Bronchoalveolar lavage fluid leukotrienes in the pathomechanism of acute inflammatory events in lung transplant recipients

Background: The pathomechanism of acute inflammatory events, i.e. infection and rejection during the follow up of lung transplanted (LTx) patients is not fully understood. Leukotrienes, products of lipoxygenase enzyme may play a potential role, however they have not been investigated before. Aims: To analyse bronchoalveolar lavage fluid (BALF) leukotrienes in lung transplant recipients. Methods: Thirty-three BALF samples were analysed in 13 LTx patients for leukotriene B4 (LTB4) and cysteinyl-leukotriene (Cys-LT) concentration. In 10 cases patients were considered stable (stable group), in 7 cases bronchial biopsy revealed acute rejection (rejection group), and in 15 cases no sign of acute rejection, but a significant (>10 3 CFU/ml) bacterial or fungal colony count was observed (infection group). Leukotrienes were determined with ELISA. Results: There was no difference in BALF total leukocyte number, lymphocyte, neutrophil or eosinophil cell count between the three groups, however a >5% neutrophil count was indicative for infection. A tendency for higher BALF LTB4 was observed in acute rejection (341±445 pg/ml, p=0.05) as well as infection (156±163 pg/ml, p=0.09) compared to stable samples (66±57 pg/ml), without any difference between acute rejection and infection (p=0.52). BALF LTB4 levels were not related to lung function or BALF cell counts. No difference was shown for Cys-LT (p>0.05). Conclusion: Our results indicate that LTB4 may play a role in the pathomechanism of acute inflammatory events in lung transplanted patients. This needs to be investigated in an extended cohort of patients in detail. The study was supported by Hungarian Respiratory Society grant.