Base-Edited Hematopoietic Stem/Progenitor Cell Gene Therapy for Treatment of CXCR4-WHIM

Background: Warts, hypogammaglobulinemia, infections and myelokathexis syndrome (WHIMs) is a rare disorder that affects the immune system. People with WHIMs can have severe infections all over their body. WHIMs is caused by a mutation in the CXCR4 gene. Treatment with drugs can help control the infections but does not cure the disorder. Researchers want to try a treatment where they collect stem cells from a person with WHIMS, use base-editing to replace the bad gene with a healthy version, and return the new cells to the person. This could cure WHIMs. Objective: To test a treatment using base-edited stem cells in people with WHIMs. Eligibility: People aged 3 years and older with WHIMs. Design: The study has 4 stages. Stage 1: Screening. Participants will be screened at 1 or more visits. They will have a physical exam with blood tests. A sample of tissue and fluid (biopsy) will be taken from the bone marrow in the hip. Stage 2: Apheresis. Blood will be taken from the body through a needle; the blood will pass through a machine that separates out the stem cells. The remaining blood will be returned to the body through a different needle. The collected stem cells will undergo gene editing. Stage 3: Treatment. Participants will stay in the hospital for about 4 weeks. They will receive 3 drugs to prepare their body for the procedure. Then the edited stem cells will be returned to their bloodstream. They will stay in the hospital until they recover. Stage 4: Follow-up. Participants will have 8 follow-up visits over 5 years. Long-term visits will continue for 15 years.