Plasma Neutrophil Elastase and its Endogenous Inhibitors as Differential Inflammatory Markers for Dengue and Pneumonia

Abstract

Introduction: Neutrophils play a crucial role in protecting the host against microbial pathogens but they produce proteolytic enzymes such as Neutrophil Elastase (NE), the uncontrolled activity of which can destroy tissue and lead to organ failure. Thus, measurement of circulating levels of NE and its endogenous inhibitors may possibly contribute to diagnosis and management of diseases. Aim: This study was aimed to evaluate the changes in levels of NE, alpha1 -Antitrypsin (a1 -AT), alpha2 -Macroglobulin (a2 -MG) as well as elastase in complex with a1 -AT (NE-a1 -AT complex) in patients with dengue and pneumonia to ascertain if they could be of use as differential inflammatory markers and as adjunct diagnostic parameters in these two distinct disease conditions. Materials and Methods: This was a comparison study including 152 individuals in which 50 were in dengue group, 50 in pneumonia group, and 52 in control group. NE was measured using N-Succinyl-tri-alanine-p-nitroanilide as substrate. a1 -AT, a2 -MG and NE-a1 -AT complex were estimated by EnzymeLinked Immunosorbent Assay (ELISA). ANOVA, Kruskal-Wallis test and Pearson’s correlation tests were used to analyse the data. The results were expressed as Mean±SD and p-value <0.001 was considered statistically highly significant. Results: The result analysis indicated that the dengue and pneumonia patients had significantly higher elastase activity with significantly reduced a1 -AT levels compared to controls. a2 -MG level were significantly decreased in dengue while the levels were significantly increased in pneumonia. Conclusion: Significantly elevated levels of NE were observed in patients with dengue and pneumonia. Significantly reduced a1 -AT in dengue and significantly increased a2 -MG in pneumonia are observations of relevance.

Keywords

• alpha1 -antitrypsin
• alpha2 -macroglobulin
• neutrophil elastase- a1-antitrypsin complex