Objective To explore the application value of lymphocyte subsets combined with various cytokines in the disease progression of elderly patients with corona virus disease 2019(COVID-19).Methods From December 2022 to January 2023,146 elderly patients with COVID-19 diagnosed in the emergency ward of the Eighth Medical Center of PLA General Hospital were selected and divided into two groups according to the prognosis:127 cases in the COVID-19 survival group,19 cases in the COVID-19 death group.In addition,51 osteoporosis patients in geriatric medicine department were collected as control group.The proportion and absolute count of lymphocyte subsets(including T,B and NK cells),and 12 cytokines in plasma(including IL-1β,IL-2,IL-4,IL-5,IL-6,IL-8,IL-10,IL-12p70,IL-17,TNF-α and IFN-γ)were compared between the control group and COVID-19 group,survival group and death group.The receiver operating characteristic(ROC)curve was used to evaluate its prognostic value in elderly patients with COVID-19 infection.Results Compared with the control group:① The proportion of NK cells in COVID-19 group was decreased,while the proportion of B cells was increased,and the differences were statistically significant(Z=-3.386,-4.140,all P<0.01).There was no significant difference in the proportion of T,CD8+T and CD4+T cells,and the differences were not statistically significant(Z=-1.244,-1.770,-0.951,all P>0.05).② The absolute numbers of T,CD8+T,CD4+T,NK and B cells in COVID-19 group were decreased,and the differences were statistically significant(Z=-9.418～-6.539,all P<0.01).③ The concentrations of IL-2,IL-6,IL-1β,IFN-γ,IL-8,IL-17,IL-12P70 and IL-10 in COVID-19 group were all increased,and the differences were statistically significant(Z=-8.851～-1.986,all P<0.05).There was no significant difference in the concentrations of IL-5,IFN-α,TNF-α and IL-4,and the differences were not statistically significant(Z=-0.460～-0.217,all P>0.05).Compared with the survival group:① There was no significant difference in the proportion of T,CD8+T,CD4+T,NK and B cells in the death group(Z=-1.873～-0.422,all P>0.05).② The absolute numbers of T,CD8+T and CD4+T cells in the death group were all decreased,and the differences were statistically significant(Z=-2.667,-2.287,-2.556,all P<0.05),while there was no significant difference in absolute numbers of NK and B cellsm and the differences were not statistically significant(Z=-1.934,-0.532,all P>0.05).③ The concentrations of IL-6,IFN-γ,IL-8,IL-17 and IL-10 in the death group were all increased,and the differences were not statistically significant(Z=-4.211～-2.655,all P<0.05),and there was no significant difference in the concentrations of IL-5,IFN-α,IL-2,IL-1β,IL-12p70,TNF-α and IL-4 the differences were not statistically significant(Z=-1.329～-0.279,all P>0.05).ROC curve analysis for the prognostic value of lymphocyte subsets combined with cytokines in elderly patients with COVID-19 showed that:the areas of total T cells,B cells and NK cells under ROC curve for predicting the prognosis of COVID-19 infection were 0.94,0.80 and 0.93,respectively.The areas of CD4+T cells and CD8+T cells under ROC curve for predicting the prognosis of COVID-19 infection were 0.93 and 0.90,respectively.The areas of IL-6,IFN-γ,IL-8,IL-17 and IL-10 in cytokines under the ROC curve for predicting the prognosis of COVID-19 infection were 0.91,0.71,0.87,0.74 and 0.90,respectively.However,the area of combined lymphocyte subsets and cytokines under ROC curve for predicting the prognosis of COVID-19 infection reached 0.99.Conclusion The immune status of elderly patients with COVID-19 was generally low.Evaluation of immune status has important clinical guidance significance in disease diagnosis,disease observation and prognosis.