The association between serological features of chronic Chlamydia pneumoniae infection and markers of systemic inflammation and nutrition in COPD patients.

INTRODUCTION: Chlamydia pneumoniae is an obligatory human pathogen involved in lower and upper airway infections, including pneumonia, bronchitis. Asymptomatic C. pneumoniae carriage is also relatively common. The association of C. pneumoniae infections with the chronic obstructive pulmonary disease (COPD) course is unclear.

OBJECTIVES: The aim of the study was to investigate the association between chronic C. pneumoniae infection and clinical features of COPD, markers of inflammation and metabolic dysfunction.

PATIENTS AND METHODS: The study included 59 patients with stable COPD who had no, or had ≥2 acute exacerbations during last year. The level of IgA and IgG antibody against C. pneumoniae, IL-6, IL-8, resistin, insulin, adiponectin and acyl ghrelin was measured in serum by enzyme-linked immunosorbent assay (ELISA).

RESULTS: No differences in clinical and functional data were observed between COPD patients without serological features of C. pneumoniae infection and chronic C. pneumoniae infection. The level of anti C. pneumoniae IgA significantly correlated with IL-8, IL-6, resistin concentration in group of frequent exacerbators. IgG level correlated negatively with acetyl ghrelin and body mass index (BMI) in patients without frequent exacerbations, in contrast to frequent COPD exacerbation group where significant correlations between IgG level and BMI was demonstrated. Serum IL-6 correlated positively with resistin and insulin and negatively with adiponectin in group of patients with serological features of chronic C. pneumoniae infection only.

CONCLUSIONS: Our study showed that chronic C. pneumoniae infection does not influence the clinical course of COPD in the both study groups. Chronic C. pneumoniae infections might be associated with a distinct COPD phenotype that affects metabolic dysfunction.