MT2018-18: Sleeping Beauty Transposon-Engineered Plasmablasts for Hurler Syndrome Post Allo HSCT

Inclusion Criteria: * Diagnosis of Mucopolysaccharidosis type IH (MPS IH, Hurler syndrome) * Underwent a previous hematopoietic stem cell transplant \>1 year prior to study enrollment * Age ≥3 years and ≤8 years at time of study registration * ≥ 10 kilograms body weight * Creatinine \<1.5 normal for gender and age. * Ejection fraction ≥ 40% by echocardiogram * Must commit to traveling to the University of Minnesota for the necessary followup evaluations * Must agree to stay in the Twin Cities area (\<45-minute drive from the Masonic Children's Hospital) for a minimum of 5 days after each cell infusion * Voluntary written parental consent prior to the performance of any study related procedures Exclusion Criteria: * Prior enzyme replacement therapy within 4 months prior to enrolling on study * History of B cell related cancer, EBV lymphoproliferative disease or autoimmune disorders * Evidence of active graft vs. host disease * Requirement for systemic immune suppression * Requirement for continuous supplemental oxygen * Any medical condition likely to interfere with assessment of safety or efficacy of the study treatment. * In the investigator's judgement, the subject is unlikely to complete all protocol required study visits or procedures, including follow up visits, or comply with the study requirements for participation.