Abstract: 　Objective] To study the inflammatory immune response to Pneumocystis canii pneumonia(PCP) in rats induced by glucocorticoid(GC).[Methods] The model of PCP was set up by injecting GC subcutanously to SD rats. Lymphocyte proportion in peripheral blood, CD4 +/CD8 + T cell ratio of PBL and lymphocyte proportion in the BALF were measured. The levels of sIL 2R and TNF α in the BALF were detected.[Results]① After the rats were immunospressed, the lymphocyte proportion in the peripheral blood and CD4 +/CD8 + ratio of PBL, and the lymphocyte proportion in the BALF were decreased, and the levels of sIL 2R, TNF α in BALF were reduced. ② The lowest levels of TNF α in BALF and CD4 +/CD8 + T cells of PBL were observed in PCP group; ③ The lymphocyte proportion in the BALF was significantly higher in PCP group than in PC negative group.[Conclusion]The reduction in the level of TNF α and CD4 + /CD8 + T cell ratio in rats treated with GC might result in PCP infection under immunosuppressive condition.

Key words: Glucocorticoid, immunosuppression, Pneumocystis carini pneumonia, inflammatory immune response.