The underlying mechanism of the effect of steroid pulse therapy on thymoma.

糖皮质激素已用于胸腺瘤。然而，激素对胸腺瘤的作用机制尚不清楚。我们将胸腺瘤切片和婴儿胸腺在HOS培养(高氧浸泡培养)下培养，肿瘤体积缩小的同时，表达较高水平糖皮质激素受体的CD4+8+双阳性未成熟胸腺细胞显著减少。用5-氟尿嘧啶(5-FU)、顺铂(CDDP)、多西紫杉醇(DOC)、卡铂(CBDCA)、紫杉醇(PTX)等药物体外培养胸腺瘤。胸腺瘤患者术前激素冲击治疗和化疗的疗效最为显著，这可能与激素冲击疗法对胸腺瘤中富含GR的CD4+8+双阳性幼稚淋巴细胞的特异性作用有关，提示激素冲击疗法可用于晚期胸腺瘤的诱导治疗。胸腺瘤的术前诊断是治疗的关键。胸腺瘤的组织学分型采用WHO分型，并对胸腺瘤相关淋巴细胞进行流式细胞仪分析，以确定CD4+CD8+双阳性细胞的比例，以预测激素冲击治疗的疗效。对针刺活检标本中回收的淋巴细胞进行流式细胞术分析是一项有用的措施。

Glucocorticoid has been used in thymomas. However, the mechanism of steroid action on thymomas is not clear.We cultured sliced thymoma and infant thymus in glucocorticoid under HOS culture (high oxygen submersion culture).The reduction in tumor size was accompanied with a marked reduction in the CD4+8+ double positive immature thymocytes that expressed higher levels of glucocorticoid receptor. Apoptotic changes were observed in both neoplastic epithelial cell and lymphocyte components following glucocorticoid.We cultured thymoma in vitro under drugs, 5-fluoroucil(5-FU), cisplatin(CDDP), docertaxel(DOC), carboplatin(CBDCA), paclitaxel(PTX). Apoptotic changes were also observed in both neoplastic epithelial cell and lymphocyte.The efficiency of pre-operative steroid pulse therapy and chemotherapy in thymoma was most prominent which is probably related to the specific effect on GR rich CD4+8+ double positive immature lymphocytes which are abundant in this type of thymoma.We propose that steroid pulse therapy can be used as induction therapy for advanced thymoma, especially those rich in associated CD4+CD8+ double positive cells. Preoperative diagnosis of thymoma is essential for this treatment. Histological classification of thymoma using WHO classification and flow cytometric analysis of the lymphocytes associated with thymoma to determine the proportion of CD4+CD8+ double positive cells will predict the response to the steroid pulse therapy. Flow cytometric analysis oflymphocytes recovered from needle biopsy samples is a useful measure for this purpose.