目的 ： 探讨环磷酰胺（CTX）的免疫增强作用机理。 ： 对单次腹腔注射50 mg/kg CTX后小鼠外周血和脾脏中淋巴细胞数量的变化进行了连续的观察，并用流式细胞术分析了注射CTX后第5天外周血淋巴细胞亚群的变化。 结果 ： 使用CTX后第1～5天外周血和脾脏中淋巴细胞数量出现了迅速的下降，同时，外周血淋巴细胞亚群中出现非T淋巴细胞比例的下降和T淋巴细胞比例的升高，且CD8+比CD4+ T淋巴细胞比例升高明显。 结论 ： 淋巴细胞数量和亚群的变化可能同CTX的免疫增强作用有关。

Objective : To explore the possible mechanism that single administration of low dose cyclophosphamide (CTX) has the ability to potentiate immunity in antitumor immunotherapy. Methods: Lymphocytes in peripheral blood and spleen were numerated after 50 mg/kg CTX was administrated intraperitoneally to Balb/c mice, and lymphocyte subsets were analyzed by flow cytometry on day 5 of the administration. Results: On day 1 to 5 after CTX administration, lymphocytes decreased promptly both in peripheral blood and in spleen, accompanying with the decrease in ratio of non-T lymphocyte subsets and the increase in ratio of T lymphocyte subsets in peripheral blood, and the increase in ratio of CD8+ T lymphocytes was more marked than that in ratio of CD4+ T lymphocytes. Conclusions: These changes might be associated with the immune potentiation effect of CTX, and our observation afforded some information in further investigating the mechanism of immune potentiation effect of CTX.

广东省自然科学基金项目（04300289）; 中国博士后科学基金项目（2004035180）