C5 deficiency

C5 is part of late complement components C5-C9. Converting C5 to C5a and C5b marks the activation of the terminal components. C5 consists of alfa and beta polypeptide located on the chromosome 9. C5 is distantly related to C3, C4 and alfa 2 macroglobulin and is produced in liver, macrophages, lung, intestine and lymphocytes. Patients with C5 deficiency have decreased total hemolytic complement activity and very little C5 functional activity. The serum of patients with C5 deficiency is unable to generate any chemotactic or bactericidal activity.

Alternative names

C5 deficiency

Complement component 5 deficiency


  • Defects of the classical complement cascade proteins