Anti-Histone Antibody Test
About Anti-Histone Antibody test
Anti-histone antibodies, also known as autoantibodies, are typically generated by the immune system. Sometimes, these autoantibodies attack the histones within the body. Histones are essential proteins found in chromatin; the main genetic material situated in the nucleus of cells in the body. The purpose of this test is to identify the presence of anti-histone antibodies in the blood serum.
Histone autoantibodies belong to a group of antinuclear antibodies (ANA), which are linked to various autoimmune disorders. In certain individuals, drugs can induce the production of histone antibodies, leading to a specific form of lupus known as drug-induced lupus erythematosus.
Thus, getting the anti-histone antibody test is recommended to support a diagnosis of drug-induced lupus.
This test is also known as
Histone Autoantibodies
Symptoms of drug-induced lupus
Fever
Fatigue
Weight loss
Muscle or joint aches
Red rash across the nose and cheek
Sensitivity to sunlight
Why is this test done?
Anti-histone antibody test is recommended
When a person experiences symptoms related to lupus that could potentially be caused by a medication they are using
To diagnose and monitor drug-induced lupus
Test Preparation
No special preparation is required for the anti-histone antibody test.
Interpretation of the results
The test result may come as positive or negative.
Positive result (A strong positive result is observed when the histone antibody, IgG is 2.6 units or higher)
A positive result would suggest the likelihood of drug-induced lupus, if an individual also has:
A. Lupus symptoms
B. Consumed a medication for a duration ranging from a few weeks to a couple of years
C. No identified autoimmune disorder before taking the medication
D. A positive ANA test
E. Low or negative autoantibodies and anti-dsDNA
F. Symptoms that resolve when the medication is discontinued
A diagnosis cannot be established solely based on a positive histone antibody result. Approximately 50% of individuals with SLE may have histone antibodies, but these are usually not caused by a specific medication. In such instances, the anti-dsDNA test will show a positive result.
Negative result (Histone antibody, IgG is 0.9 units or lower)
A negative result indicates that the signs and symptoms experienced by the individual might be due to a condition other than drug-induced lupus, such as a drug allergy. It is important to note that a negative result does not completely rule out the possibility of drug-induced lupus. A small subset of individuals may still have drug-induced lupus even in the absence of histone antibodies.
FAQs
How is the sample collected for an anti-histone antibody test?
A blood sample is collected from a vein in your arm using a small needle. Usually, this procedure does not take more than 5 minutes.
Are there any risks associated with the anti-histone antibody test?
This test involves negligible risk. There might be slight soreness or tenderness around the site where the blood is drawn. Rarely, the site can become infected.
What is the turnaround time (TAT) for the anti-histone antibody test?
The anti-histone antibody test result is usually available within 3-5 working days after the sample collection. This duration may vary depending upon the diagnostic clinic.
What types of medications are associated with drug-induced lupus?
Types of medications associated with drug-induced lupus include antibiotics, anti-seizure medications, anti-tumor necrosis factor (anti-TNF) agents,
blood pressure medications, thyroid medications etc.
If my histone antibody levels decrease, can I start taking my medication again?
It is not recommended to begin taking the medication again, as even if the antibodies decrease to extremely low or undetectable levels, a residual amount will remain. If you choose to resume your drug regimen, there is a possibility that your symptoms will reemerge and your antibody levels will rise once more. Hence, it is advised to consult your healthcare provider before starting medication.
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