Pediatric Autologous Bone Marrow Mononuclear Cells for Severe Traumatic Brain Injury

Inclusion Criteria: 1. Between 5 and 17 years of age on the day of injury, 2. Glasgow Coma Score (GCS) between 3 and 8, (best un-medicated post-resuscitation score during screening), 3. Ability to obtain legally authorized representative (LAR) consent, and complete the BMMNC/Sham harvest and cell/placebo infusion within 48 hours of the initial injury, 4. Ability to speak English or Spanish. Exclusion Criteria: 1. Known history of: a. previous brain injury, b. intellectual deficiency or psychiatric condition, defined as inability to independently function in a regular classroom that may invalidate our ability to assess post-injury changes in cognition or behavior (ADHD and/or other learning disabilities are NOT an exclusion), c. neurologic impairment and/or deficit, d. seizure disorder requiring anti-convulsant therapy, e. recently treated infection, f. renal disease or altered renal function (post-resuscitation serum creatinine \> 1.5 mg/dL), g. hepatic disease or altered liver function (post-resuscitation, non-contusion related SGPT \> 150 μ/L and/or T. Bilirubin \>1.3 mg/dL), h. cancer, i. immunosuppression as defined by WBC \< 3, 000 cells/ml at admission, j. HIV+, k. chemical or ETOH dependency, l. history of child abuse, m. premature birth (\<37 weeks GA/2500 grams) resulting in cognitive/physical disabilities and/or developmental delay. 2. Obliteration of perimesencephalic cistern on initial head CT/MRI suggesting prolonged hypoxic ischemic insult/herniation syndrome. 3. Initial hospital ICP \> 40 mm Hg. 4. Hemodynamic instability at the time of screening defined as SBP \<90 mmHg, ongoing fluid resuscitation and/or requirement for inotropic support to maintain MAP at or above normal for age - does not include CPP based inotropic support. IVF alone does not exclude from enrollment. 5. Uncorrected coagulopathy at the time of bone marrow harvest defined as INR \> 1.6, PTT \> 38 sec; PLT\< 100,000; Fibrinogen \< 100 g/dL. 6. Unstable pelvic fractures defined as requiring early operative fixation. 7. Pulmonary contusions defined as a chest x-ray with non-anatomic opacification and/or PaO2:FiO2 ratio \< 250 associated with the mechanism of injury. 8. Greater than AAST Grade 3 solid or hollow visceral injury of the abdomen and/or pelvis as diagnosed by CT or other imaging. 9. Spinal cord injury diagnosed by CT/MR imaging or clinical findings. 10. Persistent hypoxia defined as SaO2 \< 94% for \> 30 minutes occurring at any time from hospital admission to time of consent. 11. Positive pregnancy test, if applicable. 12. Concurrent participation in an interventional drug/device research study. 13. Unwillingness to return for follow-up visits. 14. Contraindications to MRI. 15. Penetrating brain injury.