Influence of inflammatory response, infection, and pulmonary function in cystic fibrosis.

AIMS: Recurrent infections and activation of the inflammatory response affect the prognosis of cystic fibrosis (CF). We investigated the relationship between inflammatory response, infection, and pulmonary function in CF.

MAIN METHODS: A clinical-cross-sectional study was conducted with 86 subjects: control group (CG, n=31, the same age and sex of the CF group), and CF group (CFG, n=55, age: 1-16 years), further distributed into CFG negative or positive bacteriology (CFGB(-)/CFGB(+)), and CFG negative or positive Pseudomonas aeruginosa (CFGPa(-)/CFGPa(+)). Using the Wald test, multiple linear regression (95% confidence interval) was performed between CG and CFG, and between CG and each of the CF subgroups (CFGB(-)/CFGB(+) and CFGPa(-)/CFGPa(+)). The inflammatory markers evaluated were myeloperoxidase (MPO), adenosine deaminase (ADA) activities, interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), nitric oxide metabolites (NOx) levels, and total and differential leukocyte counts.

KEY FINDINGS: After adjusting for sex and age, CFG compared to CG revealed an increase of MPO, IL-1β (P<0.001 in all subgroups), and CRP: CFG (P=0.002), CFGB(-) (P=0.007), CFGB(+) (P=0.009), CFGPa(-) (P=0.004) and CFGPa(+) (P=0.020). NOx (P=0.001, P<0.001), leukocytes (P=0.002, P=0.001), and neutrophils (P=0.003, P<0.001) were increased in CFGB(+) and CFGPa(+), respectively. A negative correlation between FEV1 and leukocytes (P=0.008) and FEV1 and neutrophils (P=0.031) resulted in CFG.

SIGNIFICANCE: The inflammatory response characterized by the increase of MPO, IL-1β, and CRP is determinant for CF. Also leukocytosis due to neutrophilia determines the pulmonary function deficiency in this disease.