The challenges presented by haematopoietic stem cell transplantation in children with primary immunodeficiency

or background For many primary immunodeficiencies (PIDs), haematopoietic stem cell transplantation (HSCT) offers treatment to cure disease. However, patients with PID present a unique set of challenges when considering HSCT. Sources of data Review of recent literature. Areas of agreement The most significant recent impact on successful outcome is introduction of newborn screening programmes for diagnosis of severe combined immunodeficiency—wider adoption of screening in an increasing number of countries will see further improvements. Other PIDs have better outcomes when treated earlier, before development of co-morbidities—early referral for consideration of HSCT is important. Evolution of conditioning regimens is improving short- and long-term toxicities—targeted busulfan and low-toxicity myeloablative treosulfan regimens deliver good survival with reduced short-term toxicities. Areas of controversy The most radical development, still in clinical trials, is the use of mono-antibody-based conditioning, which eliminates the requirement for chemotherapy and is likely to become much more important in HSCT for non-malignant disease in the future. Growing points Multidisciplinary working for optimum care is essential. Areas timely for developing research International collaborations are important to learn about rare presentations and complications, and to formulate the most effective and safe treatment strategies.