Treatment of Children With Autistic Spectrum Disorder With Autologous Umbilical Cord Blood, a Pilot Study

Inclusion Criteria: * Age ≥ 1.5 years to ≤ 12 years (11 years, 364 days) at the time of visit 1 * Confirmed clinical DSM-5 diagnosis of Autism Spectrum Disorder using the DSM-5 criteria * Fragile X testing performed and negative * Available and qualified umbilical cord blood unit with a minimum banked total nucleated cell dose of ≥ 2 x 10e7 cells/kg * Stable on current psychiatric medication regimen (dose and dosing schedule) for at least 2 months prior to infusion of study product * Normal absolute lymphocyte count (≥1500/uL) * Able to travel to Sheba Medical Center University three times (baseline, 6 and 12 months post-baseline), and parent/guardian is able to participate in interim surveys and interviews monthly * Parental consent Exclusion Criteria * General: * Review of medical records indicates ASD diagnosis not likely * Known diagnosis of any of the following coexisting psychiatric conditions: depression, bipolar disorder, schizophrenia, obsessive compulsive disorder * Screening data suggests that participant would not be able to comply with the requirements of the study procedures, including study outcome measures, as assessed by the study team * Family is unwilling or unable to commit to participation in all study-related assessments, including follow up for approximately 12 months * Genetic: * Records indicate that child has a known genetic syndrome such as (but not limited to) Fragile X syndrome, neurofibromatosis, Rett syndrome, tuberous sclerosis, PTEN mutation, cystic fibrosis, muscular dystrophy * Known pathogenic copy number variation (CNV) associated with ASD (e.g., 16p11.2, 15q13.2, 2q13.3) * Infectious: * Known active CNS infection * Evidence of uncontrolled infection based on records or clinical assessment * HIV positivity * 4 Medical: * Known metabolic disorder * Known mitochondrial dysfunction * History of unstable epilepsy or uncontrolled seizure disorder, Lennox Gastaut syndrome, Dravet syndrome, or other similar epileptic encephalopathy * Concurrent genetic or acquired disease or comorbidity(ies) that could require a future stem cell transplant * Significant sensory (e.g., blindness, deafness, uncorrected hearing impairment) or motor (e.g., cerebral palsy) impairment * Evidence of clinically relevant physical dysmorphology indicative of a genetic syndrome as assessed by the PIs or other investigators, including a medical geneticist and psychiatrists trained in identifying dysmporphic features associated with neurodevelopmental conditions. * Current/Prior Therapy: * History of prior cell therapy * Current or prior use of IVIG or other anti-inflammatory medications with the exception of NSAIDs * No systemic steroid therapy that has lasted \>2 weeks, and no systemic steroids within 3 months prior to enrollment. Topical and inhaled steroids are permitted.