What does a low C1q mean?
C1q deficiency is a rare disorder associated with recurrent skin lesions, chronic infections, systemic lupus erythematosus (SLE) or SLE-like diseases. It has also been associated with a kidney disease known as mesangial proliferative glomerulonephritis.
How does C1q deficiency lead to lupus?
C1q deficiency is a rare immunodeficiency, which is strongly associated with the development of systemic lupus erythematosus (SLE). A mutation in one of the C1q genes can either lead to complete deficiency or to low C1q levels with C1q polypeptide in the form of low-molecular weight (LMW) C1q.
Is C1q an antibody?
Anti-C1q antibody (Anti-C1q Ab) develops in disorders characterized by immune complex mediated injury, more commonly in skin and glomerular microvasculature. 1 Anti-C1q Ab are IgG antibodies bound to collagen like C1q.
Why is complement low in SLE?
The association between complement deficiencies and SLE could be explained by several mechanisms, including impaired clearance of immune complexes and impaired handling of apoptotic cells, aberrant tolerance induction or changes in cytokine regulation.
What causes C1-inhibitor deficiency?
Acquired C1-inhibitor deficiency and B-cell disorders The main causes of acquired C1-inhibitor deficiency are lymphoproliferative disease and autoimmune disease.
What is a normal C1q level?
C1q could be detected by the sandwich ELISA at a range of 0 μg/ml to 125 μg/ml. The average levels of serum C1q were 33.81 ± 20.36 (0.60, 82.83) μg/ml in the lupus nephritis group, which were significantly lower than that in normal controls (61.97 ± 10.50 [46.05, 86.34] μg/ml, P < 0.001).
What is the function of C1q?
A classical function of C1q is to bind immune complexes and initiate complement activation producing membrane lytic complexes, opsonins and anaphylatoxins. This classical pathway of complement activation is also elicited when C1q binds some other ligands.
What is a C1q antibody test?
C1q identifies and binds to immunoglobulin complexed to antigen and activates the complement cascade. C1q levels serve as an indicator of the amount of C1 present. The C1q Blood Test measures levels of C1q to help diagnose an inherited or acquired C1 deficiency.
What does it mean to have a low C3 complement?
Decreased C3 may be associated with acute glomerulonephritis, membranoproliferative glomerulonephritis, immune complex disease, active systemic lupus erythematosus, septic shock, and end-stage liver disease.
What does it mean when your C3 complement is low?
If only your C3 complement level is low and all other complement components are normal, it’s usually because of an inherited component deficiency. This makes it more likely that you will develop certain autoimmune disorders. More often, you will have low levels of several complement components at once.
How do you test for low C1 inhibitors?
Your doctor can order blood tests to check your complement protein levels. One of these tests is the C1 esterase inhibitor test or C1-INH test. The C1-INH test can help your doctor determine if you have enough C1-INH.
What is the role of C1q in the immune system?
C1q is a protein and together with other proteins, C1r and C1s, it forms the C1 complex. This complex is important for the activation of the complement system (a group of proteins that work with the immune system ). It also disposes cells that are dead. C1q deficiency presents in 2 different forms, absent C1q protein or abnormal C1q protein. [1]
Are there any Rare Diseases associated with C1q deficiency?
C1q deficiency 1 Summary Summary. C1q deficiency is a rare disorder associated with recurrent skin lesions, chronic infections, systemic lupus erythematosus (SLE) or SLE-like diseases. 2 Symptoms Symptoms. 3 Find a Specialist Find a Specialist. 4 Organizations Organizations. 5 Learn More Learn More. 6 GARD Answers GARD Answers.
What can be done to restore C1q production?
Treatment depends on the symptoms. Recently, it was shown that C1q production can be restored by allogeneic hematopoietic stem cell transplantation, a procedure in which a person receives blood-forming stem cells (cells from which all blood cells develop) from a genetically similar, but not identical donor. [1]
What causes a decrease in C1q in angioedema?
C1q decrease is associated with acquired bradykinin mediated angioedema, usually due to lymphoma or autoantibody but the C1 esterase inhibitor should be abnormal. Your question focused on the explanation for the C1q so will not discuss the angioedema since the C1 esterase inhibitor function is normal.
