Ramin Sami - Department of Internal Medicine, Metabolic Diseases Research Center, Qazvin University of Medical Sciences, Qazvin, Iran.
Mohammadali Zohal - Department of Internal Medicine, Metabolic Diseases Research Center, Qazvin University of Medical Sciences, Qazvin, Iran.
Alireza Marhamati - Department of Internal Medicine, Metabolic Diseases Research Center, Qazvin University of Medical Sciences, Qazvin, Iran.

Introduction: Bronchiectasis is known as an inflammatory-infectious disease. It seems that airway colonization with microorganisms can cause airway inflammationirrespective of active infection. In this study, we examine the association between serum levels of C-reactive protein (CRP) and bronchial bacterial colonization inthe absence of active infection. Materials and Methods: This is a prospective study on patients with diffuse non-cystic fibrosis bronchiectasis. Patients who were clinically stable in the previous 4 weeks were enrolled in the study. Pulmonary function tests, daily sputum volume measurement, Gram stain study and bacterial culture of sputum and serum levels of CRP were assessed in all subjects. Subjects were categorized as Pseudomonas and non-Pseudomonas according to their sputum culture results.Results: Fifty-eight subjects with mean (±SD) age of 43.6 (±14.2) years were evaluated. Twenty-eight subjects (38%) were colonized with Pseudomonas strains and 15patients (25.8%) with other microorganisms. Twenty-one individuals (36.8%) revealed no pathogen in their sputum culture. Serum levels of CRP ranged between 1-109 mg/L (15.5±19.9 mg/L). CRP levels in patients with Pseudomonas and non-Pseudomonas groups were 17.5 ± 20.54 mg/L and 13.5 ± 11.4 mg/L, respectively. This level was 13.2 ± 16.7 mg/L in those with negative sputum cultures (P=0.82). We did not observe any association between CRP level and FEV1, FEV1/FVC, extension of bronchiectasis in CT scan and sputum volume. Although it was strongly associated with Body Mass Index (P< 0.05). Conclusion: Our study showed high levels of CRP in the stable bronchiectasis independent to disease severity. CRP level was higher in those who colonized with Pseudomonas species, but this difference is not statistically significant.

Bronchiectasis, C-reactive protein, Colonization.