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Immunophenotypic and ultrastructural evidence of the langerhans cell origin of the canine cutaneous histiocytoma.

Canine cutaneous histiocytoma (CCH), a histiocytic benign, dermal, self-healing tumor in the young dog, and epidermal Langerhans cells (LC) are thought to be related. In this study, we used immunohistochemical staining and transmission electron microscopy for 5 fresh CCH and 17 fixed tumors, to examine if, on the basis of their immunophenotype and their ultrastructural morphology, these tumor cells originate as LCs. The immunophenotype of CCH: canine CD11a, 11c, 18, 45, MHC II positive and ACM1, human CD14 negative, was different from canine macrophage immunophenotype but very similar to the canine LC phenotype. Furthermore, we have described ultrastructural markers in CCH cells for the first time: these consist of coated vesicles, regularly laminated bodies, pleiomorphic inclusions, paracrystalline structures, and deep invaginations of the plasma membrane, usually observed in congenital self-healing histiocytosis, a human LC tumor, or occasionally observed in human LC. The occurrence of such immunophenotype and ultrastructural markers confirmed the common lineage of LCs and CCH cells.

Animals↗

FNAC of malignant lymphoma in an area with a high incidence of T-cell lymphoma. Correlation of accuracy of cytologic diagnosis with histologic subtype and immunophenotype.

OBJECTIVE: To analyze the usefulness of fine needle aspiration cytology on malignant lymphoma in an area with a high incidence of T-cell lymphoma and to correlate the accuracy of cytologic diagnosis with histologic subtype and immunophenotype. STUDY DESIGN: We retrospectively studied the usefulness of fine needle aspiration cytology in the diagnosis of 49 cases of nodal and extranodal non-Hodgkin's lymphoma (NHL) and seven cases of Hodgkin's disease in a total of 56 patients in whom subsequent excisional biopsy revealed lymphoid malignancy. Slides showing the results of cytologic investigation were reviewed together with the information on which histologic diagnosis was based. On the basis of pathologic variables, such as prognostic groups based on the Working Formulation, so-called grade, cell size based on the modified Rappaport classification, and--in cases of NHL--immunophenotype, the accuracy of original and reviewed cytologic diagnoses was compared. RESULTS: Of the 49 cases of NHL, 8 (16.3%) were inadequate for cytologic diagnosis, and malignant lymphoma was diagnosed or suspected in 36 (73.5%), excluding inadequate specimens; the diagnostic accuracy for NHL was 87.8%. In high grade cases, malignant lymphoma was more easily diagnosed or suspected than in those that were low or intermediate grade. The rate of inadequate cases was highest in the "mixed small and large cell" category, and cases that were "false negative" were either composed entirely of small cells or contained a small cell component. Cytologic diagnosis or suspicion of malignant lymphoma was easily obtained in the "large cell" category, followed by mixed small and large cell and "small cell." Aspirates from non-B-cell type were more frequently acellular than those of B-cell type; with regard to diagnostic accuracy, however, there was no noticeable difference between the two immunophenotypes. CONCLUSION: In many cases in the mixed small and large cell category or where the immunophenotype was non-B, the aspirate was inadequate, and no definitive diagnosis was possible. Many of our cases of T-cell lymphoma were mixed small and large cell, and in Korea, where the incidence of extranodal and T-cell lymphoma is high, the usefulness of FNAC for the initial diagnosis of malignant lymphoma is limited. For a definitive diagnosis, biopsy is required.

Biopsy, Needle↗

Simultaneous fluorescence immunophenotyping and interphase cytogenetics: a contribution to the characterization of tumor cells.

In immunocytochemical studies, the phenotypic evaluation of tumor cells is often complicated by accompanying normal cells, representing the original tissue or infiltrating leukocytes. This holds particularly true for tissues with a great morphological and immunophenotypical variability, such as bone marrow. A method that identifies mitotic tumor cells by chromosomal aberrations and permits the subsequent immunophenotypical analysis was a first progress, demonstrated by Teerenhovi et al. However, the results are usually hampered by the low number of analyzable mitoses. We demonstrate here a method that simultaneously combines immunophenotyping and in situ hybridization with centromere-specific probes. Using our method, numerically aberrant tumor cells can be identified by interphase cytogenetics and subsequently analyzed immunophenotypically. Since all interphase cells can be analyzed, we are not limited by the number and banding quality of analyzable mitoses.

Antigens, CD↗

High frequency of immunophenotype changes in acute myeloid leukemia at relapse: implications for residual disease detection (Cancer and Leukemia Group B Study 8361).

Multiparameter flow cytometry (MFC) has the potential to allow for sensitive and specific monitoring of residual disease (RD) in acute myeloid leukemia (AML). The use of MFC for RD monitoring assumes that AML cells identified by their immunophenotype at diagnosis can be detected during remission and at relapse. AML cells from 136 patients were immunophenotyped by MFC at diagnosis and at first relapse using 9 panels of 3 monoclonal antibodies. Immunophenotype changes occurred in 124 patients (91%); they consisted of gains or losses of discrete leukemia cell populations resolved by MFC (42 patients) and gains or losses of antigens on leukemia cell populations present at both time points (108 patients). Antigen expression defining unusual phenotypes changed frequently: CD13, CD33, and CD34, absent at diagnosis in 3, 33, and 47 cases, respectively, were gained at relapse in 2 (67%), 15 (45%), and 17 (36%); CD56, CD19, and CD14, present at diagnosis in 5, 16, and 20 cases, were lost at relapse in 2 (40%), 6 (38%), and 8 (40%). Leukemia cell gates created in pretreatment samples using each 3-antibody panel allowed identification of relapse AML cells in only 68% to 91% of cases, but use of 8 3-antibody panels, which included antibodies to a total of 16 antigens, allowed identification of relapse AML cells in all cases. Thus, the immunophenotype of AML cells is markedly unstable; nevertheless, despite this instability, MFC has the potential to identify RD in AML if multiple antibody panels are used at all time points. (Blood. 2001;97:3574-3580)

Adolescent↗

Diagnostic utility of flow cytometric immunophenotyping in myelodysplastic syndrome.

The myelodysplastic syndromes (MDSs) are characterized by bilineage or trilineage dysplasia. Although diagnostic criteria are well established for MDS, a significant number of patients have blood and bone marrow findings that make diagnosis and classification difficult. Flow cytometric immunophenotyping is an accurate and highly sensitive method for detection of quantitative and qualitative abnormalities in hematopoietic cells. Flow cytometry was used to study hematopoietic cell populations in the bone marrow of 45 patients with straightforward MDS. The results were compared with those obtained in a series of patients with aplastic anemia, healthy donors, and patients with a history of nonmyeloid neoplasia in complete remission. The immunophenotypic abnormalities associated with MDS were defined, and the diagnostic utility of flow cytometry was compared, with morphologic and cytogenetic evaluations in 20 difficult cases. Although morphology and cytogenetics were adequate for diagnosis in most cases, flow cytometry could detect immunophenotypic abnormalities in cases when combined morphology and cytogenetics were nondiagnostic. It is concluded that flow cytometric immunophenotyping may help establish the diagnosis of MDS, especially when morphology and cytogenetics are indeterminate. (Blood. 2001;98:979-987)

Adult↗

Immunophenotypic variations in hairy cell leukemia.

Hairy cell leukemia (HCL) exhibits a characteristic immunophenotypic profile that is strongly positive for pan-B-cell markers; positive for CD103, CD11c. and CD25; and usually negative for CD5, CD10, and CD23. We evaluated 35 HCL cases and identified atypical immunophenotypes in 12 cases (34%), including CD103- in 2 (6%), CD25- in 1 (3%), CD10+ in 5 (14%), and CD23+ in 6 (17%) cases. Among these cases one was CD103-/CD10+ and one was CD10+/CD23+. All available specimens from the 12 cases were reviewed and showed morphologic features characteristic for HCL. The initial clinical information was reviewed and showed no significant differences with that reported for typical HCL. Of the 12 cases, 11 patients received purine analogue therapy and achieved complete remissions. Our study indicates that it is not uncommon for HCL to display an unusual immunophenotype, including negativity for CD103 or CD25. Recognizing the variability of immunophenotype and correlating with morphologic and clinical features are essential for establishing an accurate diagnosis of HCL.

Adult↗

Immunophenotypic analysis of peripheral T-cell neoplasms. A multiparameter flow cytometric approach.

We retrospectively reviewed multiparameter flow cytometric analyses in 50 peripheral T-cell neoplasms (PTCNs). Results were interpreted within the context of a large cohort of nonneoplastic T-cell populations. All PTCN diagnoses were confirmed with morphologic and/or molecular analysis. Aberrant populations were defined as discrete immunophenotypic clusters exhibiting loss of or increased or diminished expression of T-cell antigens relative to internal immunophenotypically normal T-cell populations. An antigenic pattern was considered abnormal if it exceeded ranges for T-cell subsets in specific anatomic sites or was not normally encountered. Forty-six of 50 and 41 of 50 demonstrated 1 or more and 2 or more aberrations, respectively. The most common abnormally expressed antigen was CD3, followed by CD7, CD5, and CD2. Except for CD7, abnormally dim or bright antigen expression was more common than deletion. Only 3 cases were abnormal solely based on expansion of an otherwise immunophenotypically normal population; the remainder had patterns of antigen expression not seen in nonneoplastic populations. These data indicate that most PTCNs are aberrant by multiparameter flow analysis. However, results must be interpreted within the context of thorough knowledge of the immunophenotypic spectrum of nonneoplastic T cells.

Antigens, CD7↗

Discrepancies in the immunophenotype of lymphoma cells in samples obtained simultaneously from different anatomic sites.

Few studies have compared the immunophenotypic profiles of non-Hodgkin lymphoma (NHL) cells obtained simultaneously from different anatomic sites. In the present study, we compared flow cytometry immunophenotypic results in 64 consecutive NHL cases in which aspiration or biopsy of 2 sites was performed within 30 days to assess the potential discrepancy rate. In 14 cases (22%), discordant antigen expression was identified, including 4 (36%) of 11 cases with discordant morphologic features and 10 (19%) of 53 cases with concordant morphologic features in the 2 samples. Discrepancies involved 1 antigen in 10 patients and 2 antigens in 4 patients. Antigens most frequently discrepant included CD5 (n = 4), FMC7 (n = 3), and CD20 (n = 3). We conclude that the immunophenotype of NHL cells is generally stable, yet discrepancies can occur in a subset of patients. Differences in immunophenotype may relate to mechanisms of disease dissemination, influence of the microenvironment, or differential response to therapy.

Adult↗

The role of immunophenotype in acute lymphoblastic leukemia of infant age.

The prognosis of acute lymphoblastic leukemia in infants is still significantly worse than that of older children. This is thought to be due to both clinical and biological factors, such as high white blood cell (WBC) counts at diagnosis, irregular or immature phenotypes, and molecular and cytogenetical abnormalities. In order to focus the significance of immunophenotypic analysis, we have reviewed the immunophenotypic studies of 145 infants under 18 months of age treated at the AIEOP centers from 1984 to 1992. Children have been divided in three age groups of six months each; WBC count at diagnosis has been evaluated both as mean values and within different categories (< 10.10(9)/L, > 100.10(9)/L). These have been studied in correlation with immunophenotype and with the expression of single, specific markers. A significant correlation has been found between young age, high WBC count and immature phenotypes. Common ALL was more frequent in older children and showed lower WBC counts. Moreover, event-free survival was significantly better in older children with WBC count < 100.00/mm3, with CD10+, MyAg- ALL. Therefore, we suggest that immunophenotypic analysis is still an important prognostic factor and can be usefully used, together with simple clinical data, to plan therapy for ALL in infants.

Age Factors↗

Immunophenotype of bone marrow mast cells in indolent systemic mast cell disease in adults.

One of the major advances in the histological diagnosis of bone marrow (BM) involvement in mastocytosis has been the specific immunohistochemical detection of tryptase on most cells (MC), which has shown to be of great diagnostic value, especially in cases of malignant mastocytosis. On the other hand, recent studies have clearly shown that bone marrow mast cells can be specifically identified and accurately enumerated using multiparametric flow cytometry, which allow a systematic analysis of the immunophenotypic characteristics of bone marrow mast cells. Once this flow cytometric approach was applied for the analysis of BMMC from mastocytosis patients clear immunophenotypical differences were found between BMMC from normal individuals and adults with mastocytosis. The most characteristic immunophenotypic feature, both in malignant and adult indolent systemic mast cell disease, being the coexpression of CD2 and CD25 antigens, never present in normal bone marrow mast cells and, which constitute an aberrant hallmark of bone marrow mast cells in adult mastocytosis. Furthermore, bone mast cells from mastocytosis display a higher reactivity for CD35, CD63, and CD69 activation-associated antigens. Based on these results it could be concluded that the use of multiparametric flow cytometric immunophenotyping of BMMC in adult patients suffering from cutaneous mastocytosis can be of great utility for the diagnosis of BM involvement; additionally, this might also help to establish the real incidence of BM involvement in cutaneous mastocytosis.

Adult↗

T-lymphocyte immunophenotyping blind proficiency testing: a model system for CD4+ T-cells.

OBJECTIVE: To develop and evaluate methods and results for blind proficiency testing for CD4+ T-cells by T-lymphocyte immunophenotyping. DESIGN: A model system was developed to submit duplicate specimens for T-lymphocyte immunophenotyping as if they were routine patient specimens rather than proficiency specimens. Testing results were compared both interlaboratory and intralaboratory. The model system was designed to gather information on not just the analysis, but other segments of the total testing process. SETTING: Research facilities at the Graduate School of Public Health, San Diego State University, San Diego CA. PARTICIPANTS: 1) A healthy adult volunteer donating one pint of blood. 2) Laboratories offering T-lymphocyte immunophenotyping. MAIN OUTCOME MEASURES: 1) Feasibility of blind proficiency so that PT specimens are received, analyzed, and reported by laboratories without being identified as 'proficiency specimens.' 2) The ease and cost of such a system. 3) The comparability of results and report content among laboratories. RESULTS: A total of twenty-two laboratories received blind proficiency specimens. The model developed to submit specimens and receive results proved feasible. The interlaboratory coefficient of variation for CD4+ count for the four survey years ranged from 10% to 66% and for the CD4+ percent ranged from 4% to 15%. The per specimen cost in this blind proficiency testing was $437.65, approximately seven and a half times the cost for nonblinded proficiency testing or performance evaluations. CONCLUSIONS: Blind proficiency as a tool to compare laboratory test results for T-lymphocyte immunophenotyping is feasible but adds costs. The model system is useful to examine more of the laboratory total testing process than the analysis segment.

Blood Specimen Collection↗

[Immunophenotyping in acute leukemia: detection of minimal residual disease].

Immunophenotyping improves both accuracy and reproducibility of the acute leukaemia classification and is considered particularly useful for identifying poorly differentiated subtypes of acute myeloid leukaemia and lineage association of acute lymphoid leukaemia. Immunological studies of leukaemic blasts has become critical also identifying biphenotypic leukaemias and acute myeloid leukaemia expressing lymphoid associated markers. At present, while the prognostic value of individual antigen expressions is still controversial, the immunologic detection of minimal residual disease seems to be important in monitoring the acute leukaemia patients in remission. In the present study immunophenotyping of bone marrow samples of 42 patients with acute myeloid leukaemia and 13 patients with acute lymphoid leukaemia was analysed. Patients were assessed both before and after treatment by immunophenotyping, cytogenetics and polymerase chain reaction amplification. The immunophenotyping have allowed more sensitive definition of acute leukaemia relapse, but molecular genetic methods are recommended for detection of elimination of residual disease.

Adolescent↗

Immunophenotyping of leukemias using a cluster of differentiation antibody microarray.

Different leukemias express on their plasma membranes particular subsets of the 247 defined cluster of differentiation (CD) antigens, which may resemble those of precursor cells along the lineages of differentiation to mature myeloid and lymphoid leukocytes. The extent of use of CD antigen expression (immunophenotyping) for identification of leukemias has been constrained by the technique used, flow cytometry, which commonly specifies only three CD antigens in any one assay. Currently, leukemias and lymphomas are diagnosed using a combination of morphology, immunophenotype, cytochemistry, and karyotype. We have developed a rapid, simple procedure, which enables concurrent determination of 50 or more CD antigens on leukocytes or leukemia cells in a single analysis using a microarray of antibodies. A suspension of cells is applied to the array, and cells only bind to antibody dots for which they express the corresponding CD antigen. For patients with significantly raised leukocyte counts, the resulting dot pattern then represents the immunophenotype of those cells. For patients at earlier stages of disease, the diagnosis depends on recognition of dot patterns distinct from the background of normal leukocytes. Distinctive and reproducible dot patterns have been obtained for normal peripheral blood leukocytes, chronic lymphocytic leukemia (CLL), hairy cell leukemia, mantle cell lymphoma, acute myeloid leukemia, and T-cell acute lymphoblastic leukemia. The consensus pattern for CD antigen expression found on CLL cells taken from 20 patients in descending order of cells bound was CD44, HLA-DR, CD37, CD19, CD20, CD5, CD52, CD45RA, CD22, CD24, CD45, CD23, CD21, CD71, CD11c, and CD9. The antigens that provided the best discrimination between CLL and normal peripheral blood leukocytes were CD19, CD20, CD21, CD22, CD23, CD24, CD25, and CD37. Results obtained for the expression of 48 CD antigens from the microarray compared well with flow cytometry. The microarray enables extensive immunophenotyping, and the intact cells captured on antibody dots can be further characterized using soluble, fluorescently labeled antibodies.

Acute Disease↗

[Evolution of chronic lymphocytic leukemia: predictive value of immunophenotype, soluble CD23 and morphology].

UNLABELLED: Some prognostic factors are useful in chronic lymphocytic leukemia (CLL): lymphocyte doubling time, clinical stage and bone marrow pattern infiltration, while others, such as the percentage of CD38+ cells, are under study and require confirmation. The objective of this study was to evaluate whether there is an association between morphology, lymphocyte immunophenotype, soluble CD23 (sCD23) and progression free survival (PFS). A total of 36 non-treated patients were enrolled. We analysed prospectively: morphology (typical, mixed and PL-CLL); immunophenotypic profile (Matutes score); sCD23 plasma levels; clinical stage; lymphocyte doubling time; beta 2 microglobulin and karyotype abnormalities. Disease progression (need of treatment, progression to advanced stages, development of bulky organomegaly) and death related to disease were considered as events. Md of follow-up 24 mo. RESULTS: Stage 0: 11/36, PFS 80%; I: 10/36 PFS 90%; II: 13/36; III and IV: 2/36. SLE > or = II PFS 37%. p = 0.023. Lymphocyte doubling time < 12mo. 7/31; > 12mo. 24/31. PFS 28% vs. 80% p < 0.001. Karyotype: normal 13/28, abnormal 15/28. PFS 92% vs. 54% p = 0.053. Trisomy 12: positive 7/30, negative 23/30, PFS 66% vs. 65%. beta 2 microglobulin: normal 9/35; high 26/35. PFS 100% vs. 53% p = 0.006. sCD23 < 350 Ul/ml: 15/32; > 350 Ul/ml: 17/32. PFS 92% vs. 53% p = 0.005. Immunophenotype: Score 5: 15/36, Score 4: 19/36, PFS 64%. Score 3: 2/36. p = 0.516. Morphology: typical 17/35, mixed 17/35, PFS 81% vs. 57%, p = 0.099. PL-CLL 1/35. CONCLUSIONS: sCD23 was suitable to predict PFS, specially useful for early stages without additional markers of active disease. Morphology (excluding PL-CLL) and immunophenotype, two common tools, were not useful for the study purpose.

Adult↗

[Relevance of cytological and immunophenotypical analysis for the diagnosis of B-cell chronic lymphocytic leukaemia].

The objective of this study was to describe the cytological and immunophenotypical parameters evocative of B-cell Chronic Lymphocytic Leukaemia (B-CLL) and their ability to participate to the differential diagnosis of other B-chronic lymphoproliferatives disorders with blood dissemination (B-CLD). Two groups of pathology included 92 patients, 79 patients had a B-CLL and the 13 other had a B-CLD (1 Prolymphocytic Leukaemia, 12 non- Hodgkin's Lymphoma in which 4 Splenic Lymphoma with Villous Lymphocytes or SLVL). The lymphoid morphology was studied on blood smear stained with May Gr nwald Giemsa and the immunophenotypical analysis was performed by flow cytometry. The 72 patients with B-CLL were characterized by a predominance of small mature lymphocytes with a Matutes's CLL score 3 (generally CD5+, CD23+, SmIg poor expression). 4 out of B-CLL with cleaved lymphocytes 5 % showed the same immunological characteristics than the typical B-CLL cases. 3 cases of B-CLL with prolymphocytes between 5 and 55 % showed in 2 cases an immunophenotyping compatible with the diagnosis of B-CLD. The presence of shadow cells of Gumprecht was highly evocative of B-CLL. In conclusion, the cytological analysis remains at the root of any diagnosis and can be sufficient in most cases of typical CLL with the presence of shadow cells of Gumprecht on the blood smear. In case of presence of cleaved lymphocytes, the immunophenotyping becomes essential to confirme the diagnosis of B-CLL. In prolymphocytic cases, the differential diagnosis between mixed CLL and B-CLD (especially Mantle Cell Lymphoma and Marginal Zone B-Cell Lymphoma without villous lymphocytes) needs a multidisciplinary approach (clinical, cytogenetical and histological).

Antigens, CD↗

[Lymphocyte immunophenotyping and cytogenetics for more precise prognosis in patients with type B chronic lymphatic leukemia].

BACKGROUND: The B-chronic lymphocytic leukemia (B-CLL) has highly variable prognosis. Possibility of more relevant prognosis has a great impact for the beginning and mode of therapy. METHODS AND RESULTS: One hundred patients diagnosed as having B-CLL were included into the study. Beside usual examinations necessary to establish the diagnosis, cytogenetic examination for the detection of deletion 13q14, 17p13, 11q23 and trisomy 12 and immunophenotyping was done. The mean age of the patients was 58.2 years, there were 62 men and 38 women. 91 evaluated patients were divided into two groups--those with the steady disease (55 pts) and those with progressive disease (36 pts). No relation between the number of cytogenetic abnormalities and the Rai stage of the disease was found. We identified a relation between the bone marrow infiltration pattern (diffuse) and the number of cytogenetic abnormalities and the del 13q14 (p.05). Using the immunophenotyping of the lymphocytes we found a relation between the expression of CD38 and CD11c and the disease progression (p < 0.05). Neither of the method (FISH and immunophenotyping) revealed differences between results from bone marrow samples and those from peripheral blood. CONCLUSIONS: Though the cytogenetic (FISH) and immunophenotype evaluation at the time of diagnosis did not improve the ability to define better the clinical course of the B-CLL, we suggest to use both methods routinely as an important tool to identify patients who would develop the progressive disease.

Adult↗

Immunophenotypic findings in acute myeloid leukemia with FLT3 internal tandem duplication.

BACKGROUND AND OBJECTIVES: The biological characteristics and the prognostic significance of the internal tandem duplication of the FLT3 (FLT3/ITD) were investigated in a series of de novo acute myeloid leukemia (AML) patients. One hundred and fifty-six adult patients with AML were included in the study. FLT3/ITD was detected in 41 (26%) patients (FLT3/ITD(+)). DESIGN AND METHODS: The main differences observed between the groups with and without FLT3/ITD: a higher leukocyte count, a raised percentage of a normal karyotype and a more frequent M5 FAB diagnosis in the FLT3/ITD(+) patients. As regards the immunophenotype characteristics the FLT3/ITD(+) group very often expressed monocytic markers (CD36 and CD11b) and less commonly immature markers (CD34 and CD117). A promyelocytic-like immunophenotype pattern was also detected in a minority of these patients(4/36). RESULTS: The FLT3/ITD(+) patients had a shorter overall survival, a shorter event-free survival and a higher probability of relapse. Minimal residual disease (MRD) was investigated in the FLT3/ITD(+) patients using flow cytometry. This technique had a sensitivity of 62% and a specificity of 83% in relapse prediction. Minimal residual disease analysis was hampered by the low number of patients with detectable aberrant immunophenotype. INTERPRETATION AND CONCLUSIONS: A high frequency of changes in the phenotype and/or genotype pattern between diagnosis and relapse was detected (5/6). FLT3/ITD is a frequent molecular lesion in de novo adult AML and seems to be associated with a monocytic differentiation, a high leukocyte count and a poor prognosis. Immunophenotype and genotype patterns observed at relapse suggest that the FLT3/ITD(+) blasts may be genetically unstable and prone to clonal evolution. FLT3/ITD may not be a suitable target for minimal residual disease studies.

Acute Disease↗

[CD45-gating for flow cytometric immunophenotyping of leukemia].

OBJECTIVE: To establish a reliable and rapid multiparameter flow cytometric approach for leukemia immunophenotyping. METHODS: Leukemia blast cells which exhibit a character of low CD45 expression and low side scatter density are easily recognized by "CD45-SSC gating", we measured 46 patients and 3 normal persons of immunophenotyping by this gating method as well as traditional forwardscatter-side scatter (FSC-SSC) gating method. RESULTS: 5 of 46 immunophenotypic results from "FSC-SSC gating" showed false diagnosis, which were corrected by "CD45-SSC gating". Further, immunophenotypic mapping of 46 different acute leukemia were obtained by "CD45-SSC gating" and three-color staining, The expression of related antigen could be readily observed. CONCLUSIONS: "CD45-SSC gating" is a reliable and easy method to subclassify leukemia. Three-color staining, which is able to analyze the expression among two related antigens, not only be helpful in leukemia diagnosis but also contribute to study the occurrence, development and prognosis of diseases.

Adolescent↗