[Difference and significance of T-lymphocyte subsets in differential diagnosis between severe acute respiratory syndrome and common atypical pneumonia].

Background: To clarify the difference and significance of T-lymphocyte subsets in differential diagnosis between severe acute respiratory syndrome SARS) and common atypical pneumonia.
Methods: Totally 100 patients hospitalized in Beijing Ditan Hospital since March to June 2003 with clinical diagnosis of SARS were involved in this study. These patients courses of disease were over 3 weeks. These patients were divided into two groups, SARS group and common atypical pneumonia group (non-SARS group). The counts of CD3+, CD4+ and CD8+ T-lymphocyte of two groups were systematically recorded and analyzed.
Results: Sixty-five of the patients were confirmed to have common type of SARS, including 26 males and 39 females, 50 cases received methylprednisolone treatment. Thirty-five cases had common atypical pneumonia (non-SARS), 21 were males while 14 were females, 20 cases received methylprednisolone treatment. All the cases of two groups were cured in the end. The SARS patients T-lymphocyte counts decreased first and then increased. Before 15 days of disease course, mean CD3+, CD4+, CD8+ T-lymphocyte counts of SARS patients were decreased apparently (694+/-568/microl, 441+/-356/microl, 309+/-462/microl). After 15th day of disease course, the counts gradually returned to normal CD3+, CD4+, CD8+ T-lymphocyte counts of non-SARS patients were normal. Compared with patients of the same group who were not treated with glucocorticoids, T-lymphocyte counts of non-SARS patients treated with glucocorticoids had no obvious difference. But glucocorticoids had some effect on SARS patients recovery of cellular immune function, i.e., it delayed the recovery by about 6 days.
Conclusion: With or without treatment with glucocorticoids,the lowered CD3+, CD4+, CD8+ T-lymphocyte counts in the early stage are of very important significance in differential diagnosis between severe acute respiratory syndrome and common atypical pneumonia.