BD Substudy: A single arm substudy is included to assess the safety and efficacy of intramuscular transplantation of CLBS12 in patients (N=~5) with CLI categorized as 4 or 5 Rutherford score due to BD aged 20 to 80 years. Subjects who give informed consent will be screened for eligibility within 28 days before registration. Subjects will continue SOC pharmacotherapy and will also receive subcutaneous injections of GRAN® 5 µg/kg/day for 5 days (Pretreatment Days 1 5) to mobilize CD34+ cells into the peripheral blood and undergo apheresis on pretreatment Day 5 to collect CD34+ cells. The choice of pharmacotherapy will be made by the investigators.