Role of soluble triggering receptor expressed on myeloid cells-1 and serum procalcitonin in exacerbation of chronic obstructive pulmonary disease

Background
The morbidity, mortality, and quality of life of people with chronic obstructive pulmonary disease (COPD) are significantly impacted by exacerbations. Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), which act as an amplifier of the innate immune response, procalcitonin (PCT) is a polypeptide that normally produced by para follicular cells (C cells) of the thyroid and by neuroendocrine cells of the lung and intestine could be used to determine the severity of inflammation.


Objective
The aim of this study was to assess levels of sTREM-1 and PCT in COPD and evaluate the role of them in diagnosis of acute exacerbation of COPD (AECOPD) due to bacterial infections.


Patients and methods
The study was conducted on 60 individuals divided into group I (exacerbation group): included 20 patients. Group II (stable COPD group): included 20 patients. Group III (control group): included 20 individuals, apparently healthy and matched for age and sex. Assessment of sTREM-1 and serum PCT levels by enzyme-linked immunosorbent assay in addition to complete blood count, erythrocyte sedimentation rate, renal function tests, C-reactive protein, and sputum culture.


Results
sTREM-1, PCT, and neutrophil/lymphocyte ratio (NLR) were higher in the AECOPD group than in other groups. In AECOPD: the result of sputum cultures revealed; 65% Gram-negative bacteria and 35% Gram-positive bacteria, while in stable COPD: the growth of normal upper respiratory tract flora is 65% then Gram-positive bacteria (20%) then Gram-negative bacteria (15%). PCT, sTREM-1, and NLR showed a higher level in patients who had Gram-negative infection than those with Gram-positive infection, and the lowest level in those who showed growth of normal flora. Pseudomonas is the most commone causative organism of exacerbated COPD (35%), followed by Staphylococcus aureus (25%).


Conclusion
sTREM-1, NLR, and PCT level can be considered as an appropriate diagnostic marker in patients with exacerbated COPD due to bacterial infection and in differentiating them from stable COPD patients and may be used to guide medication and target management in patients with AECOPD.