Acute undifferentiated leukemia: induction of partial differentiation by phorbol ester

Expression of lineage-associated surface antigens, was studied in 7 patients with acute undifferentiated leukemia (AUL), 3 patients with acute myeloid leukemia (AML), 4 patients with acute lymphoid leukemia (ALL) and bone marrow from 2 healthy donors, before and after exposure to the differentiating agent 12-O-tetradecanoylphorbol-13-acetate (TPA). The surface antigens were identified by monoclonal antibodies (My4, My8, My9, MO1, B1, CALLA, T11) and formation of EA and EAC rosettes. Adherence to plastic was also assessed. Cells from the AML patients responded to TPA with an increase in myeloid antigen positive cells and other markers of differentiation. Four of the AUL patients showed, also, a large increase in the fraction of cells expressing one or more myeloid markers, in correlation with formation of EAC rosettes. In contrast, the percentage of cells expressing myeloid antigens, did not increase in the 4 ALL patients, or in the normal donors. These findings confirm the heterogeneity of undifferentiated leukemias, and suggest the hypothesis that some AUL's can be induced to express markers of early myeloid cells.     

Undifferentiated leukemia of infancy with t(11:17) chromosomal rearrangement. Coexpressing myeloid and B cell restricted antigens

It has been suggested that the malignant transformation, in some of the acute leukemias, may involve totipotent stem cells resulting in a biphenotypic leukemia expressing both myeloid, and lymphoid characteristics. We describe here a hybrid cell acute leukemia, in a 16-day-old infant, in whom leukemic cells coexpressed myeloid and lymphoid B cell antigens. Blast cells in the bone marrow showed L2 morphology according to the French American British (FAB) classification, with positive periodic-acid Schiff, and nonspecific esterase staining. Sudan black, and specific esterase were negative. Terminal deoxynucleotidyl transferase, was strongly positive in 5% of blasts, and faintly reactive with the rest. Karyotypic analysis demonstrated a translocation of t(11:17);(q23;p13). Immunoglobulin gene analysis revealed rearrangement of the heavy chain genes. The blasts' phenotype was HLA/DR+ B4+ My7+ My9+ common acute lymphoblastic leukemia antigen (CALLA) B1- T11-. Dual immunofluorescence staining using anti My7, and My9 fluorescein isothiocyanate, and anti B4 pycoerythrin conjugated monoclonal antibodies, and flow cytofluorometry, revealed a labeling pattern of 25% B4+; 10% to 15% My7+; 17% My9+; and 50% of cells coexpressing B4 My7, and My9 antigens. These results provide evidence for a hybrid leukemia with lymphomyeloblasts being part of a single clone, which may indicate the origin of this leukemic clone from a pluripotent (lymphoid/myeloid) stem cell.     

急性白血病细胞中CD19的表达

目的观察CD19在急性白血病(AL)中的表达与分布,为白血病的诊断、鉴别以及导向治疗提供依据.方法采用27个荧光直标单克隆抗体(单抗)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在各类型AL细胞中的表达情况进行分析.结果在116例B细胞系急性淋巴细胞性白血病(ALL)患者中,CD19的阳性率(99.1%)明显高于B细胞系其它相关性抗原的阳性率;CD19在17例含B细胞系成分的杂合型白血病(HAL)中全部表达,而在29例T细胞系ALL和7例T/My HAL则均无表达;在152例急性髓系白血病(AML)中,仅11例(7.2%)CD19阳性,明显低于其在B细胞系ALL中的阳性率(P=0.001);CD22在B/My HAL的阳性率(12/15,80.0%)明显高于CD19 -AML(0/11,0%,P＜0.001).结论 CD19对B系ALL细胞的特异性较好,敏感性较高,是诊断B细胞系ALL较为可靠的表面标记,也可作为导向治疗B细胞系ALL的理想靶点.     

Immunophenotype of leukemic blasts with small peroxidase-positive granules detected by electron microscopy

Forty-three cases of undifferentiated leukemias by light microscopy examination were diagnosed as acute myeloblastic leukemias by ultrastructural revelation of peroxidase and were subsequently studied by immunological markers. In 41 of these cases, blasts were labeled by at least one of the antimyeloid MoAbs (My 7, My 9, and 80H5). An antimyeloperoxidase polyclonal antibody was used in 23 cases and was clearly positive in 11 of them, while cytochemistry by light microscopy was negative. These myeloblasts were frequently mixed with a minority of blasts from other lineages especially promegakaryoblasts. It is noteworthy that in 6 cases myeloid and lymphoid markers (E rosette receptor, common acute lymphoblastic leukemia antigen (cALLA), CD 9, CD 19 antigens (anti-B4 MoAb] were detected on a fraction of blast cells, suggesting a bilineage leukemia. However, in double labeling experiments, blasts with myeloperoxidase coexpressed lymphoid and myeloid markers including cALLA and CD 19 antigen. In one case, blasts had a typical non-B, non-T acute lymphoblastic leukemia phenotype (HLA-DR, CD 9, CD 19, cALLA positive) without staining by any of the antimyeloid MoAbs. However, 70% of the blasts were labeled by the antimyeloperoxidase antibody and expressed peroxidase-positive granules at ultrastructural level. In conclusion, most of the AML undiagnosed by optical cytochemistry are identified by antimyeloid antibodies. Some of these cases are also stained by some antilymphoid MoAbs. Use of antibodies against myeloperoxidase may improve the diagnosis of difficult cases of acute myeloblastic leukemia.     

CD45设门多参数流式细胞术在急性白血病免疫表型分析中的应用

目的：分析急性白血病的抗原表达及其临床意义。方法：采用一组系列相关单抗直接免疫荧光标记CD45设门的多参数流式细胞术,检测35例急性白血病患者的免疫表型。结果：11例ALL中B－ALL8例,T－ALL3例,其中出现髓系抗原表达4例,占36．4％,CD34表达10例,占90．1％;24例AML中伴淋系抗原表达7例,占29．17％,CD34表达16例,占70．8％,DR的表达与CD34一致,5例M3患者均无CD34和HLA DR表达。伴髓系统原表达的ALL CR率低于髓系抗原阴性表达者（1／3及5／6）,但统计学上差异无显著性（P＞0．05）;伴淋系抗原表达的AML患者CR率明显低于淋系抗原阴性表达者（0／5及10／10）,两组间差异具有显著性（P＜0．01）。结论：CD45设门的多参数流式细胞术是分析白血病免疫表型的最好方法,白血病抗原的错义表达是预后不良的因素之一。     

多参数流式细胞术检测急性早幼粒细胞白血病微小残留病的研究

 目的 建立流式细胞术检测急性早幼粒细胞白血病（APL,AML-M3）微小残留病（MRD）的方法,初步探讨其临床价值。方法 采用一组四色荧光标记单克隆抗体组合（CD15-CD11b-CD33-CD45）,对40例初诊时经形态学及流式免疫分型诊断为M3的白血病患者及其治疗后12例骨髓标本进行检测,同时检测正常对照8例。结果　在初发M3,以CD45／SSC（侧向角散射）设门,95 % M3白血病细胞群表达CD-15 CD-11b CD+33。12例在第1疗程结束进行监测,CD45／SSC设门粒细胞群CD-15 CD-11b CD+33细胞分别为0,0.001 %,0.002 %,0.07 %,0.08 %,0.09 %,0.22 %,0.25 %,0.66 %,1.73 %,12.24 %,53.6 %和72.4 %。该方法的敏感度为10-4,远高于形态学检测法。而诱导分化后的白血病细胞首先表达CD+15和（或）CD+11b,并逐渐分化为CD++15 CD++11b CD+/-33成熟粒细胞。结论　四色荧光标记单克隆抗体组合（CD15-CD11b-CD33-CD45）,可作为流式细胞术检测M3的MRD的方法。     

Immunophenotype of blast cells in acute myeloid leukemia may be a useful predictive factor for outcome

The immunophenotype of peripheral blood blast cells was tested in 92 patients with acute myeloid leukemia (AML), who were diagnosed and treated at single centre, St Bartholomew's Hospital, from 1978-1987 with a standard adriamycin, cytosine arabinoside and 6-thioguanine regimen. Immunological analysis involved standard fluorescence flow cytometry and utilized 31 monoclonal antibodies to known myeloid antigens (of CD groups 11b, 11c, 13, 14, 15, 16, w17, 31, w32, 33, 34, 35 and 36), a number of relatively less well studied antibodies with potential specificity for AML, and a series of control antibodies to T and B lymphocytes, platelets, erythrocytes and of widespread distribution (CD45, leucocyte common; HLA-DR). The results highlighted a number of antibodies with wide myeloid reactivity, in addition to CD13 and 33 (present in 66 per cent and 76 per cent of cases, respectively), which may be of immunodiagnostic use. A number of correlations between AML cell immunophenotype and FAB morphology subtype were found; in particular five antibodies (CD11c, 10.1, Tu3, CD15 and CD16), of both predominant granulocytic and monocytic reactivity, reacted with cells of AML-M5 subtype (p less than 0.05). There was no significant correlation between immunophenotype and clinical and pathological features at presentation. Correlation with clinical outcome was not a prominent feature, in contrast to some reports based on multicentre data. However, of particular note was the strong association between early death (at less than 2 months) and the coexpression of Leucocyte Function Associated (LFA) antigens, CD11b and 11c, on patient's blast cells (p = 0.003). The relationship was independent of clinical features and persisted even if AML-M5 cases were excluded. The significance of this latter finding is unclear, but may be related to the known role of CD11b and 11c LFA antigens in the cellular response to infection.     

Review of the incidence and clinical relevance of myeloid antigen-positive acute lymphoblastic leukemia

An increasing number of papers document cases of acute leukemia in which individual blast cells co-express markers normally restricted to a single cell lineage. Numerous terms are used to refer to cases with unscheduled expression of lineage-foreign proteins; the best defined categories were hybrid acute leukemia and acute mixed-lineage leukemia. The incidence of phenotypically variant acute leukemia varies with the quality and quantity of parameters used and the stringency of the criteria employed for its definition. Considerable interest has focused on acute lymphoblastic leukemia (ALL) cells expressing one or several myeloid lineage-associated antigens (My+ ALL), CD13, CD14, CD15, CD33, and CDw65. Owing to legitimate and cryptic expression on lymphoid cells, CD11b and CD15 reagents may not be considered as specific indicators of myeloid differentiation. The reported incidence ranged from 5 to 46% in 14 studies on My+ ALL, totalling 3817 patients. Several detailed reports documented a higher incidence of My+ ALL in adults (realistically in the range 10-20%) than in children (5-10%) and in B-lineage ALL as opposed to T-lineage ALL. My+ ALL cases are more likely to display unique cytogenetic [t(9;22), 11q23, 14q32] features than My-neg ALL. There appears to be no predominant expression of a single myeloid-associated antigen among those analyzed. As the morphological diagnosis of a leukemia subtype is often imprecise, some T-neg B-neg My+ ALL cases might actually contain FAB AML-M0 populations. While the expression of myeloid-associated antigens has no apparent prognostic significance in the majority of childhood ALL subtypes, in adults myeloid antigens seem to identify a high risk group of ALL patients with a poorer response to standard ALL therapy.     

Characterization of myeloid leukemias with monoclonal antibodies 3C5 and MY9

The expression of two membrane antigens identified by the monoclonal antibodies (McAb) My9 and 3C5 has been investigated in cells from 80 acute leukemias. My9 was positive in the blasts of 33 out of the 38 (87 per cent) cases of acute myeloid leukemia (AML) tested, regardless of FAB subtype, and in 13 of 18 (72 per cent) cases of chronic granulocytic leukemia (CGL) in myeloid blast crisis. The reactivity of 3C5 was confined to myeloblastic (M1) AML, 85 per cent of cases, and to lymphoblastic leukemia (ALL) of B-lineage, 70 per cent of cases, including CGL in lymphoid transformation. My9 was negative in ALL except for an unusual case. The phenotype My9+, 3C5+ was seen exclusively in M1 (69 per cent) and M2 (14 per cent) AML. Ultrastructural analysis with the immunogold method in combination with the myeloperoxidase (MPO) reaction showed that expression of My9 increased in parallel with MPO activity whereas 3C5 was expressed mainly in myeloblasts with little MPO content. We conclude that the use of these two McAb will contribute to the diagnosis and classification of AML and may throw some light to the pathogenesis of biphenotypic acute leukemias, including TdT + AML.     

11例t(16;21)(p11;q22)急性髓系白血病病例报告并文献复习

目的:探讨11例伴t(16;21)(p11;q22)染色体易位的急性髓系白血病（acute myeloid leukemia,AML)患者的临床和实验室特点。方法:回顾性分析2007年07月至2022年03月我院收治的11例t((16;21)(p11;q22)染色体易位的AML患者临床及实验室特征并复习相关文献。结果:11例t(16;21)(p11;q22)染色体易位的白血病均为AML,FAB分型:M2型4例,M4型1例,M5型3例,AML(非M3)型3例;其中男5例,女6例。染色体R显带分析11例均可见到t(16;21)(p11;q22)染色体易位,其中9例伴有附加染色体异常。融合基因TLS/FUS-ERG检测了9例均为阳性。免疫表型除表达髓系CD34、CD117、CD33、CD13、CD38外,均表达CD56。化疗1个周期后完全缓解7例。结论:t(16;21)(p11;q22)染色体易位是一种少见的重现性染色体异常,该易位产生TLS/FUS-ERG融合基因,免疫学检测多伴CD56阳性,以AML中M2/M5型多见,化疗1个周期大部分可完全缓解,但短期内易复发,预后不良。     

Diversity of acute non-lymphocytic leukemia analyzed with monoclonal antibodies reactive with myeloid differentiation antigens

The expression of myeloid differentiation antigens on acute nonlymphocytic leukemia cells (ANLL) was analyzed with four distinctive monoclonal antibodies (MoAbs); YM-1, HL-1, 20.2 and 20.3. These four MoAbs were shown to recognize different stages of differentiation of myeloid progenitor cells (CFU-GM) and/or mature myeloid cells. Consequently, leukemia cells of 68 adult patients with ANLL were able to be divided into four groups according to their expression of the antigens defined by these MoAbs: group 1 HL-1(-), YM-1(-), 20.2(-), 20.3(-) (13 cases); group 2 HL-1(+), YM-1(-), 20.2(-), 20.3(-) (16 cases); group 3 HL-1(+), YM-1(+), 20.2(-), 20.3(-) (13 cases) and group 4 HL-1(+), YM-1/20.2/20.3(+/(-)) (26 cases). This classification elucidated not only the maturation stages of ANLL but also the diversity of ANLL. When compared with the morphological classification, acute myeloblastic leukemia (AML) cases (M1 and M2 of the FAB classification) were evenly distributed among all four groups. These data suggest that the AML group was composed of heterogeneous leukemias which expressed surface phenotypes of different maturation stages ranging from the most immature stage to the mature stage. In contrast, the mature type (group 4) was composed of not only AML (M1 and M2), but also acute monocytic leukemia (M4) and acute myelomonocytic leukemia (M5). The clinical courses of these 68 patients revealed that the complete remission rate, remission duration and survival time were not significantly different among the four groups.     

Immunophenotype of blast cells in chronic myeloid leukemia

The immunophenotype of peripheral blood blast cells from 14 patients in the chronic phase of chronic myeloid leukemia (CML) was studied using a panel of monoclonal antibodies (McAb) directed against megakaryocytic, granulomonocytic, erythroid and lymphoid antigenic determinants. The blast cells were enriched by a simple bovine serum albumin (BSA) density-cut separation and cooled in liquid nitrogen. The study was done using the alkaline phosphatase-anti-alkaline phosphatase (APAAP) technique on the thawed blast cells. A consistent pattern of reactivity with McAb was found in all patients, showing that blast cells were heterogeneous. A minor component of the blast cells react with platelet antibodies, most of them being labelled with anti-GPIIb-IIIa McAb. Anti-GPIb and Von Willebrand factor McAb detected 4 times fewer megakaryocytic blast cells, suggesting that these cells are located very early in the differentiation scheme. Two major blast cell compartments were labelled with early myelomonocytic (anti-CD13: MY7) and early erythroid (anti-CD36: FA6-152) McAb. The CD34 (My10) and DR antigens which are expressed by immature blast cells and myeloid progenitors of human bone marrow (BM) were present on more than 50% of the CML blast cells. Thus, the blast cells of chronic phase CML patients, showed the same cellular diversity as the increased progenitor cell compartment observed in this disease, and their differentiation stages seemed to be very closely related.     

Expression of human myeloid cell nuclear differentiation antigen (MNDA) in acute leukemias

Human myeloid cell nuclear differentiating antigen (MNDA) is a Mr 55,000 non-histone basic nuclear protein expressed in myeloid leukemia cell lines that are at late stages of differentiation (HL-60 and U937) and in normal granulocytes and monocytes, but is not present in lymphoid cells or in other human cells and tissues tested. Affinity purified monospecific polyclonal antibodies and rat monoclonal antibodies have been developed for the immunocytochemical detection of MNDA. Using these antibodies, we surveyed 21 cases of acute leukemia classified by French-American-British (FAB) Group criteria, two cases of biphenotypic acute leukemia and one case of blast crisis of chronic granulocytic leukemia for the presence of MNDA. The most intense staining reactions were present in the nuclei of two cases of acute promyelocytic (FAB M3) leukemia. MNDA was not detected in three of five cases of acute myeloblastic leukemia without maturation (FAB M1). The remaining two cases of the M1 category showed weak to moderate staining. No staining reaction was seen in acute lymphocytic leukemia (ALL), biphenotypic leukemia or the lymphoid blast crisis of chronic granulocytic leukemia. Variable staining reactions were demonstrated in the remaining cases. These data suggest that the presence of MNDA is correlated with myeloid and monocytic differentiation in acute leukemia, being strongly expressed in M3 type, often not detected in M1 leukemia and absent in ALL.     

Expression of NK-associated surface-antigens cd-56 and cd-16 on aml-cells

Monoclonal antibodies Leu 11a (CD16) and Leu 19 (CD56) were tested for reactivity with cells from 36 patients with acute myelogenous leukemia (AML) using two-colour flow cytometry. Blast cells were identified by a broad panel of monoclonal antibodies. In 33% (12/36) the monoclonal antibody Leu 19, which has been demonstrated to bind to the 140 kD isoform of the human neural cellular adhesion molecule N-CAM, found on peripheral natural killer (NK)-cells, neuroectodermal cells, activated T-cells, and myeloma cells, was shown to bind strongly to the leukemic cells. The monoclonal antibody Leu 11a, which recognizes a surface differentiation antigen associated with the low affinity FcRIII for IgG, expressed on NK-cells, granulocytes and macrophages were found to bind to leukemic cells of four of the 12 Leu-19 positive cases. 50% (6/12) of Leu-19 positive patients were classified as having M4 according to the French-American-British (FAB) morphology criteria. The potential diagnostic and clinical importance of CD 56 and/or CD 16 expression in acute myelogenous leukemia is presently under investigation.     

急性粒-单核细胞白血病的免疫表型及细胞遗传学特征

背景与目的:白血病中某些抗原的表达与细胞遗传学的改变密切相关。本研究旨在探讨急性粒-单核细胞白血病(acutemyelomonocyticleukemia,M4)的免疫表型特征,并分析其与细胞遗传学的关系,为其诊断及治疗提供依据。方法:采用一组系列相关单克隆抗体和三色流式细胞术对81例M4患者进行免疫表型分析,并分析有核型资料的73例患者的核型异常;同时应用双色间期荧光原位杂交(fluorescenceinsituhybridization,FISH)技术对有染色体标本的35例患者进行inv(16)检测,并分析inv(16)阳性患者的免疫表型特征。结果:81例M4患者中48例(59.3%)表达干细胞标志CD34;髓系标志以CD33(84.0%)表达最高,其次为CD13(81.5%)和CD14(24.7%);分别有23例(28.4%)和10例(12.3%)患者表达T系和B系相关抗原。11例M4Eo患者中CD13均阳性,10例CD33阳性,7例CD34阳性,5例CD2阳性。FISH检测发现14例患者inv(16)阳性,其中CD13阳性13例,CD33阳性11例,CD34阳性8例,CD14阳性5例,CD7阳性3例,CD2阳性3例。73例M4患者中,异常染色体检出率为41.1%(30/73),共检出11种主要异常核型。CD2和CD34在染色体异常患者中表达明显增高,而CD14表达减低。CD2在M4Eo中表达增高,但其表达与inv(16)无显著性相关。结论:急性粒-单核细胞白血病以髓系抗原表达为主,CD2和CD34在染色体异常患者中表达明显增高;CD2在M4Eo中表达增高。Inv(16)在M4中占40%,各抗原表达与inv(16)无显著相关性。     

Significance of aberrant immunophenotypes in childhood acute lymphoid leukemia

Leukemic cells from 51 pediatric patients (younger than 18 years) diagnosed with acute lymphoid leukemia by standard morphologic and cytochemical methods were subjected to flow cytometric studies using a panel of monoclonal antibodies against T-cell (CD1, 2, 3, 4, 5, 7, 8), B-cell (CD10, 19, 20, 21), myeloid (CD13, 14, 15, 33), and HLA-DR antigens. Cases of "conventional" acute lymphoid leukemia (leukemic cells with a normal configuration of B-cell or T-cell differentiation antigens) were observed in 26 of 51 (51%) cases, whereas cases of "aberrant" acute lymphoid leukemia (cells with abnormal patterns of B-cell or T-cell antigens or with concomitant myeloid antigens) were noticed in 25 (49%) cases. Myeloid antigen-positive acute lymphoid leukemia was observed in the leukemic cells of eight (16%) individuals. No significant differences were observed between conventional and aberrant ALL in the distribution of sex, age, leukocyte count, hemoglobin concentration, platelet count, blast count, French-American-British (FAB) type, lymphadenopathy, organomegaly, rate or duration of remission, or survival. When only myeloid antigen-positive cases were compared with myeloid antigen negative-cases, no significant correlations were observed except for duration of first remission (myeloid antigen positive, 26+ +/- 22 months; myeloid antigen negative, 40+ +/- 18 months; P less than 0.001), and duration of survival (myeloid antigen positive, 27+ +/- 24 months; myeloid antigen negative, 62+ +/- 17 months; P = 0.001). These data suggest that pediatric patients with ALL blasts possessing myeloid antigens may represent a high-risk group for length of remission and survival.     

Immunophenotype of blast cells in acute myelofibrosis

The immunophenotype of peripheral blood blast cells from six patients with acute myelofibrosis was studied using a panel of monoclonal antibodies directed against granulocytic, erythroid, megakaryocytic and lymphoid antigenic determinants. In all patients most of the blast cells were labeled with anti-HLA-DR and with the early myelomonocytic antibodies My7 (CD13), My9 (CD33) and B1-3C5 (CD34) (3/3). In three cases, platelet antibodies Edu3 (CD41) and GPIIIa (CD61) reacted with about 30% of blast cells. TdT was positive in two out of six samples studied. Lymphoid markers T3 (CD3), Leu9 (CD7), J5 (CD10), B4 (CD19) and B1 (CD20) were negative in all cases. These results suggest that blast cells are mainly of immature myelocytic origin. However, the coexistence of megakaryoblasts cannot be ruled out in the cases with a proportion of cells that are positive with Edu3 and GPIIIa antibodies.     

成人急性髓系白血病的免疫学特点及预后

目的：探讨急性髓细胞白血病（AML）的免疫表型特点。方法：使用淋系和髓系单抗,用间接免疫荧光法对70例原发性AML进行免疫表型分析。结果：所有AML患者的细胞至少被1种髓系单抗标记,各髓系抗原的表达率依次为CD33＞CD13＞CD15。所有M3患者CD9为阳性。16／70例（30％）表达CD34抗原、CD34^ AML组在年龄、外周血象及骨髓原始、幼稚细胞比例等方面与CD34^-组相比较无显著差别,但表达CD34抗原的AML常伴有HLA－DR、CD38、CD7等不成熟细胞表面标记的表达,而较成熟的髓系细胞表面标记CD15则不表达。70例AML中有16例表达淋系抗原,CD4^ 例（13．8％,M2为8．8％,M460％）;CD7^ 9例（16．9％,M1为50％,M218％,M5b16．7％）。CD4^ 的AML患者CD34为低表达,CD33表达。结论：CD9^ 、CD34^-、HLA－DR^-及CD13^ 、CD15^ 是典型M3的免疫表型特点。CD34^ AMLgn AML-M1有着密切的关系,且对化疗反应较差,证明CD34^ 的AML是一组分化程度较差的类型;提示CD7^ 和CD4^ 的AML预后差,CD7^ 的AML的一种独特类型。     

Surface expression of the alpha 2-macroglobulin receptor on human malignant blood cells.

The surface expression of the alpha 2-macroblobulin receptor (alpha 2MR), detected by a monoclonal antibody, A2MR alpha-2, was determined on mononuclear blood cells from 90 cases of malignant blood disease. Flow cytometric analyses combined with immunoblotting and ligand binding experiments revealed that alpha 2MR was expressed on malignant cells from patients with acute and chronic myelomonocytic leukemias, while no significant expression was found on malignant cells from acute and chronic lymphatic leukemia, lymphomas, plasma cell leukemias or hairy cell leukemia. In acute myeloid leukemia, alpha 2MR was expressed in 50% of the M4-M5 cases, but only in three of thirty of the morphologically undifferentiated or non-monocytic cases (M1-M3 and M6). In chronic myelomonocytic leukemia five of seven cases were alpha 2MR-positive, while only one of seven cases of chronic myeloid leukemia was positive. The monocytic nature of the hematopoietic cells reacting with A2MR alpha 2 was further confirmed by a close correlation with CD14 surface expression.     

CD9 antigen on acute non-lymphoid leukemia cells: preferential expression by promyelocytic (M3) subtype

A monoclonal antibody (S17-12), previously described to recognize subsets of myelomonocytic cells, is demonstrated to bind CD9 antigen, a surface marker of B-cell precursors, platelets and several non-hematopoietic tissues. The proportion of S17-12, CD9-positive leukemic cells was determined in 102 patients with acute non-lymphocytic leukemia. It was found to be above 75% in 14/22 M3 cases (including 3/3 of microgranular variant) and only in 1/80 cases of different FAB subtype. Complete reactivity (greater than 95%) of leukemic clonogenic cells with CD9 MoAB was restricted to 4/18 M3 cases. Therefore, a high proportion of CD9-positive cells seems to be peculiar to M3 cases. This may help in the diagnosis of cases that lack typical morphological features.