HLA-B27 (human leukocyte antigens) is a gene marker that can occur in diseases that belong to the group of seronegative spondyloarthritides (inflammation of the vertebral joints) (lack of rheumatoid factor; usually lack of rheumatoid nodules; preferentially sacroiliitis/inflammatory change of the lower spine; this includes joints between the sacrum and ilium, sacroiliac joints). These include:
- Bechterew’s disease (ankylosing spondylitis) – chronic inflammatory rheumatic disease that affects only the spine and its border joints.
- Psoriatic arthropathy (synonym: psoriatic arthritis) – joint complaints that can occur in the context of psoriasis.
- Reiter’s disease (synonyms: Reiter’s syndrome; Reiter’s disease; arthritis dysenterica; polyarthritis enterica; postenteritic arthritis; posturethritic arthritis; undifferentiated oligoarthritis; urethro-oculo-synovial syndrome; Fiessinger-Leroy syndrome; English Sexually acquired reactive arthritis (SARA)) – special form of a “reactive arthritis” (see above. ); secondary disease after gastrointestinal or urogenital infections, characterized by the symptoms of Reiter’s triad; seronegative spondyloarthropathy, which is triggered especially in HLA-B27 positive persons by an intestinal or urinary tract disease with bacteria (mostly chlamydia); Can manifest as arthritis (joint inflammation), conjunctivitis (conjunctivitis), urethritis (urethritis) and partly with typical skin changes.
- Uveitis anterior – inflammation of the anterior region of the uvea (middle eye skin), especially the iris (iris) and the ciliary muscle.
The procedure
Material needed
- EDTA blood
Preparation of the patient
- Not necessary
Disruptive factors
- Not known
Indications
- Suspicion of seronegative spondyloarthritides.
Interpretation
Interpretation of HLA-B27 positive findings.
- Ankylosing spondylitis (90-95%).
- Reiter’s disease or reactive arthritis (70-80%).
- Juvenile idiopathic arthritis with enthesitis (75%).
- Psoriatic arthropathy/psoriatic arthritis (60-70%)
- Uveitis anterior (about 50%)
- Rheumatoid arthritis (approx. 10 %)
Other notes
- As a basic diagnostic test, the following laboratory tests should be performed when rheumatoid arthritis is suspected.
- CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate).
- Rheumatoid factor (or CCP-AK)
- ANA (antinuclear antibodies)
- HLA-B27 (Histocompatibility antigens).
- If seronegative spondyloarthritides are suspected, the following laboratory tests should be performed:
- HLA-B27
- Arthritis pathogen