Abstract: ob＜x＞jective To investigate the effect of adipose derived mesenchymal stem cells (ADSCs) on immune alopecia. Methods In this study, human ADSCs and hair follicle dermal papilla cells (DPCs) were co-cultured in Transwell chamber (0.4μm). The proliferation ability of DPCs after co-culture was observed by CCK-8 method, and the induction ability of DPCs was detected by real-time fluorescence PCR.Forty male C57BL/6 mice were randomly divided into four groups: blank control group, immune alopecia group, adipose stem cell treatment group, and glucocorticoid treatment group.The immune alopecia model of mice was established to observe the changes of skin color and the growth of new hair in the depilation area of mice in each group. The length and quality of new hair in each group were calculated. The number and morphological differences of hair follicles in each group were observed by HE staining.The levels of inflammatory cytokines ICAM-1 and ELAM-1 and immune cytokines CD4 + and CD8 + around hair follicles were observed by immunohistochemistry. Results The results showed that ADSCs could effectively promote the proliferation ability of DPCs ( P<0.01), enhance the secretion function of DPCs (P<0.01), strengthen the ability of DPCs to induce hair follicle formation, and promote hair follicle into the growth phase.In the mouse model of immune alopecia, ADSCs injection increased the hair mass (P<0.05) and improved the hair growth (P<0.05). The results of HE and immunohistochemistry showed that ADSCs could down-regulate the immune function around the hair follicle and reduce the level of local inflammatory factors. Conclusion Local ADSCs injection can treat immune alopecia, which may be related to regulating local immune microenvironment and inhibiting the damage of inflammatory factors to hair follicles.It is suggested that local application of ADSCs may be a new idea for the treatment of refractory immune alopecia.