Clinical correlates of HLA‐B27 and its subtypes in enthesitis‐related arthritis variant of juvenile idiopathic arthritis in south Indian Tamil patients

Aim The aim of the study was to assess the distribution of human leukocyte antigen (HLA)‐B*27 subtypes and its correlation with disease phenotypes in children with enthesitis‐related arthritis variant of juvenile idiopathic arthritis (JIA‐ERA). Method One hundred and sixty patients (132 males, 28 females) satisfying the International League Against Rheumatism (ILAR) classification criteria for JIA‐ERA were assessed and relevant demographic, clinical and radiographic data were documented. HLA‐B*27 typing was done for all the patients and B*27 positive samples were subjected to high‐resolution gene sequencing. The effect of duration of illness, HLA‐B*27, its subtypes, and gender on the clinical phenotype were analyzed. Results The mean age of disease onset was 12.69 ± 2.4 years with a male:female ratio of 4.7:1.0. HLA‐B*27 was positive in 109/160 patients and HLA‐B*27:04 was detected in 63% followed by B*27:05 (30%). Duration of illness was greater in patients with skeletal deformity, hip arthritis, sacroiliitis, cervical spine involvement and acute anterior uveitis (AAU) (P