A PROSPECTIVE STUDY FOCUSING ON AXIAL INVOLVEMENT IN ITALIAN CAUCASIAN CHILDREN WITH HLA-B27 POSITIVE JUVENILE ONSET SPONDYLOARTHRITIS

Background: Children with juvenile onset spondyloarthritis (JSpA) usually present with peripheral arthritis and enthesitis and less frequently with sacroiliac joint and spine involvement. Contradictory data exist on the evolution of JSpA. Mexican authors found a high tendency (75%) to develop axial involvement in the first 5 years of disease evolution (1). In our previous study carried out on a cohort of children gathered in Tuscany, we found a lower frequency (15%) of axial involvement after the same period of follow-up (2). Objectives: To evaluate in a new cohort of Italian Caucasian HLA-B27 positive JSpA children coming from Southern Italy the frequency of axial involvement after a 5-year follow-up. Methods: All children aged less than 16 years affected by JSpA, seen at the Rheumatology Department of Lucania in the 1999-2008 period, entered in a special register and were followed up prospectively. Of these, only the HLA-B27 positive ones without axial involvement at the first evaluation were included in the present study. Pelvic and lumbosacral X-rays were obtained at baseline and after 5 years. The plain films of the enrolled patients were mixed with those of age-matched control subjects and read blindly to the disease status and time of evaluation. Additional X-rays and/or MRI axial evaluation were performed, during follow-up, when clinically necessary. Results: During the study period, 14 children (9 boys and 5 girls) were enrolled. Their median age at onset and disease duration were 10.3 and 1.5 years, respectively. Five had a family history of HLA-B27-associated diseases and 4 of psoriasis. During the follow-up, all children developed episodes of peripheral arthritis and/or peripheral enthesitis and/or dactylitis. One child (7.1%) had buttock pain together with peripheral enthesitis. MRI of the sacroiliac joints showed bone edema. No children showed any limitation of spinal movement during the follow-up. None presented radiological evidence of sacroiliitis or spondylitis after 5 years, including the boy with the diagnosis of sacroiliitis on MRI. Interestingly, this child showed normal MRI sacroiliac joint scans at the end of the follow-up period. Conclusion: Our present data confirm our previous observation of a low frequency of development of axial involvement in Caucasian children suffering from HLA B27 positive undifferentiated JSpA. Long-term data on this series of patients are necessary. References: 1. Burgos-Vargas R, Clark P. Axial involvement in the seronegative enthesopathy and arthropathy syndrome and its progression to ankylosing spondylitis. J Rheumatol 1989; 16: 186-91. 2. Olivieri I et al. Low frequency of axial involvement in Caucasian pediatric patients with seronegative enthesopathy and arthropathy syndrome after five years of disease. J Rheumatol 1992; 19:469-75. Disclosure of Interest: None declaredCitation: Annals of the Rheumatic Diseases, volume 68, supplement 3, year 2009, page 500Session: Paediatric rheumatology (Poster Presentations )