Open AccessComposition of calcifications in children with juvenile dermatomyositis: Association with chronic cutaneous inflammation
Author(s) -
Pachman Lauren M.,
Veis Arthur,
Stock Stuart,
Abbott Kathy,
Vicari Frank,
Patel Pravin,
Giczewski Diana,
Webb Catherine,
Spevak Lyudmila,
Boskey Adele L.
Publication year - 2006
Publication title -
arthritis & rheumatism
Language(s) - English
Resource type - Journals
eISSN - 1529-0131
pISSN - 0004-3591
DOI - 10.1002/art.22158
Subject(s) - juvenile dermatomyositis , juvenile , inflammation , osteopontin , calcinosis , pathology , medicine , osteonectin , dermatomyositis , calcification , chemistry , biology , osteocalcin , biochemistry , alkaline phosphatase , genetics , enzyme
Abstract Objective Calcific deposits develop in 20–40% of children with juvenile dermatomyositis (juvenile DM), contributing to disease morbidity and mortality. This study was undertaken to define the structure and composition of these deposits and to characterize their association with chronic inflammation. Methods We examined calcific deposits from 5 children with juvenile DM (2 boys and 3 girls). The crystal structure and mineral content of the deposits was analyzed by x‐ray diffraction, Fourier transform infrared spectroscopy, and imaging. The protein content of the deposits, following solubilization, was assayed by Western blotting. Results All 5 children had both a young age at disease onset (mean ± SD 3.3 ± 1.9 years) and, despite therapy, persistent cutaneous inflammation (mean ± SD duration 81.3 ± 58.7 months). The bone proteins, osteopontin, osteonectin, and bone sialoprotein, were identified in the protein extracts; the only mineral detected was hydroxyapatite, but the tissue was distinct from bone, with an extremely high mineral content and an irregular distribution of mineral. Conclusion These results indicate that chronic cutaneous inflammation may contribute to the formation of hydroxyapatite‐containing pathologic calcifications in children with juvenile DM.