Bronchoalveolar lavage lymphocytes as a marker of acute cellular rejection in lung transplant recipients

Abstract

<b>Introduction:</b> Acute cellular rejection (ACR) is one of the most frequent complications after lung transplantation (LT). Transbronchial biopsy (TBB) is the gold standard for the diagnosis of ACR. Bronchoalveolar lavage (BAL) is a less invasive and lower risk alternative <b>Aims:</b> To evaluate the predictive capacity of BAL cellularity to diagnose ACR in LT patients. Search for diagnostic markers of ACR in BAL and peripheral blood are established as secondary objectives <b>Methods:</b> Retrospective analysis of 434 samples (TBB and BAL) performed simultaneously in 256 patients with LT between Jan 2014 - Oct2018 In BAL samples, different cell subpopulations were evaluated by flow cytometry. In peripheral blood samples, absolute eosinophil count was evaluated at the time of performing BAL <b>Results:</b> ACR is observed in 126 of the 434 TBB (29%) Statistically significant differences were found in BAL cellularity between patients with ACR and without ACR (figure 1.A) Regarding lymphocytes, detection of &gt;20% lymphocytes in BAL has a 71% specificity for ACR diagnosis (SENS 35%, PPV 33%, NPV 73%). If the presence of &gt;200/mm3 eosinophil count is combined with the presence of &gt;20% lymphocytes in BAL, this specificity increases to 96% (SENS 17%, PPV 62%, NPV 74%) for the diagnosis of ACR in LT patients (Figure 1.B) <b>Conclusions:</b> Peripheral blood eosinophils bound to lymphocytes in BAL have high specificity for ACR diagnosis in lung transplant patients