Inclusion Criteria:

- Diagnosis of immunodeficiency or histiocytic disorder including the following:

- Severe combined immunodeficiency (SCID - all variants)

- Second bone marrow transplant (BMT) for SCID (after graft rejection)

- Omenn's Syndrome

- Reticular dysgenesis

- Wiskott-Aldrich syndrome

- Major histocompatibility complex (MHC) Class II deficiency (bare lymphocyte
syndrome)

- Hyper IgM Syndrome (CD40 Ligand Deficiency)

- Common variable immunodeficiency (CVID) with severe phenotype

- Chronic Granulomatous Disease (CGD)

- Other severe Combined Immune Deficiencies (CID)

- Hemophagocytic Lymphohistiocytosis (HLH)

- X-linked Lymphoproliferative Disease (XLP)

- Chediak-Higashi Syndrome (CHS)

- Griscelli Syndrome

- Langerhans Cell Histiocytosis (LCH)

- Acceptable stem cell sources include:

- HLA identical or 1 antigen matched sibling donor eligible to donate bone marrow

- HLA identical or up to a 1 antigen mismatched unrelated BM donor

- Sibling donor cord blood with acceptable HLA match and cell dose as per current
institutional standards

- Single unrelated umbilical cord blood unit with 0-2 antigen mismatch and minimum
cell dose of >5 x 10^7 nucleated cells/kg as per current institutional
guidelines

- Double unrelated umbilical cord blood units that are:

- up to 2 antigen mismatched to the patient

- up to 2 antigen mismatched to each other

- minimum cell dose of at least one single unit must be ≥ 3.5 x 10^7
nucleated cells/kg

- combined dose of both units must provide a total cell dose of ≥ 5 x 10^7
nucleated cells/kg

- Age: 0 to 50 years

- Performance status: Karnofsky Performance status must be at least 70% for patients >
16 years of age or Lansky Play Score ≥ 70 for patients > 16 years of age

- Consent: able to provide appropriate voluntary written consent

- Organ Function

- Renal: glomerular filtration rate (GFR) ≥ 30% of predicted and serum creatinine
≤ 2 x upper limit of normal for age

- Hepatic: aspartate aminotransferase/alanine aminotransferase (AST or ALT) ≤ 5 x
upper limit of normal (ULN) and bilirubin ≤ 5 x ULN

- Cardiac: cardiac function ≥ 40% normal by echocardiogram

Exclusion Criteria

- pregnant or breastfeeding

- active, uncontrolled infection and/or HIV positive

- acute hepatitis or evidence of moderate or severe portal fibrosis or cirrhosis on
biopsy

Donor Section Criteria:

- in general good health, in the opinion of the evaluating health care professional

- adequate partial prothrombin time (PTT), hemoglobin, white blood cell, and platelet
counts

- for females of child bearing potential not pregnant or breastfeeding (must have a
negative pregnancy test within 7 days of donation)

- no active infection

- voluntary written consent

In the case where more than one donor meets the eligibility criteria, donor selection will
be guided by the following considerations:

- Class I HLA Antigens: It will always be preferable to have a donor that is an allele
match at HLA-A, -B and -C. However, acceptable donors may have up to two Class I
allele mismatches (A, B or C), or a single HLA-A, -B, or -C allele and/or antigen
mismatch, although in either situation the class II HLA-DR must be allele matched.

- Class II HLA Antigen (HLA-DR): The preferred donor will be a full HLA-DR allele
match. However, a single allele DR mismatch donor will be acceptable provided the
donor is a full allele match at HLA-A, -B, and -C. Class II antigen mismatched
donors are not acceptable.

- HLA A, B, DRB1 identical sibling donor is preferable to an unrelated donor

- Homozygous normal donor is preferable to heterozygote (carrier)

- ABO-compatible donor is preferable to ABO-incompatible donor

- Younger donor is preferable to older

- Cytomegalovirus seronegative donor is preferable to cytomegalovirus (CMV)
seropositive donor, if the patient is CMV negative