Objectives To observe the changes of serum interleukins (IL), T lymphocyte subsets, and white blood cell (WBC) count in patients with severe acute respiratory syndrome (SARS), and to investigate the relationship between injured immune function, immune response and disturbed immune adjustment in SARS patients Methods The levels of serum IL 2, IL 10, IL 12 and T lymphocyte subset counts were measured in 35 clinically diagnosed SARS patients by using enzyme linked immunosorbant assay (ELISA) The relationship between the measured results and WBC count was further analyzed Results The level of serum IL was increased to a great extent in the 35 SARS patients, and the levels of serum IL 2, IL 10 and IL 12 were 242 53 (92 69) pg/ml, 77 43 (63 37) pg/ml and 65 94 (43 21) pg/ml, respectively The level of serum IL 2 increased markedly ( P <0 01) The peripheral blood CD 3 +, CD 4 + and CD 8 + counts were lower than normal in 23 patients (67 7%), 26 patients (74 3%) and 15 patients (42 9%), respectively The peripheral blood WBC counts were lower than 4 0×10 9/L in 10 patients, and their CD 3 +, CD 4 + and CD 8 + counts were 583 90 (315 58)×10 6/L, 272 00 (94 13)×10 6/L and 209 00 (72 21)×10 6/L, respectively The peripheral blood WBC counts were (4 0-10 0)×10 9/L in 20 patients, and their CD 3 +, CD 4 + and CD 8 + counts were 700 00 (502 96)×10 6/L, 347 00 (247 58)×10 6/L and 322 05 (228 47)×10 6/L, respectively The peripheral blood WBC counts were higher than 10 0×10 9/L in 5 patients, and their CD 3 +, CD 4 + and CD 8 + counts were 1466 00 (630 86)×10 6/L, 783 00 (311 14)×10 6/L and 640 00 (294 40)×10 6/L, respectively The decreased CD 3 +, CD 4 + and CD 8 + counts were consistent with the decreased WBC counts The level of IL in SARS patients was significantly higher than that in patients with chronic hepatitis B ( P <0 01) Conclusions The level of serum IL is closely related to cell immunity in SARS patients The level of serum IL is increased evidently while CD 3 +, CD 4 + and CD 8 + counts decrease Both serum IL and CD are associated with injury of immune function, and thus they could be regarded as a monitoring index for judging the condition of SARS patients and prescribing immune therapy Objectives To observe the changes of serum interleukins (IL), T lymphocyte subsets, and white blood cells (WBC) count in patients with severe acute respiratory syndrome (SARS), and to investigate the relationship between injured immune function, immune response and disturbed immune adjustment in SARS patients Methods The levels of serum IL 2, IL 10, IL 12 and T lymphocyte subset counts were measured in 35 clinically diagnosed SARS patients by using enzyme linked immunosorbant assay (ELISA) The relationship between the measured results and WBC count was further The results of the analysis of the levels of serum IL was increased to a great extent in the 35 SARS patients, and the levels of serum IL 2, IL 10 and IL 12 were 242 53 (92 69) pg / ml, 77 43 (63 37) pg / ml and 65 94 (4321) pg / ml, respectively The levels of serum IL 2 increased markedly (P <0.01) The peripheral blood CD 3 +, CD 4 + and CD 8 + counts were lower than normal in 23 patients (67 7%), 26 patients (74 3%) and 15 patients (42 9%), respectively The peripheral blood WBC counts were lower than 4 × 10 9 / L in 10 patients, and their CD 3 +, CD 4 + and CD 8 + counts were 583 90 ( 315 58) × 10 6 / L, 272 00 (94 13) × 10 6 / L and 209 00 (72 21) × 10 6 / L, respectively The peripheral blood WBC counts were (4 0-10 0) × 10 9 / L in 20 patients, and their CD 3 +, CD 4 + and CD 8 + counts were 700 00 (502 96) × 10 6 / L, 347 00 (247 58) × 10 6 / L and 322 05 ) × 10 6 / L, respectively The peripheral blood WBC counts were higher than 10 × 10 9 / L in 5 patients, and their CD 3 +, CD 4 + and CD 8 + counts were 1466 00 (630 86) × 10 6 / L, 783 00 (311 14) × 10 6 / L and 640 00 (294 40) × 10 6 / L, respectively The decreased CD 3 +, CD 4 + and CD 8 + counts were consistent with the decreased WBC counts The level of IL in SARS patients was significantly higher than that in patients with chronic hepatitis B (P <0.01) Conclusions The level of serum IL is closelyrelated to cell immunity in SARS patients The level of serum IL is increased evidently while CD 3 +, CD 4 + and CD 8 + counts decrease Both serum IL and CD are associated with injury of immune function, and so they could be considered as a monitoring index for judging the condition of SARS patients and prescribing immune therapy