C5 deficiency

Classical and alternative complement pathways converge in C5 complement factor, to activate the lytic pathway

• mainly synthesized by hepatocytes, but also by monocytes, lymphocytes and lung, spleen and foetal intestine cells
• C5 gene is located in chromosome 9q34.1
• C5 complement deficiency
  • a rare autosomal recessive inherited disease, associated with recurrent infections episodes, particularly meningitis and extragenital gonorrhoea by Neisseria species - these are the most frequent micro-organisms isolated in these patients
    • explained because sera from C5 deficiency patients lack bactericidal activity and have severely impaired ability to induce chemotaxis

Reference

1. Kareem S et al. Complement: Functions, location and implications. Immunology. 2023 Oct;170(2):180-192