Objective To investigate the relationship between the expression levels of mir-155/Th17 and mir-23b-3p/Tfh in peripheral blood and the prognostic value of secondary atopic dermatitis(AD)in AIDS patients.Methods In this study,80 AIDS patients were treated in our hospital from February 2021 to December 2023.The subjects were divided into AD group and non-AD group according to whether they had secondary AD.The levels of mir-155,Th17,mir-23b-3p and Tfh in peripheral blood of AD group and non-AD group were compared.Spearman method was used to analyze the relationship between levels of mir-155,Th17,mir-23b-3p and Tfh in peripheral blood and secondary AD in AIDS patients.At the same time,according to the prognosis of patients,the subjects were divided into good prognosis group and poor prognosis group,and the risk factors affecting the prognosis of patients were screened by Logistic regression analysis.Receiver operating characteristic(ROC)curve was drawn to analyze the predictive value of peripheral blood mir-155,Th17,mir-23b-3p and Tfh levels on the prognosis of AIDS patients.Results Compared with non-AD group,the levels of miR-155,Th17 and Tfh in peripheral blood of AD group were higher(P＜0.05),and the levels of miR-23b-3p were lower(P＜0.05).The level of miR-155,Th17 and Tfh in peripheral blood were positively correlated with secondary AD of AIDS(r=0.487,0.492,0.495,P＜0.05),and the level of miR-23b-3p in peripheral blood was negatively correlated with secondary AD of AIDS(r=-0.503,P＜0.05).The levels of HIV load(high dose),lymphoma,PLT,NLR,CRP,miR-155,Th17 and Tfh in the poor prognosis group were higher than those in the good prognosis group(P＜0.05),while the levels of albumin and miR-23b-3p in the poor prognosis group were lower than those in the good prognosis group(P＜0.05).Logistic regression analysis showed that lymphoma,PLT,NLR,low albumin,CRP,miR-155,Th17,Tfh and low miR-23b-3p were all risk factors for poor prognosis of AIDS patients(P＜0.05).ROC curve results showed that the AUC(95％CI)and sensitivity of combined detection of peripheral blood miR-155,Th17,Tfh and miR-23b-3p in predicting poor prognosis of AIDS patients were 0.883(0.805～0.992)and 96.70％,respectively.All of them were higher than the above peripheral blood indexes alone(P＜0.05).Conclusion The abnormal expression of miR-155,Th17,Tfh,and miR-23b-3p in peripheral blood is closely related to secondary AD in AIDS patients,and is a risk factor affecting the poor prognosis of AIDS patients.The combined detection of these indicators has a high predictive value for the poor prognosis of AIDS patients.