Abstract: The aim was to analyze the dynamic variation of T lymphocyte subset in 95 patients with severe acute respiratory syndrome (SARS).Among all 95 patients, 85 patients were survivor, 10 patients died of this severe disease.As for 85 survivor patients, the average CD⁴⁺T lymphocyte count and CD⁸⁺ T lymphocyte count were (325±190)cells/μL and (319±315)cells/μL, in 7th day of disease course, respectively, the ratio of CD⁴⁺T/CD⁸⁺ T was 1.25±0.71 which were distinctly lower than that of the normal Chinese peoples whose average CD⁴⁺T lymphocyte count were (727±255)cells/μL, CD⁸⁺ T (539±134)cells/μL, CD⁴⁺T/CD⁸⁺ T were 1.49(P= 0.001).14 days later of disease course, the immunological function of the SARS patients recovered gradually, the average CD⁴⁺T were (561±522)cells/μL, CD⁸⁺ T (370±271)cells/μL, CD⁴⁺T/CD⁸⁺ T were 1.68±1.11.21 days later, their immunological function became normal, the average number of CD⁴⁺T lymphocyte count were (675±448)cells/μL, CD⁸⁺ T lymphocyte count were (467±241)cells/μL, CD⁴⁺T/CD⁸⁺ T 1.48±0.68.While T lymphocyte subset of 10 dead cases appeared to decline in 7th day, 14th day and 21th day.first, their CD⁴⁺T lymphocyte count went down from (248±82)cells/μL in 7th day to (181±128)cells/μL in 14th day and (125±46)cells/μL in final.CD⁸⁺ T lymphocyte count from (233±115)cells/μL to (173±109)cells/μL and to (94±38)cells/μL in final.CD⁴⁺T/CD⁸⁺ T was 1.21±0.40, 1.17±0.45, 1.44±0.59.Conclusion: Activation of abnormal immune response were common in the early stage of SARS, it may be closely correlated to rapidly progression of this disease.T lymphocyte subset will recovery in the second week of disease course, However, it will have bad prognosis if T lymphocyte subset continues to go down without recovery.

Key words: severe acute respiratory syndrome, T lymphocyte subset