Histone antibodies
| Category | Immunology |
|---|---|
| Test background |
Histones are highly conserved positively charged proteins that are found in cell nuclei. They act as a spool for DNA to wrap around and can be enzymatically modified to regulate gene transcription. Histone antibodies have been reported in drug-induced lupus (DIL), an autoimmune phenomenon where symptoms similar to systemic lupus erythematous (SLE) develop within a few weeks to a few months of taking the eliciting drug. There are more than 100 drugs reported to cause DIL (e.g. procainamide, hydralazine, anti-TNFs). DIL tends to be less severe than SLE, most commonly presenting with skin rash and arthralgia, and symptoms resolve after the drug is withdrawn. Most DIL patients will have a positive ANA IIF (usually homogenous, ICAP AC1) and are negative for double stranded DNA (dsDNA) antibodies. Some anti-TNF induced lupus patients can be positive for dsDNA antibodies. Histone antibodies are found in around 75% of patients with DIL and also SLE and therefore have very limited clinical use. (https://www.ncbi.nlm.nih.gov/books/NBK441889/) |
| Clinical Indications |
Drug-induced lupus |
| Reference range | Negative |
| Sample & container required | Serum (RST rust top) |
| Sample volume | 5-10 mL blood (1 mL serum) |
| Turnaround time | 28 days |
| Notes | Not currently performed in house; this test is referred to the Protein Reference Unit (PRU), Sheffield |