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Updated: Jan 1, 2026
Monitoring Neutrophil Elastase and Cathepsin G Activity in Human Sputum Samples
Published on: May 21, 2021
Correlation of PMN elastase and PMN elastase-to-neutrophil ratio with disease activity in patients with myositis
Siyu Wu1, Wanchan Peng1, Yunli Zhang1
1Department of Clinical Laboratory, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, People's Republic of China.
Background:
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.
Methods:
PMN 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.
Results:
PMN 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.
Conclusions:
PMN 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.
Insights
Polymorphonuclear (PMN) elastase and its ratio to neutrophils (ENR) show promise as biomarkers for idiopathic inflammatory myopathies (IIMs). These markers effectively indicate disease activity and may aid in monitoring IIM progression.
Area of Science:
- Biochemistry
- Immunology
- Rheumatology
Background:
- Polymorphonuclear (PMN) elastase is implicated in inflammatory disorders.
- Idiopathic inflammatory myopathies (IIMs) are characterized by inflammation affecting muscles.
Purpose of the Study:
- To analyze PMN elastase levels in IIMs.
- To assess the association of PMN elastase with disease activity in IIMs.
Main Methods:
- Serum PMN elastase and PMN elastase-to-neutrophil ratio (ENR) were measured in 74 myositis patients and 22 controls.
- Receiver operating characteristic (ROC) curve analysis evaluated discriminant capacity against creatine kinase (CK).
- Associations with disease variables and specificity in other autoimmune diseases were assessed.
Main Results:
- PMN elastase and ENR were significantly higher in active IIMs compared to remission.
- Both markers outperformed CK in discriminating active from remission disease (AUCs up to 1.0 for ENR).
- PMN elastase and ENR correlated positively with disease activity markers and specific autoantibodies.
Conclusions:
- PMN elastase and ENR are valuable biochemical markers for assessing IIM disease activity.
- These markers can aid in monitoring disease progression and guiding treatment decisions.
