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Chromatin antibody: Make sure you know your labs

posted in Diagnosing Lupus on May 5, 2021 by

Donald Thomas

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Know your labs when you have lupus

Anti-chromatin antibodies attach to chromatin in lupus patients

Chromatin is our DNA packaged up nice and neat with other proteins such as histone and RNA. It protects our DNA. Photo: at Wikipedia.com from the NIH
Chromatin Antibody (Also called Anti-Chromatin Antibody; anti-chromatin antibody, chromatin nucleosomal antibody; nucleosome antibody).

Bottom lines:
– Elevated anti-chromatin antibodies are fairly specific for people who have lupus, but can occasionally be seen in other autoimmune disorders. They are related to anti-dsDNA antibodies.
–  They are rare in healthy people
– They may possibly increase the risk of having lupus kidney inflammation (lupus nephritis), however, having them does not mean you will get nephritis. Just make sure to have a urine sample checked regularly
– In some people, they can fluctuate with disease activity and help monitor how someone with systemic lupus erythematosus (SLE) is responding to therapy. 

I recommend that all patients get copies of their labs so they can understand more about their lupus. If you are chromatin antibody positive, then read this article to learn more.

What are anti-chromatin antibodies and what do they mean?

Chromatin refers to the complex of DNA and other proteins that form chromosomes inside the nuclei of cells. About 60% to 70% of people who have SLE are positive for these antibodies, and they appear more commonly in SLE than in other systemic autoimmune diseases. Initial studies suggested that patients with SLE who are positive for chromatin antibody may have an increased risk for developing inflammation of the kidneys (lupus nephritis); however, this has been questioned in subsequent studies.

​Sometimes it can be difficult to tell if a patient may have SLE or Sjögren’s when they first come to a rheumatologist. One study showed that if that patient is positive for chromatin antibody and negative for SSA antibody, they most likely have SLE as their diagnosis. In some people with SLE, chromatin antibodies fluctuate with disease activity, decreasing in value when there is better control of lupus and increasing when it is worse. Chromatin antibodies can also occur in other systemic autoimmune diseases, including drug-induced lupus, mixed connective tissue disease, and scleroderma.

Author

Don Thomas, MD, author of “The Lupus Encyclopedia” and “The Lupus Secrets”

REFERENCES:

– The above excerpt comes from “The Lupus Encyclopedia” prior to printing of the second edition
– Mehra, S., & Fritzler, M. J. (2014). The spectrum of anti-chromatin/nucleosome autoantibodies: independent and interdependent biomarkers of disease. Journal of immunology research, 2014, 368274. https://doi.org/10.1155/2014/368274

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11 Comments

  1. Which medications can cause chromatin antibodies? Which medications can cause drug-induced lupus?

  2. You stated, “ Chromatin antibodies can also occur in other systemic autoimmune diseases, including drug-induced lupus, …” So I’m assuming that’s what the previous commenter was referring to. I’m curious as well. I had completely normal bloodwork, then 2 weeks later had high ANA and Ant-chromatin. My rheumatologist doesn’t seem concerned because I don’t have any concerning symptoms. She believes it may be drug induced as I was on antibiotics for over a year for recurring UTI’s. Since then I’ve dealt with various pains s I it does seem to be since taking all these different antibiotics. She ran my blood work again 2 months later and the ANA and antichromatin levels dropped. She says they normally see numbers go up, not come down… not sure how accurate that is. Anyway, I’m terrified after doing research so I’m having her tests everything I can think of before asking her to put me on meds. Or is it possible to manage without meds? How do you know if it’s affecting your organs? When should I be concerned about a diagnosis if I’m not having typical symptoms?

    • Shawna: So sorry to hear of your predicament. The “unknown” and gray areas can be some of the most anxiety provoking.

      I’ll start that anti-chromatin is rarely seen in healthy individuals. So, if I have a patient who had a positive ANA then a positive anti-chromatin… they must have had something going on to make the physicians wonder about the possibility of a systemic autoimmune disease like lupus or Sjogren’s disease. Otherwise, it should not have been tested. If there is not a definitive diagnosis, I’d want to follow the patient closely with a history, physical exam and labs for CBC, chem, random urine protein/creatinine ratio, urinalysis, anti-dsDNA (chromatin is very closely related to this antibody), C3, and C4. I’d make sure that these were checked at least once: CH50, ENA, direct Coomb’s antibody, anticardiolipin antibody, lupus anticoagulant, beta-2 glycoprotein-I antibody, ribosomal-P antibody, ENA, RF, CCP, and an SPEP. I would also consider ordering the AVISE Lupus Test. If your doctor doesn’t order this… you could download the order form, find out what lab is the closest to you on the lab locator on their website, and ask your doc if it would be OK for them to order (if you fill out the paperwork ahead of time, this should be pretty easy. There is no way for me to conjecture otherwise without being your physician. I sure hope they figure things out for you.

      Donald Thomas, MD

  3. Is it possible to have lupus if you are symptomatic with matching criteria with a negative ANA titer but significantly elevated Chromatin antibody test?

    • Dear Jessica: Thanks for reading my post and commenting.

      1. Anything is possible. I’ve seen it all over 30 years. We know that autoantibodies can occur many years before SLE occurs. Scientists are now working on lab tests that may be able to identify patients with SLE years before our current ability; so hopefully this will improve in the future.
      2. However, we can also have false positive anti-chromatin antibodies. This is more likely to happen in an ANA-negative patient who has no symptoms of SLE.

      Recommend: learn the symptoms of lupus, Sjogren’s disease, and RA … if any occur in the future, get reevaluated.

      Good luck,

      Donald Thomas, MD

  4. Does a high positive anti-chromatin, positive ANA, RNP (anti-U1 and anti-U2) specifically correlate to lupus? The patient experiences myositis-like symptoms on one side of the body. Patient has high creatinine. Would this indicate MCTD and therefore no concern for lupus? Should further testing on kidney function be done?

    • Deniece: This constellation of antibodies is not specific for lupus, myositis, nor MCTD. All of these can have these antibodies. All of these can cause muscle inflammation as well (myositis). If someone has nonspecific findings that can be seen in more than one CTD and does not satisfy classification criteria for either one, yet has evidence for a CTD, most of use would use a diagnosis of undifferentiated connective tissue disease (UCTD) yet still offer treatment targeted at the manifestations (most commonly hydroxychloroquine). Regarding a high serum creatinine, I’d absolutely want to know the eGFR, urinalysis and random urine protein to creatinine ratio. Note that some drugs can also cause a high creatinine in the absence of kidney disease (this includes hydroxychloroquine and Bactrim, famotidine, and fenofibrate).

      Donald Thomas, MD

  5. Just got test results.
    SM/RNP ab 8.0 high,
    Sjogrens Ab SSA 8.0 high,
    Chromatin ab 3.3 high.
    Everything else in normal range or negative
    Is this Lupus (SLE) ??
    Thanks in advance

    • Lisa: Anti-Sm/RNP is more closely related to anti-RNP antibody than to anti-Smith. This combo (Sm/RNP, SSA, chromatin) can be seen in most of the systemic autoimmune diseases (SLE, Sjogren’s disease, polymyositis, scleroderma). These labs had to be ordered for other reasons (arthritis, Raynaud’s, low blood counts etc)… your doc would have to put all of it together to help figure out. If you have dry mouth or eyes, then Sjogren’s would definitely need to be considered. Good luck!

      Donald Thomas, MD

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