RESUMO
OBJECTIVES: Chronic recurrent multifocal osteomyelitis (CRMO), the most severe form of chronic nonbacterial osteomyelitis (CNO), is an autoinflammatory bone disorder. In the absence of diagnostic criteria or biomarkers, CNO/CRMO remains a diagnosis of exclusion. The aim of this study was to identify biomarkers for diagnosing multifocal disease (CRMO). STUDY DESIGN: Sera from 71 pediatric CRMO patients, 11 patients with osteoarticular infections, 62 patients with juvenile idiopathic arthritis (JIA), 7 patients with para-infectious or reactive arthritis, and 43 patients with acute leukemia or lymphoma, as well as 59 healthy individuals were collected. Multiplex analysis of 18 inflammation- and/or bone remodeling-associated serum proteins was performed. Statistical analysis included univariate ANOVA, discriminant analysis, univariate receiver operating characteristic (ROC) analysis, and logistic regression analyses. RESULTS: For 14 of 18 blood serum proteins, significant differences were determined between CRMO patients, at least one alternative diagnosis, or healthy controls. Multi-component discriminant analysis delivered five biomarkers (IL-6, CCL11/eotaxin, CCL5/RANTES, collagen Iα, sIL-2R) for the diagnosis of CRMO. ROC analysis allowed further reduction to a core set of 2 biomarkers (CCL11/eotaxin, IL-6) that are sufficient to discern between CRMO, healthy controls, and alternative diagnoses. CONCLUSION: Serum biomarkers CCL11/eotaxin and IL-6 differentiate between patients with CRMO, healthy controls, and alternative diagnoses (leukemia and lymphoma, osteoarticular infections, para-infectious arthritis, and JIA). Easily accessible biomarkers may aid in diagnosing CRMO. Further studies testing biomarkers in larger unrelated cohorts are warranted.
RESUMO
Chronic recurrent multifocal osteomyelitis (CRMO), the most severe form of chronic nonbacterial osteomyelitis, is an autoinflammatory bone disorder. A timely diagnosis and treatment initiation is complicated by the absence of widely accepted diagnostic criteria and an incomplete pathophysiological understanding. The aim of this study was to determine biomarkers for the diagnosis and follow-up of CRMO. Serum of 56 CRMO patients was collected at the time of diagnosis. As controls, sera from treatment-naïve age-matched patients with Crohn's disease (N = 62) or JIA (N = 28) as well as healthy individuals (N = 62) were collected. Multiplex analysis of 25 inflammation markers was performed. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U tests, canonical discriminant analysis, and mixed model variance analysis. Mostly monocyte-derived serum proteins were detectable and differed significantly between groups: IL-1RA, IL-2R, IL-6, IL-12, eotaxin, MCP-1, MIP-1b, RANTES. Multicomponent discriminant analysis allowed for the definition of algorithms differentiating between CRMO, Crohn's disease, and healthy controls. Persistently high levels of MCP-1, IL-12, sIL-2R correlated with incomplete remission in follow-up samples from CRMO patients. Discrimination algorithms allow differentiation between patients with CRMO or Crohn's disease, and healthy individuals. IL-12, MCP-1, and sIL-2R can act as markers for treatment response. Though confirmation of our findings in larger multiethnical cohorts is warranted, they may prove valuable to differentiate between otherwise healthy individuals or Crohn's disease patients with "bone pain" and CRMO patients. The elevation of mainly monocyte-derived pro-inflammatory serum proteins supports the hypothesis of pro-inflammatory monocyte/macrophages driving inflammation in CRMO.
