To investigate the expression level of cells including T, CD3⁺CD4⁺T, CD3⁺CD8⁺T,CD4^-CD8^-T, CD4⁺CD8⁺T, B, NK, CD4⁺Treg, CD8⁺Treg, CT, CD28^-CTL in peripheral blood of patients with different infectious diseases, so as to provide experimental evidence for the auxiliary diagnosis, immune monitoring, and clinical treatment of different infectious diseases.

Eighty-six cases of different types of infectious diseases diagnosed and treated in our hospital from 2017 to 2018 were selected, including 26 cases of septicemia, 30 cases of HBV and 30 cases of EBV, and in addition to 30 cases of control group. Flow cytometry was used to detect the expression of lymphocyte subsets in each group.

Compared with the control group, the expression levels of lymphocyte subsets CD3⁺CD4⁺T, CD3⁺CD8⁺T, CD4⁺CD8⁺T, B, NK, CD4⁺Treg, CTL, CD28^-CTL in patients with HBV, EBV and septicemia were significantly different (P<0.05). In HBV group, CD3⁺CD4⁺ T and CTL were elevated while NK and CD28^-CTL decreased; In HBV group, CD3⁺CD8⁺T, CD4⁺Treg and CTL increased while CD3⁺CD4⁺T and NK decreased; In septicemia group, B and CTL increased while CD4^-CD8^-T, NK and CD28^-CTL decreased. Compared with the control group, the expression levels of peripheral blood T, CD4⁺CD8⁺T, CD8⁺Treg in patients with HBV, EBV and septicemia had no significant difference (P>0.05). Compared with septicemia and HBV group, the expression of CD3⁺CD4⁺ T in EBV group decreased while the expression of CD3⁺CD8⁺ T and CTL increased. The difference was statistically significant (P<0.05); Compared with The HBV group, the expression of CD4^-CD8^-T in the septicemia group decreased. Compared with the EBV group, the expression of B in the septicemia group increased. The number of CD28^-CTL in the HBV group decreased, and the difference was statistically significant (P<0.05). In addition, it was found that the expression of CTL in the peripheral blood of the HBV group, EBV group, and septicemia group showed increased while decreased in NK.

Compared with healthy people, the expression levels of CD3⁺CD4⁺T, CD3⁺CD8⁺T, CD4^-CD8^-T, B, NK, CD4⁺Treg, CTL and CD28^-CTL lymphocyte subsets in peripheral blood of patients with different infectious diseases were different. By analyzing the changes in the expression level, this research can provide the basis for the auxiliary diagnosis, immune monitoring and clinical treatment of different infectious diseases.