Objective: To study dynamics of T lymphocyte subsets in severe acute respiratory syndrome (SARS).
Methods: Sequential anti-coagulated blood samples were collected from 46 cases of SARS patients during the 1st week, the 2nd week, the 3rd-5th week and the 8th-12th week after the infection. T lymphocyte subsets including CD3+CD4+ cells, CD3+CD8+ cells, naive CD4+ cells (CD4+CD45RA+CD62L+) and activated CD8+ cells (CD8+CD38+) were detected by 3-color flow cytometry. Fifty-six normal healthy blood donors were also detected as normal controls.
Results: Compared with the results of normal controls, both of the percentages of CD4+ cells and CD8+ cells of SARS patients were in normal levels during the 1st week, but the cell counts decreased significantly to (306 +/- 140)/mm3 and (270 +/- 143)/mm3, respectively. The cell count of naive CD4+ subset also remarkably decreased to (96 +/- 49)/mm3, and the percentage of CD8+CD38+ subset was higher than that of normal controls [(59.3 +/- 12.6)% vs (44.9 +/- 12.5)%]. During the 3rd-5th week, the CD8+ cell count and the percentage of CD8+CD38+ subset reached normal values, which were (581 +/- 356)/mm3 and (40.1 +/- 17.6)%, respectively. During the 8th-12th week, the cell counts of CD4+ cell [(578 +/- 193)/mm3] and naive CD4+ subset [(176 +/- 64)/mm3] were still less than those of normal controls, while compared with those of the 1st week, the increments were remarkable.
Conclusions: T lymphocytes of SARS patients decreased dramatically but could be obviously resumed in a short time. It will take more than 8-12 weeks for CD4+ cell and naive CD4+ subset to reach to normal levels.