococcal infections.
• To assess the incidence and outcomes of meningococcal infections in patients with complement abnormalities.

Main Methods:

• A 20-year retrospective and prospective study (1970-1989) of patients with culture-proven meningococcal disease.
• Analysis of risk factors, including underlying conditions and complement levels (C3, C4, hemolytic activity).

Main Results:

• Out of 30 patients with meningococcal infections, three (10%) had identified risk factors.
• One patient had a congenital C7 deficiency; two had acquired deficiencies due to systemic lupus erythematosus (SLE) and membranoproliferative glomerulonephritis (MPGN).
• Patients with SLE and MPGN exhibited low C3, C4, and reduced complement hemolytic activity prior to infection, indicating a significantly elevated risk.

Conclusions:

• Acquired complement deficiencies, particularly those associated with SLE and MPGN, confer a substantial risk for meningococcal infections.
• Early identification and management of complement deficiencies are crucial for preventing severe outcomes in at-risk populations.