Extracorporeal Photopheresis in Lung Transplant Rejection for Cystic Fibrosis (CF) Patients

Overview

Background/Rationale Acute rejection (AR) is common in the first year after lung transplantation. AR has usually been reversible with treatment, but it can trigger chronic rejection that is the leading causes of late morbidity and mortality. Extracorporeal photopheresis (ECP) has emerged as a promising treatment for chronic rejection. The investigators postulate that the immunoregulatory property of ECP could promote graft tolerance immediately after lung transplantation. Objectives The aim of this trial is to evaluate the safety and efficacy of ECP as induction therapy for prevention of AR in recipients affected with cystic fibrosis in the first year after lung transplantation. The extracellular vesicles in the cell-to-cell communication and immunomodulation will be also investigated. Preliminary results (personal) A preliminary study, conducted in Vienna, demonstrated that 9 patients treated with ECP as induction therapy had 0% of chronic rejection versus 50% in the control group. The Institution hosting the current project is among largest lung transplantation centers in Italy with high rate of cystic fibrosis recipients. The Institution has experience in ECP and a dedicated instrument was specifically bought for the project. Internal collaborators have strong expertise in biological aspects including the extracellular vesicle compartment.

The aim of this pilot trial is evaluate the efficacy and safety of ECP as induction therapy for prevention of AR in recipients affected of cystic fibrosis in the first year after lung transplantation. The investigators postulate that ECP could induce graft immunotolerance avoiding the development of chronic rejection. Exposing T-cells to ultraviolet light results in DNA damage and apoptosis; such form of cell death does not typically stimulate a prolonged inflammatory cascade. When re-infused to the patient, apoptotic T-cells are surrounded by antigen presenting cells (APCs). The large number of APCs encircling the damaged T-cells limits the inflammatory response and stimulates specific signalling cascades in APCs that result in anti-inflammatory cytokine production; finally, immature dendritic cells could gain tolerogenic phenotypes. Based on this process, a theory postulates that the immuno-modulation secondary to ECP is related to a general increase in regulatory T-cells that cause a down-regulation of immune responses involved in chronic rejection onset. Another theory assumes that suppressor T-cells may acquire anti-clonal immunity prompted by the APCs; therefore, a sort of T-cell vaccination is the result of leukocyte apoptosis. The intention is to use this T-cell regulation to induce immunotolerance toward the graft before the development of chronic rejection, in spite to operate when the damage is in progress. To activate this effect from the first hours after transplantation, it can be useful the immunomodulatory activity of extracorporeal photopheresis, already established by clinical studies applied to the treatment of acute and chronic rejection. The efficacy of ECP as induction therapy will be measured with the identification of AR rate in the study group versus the control group. AR is diagnosed with trans-bronchial biopsy and graded using standard histological criteria: A0 (none), A1 (minimal), A2 (mild), A3 (moderate) or A4 (severe). A stable 10% decrease of forced expiratory volume in 1 second (FEV1) on baseline will be considered as AR even though trans-bronchial biopsy is not available. In addition, lymphocyte immunophenotype (with particular regard to CD4 + and CD25 +), the cytokine profile (interleukine (IL) 4, IL-10, IL-12 measured by High Resolution Cytokines Array) and the extracellular vesicles content are tested to assess the therapeutic response. Finally, anti-HLA antibodies are tested to understand their dynamics. The ECP safety is assessed by recording every adverse effect with specific attention to opportunistic infections. In conclusion, this study aims to verify whether the induction therapy with ECP can dramatically decrease the rate of acute rejection in order to impact positively on the main cause of mortality in lung transplantation: the chronic rejection.