Abstract
BackgroundPolymorphonuclear (PMN) elastase plays an important role in a variety of inflammatory disorders. Our aim was to analyse PMN elastase in idiopathic inflammatory myopathies (IIMs) and its association with disease activity.MethodsPMN elastase levels were measured using enzyme-linked immunosorbent assay in serum samples obtained from 74 patients with myositis (58 with dermatomyositis [DM] and 16 with polymyositis [PM]) and 22 healthy controls. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the discriminant capacity of PMN elastase level and PMN elastase-to-neutrophil ratio (ENR) in patients with active and remission myositis. The association of serum PMN elastase level and ENR with disease variables was evaluated in patients with IIMs. The disease specificity of PMN elastase level and ENR was further examined in 60 patients with other systemic autoimmune diseases.ResultsPMN elastase level and ENR were significantly higher in patients with active IIMs, DM, and PM than in patients with remission. ROC curve analysis revealed that PMN elastase level and ENR both outperformed creatine kinase (CK), the currently used laboratory marker, and strongly discriminated patients with active disease and those with remission of IIMs, DM, and PM (area under the ROC curve [AUC] 0.9, 0.9, and 0.88 for PMN elastase; AUC 0.96, 0.96, and 1.0 for ENR; AUC 0.72, 0.70, and 0.80 for CK, respectively). PMN elastase level and ENR were positively correlated with myositis disease activity assessment, CK, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, C-reactive protein, and erythrocyte sedimentation rate. PMN elastase level and ENR were higher in the anti-PM-Scl positive myositis group than those in the anti-PM-Scl negative myositis group. Nevertheless, PMN elastase was not a specific disease marker for IIMs when compared with other autoimmune diseases.ConclusionsPMN elastase, particularly ENR, were significantly correlated with disease activity and could serve as useful biochemical markers for evaluating the disease activity of patients with IIMs. Thus, they are potentially helpful in monitoring disease progression and guiding treatment.
Highlights
Polymorphonuclear (PMN) elastase plays an important role in a variety of inflammatory disorders
In adult patients with myositis, several studies revealed that S100A11 [11], serum-soluble TRAIL [12], YKL-40 [13], and anti-EJ [14] are correlated with disease activity, but there is a lack of further research on their diagnostic value
After dividing the patients with idiopathic inflammatory myopathies (IIM) into subgroups, only those with DM showed significantly higher elevation of PMN elastase when compared with healthy control (HC) (1569.6 (871.1–4676.0) vs 1193.6 (518.8– 1513.9), ng/mL, P = 0.008; Fig. 1a)
Summary
Polymorphonuclear (PMN) elastase plays an important role in a variety of inflammatory disorders. Our aim was to analyse PMN elastase in idiopathic inflammatory myopathies (IIMs) and its association with disease activity. Disease activity of IIMs is currently assessed using muscle enzyme testing and clinical evaluation. Muscle enzyme testing includes serum creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) activity assessment and has been shown to moderately correlate with disease activity in IIMs [5, 6]. In adult patients with myositis, several studies revealed that S100A11 [11], serum-soluble TRAIL [12], YKL-40 [13], and anti-EJ [14] are correlated with disease activity, but there is a lack of further research on their diagnostic value. Objective biomarkers for monitoring disease activity in adult patients with myositis need further investigation
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