Establishment of cancer immunotherapy with autologous dendritic cells and tumor-specific antigens in children with refractory malignant tumors

目的：免疫治疗是近年来肿瘤治疗中一种很有前途的新方法。本研究为探讨肿瘤特异性抗原致敏的自体树突状细胞（DCs）对儿童难治性恶性肿瘤的治疗作用，采用体外致敏的DCs诱导肿瘤细胞的细胞毒性T细胞（CTL），以治疗儿童难治性恶性肿瘤。用肿瘤特异性抗原（含有对肿瘤细胞或肿瘤裂解物特异性的染色体易位连接区的合成肽）脉冲产生的未成熟DC，并以3×10^6个细胞的剂量皮下注射给患者。每周或每两周重复给药6 ~ 8次。滑膜肉瘤（SS）1.神经母细胞瘤（NB）3例。DC给药后未观察到副作用。在一个病人的ES。DC治疗后残留肿瘤消失，完全缓解维持2年以上。2例患者（55和NB）。肿瘤的生长暂时被抑制了几周，随后迅速恶化。其他2例未观察到临床改善。在SS患者中，皮肤对肿瘤裂解物的迟发型超敏反应增强，与肿瘤特异性抗原致敏的DC一起培养的T细胞在体外破坏肿瘤细胞。结论：以DC为基础的免疫治疗是一种可行的方法。耐受性良好，在治疗儿童难治性恶性肿瘤方面有希望。

Purpose : Immunotherapy has recently emerged as a promising new modality in cancer therapy. In this study. autologous dendritic cells (DCs) pulsed with tumor specific antigens in vitro were administered to patients and induced cytotoxic T cells (CTLs) against tumor cells Is in order to cure children with refractory cancers.Materials and Methods : DCs were generated from patients' peripheral blood mononuclear cells by using hrGM-CSF and hrIL-4. The generated immature DCs were pulsed with tumor specific antigens (synthetic peptides containing a junctional region of the chromosomal translocation specific to tumor cells or tumor lysates), and injected to patients subcutaneously at a dose of 3×10^6 cells. The administration was repeated weekly or biweekly 6 to 8 times.Results : Five patients with refractory or relapsed diseases (Ewing sarcoma (ES) 1. synovial sarcoma (SS) 1. neuroblastoma (NB)3) received DC therapy. No side effects were observed after DC administration. In one patient with ES. the residual tumor disappeared following DC therapy and the complete remission has been maintained for over 2 years. In two patients (55 and NB). the growth of the tumors was temporal ly suppressed for a couple of weeks, followed by the rapid exacerbation. No clinical improvement was observed in other two. In the patient with SS, the delayed-type hypersensitivity responses in skin were enhanced to tumor lysates, and T cells cultured with DCs pulsed with tumor specific antigens destroyed the tumor cells in vitro. The number of HLA-DR+ CD8+ cells and IFN-γ producing CD8+ cells increased after DC administration in patients with possible DC-mediated anti-tumor effect.Conclusions : DC-based immunotherapy was a feasible. well-tolerated and promising approach in the treatment of children with refractory malignant tumors.