Detection of extracellular cytokines: mainly detect cytokines in plasma (serum) and other fluids, and determine cytokines in plasma (serum). It can accurately reflect the expression state of cytokines, and some body fluid samples, such as cerebrospinal fluid, synovial tissue fluid, bronchial lavage fluid, pleural effusion and ascites, are directly related to specific diseases. The basic principle of flow cytometry (FCM) is to activate lymphocytes in vitro with stimulators PMA and ionomycin, and to prevent cytokines from being secreted out of cells with protein transport inhibitors such as monensin, so that the protein transport mode in cells is disrupted, causing cytokines to accumulate in Golgi apparatus, and the enhanced cytokines can be detected by flow cytometry. With the development of this technology, the problems that could only be answered in a few months by T cell cloning can be solved in a few hours. This technology has become a standard analytical method for detecting cytokine production at the single cell level. Although the cytokine-labeled flow cytometry technology has incomparable advantages over other methods, it needs to stimulate, block, fix, penetrate and label cells during the operation, and any link will affect the experimental results [8]. The commonly used detection index of flow cytometry is FCM analysis with CD4 as the gate. The percentage of TH1/ TH2 cells was determined by the expression of IFN-γ and IL-4 in CD4+ cells [9-1]. Using CD3/CD8 as the gate and FCM to detect and analyze the expression rate of TH1/ TH2 cells, the results are accurate and reliable, and the operation is convenient and quick, which is an ideal method to detect TH1/ TH2 cells [11-12]. In recent years, it has been found that CD4+T cells are polarized in different directions, and different chemokine receptors are expressed on the cell surface. chemokine receptor CCR5 is mainly expressed on the surface of TH1 cells, which is a specific marker of TH1 cells [14]. Therefore, it is high and simple to use specific monoclonal antibodies against chemokine receptors to determine the specificity of different subsets of TH. Antibodies CCR5 and CCR3 were recently developed, but they can only reflect the changes in the number of TH cells, which are consistent with the changes in function (cytokine secretion) and need further study.