HLA-B27 predicts a more extended disease with increasing age at onset in boys with juvenile idiopathic arthritis

• OBJECTIVE: Juvenile idiopathic arthritis (JIA) is a heterogeneous condition with very few clinical and laboratory signs that can help predict the course and severity of the disease in the individual patient. The cell-surface antigen HLA-B27 is well known to be associated with spondyloarthropathies, reactive arthritis, and enthesitis. HLA-B27 plays an important role in the classification of JIA, since evidence of sacroiliitis most often evolves after years of arthritis in other joints. We investigated the associations of HLA-B27 and the clinical manifestations of JIA using a method as close to a population-based study as possible.METHODS: We studied an incidence-based cohort of 305 patients collected prospectively in 3 Nordic countries (Sweden, Norway, Denmark). Clinical and serological data of the first 3 years of the disease were collected.RESULTS: HLA-B27 was found to be positive in 25.5% of the patients, and we found a higher proportion of HLA-B27-positive boys with older age at disease onset (p=0.034). Regression analysis showed a correlation of 0.7 in the HLA-B27-positive boys, pointing to a higher risk of more joint involvement with older age at disease onset. By Fisher's exact test, involvement of small joints in the lower extremities was associated with HLA-B27 in boys (p=0.011), but not in girls (p=0.687). HLA-B27 was associated with inflammatory back pain in both sexes (p=0.041 in boys, p=0.042 in girls), but with enthesitis only in boys (p<0.001 in boys, p=0.708 in girls).CONCLUSION: HLA-B27 is of increasing importance with older age at disease onset in boys with JIA, predicting more active joints within the first 3 years of disease, and also involving small joints in the lower extremity to a greater degree than in HLA-B27-negative boys. During the first 3 years of disease the occurrence of HLA-B27 is associated with inflammatory back pain in both sexes, but with enthesitis only in boys. Our data present new challenges for the ILAR classification of JIA.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Hälsovetenskap (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Health Sciences (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Pediatrik (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Pediatrics (hsv//eng)

Nyckelord

Adolescent

Age of Onset

Arthritis

Juvenile Rheumatoid/genetics

Child

Child

Preschool

Denmark

Disease Progression

Female

Genetic Predisposition to Disease/genetics

HLA-B27 Antigen/genetics

Humans

Longitudinal Studies

Male

Norway

Sex Factors

Sweden

MEDICINE

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)