C-kit receptor (CD0117) expression in acute leukemia

The murine monoclonal antibody YB5.B8 (CD117) identifies a transmembrane tyrosine kinase receptor encoded by the human c-kit proto-oncogene. In this study we investigated the expression of c-kit on different types of acute leukemia to determine the degree of specificity and sensitivity of this marker for the myeloid and lymphoid lineages. C-kit was positive in over half of the 115 cases of acute leukemia studied. Overall, two thirds of AML cases expressed c-kit, whereas only one of 23 ALL patients was c-kit positive. C-kit was also positive in 16 of 19 cases of myeloid blast crisis of myeloproliferative disorders and negative in four with a lymphoid phenotype. There was no correlation between c-kit expression and the degree of myeloid differentiation by FAB subtypes or other markers. We conclude that c-kit is a specific marker for the myeloid lineage, which is expressed early during hematopoietic differentiation and can aid the diagnosis of AML in difficult cases. More patients need to be tested to establish whether the expression of c-kit may define AML subgroups of prognostic significance.     

CD44v17在胃癌组织中的表达及其与临床生物学特性之间的关系

目的 探讨一种新的CD44变异体（CD44v17）在胃癌组织中的表达及其与临床生物学特性之间的关系.方法根据本实验室在MCF-7／Adr中新发现的1种CD44剪切拼接变异体CD44v17设计特异性引物,应用SYBR Green I荧光染料,采用实时PCR法检测87例胃癌组织及相应癌旁组织CD44v17 Mrna的表达,根据标准曲线计算CD44v17mRNA的表达量,分析CD44v17mRNA表达与胃癌临床生物学特性之间的关系.结果胃癌组织CD44v17 Mrna表达明显高于相应癌旁正常组织（P〈0.05）;肿瘤〉5 cm组CD44v17 Mrna表达与肿瘤≤5 cm组表达比较差异无显著性（P〉0.05）;未分化腺癌组表达明显高于乳头状腺癌及管状腺癌组（P〈0.05）,乳头状腺癌组CD44v17 Mrna表达与管状腺癌组比较差异无显著性（P〉0.05）;肿瘤累及浆膜及浆膜外组CD44v17 Mrna表达显著高于侵及黏膜、黏膜下层及肌层组（P〈0.05）,而肿瘤侵及黏膜及黏膜下层组的CD44v17 Mrna表达与侵犯肌层组表达比较差异无显著性（P〉0.05）.淋巴结转移组CD44v17 Mrna表达明显高于淋巴结无转移组（P〈0.05）;有肝脏转移组CD44v17 Mrna表达显著高于无肝脏转移组（P〈0.05）.结论CD44v17 Mrna在胃癌组织中高表达,可能与胃癌的侵袭、转移及预后有关.     

Low L-selectin (CD62L) expression in acute myeloid leukemia correlates with a bad cytogenetic risk

OBJECTIVES: Interactions between hemopoietic cells and the stromal microenvironment or immunoreactive cells are mediated by specific cell surface receptors. The expression of those molecules may alter the adhesive qualities (mobility and homing) as well as immune response behavior of leukemic blasts. L-Selectin (CD62L) is suggested to play a role in the redistribution and homing of hemopoietic progenitor cells to the bone marrow (BM). Down-regulation of L-selectin is responsible for mobilization of blasts from the BM into the circulation and ligation of L-selectin stimulates proliferation of progenitor cells. This could have an influence on the process of leukemia. METHOD: We have studied the expression of L-selectin on mononuclear BM cells of 36 acute myeloid leukemia (AML) patients at first diagnosis by FACS analysis using a directly fluorescein isothiocyanate conjugated antibody (clone DRE G56). RESULTS: On average the patients presented with 88% blasts in the BM. The expression tended to be higher in primary (p) AML compared with secondary (s) AML. L-Selectin was very heterogenously expressed in all FAB groups. Highest expression was found in cases with AML-M4 with four of nine cases presenting with an inv(16) karyotype. Separating our patient cohort in cytogenetic risk groups we could detect a significantly higher expression of L-selectin in cases with a 'good risk' karyotype and a very low expression in cases with a 'bad risk' karyotype (P = 0.037). Comparing patients who achieved remission after double induction therapy (responders) with patients who showed persisting disease (non-responders) we found a higher percentage of L-selectin+ cases or cells in the responder group than in the non-responder group, although the differences were not significant because of only five cases in the 'non-responder' group. Evaluating cut-off points greatest differences in relapse-free survival probabilities were found in patients who presented with > or = 30% L-selectin+ BM cells compared with cases with < 30%: 86% of cases with > or = 30% L-selectin+ cells were still in remission after a mean follow up time of only 8 months compared with only 46% in the group with < 30% L-selectin+ cells. CONCLUSIONS: We can conclude that (i) expression of L-selectin on AML blasts is variable. This reveals the great diversitiy of immunophenotypes in AML and might contribute to identify individual blast phenotypes in order to detect minimal residual disease in remission. (ii) Low L-selectin expression correlates with a bad cytogenetic risk, with a lower probability to achieve remission and with a shorter relapse-free survival time. This might reflect a decreased homing of the blasts to the BM as well as an impaired cytotoxic T-cell reaction against leukemic cells. The expression of L-selectin on leukemic blasts might be influenced by different cytokine therapies (e.g. with interferon alpha) and this might result in an altered hematologic reconstitution after cytotoxic therapies as well as in an altered immunologic recognition of blasts.     

Impact of CD133 (AC133) and CD90 expression analysis for acute leukemia immunophenotyping

BACKGROUND AND OBJECTIVES: AC133 is a novel monoclonal antibody (Moab) reacting with a population of immature/primitive or granulo-monocytic committed CD34+ve cells. Up to now, only few studies with small numbers of cases have examined AC133 (recently designated CD133) expression in acute leukemia. To determine the value of this Moab for acute leukemia immunophenotyping, we investigated a large series of leukemic cell samples for their reactivity with Moab AC133. DESIGN AND METHODS. A total of 298 cell samples from patients with de novo acute myeloid leukemia (AML) (n=142), acute lymphoblastic leukemia (ALL) (n=119), CD34+ve biphenotypic acute leukemia (n=13), and CD34+ve CML blast crisis (=BC; 21 myeloid BC/3 lymphoid BC) were investigated by flow cytometry for Moab AC133 reactivity.CD133 expression was compared with CD90(Thy-1) expression, another CD34-associated antigen. RESULTS: Fifteen (5%) samples expressed CD90, whereas 114 (38%) samples were positive for Moab AC133 (20% cut-off level). No significant differences in CD133 and CD90 expression levels between AML and ALL were observed. In AML, but not ALL, CD133 was more often expressed in CD34+ve cases than in CD34-ve ones (p<0.00001). However, CD133 expression was not restricted to CD34+ve leukemic cells in individual cell samples. All 8 pro-B-ALL cell samples with 11q23-anomalies and MLL (mixed lineage leukemia) gene translocations were positive for CD133, whereas only 2 of 9 pro-B-ALL without MLL gene translocations expressed CD133 (p<0.002). In contrast, none of the 5 AML cell samples with a t(9;11) and MLL gene translocation reacted with Moab AC133. CD34+ve CML cells in myeloid BC were less often positive for CD133 than CD34+ve de novo AML cells (p<0.0001). INTERPRETATION AND CONCLUSIONS: CD133 and CD90 expression analysis is not helpful for lineage determination in acute leukemia immunophenotyping. However, MoabAC133 may be an informative marker for the detection and further characterization of immature AML cells, as well as pro-B-ALL cells with MLL gene translocations, by flow cytometry.     

Quantitative expression of CD23 and its ligand CD21 in chronic lymphocytic leukemia

BACKGROUND AND OBJECTIVES: Cells from the great majority of patients with chronic lymphocytic leukemia (CLL) express CD23. A recent histologic study has shown that CD23 is expressed more strongly in the proliferating centers of the lymph nodes, where the large prolymphocytoid cells are located. The aim of our study was to quantify the expression of CD23 and CD21 in small and prolymphocytoid cells from patients with CLL and B-cell lymphomas, and correlate this expression with clinical parameters. DESIGN AND METHODS: Using quantitative flow cyto-metry we analyzed the antigen density of CD23 and CD21 in: 1) 101 cases of chronic lymphocytic leukemia, 84 typical, 14 with increased prolymphocytes (CLL/PL) and 3 atypical, 2) 15 cases of CD23 positive B-cell lymphoma with circulating lymphoma cells and 3) 8 normal subjects. The results were correlated with morphology and clinical staging. RESULTS: Cells from CLL and CLL/PL have a significantly higher number of CD23 molecules than normal and lymphoma B-cells (p<0.001 and p<0.001, respectively). Differences were not significant for CD21. CLL and CLL/PL cases had similar values of CD23 and CD21 molecules, but analysis at a single level showed that prolymphocytes in typical CLL and CLL/PL expressed significantly higher CD23 (p=0.001, p=0.006) and CD21 (p=0.001, p=0.001) than small lymphocytes. There was no correlation between CD23 or CD21 antigen density and clinical stages although there was a trend for a brighter CD23 in stage C patients. INTERPRETATION AND CONCLUSIONS: Since interaction between CD23 and CD21 is important for B-cell activation, proliferation and tumor formation, findings that both molecules are upregulated in prolymphocytes suggest that this is the proliferating cell component in CLL and underline the association between progression and increased prolymphocytes in typical CLL and CLL/PL.     

Characterization of Thy-1 (CDw90) expression in CD34+ acute leukemia

Thy-1 (CDw90) is a phosphatidylinositol-anchored cell surface molecule which, when coexpressed with CD34 in normal human bone marrow, identifies a population of immature cells that includes putative hematopoietic stem cells. To date, the characterization of Thy-1 expression has been confined largely to normal tissues and cell lines. In this study, we evaluated the frequency and intensity of Thy-1 expression as defined by reactivity with the anti-Thy-1 antibody 5E10 in 38 cases of CD34+ acute leukemia (21 acute myelogenous leukemia [AML], 8 chronic myelogenous leukemia [CML] in blast crisis, and 9 acute lymphoblastic leukemia [ALL]). In 34 of 38 cases (89%) the CD34+ cells lacked expression of the Thy-1 antigen. High-density Thy-1 expression was found in 1 case of CML in lymphoid blast crisis, and low- density Thy-1 expression was identified on a portion of the leukemic cells in 2 cases of AML with myelodysplastic features, and 1 case of CML in myeloid blast crisis, suggesting a possible correlation between Thy-1 expression and certain instances of stem cell disorders such as CML and AML with dysplastic features. In contrast, the dissociation of Thy-1 and CD34 expression in the majority of acute leukemias studied suggests that the development of these leukemias occurs at a later stage than the hematopoietic stem cell. Characterization of Thy-1 expression in acute leukemia may eventually provide insights into the origin of the disease. In addition, separation of leukemic blasts from normal stem cells based on Thy-1 expression may prove useful in assessing residual disease, as well as in excluding leukemic blasts from stem cell preparations destined for autologous bone marrow or peripheral stem cell transplantation.     

Platelet CD40 ligand (CD40L)--subcellular localization, regulation of expression, and inhibition by clopidogrel

This study compares the subcellular localization and the regulation of expression of the platelet activation markers CD62P and CD63 with CD40 ligand (CD40L) on the surface of washed human platelets. CD40L was expressed upon stimulation with a wide range of platelet activators. However, quantitative flow cytometry demonstrated that, as compared with CD62P and CD63, CD40L expression was low. Upon stimulation with thrombin receptor-activating peptide (TRAP-6), all activation markers were expressed. In contrast, upon stimulation with low concentrations of collagen (1-3 microg/ml), CD40L, but not the granule proteins (CD62P, CD63), were expressed. Using immunofluorescence microscopy, a cytoplasmic staining was observed for CD40L, and cytoplasmic localization of CD40L was verified by Western blotting of subcellular platelet fractions. The staining of CD40L was different from that of filamentous actin and only little association of CD40L with platelet cytoskeleton was found. Surface expression of CD40L was dependent on internal Ca2+ stores and protein kinase C, while the mitogen-activated protein kinases (ERK, p38) or tyrosine kinases were not involved. ADP (30 microM)-induced CD40L expression was not inhibited by aspirin. In contrast, clopidogrel treatment completely abolished ADP-induced expression of CD40L. Finally, the expression level of CD40L was shown to be upregulated by phorbol myristate acetate (PMA) in the promegakaryocytic cell line MEG-01.     

CD116在急性白血病中的表达及临床意义

目的：探讨ＣＤ１１６在急性白血病中的表达及临床意义。方法：对１１４例急性白血病者进行免疫表型及细胞遗传学分析。结果ＣＤ１１６在急性淋巴细胞白轿病（ＡＬＬ）中无阳性表达,而在急性髓性细胞白血病（ＡＭＬ）中阳性表达率为４２．４％;ＣＤ１１６在ＡＭＬ各亚型间出现的频率存在明显差异,阳性率Ｍ５为８３．３％,Ｍ４为４０．０％,Ｍ３和Ｍ２分别为２７．２％和１５．０。２例Ｍ５患者出现染色体＋８异常,伴ＣＤ１１６     

CD133-2 (AC141) expression analysis in acute leukemia immunophenotyping in correlation to CD34 and P-glycoprotein

A total of 49 newly diagnosed patients with acute leukemia were studied in order to assess the diagnostic value of clone AC141 of CD133 antibody by flow cytometry. AC141 expression was further compared to CD34 and P-glycoprotein, immunophenotype, morphology and cytogenetic/molecular data. Flow cytometry allowed for the detection of AC141 expression in 42.8% of the patients. A strong correlation with myeloid lineage was observed. All AC141(+) acute myeloid leukemia (AML) cases were of immature morphology and a strong concordance with CD34 expression was found. However, discordant patterns were also observed. Besides, AC141 expression correlated with CD7 in the absence of mature markers (CD14, CD15 and CD64). Similarly to CD34, P-glycoprotein levels were also significantly higher in AC141(+) AML cases. No correlation was found with cytogenetic/molecular data of the patients. In conclusion, membrane expression of AC141, in combination with other antigens, might facilitate a more precise immunologic characterization of acute leukemias and may serve as an alternative to CD34 for purging purposes in selected patients.     

Expression of two CD44 variant proteins (v3 and v6 ) in human colorectalcarcinoma and its relevance for prognosis

AIM To evaluate the expression of CD44v3 and v6 protein in colorectal carcinoma and its prognosticsignificance.METHODS One hundred and twenty-one cases of formalin-fixed paraffin-embedded colorectal carcinomaspecimens were retrospectively analyzed using EnvisionTM immunohistochemical method with the monoclonalantibody CD44v3 and v6. The median follow-up time was 67.77 months and the prognostic value of theCD44v3 and CD44v6 was assessed using univariate and multivariate survival analysis.RESULTS The positive rates of CD44v3 and v6 protein were 60.3% and 57.9%, respectively. There wassignificant correlation between CD44v3 immunoreactivity and tumor location, lymph node metastasis, distantmetastasis and Duke's stage (P< 0.05, Spearman correlation test). Significant correlation between CD44v6immunoreactivity and patients' gender, lymph node metastasis, distant metastasis, Duke's stage was alsonoticed (P < 0.05, Spearman correlation test). The 5-year survival rates were 81.25% and 60.27% inCD44v3 negative and positive cases, respectively. As CD44v6, the 5-year survival rates were 80.39% and60.00% in CD44v6 negative and positive cases, respectively; these differences between the two groups ofpatients were significant (P<0.05, Log-rank test). In multivariate analysis using the Cox regression model,CD44v3 expression emerges as an independent prognostic indicator.CONCLUSION CD44v3 and v6 might play some important roles in metastasis of colorectal carcinoma, andCD44v3 expression might be a new useful independent prognostic marker of colorectal carcinoma.