Serum Sp17 Autoantibody Serves as a Potential Specific Biomarker in Patients with SAPHO Syndrome

Abstract

SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome shows a wide variability in musculoskeletal and cutaneous manifestations, and it is therefore underrecognized and misdiagnosed in the clinic due to a lack of specific markers. In this study, we aimed to identify specific biomarkers by screening serum autoantibodies in SAPHO patients with a 17K human whole-proteome microarray. The serum anti-Sp17 autoantibody was identified and verified to be a specific biomarker in patients with SAPHO syndrome. Indeed, the level of the anti-Sp17 autoantibody was significantly increased in patients with active SAPHO compared to patients with an inactive disease and healthy controls (P < 0.05). Additionally, serum anti-Sp17 autoantibody levels correlated with those of serum hypersensitive C-reactive protein (hsCRP), the erythrocyte sedimentation rate (ESR), and β-crosslaps (β-CTx) in patients with active SAPHO disease. Moreover, anti-Sp17 autoantibody levels were markedly decreased after anti-inflammatory treatment with pamidronate disodium, which downregulated levels of hsCRP and ESR in patients with active SAPHO. Thus, serum levels of the anti-Sp17 autoantibody might serve as a specific biomarker for the diagnosis of SAPHO syndrome or for monitoring the disease status.

Current advances in antibody‐based serum biomarker studies: From protein microarray to phage display

“…Based on the human proteome microarray, many biomarkers have been identified by profiling disease-specific antibodies in sera, such as primary biliary cirrhosis [27], Behcet disease [28], and gastric cancer [11]. Recently, human proteome microarrays have been used in many other diseases for serum biomarkers, such as hepatocellular carcinoma [29], Sjögren's syndrome [30], lung cancer [31], multisystem inflammatory syndrome [32], and other diseases [33,39]. In addition, there are other proteome microarrays for screening serum biomarkers for diseases without clearly defined pathogens [40].…”