Second allogeneic stem cell transplantation for XMEN disease.

X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection and neoplasia (XMEN) disease is due to an inherited defect in immunity from loss-of-function mutations in the magnesium transporter 1 gene (MAGT1). Patients can present as adults with XMEN disease from a delayed diagnosis or lack of genetic diagnosis. Allogeneic stem-cell transplantation is curative in XMEN disease, but the mortality is high, especially in adults. Defective N-glycosylation of platelet glycoproteins impairs platelet aggregation and risks fatal mucosal haemorrhage (such as posterior epistaxis with airway obstruction and haemorrhagic shock requiring intubation) early during post-transplant aplasia. Maintaining a platelet level of at least 30×109/L until engraftment could avoid life-threatening haemorrhage. This is the first report of a successful second allogeneic stem-cell transplant in XMEN disease. Allogeneic stem-cell transplant in adults with XMEN disease should be considered as a curative option in patients with suitable donors.