Lethal Graft-Versus-Host Disease in Congenital Neutropenia Caused by p14 Deficiency After Allogeneic Bone Marrow Transplantation From an HLA-Identical Sibling

p14 is a small endosomal adaptor protein confining mitogen-activated protein kinase signaling to late endosomes [1,2]. Patientswith p14 deficiency present with a complex congenital immunode-ficiencysyndromeassociatingpigmentationdefects,growthfailure,severe congenital neutropenia (SCN) with delayed and ineffectivedegradation of ingested bacteria, and combined B and T cellimmunodeficiency [3].Clinically, p14 deficiency resembles Hermansky–Pudlak syn-drome, type 2 (HPS2), Griscelli syndrome, type 2 (GS2), andChe´diak-Higashi syndrome (CHS)—known diseases with reducedpigmentation and immunodeficiency [4–10]. All these diseaseshavebeencharacterizedonamolecularlevelandshowmutationsingenescontrollingvesiculartraffickingand/orlysosomalbiogenesis.Bone marrow transplantation (BMT) has been successfully used inCHSandGS2withoutappreciationofincreasedriskofgraft-versus-host disease (GvHD) [11–13].Here, we report on the clinical course of a patient with p14immunodeficiency and discuss how increased expression of tumornecrosis factor (TNF-) a associated with p14 deficiency may havetriggered lethal GvHD.