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Autoimmune diseases cause inflammation. C-reactive protein (CRP) should be elevated in a person with inflammation.

Is it possible that a person with an autoimmune disease (e.g. autoimmune hemolytic anemia) and without impaired CRP production has a non-detectable level of C-reactive protein in their blood serum (0.0 mg/l)?

MY OWN RESEARCH:

Most of the sources discuss only high levels of CRP as a marker of inflammation. However, Wikipedia (Autoimmune disease) says:

C reactive protein, a protein made in the liver generally increases with inflammation, and may be high in autoimmune disease.

This leaves a low CRP in an autoimmune disease as a possibility.

Furthermore, John Hopkins Lupus Center (C-reactive Protein (CRP)/Westergren Sedimentation Rate) states:

It is important to realize, though, that a low CRP value does not necessarily mean that an individual is experiencing no inflammation; a low CRP can be seen in lupus patients with active inflammation.

This confirms that CRP can be low in autoimmune diseases. But can there be no C-reactive protein in blood serum of a patient with an autoimmune disease? Maybe if the disease is currently in a state of remission?

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  • I have a auto immune inflammatory arthritis and Vietnam time my crp was elevated was xinhua chest infection. They measure my c3 and c 4 which are elected and I'm Told more accurate markers.
    – Debbie Yates
    Aug 3, 2020 at 6:29

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Although serum levels of the acute‐phase reactant C‐reactive protein (CRP) usually parallel disease activity in inflammatory states, it is widely believed that systemic lupus erythematosus (SLE) is an exception.

https://onlinelibrary.wiley.com/doi/full/10.1002/art.24316.

Well, since it is an exception we cannot say CRP levels are not reliable indicators of inflammation. The explanation for the relatively low levels of CRP in many patients with SLE has remained unclear despite many years of study. Another such exception is of systemic sclerosis.

Your question
1.Is it possible that a person with an autoimmune disease (e. g. autoimmune hemolytic anemia) and without an impaired CRP production has a non-detectable level of C-reactive protein in their blood serum (0,0 mg/l)?
2.can there be no C-reactive protein in blood serum of a patient with an autoimmune disease?

I don't really understand why do you say '0' or 'no' levels of CRP level when a normal healthy person do have some CRP level. Less than 0.3mg/dl is normal range seen in most healthy individuals. But if you question that:- Can a person with autoimmune disorder have CRP levels within the normal range, I will say Yes!

CRP levels within normal limits do not mean there is no disease progression. In 10% of RA cases with active disease acute phase reaction(APR) levels may be within normal limits.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5366934/#!po=15.2174.

Inflammatory marker such as ESR or C- reactive protein(CRP) are normal in about 60% of patients with early RA.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1079582.

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  • Thank you! I was too rigid about that 0,0 mg/l because in the example I saw the patient had this level of CRP. Your answer has helped me a lot.
    – Hinko Pih Pih
    Aug 2, 2020 at 21:39
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    Like many things in biology, the logical inverse is not necessarily true. "Some inflammatory diseases are associated with an increase in CRP" does not necessarily mean that "No increase in CRP infers a lack of an inflammatory disease". If P implies Q, then it is not always true that !P implies !Q. (Note that the contrapositive, !Q implies !P is always true). There are many other inflammatory markers beyond CRP – IL6 and TNF Alpha being two of the more important ones, and I am certain that they have their own story inside the diseases mentioned above.
    – Landak
    Aug 3, 2020 at 11:18
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    This is super interesting as I have at least one known autoimmune disease and my CRP is never elevated.
    – L.B.
    Aug 3, 2020 at 13:28

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