Background  Mobilized CD34+ cells in peripheral blood have angiogenic potential, which is an important factor in active hair growth. In addition, activated autologous platelet-rich plasma (PRP) has been reported to induce the proliferation of dermal papilla cells.

Objectives  To investigate the clinical efficacy of interfollicular injection of CD34+ cell-containing PRP preparation for pattern hair loss.

Patients and methods  CD34+ cell-containing PRP preparation was injected on the scalps of 13 patients with pattern hair loss, and 13 patients were treated with interfollicular placental extract injection as a control. The numbers of platelets in PRP were microscopically counted and CD34+ cells were evaluated with flow cytometry.

Results  Three months after the first treatment, the patients presented clinical improvement in the mean number of hairs, 20.5 ± 17.0% (< 0.0001), mean hair thickness, 31.3 ± 30.1% (< 0.0001), and mean two-point score, 84.4 ± 51.7% (< 0.0001) compared with baseline values. At 6 months, the patients presented clinical improvement in mean hair count, 29.2 ± 17.8% (< 0.0001), mean hair thickness, 46.4 ± 37.5% (< 0.0001), and mean two-point score, 121.3 ± 66.8% (< 0.0001) compared with baseline. The MIXED procedure revealed that CD34+ cell-containing PRP treatment presented a higher degree of improvement than placental extract treatment in hair thickness (= 0.027) and overall clinical improvement (= 0.023).

Conclusion  Our data suggest that the interfollicular injection of autologous CD34+ cell-containing PRP preparation has a positive therapeutic effect on male and female pattern hair loss without remarkable major side-effects.