認識慢性淋巴細胞白血病(CLL)

認識慢性淋巴細胞白血病(CLL)

何謂慢性淋巴細胞白血病CLL?

淋巴細胞是免疫系統的一部分,是人體對抗外界感染的一道天然屏障。淋巴細胞由骨髓產生,並分為B或T淋巴細胞及自然殺手細胞。而慢性淋巴細胞白血病(簡稱CLL)是成年人最常見的白血病之一,主要由B淋巴細胞於骨髓中惡性增生所引致1

惡性B淋巴細胞增生失去控制,並積聚於骨髓中,使骨髓內健康的紅血球、白血球及血小板的增長空間被佔據,此時可能造成貧血和容易出血等問題。惡性B淋巴細胞亦可蔓延至血液中,並經由血液積聚在淋巴結及其他器官例如脾臟和肝臟,影響器官的正常運作1

慢性淋巴細胞白血病有何症狀?

一般患者於被診斷時沒有明顯病徵,病情的進展亦相當緩慢。最常見的症狀包括2

  • 頸部、腋下或胃部等出現淋巴結腫脹
  • 腹痛及感到飽滯
  • 肋骨下方疼痛或腫脹
  • 夜間盜汗
  • 體重下降
  • 身體無力、長期倦怠
  • 發燒和容易感染
  • 容易出血或瘀青

慢性淋巴細胞白血病有什麽成因?

白血病的具體成因仍在研究當中,然而目前研究指出與染色體異常基因突變有關3

染色體異常

人體每個細胞有23對染色體,是基因的主要載體。如個別染色體的排序改變,也會令基因也產生變異,使白血球的失控地生長,釀成白血病,甚至破壞骨髓3

染色體異常在CLL患者中十分普遍,最常見為第13對染色體出現缺失。而在眾多染色體異常當中,以具有第17對染色體缺失的CLL最難處理4

新確診個案中第17對染色體出現缺失的情況並不常見,只佔5-9%5。然而,在復發患者當中,有接近一半患者的第17對染色體出現缺失5

免疫球蛋白重鏈可變區 (IGHV)基因突變

IGHV的基因突變狀態是評估CLL疾病進展及預後的重要原素之一。IGHV無突變型患者的病情進展較快,存活期較短6。而且,這些患者對化學免疫療法 (chemoimmunotherapy, CIT) 的緩解持續時間較短,所以一般會建議他們接受標靶藥物作第一線治療6

TP53基因突變

TP53 基因指示受損細胞是否應該被修復或破壞,避免擁有不正常遺傳資訊的細胞繼續分裂生長。TP53基因突變亦與較差的預後相關18,而超過 80% 出現第17對染色體缺失的患者也同時有 TP53基因突變19

參考資料

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  12. Keating MJ, et al. Leuk Lymphoma 1993;11 Suppl 2:167-175.
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  17. AbbVie Inc. and Genentech USA. Living With CLL Goes Beyond Treatment. Available at: https://www.cllcancer.com/living-with-cll. Accessed: 30Jun 2021.
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  19. Yu L, et al. Clin Cancer Res. 2017;23:735-745.
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