Serum calprotectin--a promising diagnostic marker for adult-onset Still's disease.

Qian Guo,Xicao Zha,Yin Su,Yuan Jia,Jianping Guo,Lei Zhu,Chun Li

doi:10.1007/s10067-015-3108-6

Abstract

Calprotectin is a calcium-binding cytosolic protein, mainly expressed in immune cells, such as neutrophils, monocytes, and macrophages. Our study aimed to evaluate the diagnostic value of calprotectin for adult-onset Still’s disease (AOSD), by comparing serum calprotectin concentrations in patients with AOSD (n = 46), rheumatoid arthritis (RA, n = 34), primary Sjögren syndrome (pSS, n = 40), systemic lupus erythematosus (SLE, n = 39), osteoarthritis (OA, n = 20), and healthy controls (HCs, n = 49). Calprotectin concentrations were significantly higher in patients with AOSD (55.26 ± 18.00 ng/ml), compared to patients with RA (39.17 ± 18.90 ng/ml), pSS (35.31 ± 19.47 ng/ml), SLE (32.21 ± 25.01 ng/ml), OA (19.24 ± 10.67 ng/ml), and HCs (8.46 ± 5.17 ng/ml). All the differences were highly significant (p < 0.001). Using receiver-operating characteristic curve, the cut-off value of calprotectin was defined as 45.488 ng/ml, and its sensitivity and specificity for AOSD diagnosis were 63.0 and 80.1 %, respectively. The positive rate of calprotectin was significantly higher in AOSD cases compared to patients with other diseases and healthy controls (p < 0.001). Serum calprotectin was positively correlated with ferritin (r = 0.294, p < 0.05), and concentration of hemoglobin was significantly lower in calprotectin-positive patients compared to negative patients in AOSD (103.49 ± 20.21 g/l vs 115.71 ± 15.59 g/l, t = −2.142, p = 0.038). These findings suggest that serum calprotectin may serve as a promising marker for the diagnosis of AOSD and monitor disease activity to a certain extent.

Highlights

Adult-onset Still’s disease (AOSD) is a systemic disease with unclear etiology, characterized by spiking fever, arthritis, evanescent rash, lymphadenopathy, hepato-splenomegaly, sore throat, neutrophilic leukocytosis, and abnormality of liver enzymes [1]
Our study aimed to evaluate the diagnostic value of calprotectin for AOSD, by comparing the serum levels of calprotectin in AOSD patients with several other autoimmune disease controls, i.e., rheumatoid arthritis (RA), primary Sjögren syndrome, systemic lupus erythematosus (SLE), osteoarthritis (OA), as well as with healthy controls (HCs)
Except the proportion of patients with sore throat was higher in calprotectin negative group than the positive group (p=0.017), there was no significant difference between the two groups in other clinical features including fever, evanescent rash, arthritis, serositis, AOSD is a systemic disease of unknown etiology

Summary

Introduction

Adult-onset Still’s disease (AOSD) is a systemic disease with unclear etiology, characterized by spiking fever, arthritis, evanescent rash, lymphadenopathy, hepato-splenomegaly, sore throat, neutrophilic leukocytosis, and abnormality of liver enzymes [1]. Before the diagnosis of AOSD, infectious, neoplastic, and other rheumatological disorders should be ruled out. Since there were no disease-specific manifestations and serologic markers, the diagnosis for AOSD and accurate determination of disease activity is difficult [3, 4]. The currently used markers for the diagnosis of AOSD included erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum ferritin, which lacking the sensitivity, specificity, and precision to diagnose AOSD and to monitor the disease activity. Specific serological marker for diagnosis and assessment of disease activity in AOSD is urgently needed

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Results

Conclusion