Complement Deficiencies Treatment & Management

Updated: Feb 15, 2022
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Michael A Kaliner, MD  more...
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Medical Care

Definitive treatment of complement deficiencies requires replacing the missing component of the cascade, either through direct infusion of the protein or through gene therapy. Because neither of these options is currently available, treatment of these patients focuses on managing the sequelae of the particular complement deficiencies.

For many patients, treatment must be focused on eradicating a particular infection, especially with encapsulated organisms such as N meningitidis. In most cases of meningococcal disease, treatment with meningeal doses of a third-generation cephalosporin covers most strains of N meningitidis.

For other patients, the complement deficiency may manifest as episodic flares of autoimmune diseases; treatment of these patients focuses on immunosuppressive therapy of these diseases.

Importantly, note that some overlap often exists between an increased susceptibility to infection and the greater tendency to develop autoimmune disease; both of these clinical situations may need to be addressed simultaneously in any one patient.



In a patient with a possible complement deficiency, consider consultation with an allergist and immunologist to determine appropriate diagnostic tests.

Also, consider consultation with a rheumatologist or infectious disease specialist to help manage acute complications of the complement deficiency.



No specific diet restrictions are required.



Activity can continue as tolerated by the patient.



Complement screening in relatives of patients with complement deficiencies might detect this primary immunodeficiency state and allow prophylaxis to prevent potentially disabling or life-threatening infections. [17]

Complement deficiencies may become apparent in adults by meningococcal and other infections. Adults with N meningitidis infection should be evaluated for a complement deficiency. [22]

Early diagnosis, use of vaccinations, and antibiotic prophylaxis may allow a normal life in hereditary C2 deficiency. [23, 3]