ObjectiveTo evaluate the safety, feasibility and efficacy of transplantation of purified peripheral blood CD34+ cells in treatment of critical ischemia of the lower extremities.MethodsFrom May 2009 to March 2010, seven cases of critical ischemia of the lower extremities received purified peripheral blood CD34+ cells transplantation, among those 6 were caused by thromboangiitis obliterans and 1 by thrombosis coexistent with nodular erythema. Mean age was ( 39 ± 11 ) years ( range 23 - 54 ), and all patients were not suitable for surgical or endovascular revascularization. G-CSF was subcutaneously injected for 5 days before apheresis for peripheral blood mononuclear cells. Then CliniMACS system was used to isolate the CD34+ cells. If the number of CD34+ cells was between 105/kg and 106/kg , they were all intramuscular injected into patients' calf and foot. ResultsTechnical success and limb salvage were achieved in all cases. The mean number of transplanted cells was (7. 1 ±2.3) × 105/kg [ range(4.6 ×105 -1 × 106 )/kg]. All cases were followed-up, ranging from 6 - 14 months (mean 8 ± 3 months). One month after transplantation, the rest pain was obviously relieved in all cases, and the Wong-Baker FACES pain rating scale score significantly decreased from 7. 1 ±2. 0(4 - 10)to 1. 1 ± 1.1 (0 -2) ,P =0. 0000. The pain-free walking distance was significantly improved from (4 ± 4) min (range 1 -10 min)to (12 ± 7 ) min (range 5 - 21min , P =0.04) at 3 months and(20.4 ± 12.5) min(range 6 -40 min, P = 0.02) at 6 months, respectively. The ankle-brachial index increased from 0. 54 ± 0. 18 ( range 0. 41 - 0. 87 ) to 0.66 ±0. 13(range 0. 52-0. 86 , P=0. 17)at 3 months and 0.72 ±0. 13(range 0.56 -0.91, P=0. 07)at 6 months, respectively. Of 6 cases with the toe ulcer, the ulcer was healed in 3 and apparently shrank in 3. Transcutaneous partial oxygen pressure rose from (29 ± 14)mm Hg(range 10 -52 mm Hg)to 46 ±14 mm Hg ( range 27 - 63 mm Hg, P = 0. 04) at 3 months and (57 ± 10) mm Hg( range 41 - 66 mm Hg, P =0.001) at 6 months,respectively.No serious complications were found either perioperatively or postoperatively.ConclusionsTransplantation of purified peripheral blood CD34+ cells is safe, feasible and effective in the treatment of critical ischemia of the lower extremities.