Urinary N-telopeptide as a Biomarker of Disease Activity in Patients with Chronic Nonbacterial Osteomyelitis Who Have Not Received Bisphosphonates

Chronic nonbacterial osteomyelitis (CNO) is a rare autoinflammatory disease that causes bone destruction, soft tissue swelling, and bone pain1. Diagnosis and treatment are hindered by a lack of a reliable laboratory test to assess disease activity. Bone inflammation in CNO is associated with increased osteoclastic activity and bone resorption, causing focal accelerated breakdown of bone collagen. This may be measured through elevated urinary N-terminal telopeptide (NTx). Miettunen, et al reported rapid decline of urinary NTx in children with CNO after pamidronate treatment and subsequent rise of NTx was correlated with disease flare2. The initial NTx from patients with CNO was not different from that of healthy children. Correlation of NTx with disease activity in patients with CNO not treated with pamidronate has not been investigated. We sought to determine if NTx values correlate with CNO disease activity in children treated without a bisphosphonate. Children with a CNO diagnosis made by a pediatric rheumatologist as well as their nonadult healthy siblings were recruited from the rheumatology clinics after written informed consent was obtained (approved by Seattle Children’s Hospital, IRB 14426, and University of Iowa, IRB 200308051). Inclusion criteria consisted of a clinical diagnosis of CNO, … Address correspondence to Dr. Y. Zhao[4][1], 4800 Sand Point Way NE, Seattle, WA 98105, USA. Email: yongdong.zhao{at}seattlechildrens.org. [1]: #ref-4