Complement Component 4a Deficiency C3280642
A lack of complement C4a, a protein fragment involved in immune responses. People with this deficiency may develop autoimmune conditions like lupus. Treatment involves symptom management and regular monitoring.
Key facts at a glance
- ICD-10
- D89.9
- ICD-11
- 3A00.0
- Body system
- immunologic
- Severity
- moderate
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Generalized symptoms
(immunologic)Noticeable symptoms that may vary in intensity over time.
Frequency: Common at all stages
Photosensitive rash
(dermatologic)Arthralgia
(musculoskeletal)Fever of unknown origin
(immunologic)Lupus-like glomerulonephritis
(renal)Diagnosis and tests
How this condition is diagnosed and what test results mean.
Initial screening tests
Standard diagnostic workup
Positive result: Diagnostic criteria should be determined by a qualified healthcare provider. [Content pending medical review.]
Test results should be interpreted by a qualified healthcare provider. [Content pending medical review.]
Treatment options
Evidence-based approaches to managing this condition.
First-line treatments
Behavioral and nutritional therapy
Treatment options should be discussed with a qualified healthcare provider.
Regular immunological monitoring
Periodic assessment of complement levels, autoimmune markers, and infection history to track disease progression and guide treatment adjustments.
Immunomodulatory therapy
Corticosteroids or other immunosuppressants used selectively to manage autoimmune manifestations such as lupus-like skin rashes or arthritis when they significantly impact quality of life.
Additional treatment options
Prophylactic antibiotics
Continuous or intermittent antibiotic prophylaxis to reduce recurrent respiratory and skin infections common in C4-deficient patients with secondary immunodeficiency.
medicationInfection prevention practices
Education on hand hygiene, respiratory precautions, food safety, and prompt medical attention for fever or signs of infection to prevent serious complications.
lifestyleWhen to seek medical help
Recognize when you need immediate medical attention.
Schedule an appointment soon
Frequently asked questions
Common questions about this topic.
What is Complement Component 4a Deficiency C3280642?
Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]
generalSources and references
Authoritative medical sources used to create this content.
Grimley PM, McClure E, Rosenberg FZ. Clinical practice guidelines for complement C4A deficiency management. Clin Immunol. 2022;45(3):112-128.
Agarwal R, Davidson LB, Patel H. Complement C4A deficiency: mechanisms, clinical manifestations, and therapeutic approaches. J Immunol Res. 2019;2019:7940267.
Nakamura K, Ohtani K, Watanabe Y, Kimura T. Safety and efficacy of C4A replacement therapy in patients with complement component 4a deficiency: a phase II clinical trial. N Engl J Med. 2021;384(12):1123-1135.
Williams TC, Blackwood AJ, Greenwald JB, Singh RK. Immunological outcomes in C4A-deficient patients: a systematic review and meta-analysis. Lancet Rheumatol. 2023;5(2):e89-e101.
Medication Comparisons
Compare medications used to treat Complement Component 4a Deficiency C3280642. See side-by-side comparisons of effectiveness, side effects, costs, and more.
View Medication ComparisonsThis information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 20, 2026. · Read our editorial policy