Fig. 1

Proposal of an integrative algorithm. This descriptive algorithm is designed to estimate probabilities for ACR or other causes of ALAD in lung transplant recipients presenting with clinical findings or a drop in lung function (FEV₁ > 10%). The integration of microbiology data, differential cytology [11] and cytokine expression levels from peripheral blood and BAL samples might assist in decision-making to increase or decrease the likelihood for ACR in the context of the clinical presentation. In the absence of standardized BAL techniques and detection methods, BAL cytokine expression levels and cut-offs have to interpreted wth caution and should be confirmed in larger studies. Since results from studies with very different designs have been included, direct translation in a clinical setting is not feasible and the use of this algorithm does not obviate the need for biopsy to confirm or exclude histology-proven ACR. * Numbers vary between different studies. ** Absence of microbiological evidence for infection