Human leukocyte antigen B27 in 453 Asian Indian patients with seronegative spondyloarthropathy.

BACKGROUND Spondyloarthropathies are a group of closely related inflammatory arthritis which involve the axial skeleton and are negative for rheumatoid factor. OBJECTIVE This case-control study was conducted to examine HLA- B27 positivity in patients with seronegative spondyloarthritis (SSA) as per ESSG criteria and compare the frequency with healthy controls because a lower positivity is reported in Indians. METHOD The study included 453 patients and 200 controls. HLA -B27 typing was done by microlymphocytotoxicity and/or by sequence specific primers (SSP) using commercial kits. Patients were categorised as Ankylosing Spondylitis (AS), Undifferentiated Spondyloarthropathy, SSA with inflammatory bowel disease, reactive arthritis, psoriatic arthritis and juvenile spondyloarthropathy. RESULTS HLA- B27 antigen was present in 56% of patient and 3.5% controls with highest frequency in juvenile spondyloarthropathy (80%), followed by AS (76%). The P value < 0.001 for all categories of SSA and overall Odds ratio was 34.9. CONCLUSION This study showed HLA-B27 frequency slightly lower than reported in Caucasian SSA patients and in our opinion HLA- B27 testing is extremely useful in young patients with suspected SSA.