Panayiotidis P, Ganeshaguru K, Foroni L, Hoffbrand A V
Department of Haematology, Royal Free Hospital and School of Medicine, London, UK.
Leukemia. 1995 Jul;9(7):1227-32.
The expression and function of the FAS antigen was analyzed in 21 patients with B chronic lymphocytic leukemia (CLL) and four with hairy cell leukemia (HCL) using a specific IgM monoclonal antibody and FACS analysis. The FAS antigen was expressed in a minority (5-41%, mean 15.6%) of the CLL cells in 10 of 21 CLL patients and this expression was not modified during spontaneous or hydrocortisone-induced apoptosis of CLL cells. In contrast, culture with gamma-interferon (gamma-IFN) upregulated the expression of FAS in all CLL patients, with 65-100% (mean 84.8%) of the cells being positive after 2 days in vitro culture. Culture with alpha-IFN induced FAS expression in 15 of 19 CLL patients tested, with 15-74% (mean 34%) of the cells being FAS+ after 2 days culture. IL-4 and IL-10, lymphokines that inhibit and promote CLL apoptosis respectively, did not modify the expression of FAS. These results from FACS analysis were consistent with FAS mRNA analysis of fresh and cultured CLL cells, using a semi-quantitative reverse transcriptase (RT)-PCR technique. Although IL-4 and IFNs prevent apoptotic cell death of CLL cells in vitro, the present results show that IFNs induce the expression of the apoptosis-inducing protein FAS. However, FAS+ CLL cells were not killed in the presence of anti-FAS monoclonal antibody (while the FAS+ Jurkat and four lymphoblastoid cell lines were killed). This resistance is not due to a mutated FAS protein, since only wild-type FAS cDNA was demonstrated in the leukemic cells of three CLL patients. In four HCL patients 34-53% (mean 44.5%) of the leukemic cells were FAS+ and they were also resistant to the anti-FAS mediated cytotoxicity. The combination of high bcl-2 protein levels and resistance to anti-FAS mediated cytotoxicity may contribute to the extended in vivo survival of CLL and HCL cells.
使用特异性IgM单克隆抗体和流式细胞术分析（FACS分析），对21例B慢性淋巴细胞白血病（CLL）患者和4例毛细胞白血病（HCL）患者的FAS抗原表达及功能进行了研究。在21例CLL患者中的10例中，少数（5 - 41%，平均15.6%）的CLL细胞表达FAS抗原，且在CLL细胞自发凋亡或氢化可的松诱导凋亡过程中，这种表达未发生改变。相比之下，用γ干扰素（γ - IFN）培养可使所有CLL患者的FAS表达上调，体外培养2天后，65 - 100%（平均84.8%）的细胞呈阳性。用α - IFN培养19例接受检测的CLL患者中的15例可诱导FAS表达，培养2天后，15 - 74%（平均34%）的细胞FAS呈阳性。分别抑制和促进CLL细胞凋亡的细胞因子IL - 4和IL - 10，并未改变FAS的表达。这些流式细胞术分析结果与使用半定量逆转录酶（RT）- PCR技术对新鲜及培养的CLL细胞进行FAS mRNA分析结果一致。尽管IL - 4和干扰素在体外可防止CLL细胞发生凋亡性细胞死亡，但目前结果表明干扰素可诱导凋亡诱导蛋白FAS的表达。然而，在存在抗FAS单克隆抗体的情况下，FAS阳性的CLL细胞并未被杀死（而FAS阳性的Jurkat细胞和四种淋巴母细胞系被杀死）。这种抗性并非由于FAS蛋白发生突变，因为在3例CLL患者的白血病细胞中仅证实存在野生型FAS cDNA。在4例HCL患者中，34 - 53%（平均44.5%）的白血病细胞FAS呈阳性，且它们也对抗FAS介导的细胞毒性具有抗性。高bcl - 2蛋白水平与抗FAS介导的细胞毒性抗性相结合，可能有助于CLL和HCL细胞在体内的长期存活。
