Macrolides for the Treatment and Prevention of BOS

Abstract

Chronic lung allograft rejection or its clinical correlate, the bronchiolitis obliterans syndrome (BOS), characterized by a persistent decline in forced expiratory volume in 1 s (FEV1) from an established baseline, is the single most important cause of death in lung transplant recipients after the first postoperative year. BOS is thought to be the final common endpoint of various injuries to the pulmonary allograft, triggering different innate and adaptive immune responses. Most preventive and therapeutic strategies for BOS have thus far been largely unsuccessful. However, the introduction of macrolide antibiotics, such as clarithromycin or particularly azithromycin (AZI), in the field of lung transplantation (LTx) as of 2003 made it clear that some patients with established BOS might in fact benefit from such therapy due to its various anti-inflammatory and immunomodulatory properties, as summarized in this chapter. Particularly in patients with an increased bronchoalveolar lavage (BAL) neutrophilia, AZI treatment could result in an increase in FEV1 of at least 10 %. More recently, it has become clear that prophylactic therapy with AZI actually may prevent BOS and improve FEV1 after LTx. However, one should always be aware of possible adverse effects related to AZI when implementing this drug as prophylactic or long-term treatment. Even so, AZI therapy after LTx can generally be considered as safe.