The differential diagnosis of acute lymphoblastic leukemia (ALL) from other small round blue cell tumors in children is very important for proper treatment, but sometimes difficult. CD45 is expressed on almost all-human leukocytes and not expressed on other small round blue cell tumors. Moreover, CD19 is expressed on all stages of B lineage cells and loss of this antigen is very rare in precursor B-cell ALL. We report a case of ALL with atypical morphology and immunophenotype. A 6-yr-old girl presented with fever and weight loss. Many abnormal cells with variable sized, high nuclearcytoplasmic ratio and distinct nucleoli were counted 23% in bone marrow. The results of immunophenotyping were negative for CD45, CD19, CD10, CD20, CD3, CD5, CD7, CD56/16, CD13, and CD33 and positive for CD22, TdT, and CD34. The immunohistochemical staining of bone marrow biopsies was positive for CD79a, CD10, TdT and CD99. The cytogenetic study showed normal karyotype but amplification of MLL (myeloid/lymphoid or mixed lineage leukemia) gene was suggestive in the fluorescent in situ hybridization. The patient received the standard chemotherapy for acute lymphoblastic leukemia and reached complete remission.
Acute Disease ; Antigens, CD19/*analysis ; Antigens, CD45/*analysis ; Bone Marrow/*pathology ; Child ; Female ; Humans ; In Situ Hybridization ; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma/diagnosis/*pathology

Human embryonic stem (ES) cells can be induced to differentiate into hematopoietic precursor cells via two methods: the formation of embryoid bodies (EBs) and co-culture with mouse bone marrow (BM) stromal cells. In this study, the above two methods have been combined by co-culture of human ES-cell-derived EBs with human BM stromal cells. The efficacy of this method was compared with that using EB formation alone. The undifferentiated human ES cell line SNUhES3 was allowed to form EBs for two days, then EBs were induced to differentiate in the presence of a different serum concentration (EB and EB/high FBS group), or co- cultured with human BM stromal cells (EB/BM co-culture group). Flow cytometry and hematopoietic colony-forming assays were used to assess hematopoietic differentiation in the three groups. While no significant increase of CD34+/CD45- or CD34+/CD38- cells was noted in the three groups on days 3 and 5, the percentage of CD34+/CD45- cells and CD34+/ CD38- cells was significantly higher in the EB/BM co-culture group than in the EB and EB/high FBS groups on day 10. The number of colony-forming cells (CFCs) was increased in the EB/BM co-culture group on days 7 and 10, implying a possible role for human BM stromal cells in supporting hematopoietic differentiation from human ES cell-derived EBs. These results demonstrate that co-culture of human ES-cell-derived EBs with human BM stromal cells might lead to more efficient hematopoietic differentiation from human ES cells cultured alone. Further study is warranted to evaluate the underlying mechanism.
Stromal Cells/physiology ; Stem Cells/*cytology ; Humans ; Hematopoietic Stem Cells/*cytology ; Embryo/*cytology ; Coculture Techniques ; Cells, Cultured ; *Cell Differentiation ; Bone Marrow Cells/*cytology ; Antigens, CD45/analysis ; Antigens, CD38/analysis ; Antigens, CD34/analysis

To investigate the differential expression of various types of leukocyte common antigen (LCA) isoforms during development, we analyzed human fetal lymphoid organs, including the thymus, liver, spleen, and bone marrow from 14 weeks to 29 weeks of gestational age by immunohistochemical and flow cytometric methods. In fetal thymus, over 90% of thymocytes throughout the entire fetal life expressed CD45RO and CD45RB, while CD45RA was expressed only in less than 5% of thymocytes. This expression pattern of LCA isoforms was established by a gestational age of 14 weeks or earlier, and persisted throughout the fetal period. The tissue distribution was different from each isoform; CD45RO-positive thymocytes were found in both the cortex and medulla at the 14th week with low intensity, but was localized in the cortex with increasing fetal age. CD45RB-positive thymocytes distributed mainly in the medulla from early gestational age. Among extrathymic lymphoid organs, a small portion of lymphoid cells expressing leukocyte common antigens appeared first in the liver at 10-12 weeks of gestational age and was followed by a small number in the spleen and bone marrow by 13-15 weeks. All lymphoid cells in these extrathymic lymphoid organs at this stage were CD19+ B cells. The number of these CD19+ cells increased abruptly during the early period of mid-gestational age. The pattern of tissue distribution of each LCA isoform in the fetal liver and spleen correlated well with the patterns of quantitative analysis by flow cytometry. In summary we found that different LCA isoforms expressed in cell-type-specific pattern and showed different tissue distribution during the period of fetal development, and that LCA was the earliest antigen expressed by lymphocytes in the thymus and extrathymic lymphoid organs in our series.
Antigens, CD45/*analysis ; Bone Marrow/immunology ; Female ; Fetus/*immunology ; Flow Cytometry ; Human ; Immunoenzyme Techniques ; Liver/immunology ; Lymphoid Tissue/*immunology ; Pregnancy ; Spleen/immunology

PURPOSE: Local activation of the complement system plays a role in target organ damage. The aim of our study was to investigate the influence of cyclosporine (CsA)- induced renal injury on the complement system in the kidney. MATERIALS AND METHODS: Mice fed a low salt (0.01%) diet were treated with vehicle (VH, olive oil, 1mL/kg/day) or CsA (30mg/kg/day) for one or four weeks. Induction of chronic CsA nephrotoxicity was evaluated with renal function and histomorphology. Activation of the complement system was assessed through analysis of the expression of C3, C4d, and membrane attack complex (MAC), and the regulatory proteins, CD46 and CD55. CsA treatment induced renal dysfunction and typical morphology (tubulointerstitial inflammation and fibrosis) at four weeks. RESULTS: CsA-induced renal injury was associated with increased the expression of C3, C4d, and MAC (C9 and upregulation of complement regulatory proteins (CD 46 and CD55). Immunohistochemistry revealed that the activated complement components were mainly confined to the injured tubulointerstitium. CONCLUSION: CsA-induced renal injury is associated with activation of the intrarenal complement system.
Animals ; Antigens, CD45/analysis ; Antigens, CD46/analysis ; Antigens, CD55/analysis ; Complement C3/analysis ; Complement C4b/analysis ; Complement Membrane Attack Complex/analysis ; Complement System Proteins/*analysis ; Cyclosporine/*toxicity ; Disease Models, Animal ; Immunity, Innate/drug effects ; Immunoblotting ; Immunohistochemistry ; Immunosuppressive Agents/toxicity ; Kidney/*drug effects/immunology/pathology ; Kidney Diseases/*chemically induced/immunology ; Mice ; Microscopy, Confocal ; Peptide Fragments/analysis

Granulocytic sarcoma (GS) is an extramedullary tumor composed of immature myeloid cells, typically occurring during the course of acute myelogenous leukemia. Non-leukemic GS, that is, GS with no evidence of overt leukemia and no previous history of leukemia, is very rare, and even more unusual is nonleukemic GS of the bile duct. We report a case of nonleukemic GS of the bile duct. The patient was initially misdiagnosed as a bile duct carcinoma arising in the hilum of the liver (so-called Klatskin tumor), and received a right lobectomy of the liver. Histological examination of the tumor yielded the diagnosis of GS, and the bone marrow biopsy did not show any evidence of leukemia. Considering the risk of subsequent development of overt leukemia, the patient was treated with two cycles of combination chemotherapy as used in the cases of acute myelogenous leukemia. To date, he has remained free of disease 15 months after treatment.
Tomography, X-Ray Computed/methods ; Sarcoma, Granulocytic/*diagnosis/metabolism/radiography ; Radiography, Abdominal ; Peroxidase/analysis ; Male ; Immunohistochemistry ; Humans ; Diagnosis, Differential ; Bile Ducts/chemistry/pathology ; Bile Duct Neoplasms/*chemically induced/metabolism/radiography ; Antigens, CD45/analysis ; Adult

BACKGROUND: Since the recent introduction of radioimmunotherapy (RIT) using antibodies against cluster of differentiation (CD) 45 for the treatment of lymphoma, the clinical significance of the CD45 antigen has been increasing steadily. Here, we analyzed CD45 expression on lymphocyte subsets using flow cytometry in order to predict the susceptibility of normal lymphocytes to RIT. METHODS: Peripheral blood specimens were collected from 14 healthy individuals aged 25-54 yr. The mean fluorescence intensity (MFI) of the cell surface antigens was measured using a FACSCanto II system (Becton Dickinson Bioscience, USA). MFI values were converted into antibody binding capacity values using a Quantum Simply Cellular microbead kit (Bangs Laboratories, Inc., USA). RESULTS: Among the lymphocyte subsets, the expression of CD45 was the highest (725,368+/-42,763) on natural killer T (NKT) cells, 674,030+/-48,187 on cytotoxic/suppressor T cells, 588,750+/-48,090 on natural killer (NK) cells, 580,211+/-29,168 on helper T (Th) cells, and 499,436+/-21,737 on B cells. The Th cells and NK cells expressed a similar level of CD45 (P=0.502). Forward scatter was the highest in NKT cells (P<0.05), whereas side scatter differed significantly between each of the lymphocyte subsets (P<0.05). CD3 expression was highest in the Th and NKT cells. CONCLUSIONS: NKT cells express the highest levels of CD45 antigen. Therefore, this lymphocyte subset would be most profoundly affected by RIT or pretargeted RIT. The monitoring of this lymphocyte subset during and after RIT should prove helpful.
Adult ; Antibodies/immunology ; Antigens, CD45/*analysis/immunology ; B-Lymphocytes/immunology/metabolism ; CD8-Positive T-Lymphocytes/immunology/metabolism ; Female ; Flow Cytometry/*methods ; Fluorescein-5-isothiocyanate/chemistry ; Fluorescent Dyes/chemistry ; Humans ; Killer Cells, Natural/immunology/metabolism ; Lymphocytes/immunology/*metabolism ; Lymphoma/radiotherapy ; Male ; Middle Aged ; Natural Killer T-Cells/immunology/metabolism ; Protein Binding ; Radioimmunotherapy ; Reagent Kits, Diagnostic ; T-Lymphocytes, Helper-Inducer/immunology/metabolism

BACKGROUND: Since the recent introduction of radioimmunotherapy (RIT) using antibodies against cluster of differentiation (CD) 45 for the treatment of lymphoma, the clinical significance of the CD45 antigen has been increasing steadily. Here, we analyzed CD45 expression on lymphocyte subsets using flow cytometry in order to predict the susceptibility of normal lymphocytes to RIT. METHODS: Peripheral blood specimens were collected from 14 healthy individuals aged 25-54 yr. The mean fluorescence intensity (MFI) of the cell surface antigens was measured using a FACSCanto II system (Becton Dickinson Bioscience, USA). MFI values were converted into antibody binding capacity values using a Quantum Simply Cellular microbead kit (Bangs Laboratories, Inc., USA). RESULTS: Among the lymphocyte subsets, the expression of CD45 was the highest (725,368+/-42,763) on natural killer T (NKT) cells, 674,030+/-48,187 on cytotoxic/suppressor T cells, 588,750+/-48,090 on natural killer (NK) cells, 580,211+/-29,168 on helper T (Th) cells, and 499,436+/-21,737 on B cells. The Th cells and NK cells expressed a similar level of CD45 (P=0.502). Forward scatter was the highest in NKT cells (P<0.05), whereas side scatter differed significantly between each of the lymphocyte subsets (P<0.05). CD3 expression was highest in the Th and NKT cells. CONCLUSIONS: NKT cells express the highest levels of CD45 antigen. Therefore, this lymphocyte subset would be most profoundly affected by RIT or pretargeted RIT. The monitoring of this lymphocyte subset during and after RIT should prove helpful.
Adult ; Antibodies/immunology ; Antigens, CD45/*analysis/immunology ; B-Lymphocytes/immunology/metabolism ; CD8-Positive T-Lymphocytes/immunology/metabolism ; Female ; Flow Cytometry/*methods ; Fluorescein-5-isothiocyanate/chemistry ; Fluorescent Dyes/chemistry ; Humans ; Killer Cells, Natural/immunology/metabolism ; Lymphocytes/immunology/*metabolism ; Lymphoma/radiotherapy ; Male ; Middle Aged ; Natural Killer T-Cells/immunology/metabolism ; Protein Binding ; Radioimmunotherapy ; Reagent Kits, Diagnostic ; T-Lymphocytes, Helper-Inducer/immunology/metabolism