Objective To investigate the common opportunistic infections and the characteristics of peripheral lymphocyte subsets in patients with systemic lupus erythematosus (SLE). Methods From December 2013 to December 2016, peripheral lymphocyte subsets were consecutively detected by flow cytometry in treated SLE patients with or without opportunistic infections(OIs).The lymphocyte subsets in healthy donors were used as normal control group. Results A total of 145 treated SLE patients were enrolled including 108 with OIs and 37 without OIs.The common OIs were cytomegalovirus(CMV)diseases (66/108), Pneumocystis jirovecii pneumonia (PJP, 16/108), other fungal infections (16/108), Epstein-Barr virus (EBV, 15/108) and tuberculosis (14/108). Compared with treated SLE without OIs, total lymphocyte, CD4+T,and CD8+T lymphocyte counts were significantly reduced in SLE with OIs[1 260(780,1 810)cells/μl vs. 565(399,1 043)cells/μl,P<0.001; 485(280,811)cells/μl vs. 173(95,327)cells/μl,P<0.001; 464 (339,764)cells/μl vs.265(158,424)cells/μl,P=0.003,respectively].Conclusions The common OIs in treated SLE patients were CMV diseases,PJP,other fungi,EBV and tuberculosis.OIs are prone to develop in SLE patients with severe lymphocytopenia,especially CD4+T cell depletion.

Objective: To investigate the characteristics and prognostic value of peripheral blood T lymphocyte subsets in patients with severe influenza. Methods: This was a single-center cross-sectional study in influenza patients admitted to Peking Union Medical College Hospital from August 2017 to April 2018. Peripheral blood lymphocyte subsets were detected by flow cytometry in both patients and 108 healthy controls. Influenza patients were divided into mild group and severe group. Severe patients were further classified into alive and fatal subgroups. Results: A total of 42 influenza patients were recruited in this study, including 24 severe cases (6 deaths). The remaining 18 cases were mild. The peripheral blood lymphocyte counts and lymphocyte subset counts (B, NK, CD4⁺T, CD8⁺T) in either mild patients[795 (571,1 007), 43 (23,144), 70 (47,135), 330 (256,457), 226 (148,366) cells/μl respectively] or severe patients[661 (474,1 151),92 (52,139), 54 (34,134), 373 (235,555), 180 (105,310) cells/μl respectively] were both significantly lower than those of healthy controls [1 963 (1 603,2 394),179 (119,239), 356 (231,496), 663 (531,824), 481 (341,693) cells/μl respectively]. Meanwhile, the T cells and CD8⁺T counts in fatal patients [370 (260,537) cells/μl and 87 (74,105) cells/μl] were significantly lower than those in severe and alive patients [722 (390,990) cells/μl and 222 (154,404) cells/μl]. CD8⁺HLA-DR/CD8⁺and CD8⁺CD38⁺/CD8⁺T cell activating subgroups in mild cases[(53.7±19.2)% and 74.8% (64.1%,83.7%) respectively] were significantly higher than those in severe cases[(38.5±21.7)% and 53.3% (45.3%,67.2%) respectively].Moreover,CD8⁺HLA-DR/CD8⁺count in severe and alive group was higher than that in fatal group [(46.1±19.1)% vs. (18.2±14.6)%, P<0.01]. Logistic regression analysis showed that CD8⁺T cell count (OR=0.952, 95%CI 0.910-0.997, P=0.035) and CD8⁺HLA-DR/CD8⁺T (OR=0.916, 95%CI 0.850-0.987, P=0.022) were both negatively correlated with mortality.Peripheral blood lymphocyte counts in mild cases rapidly decreased within 1 day after diagnosis, and returned to the basic level one week later. Conclusions All peripheral blood lymphocyte subsets (T,B,NK) in patients with influenza are significantly reduced. These findings are consistent with the immunological characteristics of respiratory viral infections, in which peripheral lymphocytes (especially T cells) migrate to respiratory tract in the early stage and circulate to the peripheral blood after recovery. The activated CD8⁺T cell counts in peripheral blood are negatively correlated with the severity of disease, which could be considered as a prognostic indicator of severe influenza.