Longterm low-dose therapy with macrolides in cystic fibrosis

Abstract

Background – Modulation of the immune response is an attractive alternative approach to therapy in CF. In this regard macrolides with their additional anti-inflammatory properties may be useful in the treatment of CF lung disease. Objective  – to assess action and potential mechanisms of long-term low-dose therapy with 15- and 14-member lactone ring macrolides in children with CF. Methods – Twenty-five CF patients (14 m, 11f; age range 6.5–16 yrs) were treated with azithromycin (SUMAMED^®) in the dose 250 mg 2 times a week or clarithromycin in dose 250 mg every other day and basic therapy (ensymes; mucolytics, including rhDNAse; vitamins). The patients were routinely evaluated every three months. This evaluation included anthropometric measurements (Wt/Ht, %), physical examination, pulmonary function test (FEV₁, FVC), microbiology of sputum (respiratory cultures), inflammatory markers in the sputum samples (neutrophil elastase activity, TNF-α, IL-4, IL-8, IFNγ concentrations) and in peripheral blood (sensitivity of lymphocytes to antiproliferative effect of glucocorticoids). Results – During the six-month period before the start of macrolides most patients had experienced a decline in FVC and FEV1 (-3.3±2% and -2±1.5% predicted, respectively). Following the treatment the lung disease progression became slower (FVC: 7.0±2.1% and FEV1: 7.1±2.1%, both p=0.02). The effect was more pronounced in the patients with FVC<70 %. Before macrolides treatment this subjects showed a loss of the mean semiannual changes in FVC (-6.0±3.0%) and FEV1 (-3.3±2.4%). After six month treatment with macrolides we noticed a significant improvement in lung function (FVC: 8.6±3.6 %, FEV₁: 9.4±3.0%, both p=0.03). The patients with poor lung function showed an essential elevation of neutrophil elastase activity (from 60.0±15.1 to 130.1 ±30.4 U/mg protein; p=0.05) and decrease of TNF-β (from 68.0±34.1 to 9.3±2.3 lU/mg protein; p=0.02) in their sputum. Authors postulate that elastase activity elevation is associated with destruction of neutrophils following the antiinflammatory treatment. Discussion – Our preliminary findings suggest some potential mechanisms, by which long-term low-dose 15- and 14-member lactone ring macrolides therapy may be beneficial in CF.