OBJECTIVETo observe changes in T cell subsets and TH1/TH2 secreted cytokines in the plasma of patients with hemorrhagic fever with renal syndrome (HFRS).

METHODSTotally 22 patients with HFRS (9 mild cases and 13 moderate cases) were enrolled. Blood samples were taken 1, 4, and 12 weeks after presentation. T cell subsets were tested by flow cytometry (FCM), and the expression of cytokines in plasma were analysed with enzyme-linked immunosorbent assay (ELISA). Another 16 healthy blood donors were enrolled as the control group.

RESULTSCD3 + CD8 + T lymphocytes increased at week 1 and 4 (P < 0.01), which was more significant in mild cases than in moderate cases (P < 0.05). The change of CD3 + CD4 + T lymphocytes during the disease course were not significantly different from that in control group (P > 0.05). One week after presentation, TH1 [interleukin (IL)-2 and interferon-gamma (IFN-gamma)] and TH2 (IL-6, IL-10) cytokine productions were significantly higher in HFRS patients than in the control group (P < 0.01); IL-2 and IL-10 remained high levels during the whole observation period, and were still significantly higher than in the control group (P < 0.01). At week 4, the plasma IL-5 level was significantly higher in HFRS patients than in the control group (P < 0.01), and were still significantly higher than in the control group at week 12 (P < 0.01). At week 1 and 4, the plasma INF-gamma levels were significantly higher in moderate patients than in mild patients (P < 0.05); at week 12, the plasma IL-10 level was significantly higher in moderate patients than in mild patients(P < 0.05).

CONCLUSIONSCD3 + CD4 + T lymphocytes remarkably increases at the early stage of disease in patients with mild HFRS. The early cell mediated immune response is helpful for disease control. The cytokines INF-gamma and IL-10 increase more obviously in moderate patients, indicating that cytokines also are key pathogenic factors of HRFS.