Hematopoietic stem cell transplantation for CD40 ligand deficiency: results from an EBMT/ESID-IEWP-SCETIDE-PIDTC Study

Abstract Background CD40 ligand (CD40L) deficiency, an X-linked primary immunodeficiency, causes recurrent sinopulmonary, Pneumocystis and Cryptosporidium infections. Long-term survival with supportive therapy is poor. Currently, the only curative treatment is hematopoietic stem cell transplantation (HSCT). Objective We performed an international collaborative study to improve patients' management, aiming to individualize risk factors and determine optimal HSCT characteristics. Methods We retrospectively collected data on 130 patients who underwent HSCT for CD40L deficiency between 1993-2015. We analyzed outcome and variables relevance with respect to survival and cure. Results Overall survival (OS), event-free survival (EFS) and disease-free survival (DFS) were 78.2%, 58.1% and 72.3% 5 years post-HSCT. Results were better in transplants performed ≥2000 and in children Conclusion HSCT is curative in CD40L deficiency, with improved outcome if performed before organ damage development. MAC is associated with better OS, EFS and DFS. Prospective studies are required to compare risks of HSCT with those of life-long supportive therapy.