Eosinophilic alveolitis in BAL after lung transplantation

Lung transplantation has become a therapeutic option for patients with end stage lung disease. However, outcome after transplantation is complicated by episodes of rejection and infections. Bronchoalveolar lavage is a valuable tool in monitoring patients after transplantation, since it allows the detection of pathogens. A marker specifically indicating rejection from changes in BAL fluid has not been found yet. Especially changes in differential cell count, like lymphocytosis or an increase in polymorphnuclear granulocytes, are unspecific. The role of high eosinophil levels in BAL has not been elucidated yet. We analyzed 25 BAL samples and clinical data of 4 patients who underwent lung transplantation and presented with recurrent episodes of eosinophilic alveolitis in BAL. All patients demonstrated a deterioration of clinical condition, lung function, and blood gas analysis during times of eosinophilia in BAL, compared to previous examinations. In all cases, eosinophilia in BAL was accompanied by rejection. All patients were finally treated with high doses of steroids, resulting in improvement of all parameters. Eosinophilia was not associated with significant changes in the IL-5 concentration in BAL or the pattern of IL-5 expression in BAL cells. In conclusion, eosinophilic alveolitis may indicate acute rejection in patients after lung transplantation, if other causes of eosinophilia are excluded.