T cell receptor alpha-, beta-, and gamma-genes in T cell and pre-B cell acute lymphoblastic leukemia

We examined alpha-, beta-, and gamma-T cell receptor (TCR) gene activation within acute lymphoblastic leukemias (ALLs) that represent early stages of B and T cell development. We wished to determine if TCR rearrangement and expression was lineage restricted, showed any developmental hierarchy, or could identify new subsets of T cells. Rearrangement of gamma and beta TCR genes occurred early in development but in no set order, and most T-ALLs (22/26) were of sufficient maturity to have rearranged both genes. T-ALLs preferentially rearranged C gamma 2 versus the C gamma 1 complex; no preference within the beta locus was apparent. Once rearranged, the beta TCR continued to be expressed (11/13), whereas the gamma TCR was rarely expressed (3/14). The alpha TCR was expressed only in more mature T-ALLs (8/14) that usually displayed T3. The 3A-1 T cell associated antigen appeared earliest in development followed by T11 and T3. Within pre-B cell ALL a higher incidence of lineage spillover was noted for gamma TCR rearrangements (8/17) than for beta rearrangements (3/17). This also contrasts with the only occasional rearrangement of immunoglobulin (Ig) heavy chains (3/25) in T-ALL. However, in pre-B ALL the pattern of gamma TCR usage was distinct from that of T cells, with the C gamma 1 complex utilized more frequently. Almost all ALLs could be classified as pre-B or T cell in type by combining Ig and TCR genes with monoclonal antibodies recognizing surface antigens, although examples of lineage duality were noted. Unique subpopulations of cells were discovered including two genetically uncommitted ALLs that failed to rearrange either Ig or TCR loci. Moreover, two T lymphoblasts were identified that possessed the T3 molecule but failed to express alpha plus beta TCR genes. These T-ALLs may represent a fortuitous transformation of T cell subsets with alternative T3-Ti complexes.     

B cell origin of non-T cell acute lymphoblastic leukemia. A model for discrete stages of neoplastic and normal pre-B cell differentiation.

The expression of B cell associated and restricted antigens on tumor cells isolated from 138 patients with non-T cell acute lymphoblastic leukemia (non-T cell ALL) was investigated by flow cytometric analysis by means of a panel of monoclonal antibodies. Tumor cells from these patients could be assigned to one of four subgroups: human leukocyte antigen-DR-related Ia-like antigens (Ia) alone (4%, stage I); IaB4 (14%, stage II); IaB4CALLA (33%, stage III); and IaB4CALLAB1 (49%, stage IV). The expression of B cell-restricted antigens (B4 and B1) and rearrangements of Ig heavy chain genes provided strong evidence for the B cell lineage of stages II, III, and IV tumors. The lineage of the Ia alone group is still unknown. The B4 antigen was expressed on approximately 95% of all non-T cell ALLs tested, and given its absence on T cell and myeloid tumors, it appears to be an exceptional marker to define cells of B lineage. The demonstration that Ia alone, IaB4, IaB4CALLA, and IaB4CALLAB1 positive cells can be readily identified by dual fluorescence analysis in normal fetal and adult bone marrow provided critical support for the view that these leukemic pre-B cell phenotypes were representative of the stages of normal pre-B cell differentiation. It was interesting that the IaB4+ cell was more frequently identified in fetal bone marrow than in adult marrow, whereas the predominant cell found in adult marrow expressed the IaB4CALLAB1 phenotype. These data suggest that the leukemogenic event may be random, since the predominant pre-B cell leukemic phenotype appears to correspond to the normal pre-B cell phenotype present in these hematopoietic organs. Our observations provide an additional distinction between adult and childhood ALL, since these studies show that most non-T cell ALLs seen in children less than 2 yr old are of stage II phenotype, whereas the majority of non-T ALLs in adults are of stage IV phenotype. Finally, it should be noted that the present study suggests that the analysis of leukemic B cell phenotypes and their normal counterparts can provide a mechanism for the investigation and orderly definition of stages of pre-B cell differentiation in man.     

A unique cell surface antigen identifying lymphoid malignancies of B cell origin.

A monoclonal antibody (anti-B1) specific for a unique B cell surface differentiation antigen was used to characterize the malignant cells from patients with leukemias or lymphomas. All tumor cells from patients with lymphomas or chronic lymphocytic leukemias, bearing either monoclonal kappa lambda light chain, expressed the B1 antigen. In contrast, tumor cells from T cell leukemias and lymphomas or acute myeloblastic leukemia were unreactive. Approximately 50% of acute lymphoblastic leukemias (ALL) of non-T origin and 50% of chronic myelocytic leukemia in blast crisis were also anti-B1 reactive. moreover, 21 of 28 patients with the common ALL antigen (CALLA) positive form of ALL were anti-B1 positive, whereas 0 of 13 patients with CALLA negative ALL were reactive. These observations demonstrate that an antigen present on normal B cells is expressed on the vast majority of B cell lymphomas and on approximately 75% of CALLA positive ALL, suggesting that these tumors may share a common B cell lineage.     

探讨流式细胞术检测胞浆抗原的方法及其在白血病免疫分型中的意义

为探讨用流式细胞术检测胞浆抗原的方法及其在免疫分型中的意义，采用三色或四色直接免疫荧光标记法检测56例患17种膜抗原表达，并采用4种透膜剂处理细胞后用流式细胞仪测定胞浆（c)CD3,CD22,CD79a，CD13，CD33及髓过氧化物酶（MPO）的表达。结果显示，用FACS透膜液处理细胞后，胞浆抗原的阳性百分比最高，而细胞的光散射（SSC）及CD45的荧光强度不变。18例急性髓细胞白血病（AML）患，16例MPO阳性；4例T－ALL患，虽然膜cCD3阴性，而胞浆cCD3均为阳性；13例B－ALL患中，9例cCD22阳性。对5例B－ALL检测了cCD79a，结果全部阳性。38例急性白血病（AL）患中，18例表达1个系列以上的膜标记；在21例急性非淋巴细胞白血病（ANLL）患中，8例表达CD7；17例ALL中，7例CD13阳性。经胞浆抗原检测后，只有2例分别符合双表型和混合型AL特点，提示cCD3,cCD22,cCD79a和cMPO为系列特异性标志，对诊断及鉴别双表型或双克隆AL尤为重要。     

Bi-phenotypic leukemia and hybrid leukemia]

Phenotypes of leukemic cells can be determined through dual staining with pairs of FITC-labeled and PE-labeled monoclonal antibodies using a laser flow cytometer. Hybrid acute leukemia (HAL) was diagnosed when leukemic cells expressed 2 or more lymphoid markers and at least one myeloid maker simultaneously. Based on this criteria, forty out of 111 cases with untreated acute leukemia were diagnosed as HAL, 16 of 41 (39%) patients with acute lymphoblastic leukemia and 15 of 70 (21%) patients with acute non-lymphocytic leukemia were diagnosed as having HAL. We classified these HAL cells into 4 types by the following items. Type I; leukemic cells expressed only CD33 and 2 or more B-cell antigens, type II; only CD33 and 2 or more T-cell antigens, type III; CD13 and/or CD33 and 2 or more B-cell antigens, and type IV; CD13 and/or CD33 and 2 or more T-cell antigens. There were 7 type I cases and 16 type III cases. The leukemic cells of these two types were thought to be ALL cells expressing one or several myeloid lineage-associated antigens. There were 4 type II cases and 10 type IV cases. Type II and IV were regarded as lymphoid-lineage associated antigens positive AMLs. At least in adults, the expression of myeloid-associated antigens of ALL cells seems to identify a high risk group of ALL patients with a poorer response to standard ALL therapy.     

T cell receptor gamma and delta rearrangements in hematologic malignancies. Relationship to lymphoid differentiation.

We have studied recombinatorial events of the T cell receptor delta and gamma chain genes in hematopoietic malignancies and related these to normal stages of lymphoid differentiation. T cell receptor delta gene recombinatorial events were found in 91% of acute T cell lymphoblastic leukemia, 68% of non-T, non-B lymphoid precursor acute lymphoblastic leukemia (ALL) and 80% of mixed lineage acute leukemias. Mature B-lineage leukemias and acute nonlymphocytic leukemias retained the T-cell receptor delta gene in the germline configuration. The incidence of T cell receptor gamma and delta was particularly high in CD10+CD19+ non-T, non-B lymphoid precursor ALL. In lymphoid precursor ALL, T cell receptor delta was frequently rearranged while T cell receptor gamma was in the germline configuration. This suggests that TCR delta rearrangements may precede TCR gamma rearrangements in lymphoid ontogeny. In T-ALL, only concordant T cell receptor delta and gamma rearrangements were observed. Several distinct rearrangements were defined using a panel of restriction enzymes. Most of the rearrangements observed in T-ALL represented joining events of J delta 1 to upstream regions. In contrast, the majority of rearrangements in lymphoid precursor ALL most likely represented D-D or V-D rearrangements, which have been found to be early recombinatorial events of the TCR delta locus. We next analyzed TCR delta rearrangements in five CD3+TCR gamma/delta+ ALL and cell lines. One T-ALL, which demonstrated a different staining pattern with monoclonal antibodies against the products of the TCR gamma/delta genes than the PEER cell line, rearranges J delta 1 to a currently unidentified variable region.     

多参数流式细胞术分析505例急性淋巴细胞白血病跨系列表达方式

跨系列抗原表达是白血病免疫表型的一个重要特征。对于急性淋巴细胞白血病（ALL）的跨系表达方式,目前国内尚缺乏大样本多参数的研究报道。本研究利用三色流式细胞术探讨505例ALL（431例B—ALL,74例T—ALL）患者23种系相关抗原的跨系表达方式。结果显示：全部ALL病例中,髓系抗原的表达率为56．4％,其中以CD13（32．7％）的表达最常见,其次为CD33（29．5％）、CD15（19．2％）和CD11b（7．7％）。CD13／CD33在CD34^＋病例中的表达高于CD34^＋病例。在B—ALL中,T系抗原CD4、CD5、CD7和CD2的表达率依次为6．3％、2．8％、1．9％和1．4％,并且CD7^＋、CD2^＋和CD4^＋病例通常共表达CDl3和（或）CD33。在T—ALL,B系抗原cCD79a、CD19和CD22的表达率分别为8．1％、6．8％、和2．8％,而全部CD19和CD22表达者均伴CD13／CD33表达。结论：ALL的跨系袁达多存在未成熟的阶段,以跨髓系抗原的表达最常见（B^＋M^＋,T^＋M^＋）,偶有B系、T系和髓系抗原的共表达（B^＋T^＋M^＋）,仅有B系和T系跨系表达的极少（B^＋T^＋M^-）。     

急性白血病细胞CD19和CD20表达比较

本研究目的是观察CD19和CD20在急性白血病（AL）细胞中的表达与分布,为急性B系白血病靶向分子的选择提供合理依据.采用27个荧光直标单克隆抗体及CD45/SSC双参数设门多色流式细胞术对321例AL细胞进行免疫诊断和分型,并对CD19和CD20在各种类型AL细胞中的表达情况进行分析.结果表明,在116例B系ALL病例中,CD19持续稳定表达,其阳性率（115/116,99.1%）明显高于CD20（33/116,28.4%,P=0.001）;在17例含B系成分的混合型白血病（acute mixed lineage leukemia,AMLL）细胞中,前者的阳性率也明显高于CD20（P＜0.01）,而在29例T细胞系ALL和7例T/My HAL细胞中,两者均无表达;在152例急性髓系白血病（AML）细胞中,CD19和CD20阳性率均很低,分别为7.2%和2.0%;CD19和CD20在B-ALL及B/My AMLL组中的荧光强度差别有显著性（t=20.68,P＜0.001）;CD19和CD20的特异性分别为92.3%（132/143）和92.7%（38/41）,敏感性分别为99.2%（132/133）和28.6%（38/133）,前者敏感性明显高于后者（X^2=144.018,P=0.001）.结论：CD19在B细胞系细胞的各分化阶段上持续稳定表达,反应谱比CD20宽,特异性及敏感性均高,尤其是其敏感性显著高于后者.这提示CD19抗原分子可能成为治疗B系ALL的最佳靶点.     

112例成人急性白血病免疫分型

目的 探讨成人急性白血病（AL）免疫分型标准及其意义,了解成人AL抗原表达规律和免疫亚型分布情况。方法 细胞膜抗原采用单克隆抗体双色直接免疫荧光标记法,胞浆内抗原采用单色直接免疫荧光标记法及流式细胞术,分型标准试用抗体积分系统。结果 （1）未分化型占0.9%;单纯型占51.8%,其中急性髓系白血病（AML）占34.8%,B淋巴细胞白血病（B-ALL）占13.4%,T淋巴细胞白血病（T-ALL）占3.6%;变异型占38.4%,其中髓系占27.7%,淋巴细胞系占10.7%;混合型占8.9%。（2）AL患者CD34阳性占50%,M3患者HLA-DR均为阴性,AML变异型伴CD7阳性最常见,然后依次为CD10阳性,CD19阳性、CD20阳性,B-ALL变异型依次为CD13阳性,CD33阳性,CD7阳性,T-ALL变异型依次为CD33阳性,CD10阳性,CD19阳性,混合型以B淋巴细胞和随细胞系共同表达最多（70%）,其次为T、B、髓细胞系共表达（20%）及T细胞系和髓细胞系共表达（10%）。结论 本方法直接准确地反映成人AL免疫分型特点,特别是采用数字化分型指标。简洁、客观、易于掌握。     

CD45RA和CD45RO抗原在白血病细胞上的表达及意义

探讨ＣＤ４５ＲＡ和ＣＤ４５ＲＯ抗原在白血病及其亚型中的表达和分布及其在白血病鉴别诊断中的应用价值。     

高白细胞性白血病的生物学特性研究

本研究探讨高白细胞性白血病（HAL）的生物学特点及其临床意义.采用CD45/SSC双参数散点图设门,应用三色流式细胞术,对48例HAL患者及73例NHAL患者骨髓标本进行免疫分型,并对其中74例进行核型分析.结果表明：HAL组骨髓象中红系比例明显低于NHAL组,差异具统计学显著意义（P＜0.05）;AML中HAL组CD14阳性率明显高于NHAL组,差异具统计学显著意义（P＜0.05）;ALL中HAL组CD8阳性率明显高于NHAL组,而CD22,cCD79a明显低于NHAL组,差异具统计学显著意义（P＜0.05）;HAL组与NHAL组在系列抗原专一表达及交叉表达上无统计学差异（P＞0.05）;HAL缓解率低于NHAL.结论：HAL比NHAL骨髓受抑程度更重,AML中单核细胞性白血病发生高白细胞性白血病的可能性高,ALL中HAL比NHAL更易于表达T系抗原,HAL的白血病细胞较NHAL处于更早分化阶段,同时HAL预后不佳.     

Identification of malignant plasma cell precursors in the bone marrow of multiple myeloma.

Precursors of plasma cells were studied in the bone marrow of 28 patients with multiple myeloma, plasma cell leukemia, and benign monoclonal gammopathy. Pre-B and B cell populations were analyzed with anti-B monoclonal antibodies corresponding to the clusters standardized at the Leucocyte Typing Workshops in Paris and Boston (CD9, CD10, CD19-22, CD24). In advanced forms of plasma cell malignancies, such as cases of multiple myeloma in stages II and III and of plasma cell leukemia, some cells of lymphoid morphology expressed common acute lymphoblastic leukemia antigen (CALLA, CD10) and HLA-DR, but contained no detectable terminal deoxynucleotidyl transferase enzyme. These CALLA+ cells were absent in benign monoclonal gammopathies. In multiple myeloma, the CALLA+ cells were negative for surface and cytoplasmic immunoglobulins (Ig), and, unlike CALLA+, terminal deoxynucleotidyl transferase (TdT+) pre-B cells in the normal bone marrow also failed to react with antibodies to B cell-associated antigens such as CD9, CD19, CD22, and CD24. The CALLA+, Ig- cells could be regarded as preplasmacytic since, after having been separated and stimulated with the phorbol ester 12-0-tetradecanoyl-phorbol-13 acetate in vitro, they transformed into plasma cells and synthesized the same heavy and light chains as myeloma cells.     

Cell surface antigens of murine leukemias induced by radiation leukemia virus. Recognition of individually distinct cell surface antigens by cytotoxic T cells on leukemias expressing crossreactive transplantation antigens

The specificity of transplantation immunity and T cell cytotoxicity against leukemias induced by RadLV was examined. Subcutaneous inoculation of two RadLV leukemias induced in BALB/c mice, BALBRVB and BALBRVD, resulted in initial tumor growth in CB6F1 mice, followed by complete tumor regression. Mice that had rejected leukemias BALBRVB or BALBRVD were subsequently challenged with various tumors of BALB/c origin. The growth of all five RadLV leukemias tested, and of one radiation-induced leukemia, was significantly inhibited. Another radiation-induced leukemia, a methylcholanthrene-induced sarcoma, and a leukemia induced by the Moloney leukemia virus, were not inhibited. The results indicate that RadLV leukemias share cell surface antigens that induce transplantation immunity in vivo. Cytotoxic lymphocytes were generated by coculturing spleen cells from mice that had rejected leukemia BALBRVB or BALBRVD with the corresponding leukemia cells. Direct tests and inhibition tests showed that such cytotoxic cells recognized individually specific antigens on leukemias BALBRVB and BALBRVD, distinct from the shared antigens detected in transplantation experiments. The effector cells in cytotoxicity assays were Thy-1+, Lyt-1+,-, Lyt-2+, and Lyt-3+ T cells.     

细胞芯片在急性淋巴细胞白血病免疫分型中的应用

目的设计一种细胞芯片,只需简单步骤,可将不同膜抗原的细胞分离、固定在相应抗体区域。并进行急性淋巴细胞白血病(ALL)免疫分型。方法将CD2、CD3、CD4、CD5、CD7、CD8、CD9、CD10、CD11a、CD13、CD14、CD15、CD19、CD20、CD22、CD33、CD34、CD44、CD45、CD45RA和HLA-DR等21种单克隆抗体(每种抗体2个点)固定于醛基玻片上,以刀豆凝集素做阳性对照和指示点,形成9×7的微阵列。从20例健康志愿者和20例ALL患者0.5~1ml全血中分离出的单个核细胞,其中半量用吖啶橙预染5min,两部分细胞经PBS洗涤3次后与细胞芯片反应,轻洗去未结合细胞。未预染细胞的芯片经2.5%戊二醛固定后进行瑞氏染色,用光学显微镜直接观察。预染细胞的芯片用GeneTACⅣ扫描仪进行扫描。结果ALL患者与健康志愿者的淋巴细胞抗原表型有十分明显的差别,其中单一抗体强阳性的有15例,T-ALL中2例CD3强阳性、2例CD4强阳性2、例CD7强阳性和1例CD5强阳性,B-ALL中2例CD10强阳性3、例CD19强阳性、1例CD20强阳性和2例HLA-DR强阳性,双克隆抗体阳性的有5例,其中2例CD4、CD7强阳性,2例CD4、CD5强阳性,1例CD4、CD11a强阳性,与临床诊断相符。强阳性点上的幼稚淋巴细胞与非强阳性点上的细胞无论在细胞数量、细胞大小、形态规则性上都有明显的不同,用显微镜观察十分明显。结论选用玻片做为载体,操作简单易行,结果便于观察,从而实现免疫学与形态学相结合。ALL显示了恶性肿瘤的单克隆增生的性质。     

bcr/abl融合转录子阳性的B细胞型急性淋巴细胞白血病免疫表型特点

为探讨B细胞型急性淋巴细胞白血病(B-ALL)中bcr／abl融合转录子阳性白血病细胞的生物学特征，用流式细胞术检测26例bcr／aN阳性及32例bcr／abl阴性B-ALL病例的免疫表型，用PC双法检剩免疫球蛋白重链(IgH)基因重排。结果表明：所有的病例均为CDl9阳性。bcr／abl阳性与bcr／aN阴性B-ALL表面分子有显统计学差学异（P＜0．05)的是CD34(96．2％与65．6％)，CDl0(96．2％与71.8％)及CD38(43．8％与95．4％)。在26例bcr／abl阳性病例中，原始细胞共表达CDl0 ／CDl9 ／CD34 ，CDl0 ／CD34 ／HLA—DR 和CDl0 ／CD34 ／CD38—分别为92．3％(24／26)，73．1％(19／26)和56。2％(9／16)。对bcr／abl阳性组的17例进行了IgH基因重排检剩，10例阳性(58．8％)。14例bcr／abl阴性组中12例(85．7％)阳性。在32例bcr／aN阴性病例中，原始细胞共表达CDl0 ／CDl9 ／CD34 和CDl0 ／CD34 ／HLA—nR 分别为43．8％(14／32)和37.5％(12／32)，无1例表型为CDl0 ／CD34 ／CD38—。结论：bcr／abl阳性B-ALL患CD34和CDl0阳性率较高，而CD38阳性率较低，且IgH基因重排检出率较低，其独特的免疫表型特征是CDl0 ／CD34 ／CD38-。该研究结果提示该类型白血病细胞具有较早期的B系祖细胞免疫表型特点。     

Flow Cytometry Immunophenotyping Evaluation in Acute Lymphoblastic Leukemia: Correlation to Factors Affecting Clinic Outcome

The authors conducted a flow cytometry immunophenotyping study in patients with acute lymphoblastic leukemia (ALL) from Natal, Rio Grande do Norte, Brazil. The patients (n = 126) were newly diagnosed using a panel of monoclonal antibodies: CD1a, CD2, CD3, CD4, CD7, CD8, CD10, CD13, CD33, CD14, CD19, CD22, CD79a, CD117, CD34, anti‐IgM, anti‐TdT, anti‐HLA‐Dr, and anti‐human kappa and lambda light chains. Additional data, such as patients' age and gender, clinical and laboratory findings such as presence of tumor masses, lymphadenopathy, hepatomegaly, splenomegaly, leukemic infiltration in the central nervous system (CNS) were also investigated. Results showed that 56.7% of the cases were B‐lineage ALL and 55% were T‐cell ALL. Also, we found that males were more affected by the disease, regardless of immunological classification. The correlation between age and immunological subtypes showed that the B‐lineage ALL occurred more frequently in patients aged under 15while the T‐cell ALL subtype was more frequent in adults. Immunophenotypic profiles and morphological subtypes showed a direct correlation between L3 subtype and B‐lineage ALL, while L1 and L2 subtypes correlated more often with B‐cell lineage and T‐cell ALL, respectively. Correlation analysis between immunophenotypic and clinical profiles showed that T‐cell ALL was more associated with a higher incidence of lymphadenopathy, hepatomegaly, splenomegaly and CNS leukemic infiltration, also showing a greater blast cell count in peripheral blood than the other subgroups. The presented data suggest that immunophenotyping is an important method in the diagnosis, monitoring and prognostic assessment in determining the pathological mechanisms of evolution of ALL.     

282例急性白血病流式细胞术免疫分型的特点分析

目的探讨急性白血病免疫表型特征及诊断价值。方法采用流式细胞术三色荧光直接标记技术检测282例AL患者,根据抗体积分系统进行分型。结果①按免疫表型的特征可将急性白血病分为4类:单表型急性白血病(82.27％),表达某一系列抗原为主的急性白血病(9.22％),急性杂合性白血病(HAL)(7.09％),未分化型急性白血病(AUL)(1.42％);②80％以上急性非淋巴细胞白血病(ANLL)患者主要表达MPO(96.38％)、CD13(89.86％)、CD33(69.57％),90％以上急性淋巴细胞白血病(ALL)主要表达cCD79a(100％)、CD19(93.67％)或cCD3(100％)、CD2(100％),表达某一系列抗原为主的AL以急性B淋巴细胞白血病伴随系表达(My B-ALL)为主(62.50％),HAL以B-ALL及MAL为主。结论流式细胞仪三色免疫荧光直接标记法进行AL免疫分型,cCD3、cCD79a、MPO为系列特异性标志,CD117为早期髓细胞的标志,对AL的诊断及一些特殊类型的白血病的确诊、治疗和预后均有重要意义。     

50例成人急性淋巴细胞白血病免疫表型分析

目的研究成人急性淋巴细胞白血病(ALL)的免疫表型特征,并分析免疫表型与细胞形态学及细胞遗传学的关系。方法应用一组系列相关单克隆抗体和CD45／SSC设门的三色流式细胞术对50例初治成人ALL进行免疫表型研究。结果 50 例ALL中42例B系来源,5例T系ALL,3例T／B混合型ALL。27例伴有髓系抗原表达(54％),髓系抗原主要表达CD13、CD33。大部分病例(90％)幼稚细胞均出现CD45的缺失及弱表达。细胞学形态学分析发现所分析病例中FAB-L1占多数(67％)、L2 27 ％。2例L3其免疫表型为B-祖细胞及成熟B细胞表型。20例存在染色体异常,其中6例染色体数目异常,涉及的异常为 8、-X、-7、-11、-4、、6和、13。染色体结构异常最多见为t(9;22),且均伴有髓系抗原的表达。结论 ALL免疫表型不是单独的诊断标准,其与细胞形态学及遗传学密切相关。     

Continuing rearrangement but absence of somatic hypermutation in immunoglobulin genes of human B cell precursor leukemia

Southern blot analyses revealed that cells from nearly 30% of childhood B cell precursor acute lymphoblastic leukemias (ALLs) contained more than two rearranged, nongermline bands for Ig heavy chain genes. DNA corresponding to these bands was molecularly cloned from two cases which showed three and seven rearranged bands, respectively. Nucleotide sequence analysis of the cloned DNA demonstrated that each band represented different VDJ or DJ rearrangements. While the same DJ joints were shared by several rearrangements, different DJ joints were found in the majority of rearrangements, precluding V region substitution as an explanation for the multiplicity of heavy chain rearrangements in these leukemias. Most of the V region segments involved in these rearrangements were restricted to VH region families that have been shown previously to be preferentially rearranged in human fetal B lineage cells. Sequence analysis of multiple copies of the same VDJ rearrangements from different cells revealed no somatic mutation, a mechanism responsible for detection of extra rearranged Ig DNA bands in certain other B lineage tumors. The data suggest that in some cases of ALL Ig heavy chain genes begin and continue to rearrange de novo within the neoplastic B cell precursor populations derived from an original malignant cell transformed at a stem cell stage of differentiation.