流式细胞术在血液学中的应用(二)
二、 流式细胞术在血液病学中应用
(一)白血病的分类研究
B-cell ALL
1.TdT positive.
2.CD10 positive, except for progenitor B-cell ALL.
3.HLA-DR positive.
4.CD19 frequently present without CD20.
5.Positive cytoplasmic μ chain in pre-B-cell type only.
6.Monoclonal surface immunoglobulin in L3 only.
7.Immunoglobulin gene or T-cell receptor gene rearrangement.
T-cell ALL
1.Positive TdT.
2.Usually negative CD10 and HLA-DR (more frequently positive in adult T-ALL).
3.CD7 is frequently the only positive T-cell marker, but all T-cell markers can be present.
4.T-cell receptor gene rearrangement.
Acute Myeloblastic Leukemia without Maturation (M1)
1.Greater than 90% of myeloblasts in the bone marrow.
2.Greater than 3% MPO-positive blasts in the bone marrow.
3.Blasts positive for CAE.
4.Blasts positive for CD33/CD13, HLA-DR.
5.Blasts negative for CD14, CD15,CD41/CD61,glycophorin.
6.Immunoglobulin and/or TCR gene arranged in mixed-lineage leukemia.
7.Specific cytogenetic abnormalities: t(9;22)(q34;q11) and inv(3) (q21;q26).
Acute Myeloblastic Leukemia with Maturation (M2)
1.30-90% of myeloblasts present in bone marrow.
2.Less than 20% monocytic precursors in the bone marrow
3.Less than 5×10 9 /L monocytic precursors in the peripheral blood.
4.Cytochemical stain for blasts: Positive for
myelo-peroxidase and chloroacetate esterase but negative for
α-naphthyl butyrate esterase.
5.Monoclonal antibody panel:Positive for CD13,CD15,CD33,HLA-DR,but negative for CD14.
6.Specific cytogenetic abnormality: t(8;21)(q22;q22).
Acute Promyelocytic Leukemia (M3)
1.Presence of more than 30% hypergranular (or hypogranular) promyelocytes in the bone marrow.
2.Presence of multiple Auer rods in the cytoplasm of leukemia.
3.Cytochemical staining: Strongly positive for myeloperoxidase
and chloroacetate esterase, but negative for a-naphthyl
butyrate esterase.
4.Immunophenotypeing : Positive for myelomonocytic antigens
(CD13,CD15,CD33),negative for monocytic antigen (CD14) and HLA-DR.
5.Abnormal karyotype : t(15;17) detected by cytogenetic or molecular biological techniques.
6.Coagulation work up: Decreased platelets and fibrinogen;
prolonged prothrombin, activated partial thromboplastin and
thrombin times, and increased levels of fibrin degradation
products.
Acut Myelomonocytic Leukemia(M4)
1.Presence of at least 30% myeloblast-monboblasts in bone marrow.
2.Monocytic component : More than 20% but less than 80% in bone marrow.
3.If monocytic component is less than 20% in the bone marrow.
A.Monocyte count in peripheral blood should be greater than 5×10 9 /L.
B.Serum lysozyme concentration should exceed three times the normal value.
4.Myeloblasts :More than 20% in bone marrow.
5.Myeloperoxidase positive cells : More than 3%.
6.Chloroacetate esterase and a-naphthyl butyrate esterase-positive cells: Roughly more than 20% each.
7.Abnormal chromosome 16 in M4 : Associated with M4 EO subtype.
8.Immunophenotype : Positive for CD13,CD14,CD15,CD33,and HLA-DR ,negative for CD41/CD42/CD61 and glycophorin A.
Acute Monoblastic Leukemia (M5)
1.Presence of more than 80% monocytic component among the nonerythroid cells in the bone marrow.
A.M5a: 80% or more of monocytic components are monoblasts.
B.M5b: Predominantly monocytes and promonocytes.
2.Elevation of serum and urine lysozyme levels.
3.Cytochemistry:
Myeloperoxidase : may or may not be positive.
Nonspercific esterase : strongly positive .
Specific esterase and periodic acid-Schiff: usually negative .
4. Immunophenotype : Positive for
CD11c,CD13,CD14,CD15,CD33,HLA-DR,negative for CD41, CD42, CD61
and glycophorin.
5. Cytogenetics : Association with t/del(11)(q23).
Acute Megakaryoblastic Leukemia (M6)
1.Presence of at least 50% erythroblasts among all nucleated cells in the bone marrow.
2.Presence of at least 30% myeloblasts among all nonerythroid cells in the bone marrow.
3.PAS positivity in all mature and immature nucleated erythroid cells.
4.Glycophorin-A antibody or other erythroid antibodies: The only reliable antibody for phenotyping.
5.React variably to myelomonocytic (CD13,CD33) and platelet (CD41) antibodies.
6.Most frequent cytogenetic abnormalities: -5/5q- ,-7/7q- .
Acute Megakaryoblastic Leukemia (M7)
1.Presence of 30% or more megakaryoblasts in the bone marrow.
2.Excess of blasts with increased numbers of maturing
megakaryocytes in bone marrow biopsy , plus identification of
megakaryoblasts in the peripheral blood and bone marrow
aspirate by immunologic techniques.
3.Electron microscopic identification of platelet peroxidase in leukemic cells.
4.Monoclonal antibodies : CD41,CD42,and CD61 are specific for megakaryoblastic.
5.Myelomonocytic markers : Positive for CD33 but negative for CD13,CD14 and CD15.
6.PAS Staining pattern in megakaryocyte-megakaryoblasts :
Periphery of cytoplasm and concentrated on cytoplasmic blebs.
7.t(1;22)(p13;q13): Specific for M7 infants.
(二)白血病细胞动力学
1、不同类型急性白血病细胞动力学差异不大。
2、RNA含量与细胞增殖活性呈正相关,G1期细胞DNA含量高于G0期。RNA高的细胞具有较高的增殖能力。
3、治疗前RNA高的急性白血病,化疗效果好,缓解期较长;RNA含量越低,则更多的细胞处于G0期,化疗效果差,不易缓解。一旦获得缓解,缓解期相当长。
4、DNA非整倍体是恶性细胞的标志,但急性白血病的DNA非整倍体检出率低于实体肿瘤。
(三)预测化疗效果和微小残留病变(MRD)
1、小剂量阿糖胞苷(Ara-C)由于阻断DNA的合成而使S期增高;
2、小剂量阿糖胞苷(Ara-C)由于杀死S期细胞而使S期减少;
3、应用FCM动态观察化疗前后细胞动力学参数的变化,发现化疗有效者,化疗后S期和RNA 指数下降比无效者明显,且S期恢复较快。
4、MRD是白血病复发的根源。
(1)DNA非整倍体监测化疗效果;探测1%-3%残留白血病细胞;有DNA非整倍体的缓解期白血病多在三个月内复发。
(2)检测白血病相关抗原
CALLA+/TdT+ 抗原监测急淋或TdT+/CD5+抗原监测T细胞急淋。
(3)运用FCM分选感兴趣细胞分子水平的研究,如PCR、FISH等。
(四)其他恶性血液病的应用
1.骨髓增生异常综合征(MDS)
(1)依细胞动力学特点可分为RA、RARS、RAEB、CMML。
(2)低S期者预示生存期短。
(3)DNA非整倍体可作为MDS转化为白血病的早期指标。
2.慢性淋巴细胞白血病(CLL)
(1)表面Ig荧光强度弱是CLL的特点,借此区别慢性淋巴细胞性淋巴瘤和幼稚淋巴细胞性白血病。
(2)慢淋的细胞动力学特点是骨髓和外周血的S期低(0.2),而淋巴结的S期却高达60%。其RNA含量低于正常淋巴细胞,通常难以发现DNA非整倍体。
3.慢性粒细胞白血病(CML)
(1)CML是一种累及多种细胞系的白血病。
(2)90%以上CML Ph+,借此可探测MRD。
(3)CML急变时,可发现DNA非整倍体,急粒变时RNA升高,急淋变时RNA 下降。
(4)CML细胞动力学与正常造血细胞没有明显差异。
4.淋巴瘤
(1)大多数低危淋巴瘤的DNA多为二倍体或近二倍体。
(2)滤泡性淋巴瘤为近二倍体或近四倍体。
(3)弥漫性大细胞淋巴瘤多为高二倍体,Burkitt淋巴瘤为二倍体或高二倍体。
(4)滤泡性淋巴瘤主要表达B细胞标志,但不表达CD5,可区分滤泡性淋巴瘤白血病和CLL,区别Burkitt淋巴瘤(SIgG+,CD10-)和小细胞无核裂淋巴瘤(SIgG+,CD10+)。
(5)何杰金氏病多为二倍体,增殖活性不高,10%病人可为四倍体或高四倍体,伴有较多R—S细胞(CD15+、CD30+)。
5.骨髓瘤
骨髓瘤是干细胞疾病,其DNA非整倍体探测率高于其他恶性血液病(60%-80%),增殖活性低,RNA含量高,这些参数在不同类型的骨髓瘤中有一定预后意义。
(五) 分选造血细胞
分选细胞是FCM的又一重要功能,目前主要用于:
(1)骨髓移植,清除自身骨髓中恶性细胞或异体骨髓中参与移植反应的细胞。
(2)分选造血干细胞。
(3)进行分子生物学研究。
三.FCM在白血病基因产物的表达和细胞凋亡的检测
1.P53基因
P53是一种抑癌基因产物,此基因突变是包括白血病在内的恶性肿瘤常见的遗传学
变化。
2.P21ras原癌基因
其编码蛋白均为P21,对细胞分化生长起重要作用,其活化也是肿瘤发生的主要原因之一。
3.Bcl-2抗凋亡基因
Bcl-2高度表达不仅可抑制白血病细胞凋亡,使其长期存活,而且对治疗反应差。
4.凋亡 (apoptosis)
凋亡也称细胞程序性死亡(programmed cell death,PCD)是细胞自我死亡的一种形式,是基因导向的细胞自我破坏的过程,通过细胞内核酸内切酶使核小体间DNA裂解,细胞死亡巨噬细胞清除。
5.P170多药耐药基因
其mdr-1编码P170蛋白是细胞膜泵,将进入细胞内的化疗药物主动泵出细胞,使细胞内药物和浓度降低,白血病细胞表达P170,则诱导缓解率减低,复发率高和持续缓解时间短。
6.谷胱甘肽转移酶(GST)
GST主要涉及细胞解毒包括对某些化疗药物的分解,使进入细胞内的药物浓度降低。
FCM具有多参数检测的优点,一次可检测细胞周期分布、DNA倍体,P53、P21、bcl-1、P170、GST、凋亡等,并可研究参数间相互关系。随着特异单克隆抗体的增多,FCM检测的项目也越来越多,其快速、简便、同一标本可检测多项等到特点使FCM
至今应用不衰。
四.FCM在器官和骨髓移植的应用
(一) 移植前
1.交叉配型
2.监测骨髓中的肿瘤细胞或造血干细胞
(二) 移植后FCM可用于监测移植后血液或植物内免疫成分的变化,以预测移植后免疫排斥反应、细胞免疫抑制治疗效果和移植物存活情况。
五.FCM在免疫血液病中的应用
FCM在免疫血液病的应用主要有以下几方面:
1.定量测定结合在细胞膜上免疫球蛋白或补体,协助自身免疫性溶血性贫血的诊
断。
2.探测少见的细胞群,如骨髓移植后所出现的嵌合体。
3.探测血小板和白细胞抗体,协助诊断血小板减少性紫癜和输血后免疫性血小板
减少。
4.检测细菌、病毒、寄生虫以及其所引起的免疫反应,协助感染性疾病的诊断和病原体确立。
FCM在血液学有广泛的应用前景,特别是随着免疫标记物的发展,FCM程序化和质量控制的采用,以及与分子生物学完美地结合,将会对血液学定量研究产生巨大推动力。