T-Cell Depletion and Stem Cell Transplant for Immune Deficiencies and Histiocytic Disorders

Inclusion Criteria: * Any patient from birth to \< 55 years of age fulfilling the following criteria will be eligible for this study. * Patients meeting clinical diagnostic criteria for Hemophagocytic Lymphohistiocytosis (HLH) * Patients meeting clinical diagnostic criteria or genetic diagnosis of X-linked lymphoproliferative disorder (XLP) and whose disease is ACTIVE but STABLE, or NON-ACTIVE/QUIESCENT. * Patients with Chediak-Higashi Syndrome who meet the following diagnostic criteria and whose disease is ACTIVE but STABLE, or NON-ACTIVE/QUIESCENT as defined in Appendix V of the study protocol. * Patients with Viral Associated Hemophagocytic Syndrome (VAHS) - if relapsed after other therapy or supportive care. Diagnostic criteria as above for HLH. Disease status must be ACTIVE but STABLE, or NON-ACTIVE/QUIESCENT as defined in Appendix V. It is cautioned that many patients with HLH or familial hemophagocytic lymphohistiocytosis (FHL) will have a viral infection at time of initial presentation and may therefore be misdiagnosed as having VAHS. * Griscelli Syndrome * Primary immune deficiencies with non-genotypic identical donors only. * Progressive Langerhans cell histiocytosis unresponsive to standard therapy. * Other non-malignant hematological disorders in which stem cell transplant with a myeloablative regimen is indicated. * Diamond Blackfan Anemia if transfusion dependent * Schwachman Diamond Syndrome: with cytopenias or transformation to myelodysplastic syndrome (MDS) …