Inflammatory markers of lung disease in adult patients with cystic fibrosis

Predictors of mucoid Pseudomonas colonization in cystic fibrosis patients

RATIONALE

Chronic mucoid Pseudomonas aeruginosa within the airway in cystic fibrosis (CF) patients can determine prognosis. Understanding the risk factors of mucoid P. aeruginosa acquisition may change how we deliver care. This study aims to evaluate whether presence of risk factors reported to predict disease severity including gender, CFTR genotype, bacterial organisms in airway cultures, and serum levels of vitamins A and E, albumin, C-reactive protein, alpha 1-antitrypsin, and immunoglobulins increased the risk of mucoid P. aeruginosa acquisition.

METHODS

Primary endpoint was age at first transition from negative to positive culture for mucoid P. aeruginosa. Cox proportional hazards regression with time-dependent covariates examined development of mucoid P. aeruginosa infection and its association with longitudinally measured serum biomarkers, pulmonary function, and culture results for other organisms.

RESULTS

Median ages at CF diagnosis and at first culture were 0.55 and 5.7 years, respectively. Median number of cultures/patient was 17. Of the 323 subjects, 150 developed mucoid P. aeruginosa during a median 8.1 years' follow-up. In multivariate analysis, gender (relative hazard [RH] 0.55 for male vs. female, P = 0.001), number of DF508 alleles (RH 1.66 for 1 or 2 vs. 0, P = 0.04), FEV(1) % (RH 1.16 for 10% decrease, P = 0.008), and most recent Staphylococcus aureus status (RH 0.24 for positive vs. negative, P < 0.0001) remained statistically significant.

CONCLUSION

Female gender, number of DF508 alleles, decreased lung function, and lack of S. aureus on recent sputum culture are important risk factors for early detection of mucoid P. aeruginosa.

Anti-inflammatory approaches to cystic fibrosis airways disease

PURPOSE OF REVIEW

Therapy aimed at combating excessive lung inflammation should benefit patients with cystic fibrosis. This article reviews anti-inflammatory strategies, focusing on new evidence published since 2006.

RECENT FINDINGS

Use of oral corticosteroids was associated with benefit in an epidemiological study but they are still not recommended; high dose inhaled corticosteroids may cause harm (effect on growth), but they can safely be withdrawn in many patients. Some small beneficial effect of ibuprofen was seen in a multicentre study, but it is unlikely that this will change practice. Altering the imbalance seen in fatty acid metabolism with omega3 polyunsaturated fatty acid supplementation may be helpful but therapeutic benefit is not yet proven. Combating cysteinyl leukotrienes has potential but benefit remains to be proved. The beneficial effect of macrolides has been confirmed in patients with milder disease, but caution is needed because of emerging resistance patterns. Renewed research interest in antiproteases has not demonstrated any significant benefit.

SUMMARY

The ideal therapeutic drug, with the optimal balance of benefit and harm, is not yet available.

Sputum biomarkers of inflammation in cystic fibrosis lung disease

Pulmonary biomarkers are being used more frequently to monitor disease activity and evaluate response to treatment in individuals with cystic fibrosis (CF). This article summarizes the current state of knowledge of biomarkers of inflammation relevant to CF lung disease, and the tools to measure inflammation, with specific emphasis on sputum. Sputum is a rich, noninvasive source of biomarkers of inflammation and infection. Sputum induction, through the inhalation of hypertonic saline, has expanded the possibilities for monitoring airway inflammation and infection, especially in individuals who do not routinely expectorate sputum. We critically examine the existing data supporting the validity of sputum biomarkers in CF, with an eye toward their application as surrogate endpoints or outcome measures in CF clinical trials. Further validation studies are needed regarding the variability of inflammatory biomarker measurements, and to evaluate how these biomarkers relate to disease severity, and to longitudinal changes in lung function and other clinical endpoints. We highlight the need to incorporate sputum collection, by induction if necessary, and measurement of sputum biomarkers into routine CF clinical care. In the future, pulmonary biomarkers will likely be useful in predicting disease progression, indicating the onset and resolution of a pulmonary exacerbation, and assessing response to current therapies or candidate therapeutics.