C1q-CIC Levels: Implications for Autoimmune Diseases

Inquiry about complement C1Q?

The C1q-CIC value is 8.2, which is considered equivocal based on the reference values (Negative: < 4.4 μg Eq/ml; Equivocal: 4.4 - <10.8 μg Eq/ml; Positive: >= 10.8 μg Eq/ml).
Currently, there are no autoimmune diseases, with negative antinuclear antibodies and other specific antibodies such as anti-dsDNA also being negative.
Liver function tests are normal.

An equivocal C1q-CIC value may indicate the presence of circulating immune complexes, which can occur in various conditions, including infections, inflammatory diseases, or even transient immune responses.
However, it does not necessarily indicate a specific disease or immediate concern, especially in the absence of other autoimmune markers.
Regarding the potential for developing systemic lupus erythematosus (SLE), an equivocal result alone does not predict the onset of SLE.
Continuous monitoring and follow-up with your healthcare provider are recommended to assess any changes in your health status over time.
If you have concerns, discussing them with your physician would be beneficial for personalized advice and management.

Xiao Yu, 30~39 year old female. Ask Date: 2022/05/17

Dr. Gao Jiankai reply Internal Medicine

Hello, thank you for your question.
C1q is a protein related to immune function in the body, while CIC (Circulating Immune Complex) refers to immune complexes circulating in the blood, which are protein aggregates formed by antibodies and antigens.
In principle, the body normally produces CICs during its regular functioning, but these CICs are quickly cleared from the bloodstream.
If the body is unable to clear CICs properly, leading to their accumulation in various parts of the body, it can trigger abnormal immune responses, such as vasculitis or lupus erythematosus.
C1q is a precursor protein that induces the formation of CICs; abnormal levels or insufficient amounts of C1q are also associated with immune diseases.
Therefore, these two are often tested together.
Currently, although your C1q levels are in a gray area, we do not rely solely on a single indicator.
Considering that your CIC and other immune function tests are normal, I believe the situation is manageable, and the likelihood of developing systemic lupus erythematosus (SLE) is very low, so please do not worry.
This message is from the Allergy, Immunology, and Rheumatology Department of Changhua Hospital, Ministry of Health and Welfare, caring for you.

Reply Date: 2022/05/17

More Info

The C1q-CIC (C1q Circulating Immune Complex) test is a valuable tool in assessing immune system function and potential autoimmune diseases. Your reported value of 8.2 μg Eq/ml falls within the equivocal range (4.4 - <10.8 μg Eq/ml), which indicates that while it is not definitively abnormal, it is also not within the normal range. Understanding the implications of this result requires a deeper look into the role of C1q and circulating immune complexes in the body.

C1q is a component of the complement system, which plays a crucial role in the immune response. It helps in the clearance of immune complexes and apoptotic cells. When C1q levels are low or when there is an accumulation of circulating immune complexes, it can indicate an underlying issue, such as an autoimmune disease. However, your negative results for other autoimmune markers, including anti-nuclear antibodies (ANA) and anti-dsDNA, suggest that there is currently no active autoimmune disease.

Several factors can contribute to an equivocal C1q-CIC level. These may include transient infections, environmental factors, or even physiological stress. It is also important to consider that immune complex levels can fluctuate based on various conditions, including recent illnesses or vaccinations. Since your liver function tests are normal and you have no symptoms of autoimmune disease, it is likely that your C1q-CIC level may not be indicative of a serious underlying condition.

Regarding your concern about whether this abnormality could lead to systemic lupus erythematosus (SLE) in the future, it is essential to understand that while elevated C1q-CIC levels can be associated with SLE, your current negative autoimmune markers significantly reduce this risk. SLE is a complex disease with multiple contributing factors, including genetic predisposition, environmental triggers, and hormonal influences. A single equivocal test result, especially in the absence of other markers, does not predict the development of SLE.

In summary, while your C1q-CIC level is equivocal, it does not necessarily indicate a cause for alarm, especially given your overall negative autoimmune profile and normal liver function. It would be prudent to monitor your health and maintain regular check-ups with your healthcare provider. If you experience any new symptoms or changes in your health status, further evaluation may be warranted.

In the context of autoimmune diseases, it is crucial to maintain a holistic view of your health. Regular monitoring of your immune markers, alongside a healthy lifestyle, can help in early detection and management of any potential issues. If you have ongoing concerns, discussing them with a rheumatologist or an immunologist may provide additional insights and peace of mind.

Similar Q&A

Understanding Complement Levels and Autoimmune Disease Risks: Key Insights

Hello, doctor. Thank you for your response. In your previous article, you mentioned that complement proteins are produced by the liver, so liver disease can lead to decreased complement levels. For normal individuals, it is related to their constitution, and such individuals have...

Dr. Gao Jiankai reply Internal Medicine
Hello, thank you for your questions. Here are my responses: 1. Are you asking if low complement levels in healthy individuals could increase their likelihood of developing autoimmune diseases in the future, or if individuals who already have autoimmune diseases could have low co...

Understanding Abnormal ANA and Complement Levels: Causes and Next Steps

Hello Doctor, my wife has had abnormal antinuclear antibody (ANA) levels in her blood tests over the past few years (both AC-1 and AC-4 are affected), with titers fluctuating between a maximum of 1:320 and a minimum of 1:80. The most recent test showed a titer of 1:160. Currently...

Dr. Gao Jiankai reply Internal Medicine
Hello, thank you for your question. The presence of abnormal ANA along with decreased C3 and C4 levels suggests a higher likelihood of an autoimmune disease. C3 and C4 are produced by the liver, and generally, they increase in response to stress or infection. However, in cases of...

Low C3 Levels and Edema: Exploring Potential Causes and Next Steps

Stage I thyroid cancer, right thyroidectomy medication: OncoTect 50mg/day. Received one dose of the AZ vaccine, experienced adverse effects after a full meal, and has not been diagnosed since May due to lower limb edema. Consulted at the Integrative Medicine Department of Veteran...

Dr. Gao Jiankai reply Internal Medicine
Hello, thank you for your inquiry. There are no specific issues with immune function, and a decrease in C3 does not have particular significance. It is recommended to continue monitoring with the Metabolism Department. The Allergy, Immunology, and Rheumatology Department at Chang...

Understanding Low C3 and C4 Levels: Do They Indicate Immune System Disorders?

Hello Doctor: Recently, I had a blood test at the Metabolism Department and found that my C3 and C4 complement levels were low, and my white blood cell count was around 3100. I would like to ask if this indicates an immune system disease? Do I need treatment, or should I only see...

Dr. Gao Jiankai reply Internal Medicine
Hello Rita, thank you for your message. Complement proteins are related to the immune system and typically increase during infections; however, in some immune system disorders, complement levels may be low, which can serve as a reference for diagnosing related immune diseases and...