Also Known As: Histone Autoantibodies, Anti-Histone Antibodies, Histone IgG, AHA
What Is A Histone Antibodies Test?
The Histone Antibodies Test is used to diagnose and monitor symptoms related to lupus due to a particular medication/drug (drug-induced lupus). Histone antibodies are also called autoantibodies, usually produced by your immune system. Sometimes these autoantibodies begin to target the body's histones. These histones are proteins integral to chromatin, the primary genetic material located in the nucleus of almost all body cells. Since these histones are found within the cells, this self-target phenomenon can lead to different symptoms throughout your body. This test helps detect the presence of such histone antibodies in the blood serum.
Here, it is essential to mention that histone autoantibodies are among the many types of ANA, i.e., antinuclear antibodies. These antinuclear antibodies are also linked with a wide range of autoimmune diseases. The absence or presence of some specific ANAs helps determine which disorder you might be subjected to.
What Is The Test Used For?
The Histone Antibodies Test is generally used to diagnose, analyze, and evaluate drug-induced lupus. It is crucial for people who take particular medications for their health concerns. Many drugs can stimulate the production of histone antibodies in some individuals and lead to the formation of a kind of lupus called drug-induced lupus erythematosus. According to different studies and researchers, around 95% of people with drug-induced lupus have high histone antibodies in their bloodstream. These autoantibodies can also be found in 50% of people with non-drug-induced lupus and 20% in those with other kinds of connective tissue disorders.
Drugs that have been associated with drug-induced lupus erythematosus include:
Some other common examples of medications linked with drug-induced lupus are:
- Anti-seizure medications
- Different types of antibiotics
- Thyroid medications
- Anti-tumor necrosis factor agents, i.e., anti-TNF agents
- Blood pressure medications
This particular test helps distinguish drug-induced lupus from other forms of lupus, such as systemic lupus erythematosus or SLE. It can also help recognize one autoimmune disorder from another depending on its causes and symptoms. While it is not the main diagnostic procedure for drug-induced lupus, its performance is consistent with the diagnosis. Your doctor will typically order this test with or following the ANA test along with anti-double-stranded DNA (anti-dsDNA test) to present his diagnosis. If you are diagnosed with drug-induced lupus, the health care provider will discontinue the identified drug with your doctor's recommendation.
Why And When Do You Need The Histone Antibodies Test?
Your doctor or health care provider will order the histone antibody test if you are taking a drug for several days, weeks, months, or even years. The test is also suggested if the consumption of these drugs leads to some signs and symptoms related to drug-induced lupus. This is also true if you don't have a prior family or personal history of autoimmune disorders. The doctor will check you for symptoms like:
- Fatigue or extreme tiredness
- Arthritis like pain in one or more joints but without any joint inflammation
- Muscle pain or myalgia
- Extreme sensitivity to light
- Sudden weight loss
- Red rash that appears like a butterfly across the cheek and nose areas, i.e., malar rash
Some signs and symptoms involve complications of the central nervous system and kidneys due to systemic lupus erythematosus but are rare only for drug-induced lupus. Your doctor might repeat the histone antibody test at intervals after discontinuing the drug to monitor the decrease in histone antibody levels.
What Kind Of Sample Is Required For The Test?
During this test, your health care professional will draw a blood sample from a vein in your arm through a small needle. Once the needle is inserted, a small amount of your blood will be collected in the vial or test tube. You might feel a little sting when the needle goes in or out during the procedure. The test procedure is straightforward and will only take less than 5 minutes.
Do You Need To Prepare For The Test?
Since it is a standard blood serum test, you don't need to prepare for anything specially. It is better to have a detailed chat with your doctor regarding your medications and supplements. You can eat or drink as usual unless your doctor advises you otherwise.
Are There Any Risks To This Test?
There is almost no risk to having a blood test. You might feel a little sting, pain, or bruising while giving out the sample, but usually, the symptoms are moderate and go away quickly.
What Do The Test Results Mean?
The results of the histone antibody test depend upon several factors. You may get a positive result meaning that you are likely to have encountered drug-induced lupus if also indicating:
- Histone antibody levels that start to decrease with the discontinuation of a particular drug
- Positive ANA test results
- If you are taking a drug, especially the one linked with this condition, for many weeks, months, or years
- Symptoms associated with lupus
- Signs and symptoms that resolve on their own when the drug is discontinued
- Negative or low anti-dsDNA along with the other autoantibodies
- No specified autoimmune disorder before taking the drug
However, positive histone antibody test results cannot establish a diagnosis alone. 50% of patients with systemic lupus erythematosus will show histone antibodies even though a particular drug does not induce it. Your doctor will perform other related tests to assess your health concerns in such circumstances.
A negative histone antibody test result indicates that your signs and symptoms are due to a medical condition other than drug-induced lupus. It can be due to drug allergy but remember that a small portion of people have drug-induced lupus even if they don't have histone antibodies in their blood plasma.
Related Tests: Anti-Jo-1 Blood Test, Antinuclear Antibodies (ANA) Direct Blood Test, Antinuclear Antibodies (ANA) Comprehensive Blood Test, Anti-dsDNA (Double-stranded) Antibodies Blood Test