Abstract: Objective To observe the dynamic changes of immunoinflammatory factors during the course of carbon dioxide (CO2) fractional laser combined with compound betamethasone in vitiligo and their correlation with recurrence. 
Methods One hundred patients with vitiligo who were treated with CO2 fractional laser combined with compound betamethasone in our hospital were selected and divided into recurrence group and non-recurrence group according to the recurrence of the disease at 6 months after healing. The levels of interleukin-17 (IL-17), interferon-γ (IFN-γ) and interleukin-10 (IL-10) were compared between two groups before treatment, after treatment for two times and after completion of treatment, and the factors associated with recurrence were analyzed by logistic regression. The receiver operating characteristic (ROC) curve was used to analyze the value of IL-17, IFN-γ and IL-10 in predicting recurrence after treatment for two times and after completion of treatment. The time to recurrence in patients with different IL-17, IFN-γ, and IL-10 levels was compared, and Pearson analysis was used to analyze the relationship between IL-17, IFN-γ, and IL-10 and time to recurrence. 
Results There were more patients with family history of vitiligo in the recurrence group than in the non-recurrence group, and the severity of disease was greater than in the non-recurrence group (P＜0.05). IL-17 and IFN-γ levels were higher in the recurrence group than in the non-recurrence group after treatment for two times and after completion of treatment, and IL-10 level was lower than that in the non-recurrence group (P＜0.05). Logistic regression analysis showed that family history of vitiligo, severity of disease, and the levels of IL-17 and IFN-γ were all independent risk factors associated with recurrence, and the levels of IL-10 was a protective factor associated with recurrence (P＜0.05). The AUC of IL-17, IFN-γ, and IL-10 for predicting recurrence after completion of treatment was greater than that of IL-17, IFN-γ, and IL-10 after treatment for two times (Z=3.784, 2.591, 6.264, P＜0.05); the AUC of IL-17+IFN-γ+IL-10 for predicting recurrence after completion of treatment was greater than that of IL-17+IFN-γ+IL-10 after completion of treatment (Z=2.260, P＜0.05). Time to recurrence was shorter in patients with high levels of IL-17 and IFN-γ than in those with low levels, and longer in patients with high levels of IL-10 than in those with low levels (P＜0.05). IL-17 and IFN-γ were negatively correlated with time to recurrence after completion of treatment (r=-0.838, -0.773, P＜0.05), and IL-10 was positively correlated with time to recurrence (r=0.814, P＜0.001). 
Conclusion The dynamic changes of IL-17, IFN-γ and IL-10 levels during the course of CO2 fractional laser combined with compound betamethasone  in vitiligo are related to recurrence after healing, and the combined detection of the three levels after completion of treatment can be used as a scheme to predict recurrence, thus providing important reference information for clinical prevention and control of recurrence. 

Key words: vitiligo, lasers, gas, betamethasone