Peripheral Blood Eosinophil Count as a Marker of Pulmonary Allograft Rejection

Abstract

Purpose Non-invasive methods for early diagnosis of acute cellular rejection (ACR) are needed. Previous studies of other solid organ transplanted recipients have shown a relationship between the eosinophil count in peripheral blood (EOSp) and the presence of ACR. However, the relationship between this biomarker and ACR in lung transplant patients remains unclear.Objective: To asses the relationship between EOSp and the presence of allograft rejection in lung transplant recipients. Methods A retrospective clinical review of 363 transbronchial biopsies (BTB) performed in 194 lung transplant patients between 2014 and 2018. We analyzed: age, date of transplant, the presence and degree of ACR, and the simultaneous absolute number of EOSp. BTB indications were classified as: 1. Protocol BTB in the first month after transplant and after ACR treatment. 2. Decrease of lung function. 3. Other indications The relationship between the EOSp count and ACR was analyzed by the Chi-square test . We calculated the sensitivity, specificity of the EOSp count to diagnose ACR. The precision of the EOS count to predict ACR was analyzed using a receiver operating characteristic ROC curve. Results BTB showed ACR in 117 of 363 cases (32.2%). The most frequent ACR degree was A2 (53%). The EOSp count in patients with ACR was higher than non-ACR patients (197 vs. 92.7; p 197 EOSp was 91% and the area under the ROC curve was 0.724 with 95% confidence interval (CI) 0.636-0.813. Conclusion The monitoring of the EOSp count can be useful to increase the diagnostic yield for ACR of BTB performed by protocol or lung function deterioration.