HLA-B27 gene has polymorphism, which is a collective term for a group of genes composed of multiple subtypes. The nucleotide sequences of each subtype have individual site differences. Since the association between HLA-B27 and AS was first reported in 1973, it has been confirmed that B27 plays an important role in the pathogenesis of SpA.
A large number of clinical studies have confirmed that the HLA-B27 positive rate in patients with SpA is significantly increased, but the HLA-B27 carrier rate is not entirely the same for various diseases. About 90% to 95% of AS patients are HLA-B27 positive, 60% to 80% of reactive arthritis (ReA), 80% of juvenile spinal arthritis (JSpA), and 50% of patients with psoriasis or enteropathy-related arthritis with spinal joint involvement are HLA-B27 positive. Individuals with HLA-B27 positive are 100 times more likely to develop SpA than individuals with negative HLA-B27.
In the Chinese Han population, HLA-B * 2705 and HLA-B * 2704 constitute the dominant subtypes of HLA-B * 27, while the rest still exist, such as B * 2707270227062715271127222708. Research has found that B2704, B2705, and B * 2702 are highly correlated with AS, while B * 2706, and B * 2709 are considered to have poor correlation or protective effects with AS.
The onset of diseases such as SpA is mostly slow and insidious. When the imaging examination shows signs of diagnosis, the patient's condition has progressed to the advanced stage of the disease, with a high disability rate and low quality of life. Therefore, clinical testing of the HLA-B27 gene is used to diagnose suspected patients.
The HLA-B27 genotyping kit uses polymerase chain reaction sequence specific primer (PCR-SSP) to qualitatively detect the HLA-B * 2704 and HLA-B * 2705/07 alleles in whole blood samples, which can provide a reference for the diagnosis and treatment of SpA.