嵌合抗原受體-T細(xì)胞免疫治療在血液系統(tǒng)惡性腫瘤中的應(yīng)用進(jìn)展

克曉燕

100191北京市，北京大學(xué)第三醫(yī)院血液科

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·新進(jìn)展·

嵌合抗原受體-T細(xì)胞免疫治療在血液系統(tǒng)惡性腫瘤中的應(yīng)用進(jìn)展

克曉燕

100191北京市，北京大學(xué)第三醫(yī)院血液科

【摘要】嵌合抗原受體(CAR)將單鏈抗體可變區(qū)與T細(xì)胞的活化基序相融合，使其修飾的T細(xì)胞具有非主要組織相容性復(fù)合物(MHC)限制性識(shí)別腫瘤抗原及殺傷靶細(xì)胞的雙重功能。CAR細(xì)胞內(nèi)區(qū)的結(jié)構(gòu)從表達(dá)單一信號(hào)分子的第1代，發(fā)展為添加1個(gè)及2個(gè)以上共刺激分子的第2代和第3代以及增加了編碼CAR和/或其啟動(dòng)子、自殺基因等的第4代，使T細(xì)胞在體內(nèi)的存活時(shí)間和殺傷能力明顯增強(qiáng)且能夠調(diào)控。本文就CAR-T細(xì)胞免疫治療的原理、在血液系統(tǒng)惡性腫瘤中的應(yīng)用以及主要不良反應(yīng)和應(yīng)對(duì)措施進(jìn)行分析，發(fā)現(xiàn)應(yīng)用CAR-T細(xì)胞免疫治療多種血液系統(tǒng)惡性腫瘤取得了較好臨床療效，其中以靶向CD(19)的CAR-T細(xì)胞免疫治療療效尤為突出，患者的生存期延長(zhǎng)、生活質(zhì)量改善并且不良反應(yīng)較少。CAR-T細(xì)胞免疫治療的主要不良反應(yīng)是脫靶效應(yīng)和細(xì)胞因子釋放綜合征，需要引起臨床足夠重視。

【關(guān)鍵詞】血液腫瘤；嵌合抗原受體；T細(xì)胞；免疫治療

克曉燕.嵌合抗原受體-T細(xì)胞免疫治療在血液系統(tǒng)惡性腫瘤中的應(yīng)用進(jìn)展[J].中國(guó)全科醫(yī)學(xué)，2016，19(12)：1361-1366.[www.chinagp.net]

Ke XY.Application of CAR-T cell immunotherapy in the treatment of hematological malignancy[J].Chinese General Practice，2016，19(12)：1361-1366.

傳統(tǒng)的放療、化療、手術(shù)、造血干細(xì)胞移植等治療方法延長(zhǎng)了部分血液系統(tǒng)惡性腫瘤患者的生存時(shí)間，但是復(fù)發(fā)、難治甚至耐藥現(xiàn)象，仍是目前面臨的巨大挑戰(zhàn)。近年來(lái)，細(xì)胞免疫治療因在腫瘤的治療中取得了突破性進(jìn)展，成為血液系統(tǒng)等多種腫瘤治療的重要手段，被Science雜志列為2013年十大科學(xué)突破的首位[1]。其中，嵌合抗原受體(chimeric antigen receptor,CAR)-T細(xì)胞免疫治療進(jìn)展尤為突出，自Gross等[2]1989年首次提出這一概念至今，CAR-T細(xì)胞在治療包括白血病、淋巴瘤、黑色素瘤、神經(jīng)母細(xì)胞瘤、肉瘤等的多項(xiàng)臨床研究中表現(xiàn)出了良好的靶向性、殺傷活性和持久性，成為治療血液系統(tǒng)惡性腫瘤的有效方法。本文將主要介紹CAR-T細(xì)胞免疫治療在血液系統(tǒng)惡性腫瘤中的原理、臨床應(yīng)用、主要不良反應(yīng)及應(yīng)對(duì)措施等。

1CAR-T細(xì)胞免疫治療原理

1.1CAR-T細(xì)胞作用原理T細(xì)胞的活化有賴于雙信號(hào)系統(tǒng)共同作用：第一信號(hào)由T細(xì)胞表面受體(TCR)與Ⅰ類、Ⅱ類主要組織相容性復(fù)合物(major histocompatibility complex，MHC)結(jié)合；第二信號(hào)主要由抗原遞呈細(xì)胞上的B7家族分子與其在T細(xì)胞上的配體CD28相結(jié)合產(chǎn)生協(xié)同刺激信號(hào)(即B7/CD28協(xié)同刺激信號(hào))[3]。CAR-T細(xì)胞免疫治療是利用基因工程的方法，將識(shí)別目標(biāo)抗原的單鏈抗體與間隔區(qū)、跨膜基序和T細(xì)胞的活化基序等結(jié)合為一體，利用該融合基因修飾T細(xì)胞，既能夠特異性識(shí)別并結(jié)合腫瘤抗原，又具備T細(xì)胞自我更新和殺傷能力，可不受腫瘤局部微環(huán)境免疫抑制、以非MHC限制性的方式特異性殺傷腫瘤細(xì)胞[4]。

1.2CAR的結(jié)構(gòu)CAR的模塊化結(jié)構(gòu)主要包括：細(xì)胞外抗原結(jié)合區(qū)、鉸鏈區(qū)、中間的跨膜區(qū)域和細(xì)胞內(nèi)信號(hào)轉(zhuǎn)導(dǎo)區(qū)(見(jiàn)圖1)[5]。細(xì)胞外區(qū)為單克隆抗體的單鏈可變區(qū)(single chain variable fragment,scFv)，由輕鏈和重鏈共同組成，能夠識(shí)別特定腫瘤抗原；跨膜區(qū)有H2-Kb、FcεRIc、CD4、CD7、CD8、CD28和CD3ζ等[6]，將CAR結(jié)構(gòu)錨定于T細(xì)胞膜上；細(xì)胞內(nèi)區(qū)為T 細(xì)胞受體TCR/CD3ζ鏈或免疫球蛋白 Fc 受體 FcεRIγ鏈，含有免疫受體酪氨酸活化基序(immunoreceptor tyrosine-based activation motifs,ITAMs)，可發(fā)揮信號(hào)轉(zhuǎn)導(dǎo)功能[4]。目前，已有多種腫瘤抗原可用作細(xì)胞外區(qū)識(shí)別，包括CD19、CD20、表皮生長(zhǎng)因子受體(EGFR)、前列腺特異性膜抗原(PSMA)、人類表皮生長(zhǎng)因子受體2(HER-2)/neu、GD2、ROR1和碳酸酐酶Ⅸ(CAⅨ)等[7]。不同的跨膜區(qū)表達(dá)CAR的能力不同，Pulè等[8]發(fā)現(xiàn)，含有CD28的跨膜區(qū)表達(dá)CAR的能力最強(qiáng)，含有CD134(OX40)的跨膜區(qū)次之，而含有CD3ζ的跨膜區(qū)表達(dá)能力最低。

圖1　CAR的結(jié)構(gòu)

根據(jù)細(xì)胞內(nèi)的區(qū)結(jié)構(gòu)不同，CAR可劃分為4代：第1代CAR(scFv+信號(hào)轉(zhuǎn)導(dǎo)區(qū))，細(xì)胞內(nèi)區(qū)只表達(dá)單一的信號(hào)分子(TCR/CD3ζ鏈或FcεRIγ鏈)，不表達(dá)共刺激分子，能夠識(shí)別靶抗原并激活T細(xì)胞，但不轉(zhuǎn)導(dǎo)增殖信號(hào)和誘導(dǎo)細(xì)胞因子產(chǎn)生，體內(nèi)無(wú)法持續(xù)抗腫瘤；第2代CAR(scFv+信號(hào)轉(zhuǎn)導(dǎo)區(qū)+一種共刺激分子)，細(xì)胞內(nèi)區(qū)添加了一個(gè)共刺激分子〔如CD27、CD28、OX40、可誘導(dǎo)共刺激分子(inducible costimulatory molecule,ICOS)或CD137(4-1BB)等〕，可實(shí)現(xiàn)協(xié)同刺激分子和細(xì)胞內(nèi)信號(hào)的雙重活化，使T細(xì)胞持續(xù)增殖并釋放細(xì)胞因子，提高T細(xì)胞的抗腫瘤能力[9]；第3代CAR(scFv+信號(hào)轉(zhuǎn)導(dǎo)區(qū)+二種以上共刺激分子)，細(xì)胞內(nèi)區(qū)整合了2個(gè)以上的協(xié)同刺激分子，與第2代CAR相比，T細(xì)胞活化、增殖、分泌細(xì)胞因子及細(xì)胞毒素作用更強(qiáng)，但靶向識(shí)別特異性降低，低親和分子亦可促進(jìn)T細(xì)胞活化，可產(chǎn)生細(xì)胞因子風(fēng)暴[10- 11]；第4代CAR(又稱TRUCKs)，在第3代CAR的基礎(chǔ)上增加了編碼CAR和/或其反應(yīng)性啟動(dòng)子的載體，在轉(zhuǎn)基因產(chǎn)生的細(xì)胞因子作用下CAR產(chǎn)生有效信號(hào)，并能夠招募免疫系統(tǒng)其他成員，放大抗腫瘤免疫效應(yīng)[12-13]。最近一項(xiàng)研究在動(dòng)物體內(nèi)應(yīng)用雙特異性CAR-T細(xì)胞，發(fā)現(xiàn)其具有招募抗體以及抗腫瘤的活性[14]。也有研究在CAR結(jié)構(gòu)中引入自殺基因，以調(diào)控T細(xì)胞的殺傷能力和擴(kuò)增能力[15]；還可構(gòu)建對(duì)多種腫瘤均有很強(qiáng)親和力的通用CAR(universal CAR,uCAR)，通過(guò)使T細(xì)胞迅速擴(kuò)增、產(chǎn)生大量細(xì)胞因子，增強(qiáng)其抗腫瘤作用[16-17]。

本文背景和要點(diǎn)：

近年來(lái)，隨著分子生物學(xué)、免疫學(xué)等基礎(chǔ)學(xué)科的進(jìn)展，細(xì)胞免疫治療成為包括血液惡性腫瘤在內(nèi)的多種惡性腫瘤治療的重要手段，被Science雜志列為2013年十大科學(xué)突破之首。其中，關(guān)于嵌合抗原受體(CAR)-T細(xì)胞的臨床研究首先在血液系統(tǒng)惡性腫瘤的治療中取得了令人振奮的效果，靶向CD19的CAR-T細(xì)胞免疫治療能夠?qū)⒓毙粤馨图?xì)胞白血病患者的完全緩解率提高至90%，成為目前研究的熱點(diǎn)。另一方面，CAR-T細(xì)胞免疫治療還處于發(fā)展階段，在淋巴瘤、骨髓瘤等血液系統(tǒng)惡性腫瘤及實(shí)體瘤的治療中還有很大的發(fā)展空間。本文對(duì)CAR-T細(xì)胞免疫治療的原理、應(yīng)用于血液系統(tǒng)惡性腫瘤的臨床試驗(yàn)以及該療法主要的不良反應(yīng)和應(yīng)對(duì)措施進(jìn)行評(píng)價(jià)及分析，旨在為CAR-T細(xì)胞免疫治療更規(guī)范、有效的應(yīng)用于血液系統(tǒng)腫瘤提供思路和方向。

2CAR-T細(xì)胞免疫治療的臨床應(yīng)用

目前，應(yīng)用CAR-T細(xì)胞免疫治療血液系統(tǒng)惡性腫瘤，主要包括構(gòu)建靶向CD19、CD20、Kappa輕鏈、CD22、CD23、CD30、CD33、CD38、CD70等抗體的CAR來(lái)修飾T細(xì)胞進(jìn)行臨床試驗(yàn)，其中以靶向CD19的CAR-T細(xì)胞免疫治療的療效尤為突出[5,18]。

2.1CAR-T細(xì)胞免疫治療在白血病中的應(yīng)用CD19特異性表達(dá)于惡性B細(xì)胞和正常B細(xì)胞以及B細(xì)胞前體細(xì)胞，而造血干細(xì)胞及非造血細(xì)胞則不表達(dá)CD19，因此目前靶向CD19的CAR-T細(xì)胞免疫治療在臨床上研究最多[19]。早期應(yīng)用第1代靶向CD19的CAR-T細(xì)胞，因缺乏共刺激分子、T細(xì)胞體內(nèi)存活時(shí)間較短、釋放細(xì)胞因子有限，治療效果并不顯著[20]。后續(xù)臨床試驗(yàn)多選用第2代CAR-T細(xì)胞，抗腫瘤作用明顯提升，如Maude等[21]應(yīng)用自體抗CD19的第2代CAR-T細(xì)胞(CTL019)免疫治療30例復(fù)發(fā)/難治急性淋巴細(xì)胞白血病(acute lymphoblastic leukemia,ALL)患兒，其中90%(27例)達(dá)完全緩解(CR)，持續(xù)緩解6個(gè)月的無(wú)事件生存率為67%，即使干細(xì)胞移植失敗的患者亦可持續(xù)緩解達(dá)24個(gè)月；Davila等[22]應(yīng)用自體抗CD19的第2代19-28z CAR-T細(xì)胞免疫治療16例復(fù)發(fā)ALL的成人患者，CR率亦達(dá)到88%；Lee等[23]應(yīng)用自體抗CD19的第2代CAR-T細(xì)胞免疫治療20例復(fù)發(fā)/難治的兒童和成人ALL患者，CR率可達(dá)70%，61%的患者腦脊液中可檢測(cè)到CAR-T細(xì)胞，且輸注1×106個(gè)/kg CAR-T細(xì)胞未出現(xiàn)明顯不良反應(yīng)。

一些臨床前研究發(fā)現(xiàn)，CAR-T細(xì)胞免疫治療可能具有根治急性髓細(xì)胞白血病(acute myeloid leukemia,AML)的潛力，但多數(shù)AML細(xì)胞與造血干細(xì)胞或早期祖細(xì)胞公用抗原，故限制了其應(yīng)用[24]。最早被選作CAR-T細(xì)胞免疫治療AML的靶點(diǎn)是Lewis Y寡糖抗原(LeY)，應(yīng)用LeY-CAR-T細(xì)胞免疫治療AML移植瘤NOD/SCID鼠，可明顯減緩腫瘤生長(zhǎng)[25]。之后一項(xiàng)Ⅰ期臨床試驗(yàn)應(yīng)用靶向LeY抗原的自體第2代CAR-T細(xì)胞免疫治療4例復(fù)發(fā)的AML患者，其中1例達(dá)細(xì)胞學(xué)緩解，其余3例獲得了部分緩解(PR)/病情穩(wěn)定(SD)，且未見(jiàn)明顯不良反應(yīng)[26]。應(yīng)用抗CD123的第2代CAR-T細(xì)胞(CD123scFv-CD127-CD3ζ)免疫治療AML免疫缺陷小鼠，可清除AML細(xì)胞，顯示了其良好的療效，但因CD123也表達(dá)于部分造血祖細(xì)胞，靶向CD123的CAR-T細(xì)胞亦能殺傷正常人的造血祖細(xì)胞[27]。因此，對(duì)于CAR-T細(xì)胞免疫治療在AML患者中的應(yīng)用除仍需繼續(xù)尋找更加特異的腫瘤標(biāo)志物外，還需積極尋找其他聯(lián)合治療方案。

對(duì)于慢性淋巴細(xì)胞白血病(chronic lymphocytic leukaemia,CLL)，研究發(fā)現(xiàn)靶向CD19的CAR-T細(xì)胞可在體內(nèi)以指數(shù)方式擴(kuò)增以清除腫瘤，14例復(fù)發(fā)/難治CLL患者的總反應(yīng)率達(dá)57%(8/14)，其中2例CR患者體內(nèi)的CAR-T細(xì)胞免疫治療作用可長(zhǎng)達(dá)4年[28]，且添加CD28共刺激分子的靶向CD19的CAR-T細(xì)胞免疫治療甚至對(duì)異基因干細(xì)胞移植后的復(fù)發(fā)CLL患者也顯示了良好的療效[29]。然而，對(duì)于同樣為惡性B細(xì)胞腫瘤的CLL患者，靶向CD19的CAR-T細(xì)胞免疫治療的療效卻低于ALL患者，可能源于其不同于ALL患者的體內(nèi)微環(huán)境。

細(xì)胞內(nèi)蛋白WT1過(guò)表達(dá)于多種急慢性白血病和實(shí)體腫瘤細(xì)胞中，Rafiq等[30]使用ESK1 TCRm(又稱WT1 28z)作為CAR，能夠特異性殺傷WT1-HLA-A*02:01陽(yáng)性的多種腫瘤細(xì)胞，提示CAR-T細(xì)胞免疫治療亦可靶向腫瘤細(xì)胞內(nèi)蛋白抗原，這就為特異性腫瘤抗原的選擇拓寬了思路。

2.2CAR-T細(xì)胞免疫治療在淋巴瘤中的應(yīng)用應(yīng)用靶向CD19的CAR-T細(xì)胞免疫治療非霍奇金淋巴瘤(non-Hodgkin′s lymphoma,NHL)患者顯示了較好的療效，但與治療ALL患者療效相比仍需優(yōu)化改進(jìn)[31]。Kochenderfer等[32-33]首先報(bào)道了一部分濾泡淋巴瘤(FL)患者應(yīng)用靶向CD19的CAR-T細(xì)胞免疫治療后可達(dá)PR，隨后該課題組將靶向CD19的CAR-T細(xì)胞免疫治療應(yīng)用于彌漫大B細(xì)胞淋巴瘤(DLBCL)患者，發(fā)現(xiàn)4/7患者達(dá)CR，2/7患者達(dá)PR，4例CR患者中3例持續(xù)緩解9～22個(gè)月[34]。Schuster等[35]應(yīng)用靶向CD19的CAR-T細(xì)胞免疫治療復(fù)發(fā)/難治性NHL患者的Ⅱa期臨床試驗(yàn)，總反應(yīng)率達(dá)67%(其中12例DLBCL患者的反應(yīng)率為50%，6例FL患者反應(yīng)率則為100%)，中位隨訪6個(gè)月患者的無(wú)進(jìn)展生存率為59%。

一項(xiàng)Ⅰ期臨床試驗(yàn)應(yīng)用靶向CD20分子的第3代CAR-T細(xì)胞免疫治療4例復(fù)發(fā)的惰性B細(xì)胞淋巴瘤和套細(xì)胞淋巴瘤患者顯示了較好療效，2例患者持續(xù)無(wú)疾病進(jìn)展期分別達(dá)12個(gè)月和24個(gè)月，且均耐受良好，無(wú)明顯不良反應(yīng)[36]。將靶向CD30的CAR負(fù)載于EB病毒特異性細(xì)胞毒性T細(xì)胞(EBV-CTLs)制備CD30CAR(+) EBV-CTLs，該細(xì)胞能夠在霍奇金淋巴瘤(Hodgkin′s lymphoma,HL)移植瘤模型中發(fā)揮抗腫瘤作用[37]。Mihara等[38]應(yīng)用抗CD123的第2代CAR-T細(xì)胞(CD123scFv-CD127-CD3ζ)免疫治療HL移植瘤小鼠，6個(gè)月的無(wú)復(fù)發(fā)生存率為100%。

2.3CAR-T細(xì)胞免疫治療在多發(fā)性骨髓瘤(multiple myeloma,MM)中的應(yīng)用近50%的MM患者表達(dá)LeY抗原，而應(yīng)用LeY-CAR-T細(xì)胞免疫治療能夠明顯延遲骨髓瘤異種移植物NOD/SCID鼠中的生長(zhǎng)[25]。Ruella等[39]應(yīng)用靶向CD38、CD56的CAR-T細(xì)胞免疫治療MM，顯示了較強(qiáng)的細(xì)胞毒性。在78例MM患者骨髓活檢樣本中，免疫組化染色顯示腫瘤-睪丸抗原NY-ESO-1表達(dá)率為9.7%，將NY-ESO-1作為腫瘤抗原設(shè)計(jì)CAR-T細(xì)胞免疫治療，能夠顯著抑制抗原陽(yáng)性的MM移植瘤小鼠的腫瘤生長(zhǎng)[40]。

2.4CAR-T細(xì)胞免疫治療在其他血液病中的應(yīng)用應(yīng)用Ⅷ因子的CAR(FⅧscFv-CD28-CD3ζ)修飾調(diào)節(jié)性T細(xì)胞(Treg細(xì)胞)，發(fā)現(xiàn)FⅧCAR-Treg細(xì)胞可誘導(dǎo)針對(duì)Ⅷ因子抗體的免疫耐受，提示其可能在Ⅷ因子抗體陽(yáng)性的血友病A患者中具有較好的應(yīng)用前景[41]。可見(jiàn)，應(yīng)用CAR技術(shù)修飾其他免疫相關(guān)細(xì)胞可能為惡性腫瘤以外的血液病、乃至自身免疫病提供一種新的研究方向。

2.5CAR-T細(xì)胞免疫治療在實(shí)體腫瘤中的應(yīng)用基于實(shí)體腫瘤缺乏較理想的特異性表面抗原，且具有不同的免疫抑制機(jī)制，CAR-T細(xì)胞免疫治療的療效不及血液腫瘤(特別是B細(xì)胞惡性腫瘤)，但其在黑色素瘤、神經(jīng)母細(xì)胞瘤、肉瘤、間皮瘤、胰腺癌等腫瘤中取得了較好的療效，如Morgan等[42]應(yīng)用靶向人黑色素瘤標(biāo)志物α-MART-1的CAR-T細(xì)胞免疫治療17例轉(zhuǎn)移性黑色素瘤患者發(fā)現(xiàn)，2例患者腫瘤完全消退，其余患者外周血中持續(xù)存在高比例(9%～56%)的回輸T細(xì)胞，且病情穩(wěn)定；Louis等[43]應(yīng)用靶向神經(jīng)節(jié)苷脂2(GD2)的CAR-T細(xì)胞免疫治療19例高危神經(jīng)母細(xì)胞瘤患者，11例進(jìn)展期患者中3例達(dá)到CR，這些CAR-T細(xì)胞可在患者體內(nèi)擴(kuò)增、持續(xù)存在并與患者長(zhǎng)期生存相關(guān)。人腺癌中過(guò)表達(dá)HER-2，應(yīng)用抗-HER-2的CAR-T細(xì)胞免疫治療19例HER-2+的肉瘤患者，未見(jiàn)明顯與輸注劑量相關(guān)的CAR-T細(xì)胞毒性，總生存期為5.1～29.1個(gè)月，中位生存期為10.3個(gè)月，其中4例患者SD達(dá)3～14個(gè)月[44]。應(yīng)用間皮素特異性mRNA-CAR-T細(xì)胞免疫治療間皮素高表達(dá)的晚期實(shí)體腫瘤患者(1例惡性胸膜間皮瘤和1例轉(zhuǎn)移性胰腺癌)，也取得了較好的抗腫瘤作用[45]。另外，由于腫瘤新生血管與腫瘤的生長(zhǎng)與轉(zhuǎn)移關(guān)系密切，應(yīng)用靶向新生血管中過(guò)表達(dá)的血管內(nèi)皮生長(zhǎng)因子受體2(VEGFR-2)的CAR-T細(xì)胞進(jìn)行免疫治療，能夠抑制不同的小鼠腫瘤生長(zhǎng)，且對(duì)正常組織無(wú)明顯損傷，進(jìn)而發(fā)揮間接抗腫瘤作用[46-47]。

3CAR-T細(xì)胞免疫治療的主要不良反應(yīng)及應(yīng)對(duì)措施

CAR-T細(xì)胞免疫治療為包括血液病在內(nèi)的多種晚期惡性腫瘤患者帶來(lái)治愈希望的同時(shí)，也帶來(lái)諸多不良反應(yīng)，甚至一些是致命的，需要引起臨床足夠的重視。

3.1脫靶效應(yīng)(on-target toxicity)脫靶效應(yīng)常見(jiàn)于應(yīng)用CAR-T細(xì)胞免疫治療實(shí)體腫瘤的患者中，主要由于CAR定向的靶抗原多為腫瘤相關(guān)抗原(TAA)，其并非腫瘤細(xì)胞所特有，且在正常組織中存在不同程度的表達(dá)，因此對(duì)靶抗原親和力強(qiáng)、殺傷能力強(qiáng)的CAR-T細(xì)胞在清除腫瘤的同時(shí)也會(huì)攻擊正常組織。HER-2-CAR-T細(xì)胞可殺傷低表達(dá)HER-2的肺組織，引起致命性肺損傷[48]。靶向CD19的CAR-T細(xì)胞免疫治療過(guò)程中會(huì)出現(xiàn)B細(xì)胞無(wú)能[49]。因此，可采取以下措施預(yù)防和治療脫靶效應(yīng)：(1)選擇僅表達(dá)于腫瘤細(xì)胞而在正常細(xì)胞不表達(dá)的腫瘤特異性抗原(TSA)；(2)研發(fā)與靶抗原具有特定親和力的CAR；(3)構(gòu)建跨信號(hào)CAR，不直接相連CAR結(jié)構(gòu)中的T細(xì)胞活化信號(hào)CD3ζ與共刺激信號(hào)CD28分子[50]；(4)輸注丙種球蛋白治療靶向CD19的CAR-T細(xì)胞免疫治療引起的B細(xì)胞缺乏等[49]。

3.2細(xì)胞因子釋放綜合征(cytokine release syndrome,CRS)第2、3代CAR中引入了共刺激分子，使T細(xì)胞的活化、增殖、殺傷能力大幅度增強(qiáng)，在治療過(guò)程中產(chǎn)生大量細(xì)胞因子并釋放入血，引起患者惡心、頭痛、心動(dòng)過(guò)速、低血壓、胸悶、氣促等臨床癥狀，嚴(yán)重者可導(dǎo)致急性呼吸窘迫綜合征或多器官功能衰竭[48,51]。CRS是CAR-T細(xì)胞免疫治療過(guò)程中常見(jiàn)的致死性并發(fā)癥，需要高度警惕，可采取以下措施進(jìn)行控制：(1)研發(fā)更加安全的CAR結(jié)構(gòu)并嚴(yán)格限制每次輸注的CAR-T細(xì)胞數(shù)量；(2)適當(dāng)應(yīng)用糖皮質(zhì)激素及細(xì)胞因子拮抗劑〔如IL-6阻斷劑—塔西單抗(Tocilizumab)〕[52]；(3)在降低腫瘤負(fù)荷后應(yīng)用CAR-T細(xì)胞免疫治療。

4小結(jié)及展望

CAR-T細(xì)胞免疫治療時(shí)應(yīng)用靶向腫瘤抗原的CAR修飾T細(xì)胞，將抗原抗體的高親和性與T細(xì)胞的殺傷效應(yīng)相結(jié)合，在多種惡性腫瘤(特別是B細(xì)胞血液腫瘤)的治療中取得了令人欣喜的療效[21-23]，成為現(xiàn)今腫瘤免疫治療的熱點(diǎn)，具有廣闊的應(yīng)用前景。然而，在提升CAR-T細(xì)胞抗腫瘤能力的同時(shí)減少其不良反應(yīng)等問(wèn)題仍存在諸多挑戰(zhàn)，應(yīng)重視特異性腫瘤抗原的選取，CAR結(jié)構(gòu)的優(yōu)化改進(jìn)。另外，CAR-T細(xì)胞免疫治療與其他細(xì)胞免疫治療技術(shù)及傳統(tǒng)放化療的結(jié)合，CAR-T細(xì)胞具體回輸?shù)臅r(shí)機(jī)、劑量、次數(shù)、抗腫瘤效應(yīng)的調(diào)控、有效評(píng)估系統(tǒng)的界定，CAR-T細(xì)胞免疫治療與造血干細(xì)胞移植的聯(lián)合及復(fù)發(fā)患者的治療選擇等問(wèn)題均需要大量的臨床前研究及多中心大樣本臨床試驗(yàn)進(jìn)一步研究。因此，針對(duì)這些亟待解決的問(wèn)題進(jìn)行深入探討，將為CAR-T細(xì)胞免疫治療大規(guī)模應(yīng)用于血液系統(tǒng)惡性腫瘤提供新的思路和方向。

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(本文編輯：李婷婷)

Application of CAR-T Cell Immunotherapy in the Treatment of Hematological Malignancy

KEXiao-yan.DepartmentofHematology,PekingUniversityThirdHospital,Beijing100191，China

【Abstract】Chimeric antigen receptor (CAR) connects single-chain variable fragment and activation motif of T cells,which allows modified T cells possess dual functions of recognizing tumor antigens in an MHC unrestricted way and killing the target cells.The intracellular structures of CAR has changed over time,from the first generation with the expression of single signal molecule,to the second and third generation adding one or two and multiple costimulatory endodomains,and to the fourth generation combining with the domains of coding CAR and/or the promoter,and suicide gene.They enhance and regulate the persistence and cytotoxicity of modified T cells.This paper summarized the available data on the principle of CAR-T cell immunotherapy,its application in the treatment of hematological malignancy,and the main adverse reactions and response measures.It was found that chimeric antigen receptor-T (CAR-T) cells have received better therapeutic effect in many types of hematological malignancy,remarkably for the CAR-T cell immunotherapy targeting CD(19);patients who adopt cell immunotherapy have prolonged survival,improved quality of life,and less adverse reactions.The main adverse reactions of CAR-T cell immunotherapy are on-target toxicity and cytokine release syndrome,which must be paid more attention.

【Key words】Hematologic neoplasms；Chimeric antigen receptor；T cell；Immnunotherapy

(收稿日期：2016-01-29；修回日期：2016-03-01)

【中圖分類號(hào)】R 730.263

【文獻(xiàn)標(biāo)識(shí)碼】C

doi：10.3969/j.issn.1007-9572.2016.12.001