A histone antibodies test is a blood test that measures the levels of antibodies against histones in the blood. Histones are proteins found in the nucleus of cells, where they help package and organize DNA. Antibodies are proteins produced by the immune system that target foreign substances, such as viruses or bacteria, but in some cases, they can also target the body's own proteins, leading to autoimmune diseases.
Key points:
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Purpose: Diagnose autoimmune diseases, particularly those affecting the connective tissues, such as systemic lupus erythematosus (SLE) and drug-induced lupus.
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Indications: A histone antibodies test may be ordered if a person has symptoms suggestive of an autoimmune disease, such as joint pain, fatigue, skin rashes, or fever. It may also be ordered if someone has been exposed to medications known to cause drug-induced lupus, such as certain antihypertensive drugs or antiseizure medications.
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Procedure: The test involves taking a blood sample from a vein, usually from the arm. The blood is then sent to a laboratory for analysis.
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Interpretation: Elevated levels of histone antibodies in the blood may indicate an autoimmune condition, particularly drug-induced lupus or SLE. However, not all individuals with elevated histone antibodies have symptoms of autoimmune disease.
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Limitations: While elevated levels of histone antibodies can be associated with autoimmune diseases, they are not specific to any one condition. Other tests, such as antinuclear antibody (ANA) testing, are often performed alongside histone antibody testing to help confirm a diagnosis.