Clara Cell Protein (Club Cell Protein) is a New Diagnostic Molecular Candidate Biomarker in Nosocomial Pneumonia

Abstract

Nosocomial pneumonia (NP) remains a relevant problem of resuscitation. Molecular biomarkers are significant promises for diagnosing NP. Objective: to estimate the informative value of the plasma levels of Clara cell protein (Club Cell Protein, CCP) as a diagnostic molecular candidate biomarker in NP. Subjects and methods. The investigation was conducted at the Research Institute of General Reanimatology (RIGR), Russian Academy of Medical Sciences (RAMS), in 2010—2013. It included 85 patients in accordance with the criteria of inclusion and exclusion and 30 donors. Acute respiratory distress syndrome and its stages were diagnosed using the criteria of RIGR, RAMS. Plasma Clara cell protein (CCP) levels were measured by the enzyme immunoassay Human Clara Cell Protein ELISA, RD191022200, BioVendor, USA. The findings were statistically analyzed using the package Statistica 7.0. ROC curve analysis was made to determine the sensitivity and specificity of CCP. The difference at p<0.05 was considered significant. Results. On days 1, 3, 5, and 7 of the investigation, the plasma CCP levels in patients with NP were lower than in those without this disease. Within all these days, the plasma CCP concentrations in patients with and without NP were higher than in healthy donors. On days 1 and 3, the plasma content of CCP was much lower in patients in whom NP had been caused by Pseudomonas aeruginosa (in association with other pathogens) than in those with NP uncaused by Pseudomonas aeruginosa. Within the first 24 hours, the CCP level of 17.5 ng/ml had 86.5% sensitivity and 66.7% specificity in diagnosing Pseudomonas aeruginosainduced NP (area undercurve, 0.74; 95% confidence interval, 0.630—0.829; p=0.0001). The prognostic value of the positive and negative results of this test was 81.8 and 74.1%, respectively. Conclusion. The time course of changes in the plasma levels of Clara cell protein was studied in the patients with nosocomial pneumonia. Clara cell protein was shown to be of informative value in the diag nosis of Pseudomonas aeruginosainduced NP; on the day when nosocomial pneumonia was diagnosed, the plasma CCP level of 17.5 ng/ml had 86.5% sensitivity and 66.7% specificity in diagnosing Pseudomonas aeruginosainduced NP.