Late-Onset Progressive Multifocal Leukoencephalopathy (PML) and Lymphoma in a 65-Year-Old Patient with XIAP Deficiency.

Patient I.1 died from PML; Patient III.1 developed severe early-onset inflammatory bowel disease and was successfully treated, at 9 years with allogeneic HSCT from haploidentical donor using a reduced-intensity conditioning regimen; Patient III.3 died of neonatal HLH; Patient III.4 is asymptomatic; Patient III.5 developed auto-inflammatory symptoms at 8 years and was successfully treated at 12 year with allogeneic HSCT from matched sibling donor using a reduced-intensity conditioning protocol. To the Editor X-linked inhibitor of apoptosis (XIAP) deficiency (also known as X-linked lymphoproliferative syndrome type 2/XLP-2), caused by I XIAP i mutations, is a rare primary immunodeficiency (PID) [[1]]. The main clinical features of XLP-2 are (i) elevated susceptibility to hemophagocytic lymphohistiocytosis (HLH) (most frequently in response to Epstein-Barr virus (EBV) infection), (ii) recurrent splenomegaly, and (iii) inflammatory bowel disease (IBD). [Extracted from the article]