Ex vivo treatment of cytomegalovirus in human donor lungs using a novel chemokine-based immunotoxin

• DOI: 10.1016/j.healun.2021.10.010
• Publication Date: 2021-10-25T20:45:47Z
• Authors: Rafaela V.P. Ribeiro; Terrance Ku; Aizhou Wang; Layla Pires; Victor H. Ferreira; Vinicius Michaelsen; Aadil Ali; Marcos Galasso; Sajad Moshkelgosha; Anajara Gazzalle; Mads G. Jeppesen; Mette M. Rosenkilde; Mingyao Liu; Lianne G. Singer; Deepali Kumar; Shaf Keshavjee; John Sinclair; Thomas N. Kledal; Atul Humar; Marcelo Cypel
• Keywords: Ex vivo

Transmission of latent human cytomegalovirus (HCMV) via organ transplantation with post-transplant viral reactivation is extremely prevalent and results in substantial adverse impact on outcomes. Therapies targeting the latent reservoir within the allograft to mitigate viral transmission would represent a major advance. Here, we delivered an immunotoxin (F49A-FTP) that targets and kills latent HCMV aiming at reducing the HCMV reservoir from donor lungs using ex-vivo lung perfusion (EVLP).HCMV seropositive human lungs were placed on EVLP alone or EVLP + 1mg/L of F49A-FTP for 6 hours (n = 6, each). CD14+ monocytes isolated from biopsies pre and post EVLP underwent HCMV reactivation assay designed to evaluate viral reactivation capacity. Off-target effects of F49A-FTP were studied evaluating cell death markers of CD34+ and CD14+ cells using flow cytometry. Lung function on EVLP and inflammatory cytokine production were evaluated as safety endpoints.We demonstrate that lungs treated ex-vivo with F49A-FTP had a significant reduction in HCMV reactivation compared to controls, suggesting successful targeting of latent virus (76% median reduction in F49A-FTP vs 15% increase in controls, p = 0.0087). Furthermore, there was comparable cell death rates of the targeted cells between both groups, suggesting no off-target effects. Ex-vivo lung function was stable over 6 hours and no differences in key inflammatory cytokines were observed demonstrating safety of this novel treatment.Ex-vivo F49A-FTP treatment of human lungs targets and kills latent HCMV, markedly attenuating HCMV reactivation. This approach demonstrates the first experiments targeting latent HCMV in a donor organ with promising results towards clinical translation.