Mutations in the Dedicator of Cytokinesis-8 (DOCK8) gene are responsible for an immunodeficiency disease characterized by: severe cutaneous and sinopulmonary infections with bacterial organisms; extensive cutaneous viral infections with Herpes simplex, Herpes zoster, Molluscum contagiosum, and Human Papilloma Virus; a marked elevation in serum IgE levels and eosinophilia; homozygous or compound heterozygous mutations in the dedicator of cytokinesis 8 (DOCK8) gene. Patients with DOCK8 deficiency die from severe infections, squamous cell carcinomas, or hematological malignancies. Allogeneic hematopoietic stem cell transplantation (HSCT) represents a potentially life-saving treatment for immunodeficiency diseases such as DOCK8 deficiency. In this study we will evaluate the efficacy and safety of allogeneic HSCT for DOCK8 deficiency. We are particularly interested in determining whether allogeneic HSCT using different donor sources and conditioning regimens reverses the lethal disease phenotype in DOCK8 deficiency by reconstituting normal host defense. The development of lethal squamous cell carcinomas and lymphomas arising from the immunodeficiency in DOCK8 deficiency supports therapeutic intervention before overt malignancy arises.