Classically, MSC are identified by a CD45-CD106+ phenotype. In this study, we found that mouse MSC achieve this characteristic phenotype only at later passages. With increasing passages, CD45 (hematopoietic marker) expression shifts to negativity, whereas CD106 (vascular cell adhesion molecule-1) expression becomes increasingly positive. These results demonstrate that MSC cells cultured from mouse bone marrow acquire a classical MSC immunophenotype (CD45-CD106+) in later passages.
Ki-1-positive anaplastic large cell lymphoma (Ki-1 ALCL), one of the more recently described pleomorphic types of lymphoma, affects mostly children and adolescents and is sometimes mistaken for carcinoma or sarcoma.
Hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) are sensitive targets for benzene-induced hematotoxicity and leukemogenesis. The impact of benzene exposure on the complex microenvironment of HSCs and HPCs remains elusive. This study aims to investigate the mechanism linking benzene exposure to targeting HSCs and HPCs using phenotypic and clonogenic analyses. Mouse bone marrow (BM) cells were exposed ex vivo to the benzene metabolite, 1,4-benzoquinone (1,4-BQ), for 24h. Expression of cellular surface antigens for HSC (Sca-1), myeloid (Gr-1, CD11b), and lymphoid (CD45, CD3e) populations were confirmed by flow cytometry. The clonogenicity of cells was studied using the colony-forming unit (CFU) assay for multilineage (CFU-GM and CFU-GEMM) and single-lineage (CFU-E, BFU-E, CFU-G, and CFU-M) progenitors. 1,4-BQ demonstrated concentration-dependent cytotoxicity in mouse BM cells. The percentage of apoptotic cells increased (p < 0.05) following 1,4-BQ exposure. Exposure to 1,4-BQ showed no significant effect on CD3e(+) cells but reduced the total counts of Sca-1(+), CD11b(+), Gr-1(+), and CD45(+) cells at 7 and 12 μM (p < 0.05). Furthermore, the CFU assay showed reduced (p < 0.05) clonogenicity in 1,4-BQ-treated cells. 1,4-BQ induced CFU-dependent cytotoxicity by significantly inhibiting colony growth for CFU-E, BFU-E, CFU-G, and CFU-M starting at a low concentration of exposure (5μM); whereas for the CFU-GM and CFU-GEMM, the inhibition of colony growth was remarkable only at 7 and 12μM of 1,4-BQ, respectively. Taken together, 1,4-BQ caused lineage-related cytotoxicity in mouse HPCs, demonstrating greater toxicity in single-lineage progenitors than in those of multi-lineage.
Tumors of dendritic reticulum cells are rare neoplasms that exhibit significant morphologic overlap with other malignancies. Fine-needle aspiration cytologic appearances of this neoplasm are not well understood. A 33-yr-old woman presented with a rapidly growing nodular mass in the right upper cervical region and right-sided ptosis. Fine-needle aspiration cytology of the mass showed dissociated as well as clustered, large, polygonal cells that showed high nuclear-cytoplasmic ratio. Nuclei were round, oval, or irregular in shape. Large and small blastoid forms with prominent nucleoli and chromatin clumping as well as binucleated cells and cells with lobulated nuclei were seen. Numerous mitoses were observed. The tumor cells expressed focal immunocytochemical reactivity to CD45 and CD68, but were negative for CD2, CD3, CD4, CD8, CD20, CD30, CD45RO, epithelial membrane antigen (EMA), cytokeratin, and HMB45. Histologic sections of the biopsy from the growth showed nodal tissue effaced by a tumor composed of large, pleomorphic neoplastic cells with some binucleate and multinucleate forms resembling Reed-Sternberg cells. The intervening stroma contained numerous small lymphocytes. Tumor cells expressed vimentin, S-100 protein, CD68, and MAC387, but were negative for LCA, CD1a, CD3, CD15, CD20, CD21, CD23, CD30, CD35, carcino-embryonic antigen, HMB45, cytokeratin AE1/3, EMA, myeloperoxidase, lysozyme, smooth-muscle actin, and desmin. The combined histologic and immunohistologic features suggested a histiocytic/dendritic reticulum cell neoplasm and a diagnosis of interdigitating dendritic reticulum cell sarcoma was made.
The lymphocyte subset expressing the gamma delta T cell receptor is increased in several infectious diseases including HIV infection. In this study the expression on gamma delta lymphocytes of the T cell activation markers CD25, HLA-DR and CD38, as well as the two isoforms of CD45, namely CD45RA and CD45RO, was determined in the peripheral blood of 56 HIV-infected intravenous drug users and 34 HIV-seronegative blood donors by two-colour flow cytometry. The percentage of gamma delta lymphocytes expressing HLA-DR and CD38 was higher than those in HIV-seronegative controls (P < 0.001 and P < 0.0001, respectively). Furthermore the HLA-DR+gamma delta+ lymphocytes correlated inversely with CD4+ T lymphocyte absolute count (P < 0.02 for both). The levels of gamma delta lymphocytes expressing CD25, CD45RA and CD45RO were similar to those in HIV-seronegative controls. Activated gamma delta lymphocytes may play a role in the HIV disease process and could provide a useful marker for disease progression.
Anaplastic large cell lymphoma (ALCL) is a rare tumour, accounting for approximately 3% of adult non-Hodgkin lymphomas.1 Primary systemic ALCL frequently involves both lymph nodes and extranodal sites. A 44-year-old woman presented with a firm, mobile mass in the left iliac fossa region. Ultrasound findings showed a well defined inhomogenous soft tissue mass, measuring 4x4x2.6cm in the deep subcutaneous region. Histopathological examination revealed that the mass was infiltrated by large lymphoid cells with marked nuclear atypia including kidney-shaped nuclei. These neoplastic cells expressed anaplastic lymphoma kinase (ALK) (both nuclear & cytoplasmic staining), CD30 and EMA but not for T-cell (CD45RO and CD3), and B-cell (CD20 & CD79α) markers. Fluorescence in situ hybridization (FISH) analysis showed a t(2;5)(p23;q35) chromosomal translocation. Subsequently the patient developed shortness of the breath and a thoracic computed tomography (CT) scan showed a mass encasing the right upper lobe bronchus. She also had bilateral axillary lymph nodes, measuring 1 cm in diameter (biopsy was not done). The mediastinum and endobronchial region did not show any abnormalities. She received 6 cycles of CHOP chemotherapy and remained disease free 2 years after diagnosis. ALCL, rarely present as a soft tissue tumour and this disease should be included as a differential diagnosis of any soft tissue mass.
BACKGROUND: Asthma is a complicated network of inflammatory reactions. It is classified into mild, moderate, and severe persistent asthma. The success of asthma therapy relies much on understanding the underlying mechanisms of inflammation at each stage of asthma severity. The aim of this study was to explore the differences in apoptotic potential, CD4/CD8 ratio, memory compartment, and T- helper (Th) 1 and 2 profile of peripheral blood lymphocytes (PBL) in patients with mild intermittent asthma and severe persistent asthma during exacerbation periods.
RESULTS: Four research lines were investigated and compared among mild asthmatics, severe asthmatics, and healthy groups by applying immunocytochemical staining of PBL. Antiapoptotic and proapoptotic proteins with Bcl-2/Bax ratio, CD4, CD8 markers with CD4+/CD8+ ratio, CD45RO+, CD45RA+ markers with memory/naive ratio (CD45RO+/CD45RA+). Th2/Th1 cytokines balance represented by IL-4/IFN-gamma ratio was measured by enzyme-linked immunosorbent assay (ELISA) for in vitro PBL cytokine synthesis. It was found that Bcl-2/Bax ratio was higher in severe than in mild asthmatics which in turn was higher than in healthy group. And memory/naive ratio of PBL was higher in severe than in mild asthmatics. Moreover, memory cells, CD45RO+ and CD45RO+/CD45RA+ ratio were correlated directly with Bcl-2/Bax, in severe and mild asthma patients. In contrast, CD4+/CD8+ ratio was not changed significantly among healthy group, mild and severe asthmatics. However, CD8+ cells were correlated directly with memory cells, CD45RO+, in severe asthmatics only. Interestingly, the dominant profile of cytokines appeared to change from T helper 2 (Th2) in mild asthmatics to T helper 1 (Th1) in severe asthmatics where the lowest in vitro IL-4/IFN-gamma ratio and highest IFN-gamma were found.
CONCLUSION: It was concluded that the underlying mechanisms of inflammation might vary greatly with asthma stage of severity. Mild intermittent asthma is mainly Th2 allergen-oriented reaction during exacerbations with good level of apoptosis making the inflammation as self-limiting, while in severe persistent asthma, the inflammatory reaction mediated mainly by Th1 cytokines with progressive loss of apoptosis leading to longer exacerbations, largely expanded memory cells, CD45RO+, leading to persistent baseline inflammation.
Several techniques have been devised for the dissociation of tissues for primary culture. These techniques can affect the quantity and quality of the isolated cells. The aim of our study was to develop the most appropriate method for the isolation of human umbilical cord-derived mesenchymal (hUCM) cells. In the present study, we compared four methods for the isolation of hUCM cells: three enzymatic methods; collagenase/hyaluronidase/trypsin (CHT), collagenase/trypsin (CT) and trypsin (Trp), and an explant culture (Exp) method. The trypan blue dye exclusion test, the water-soluble tetrazolium salt-1 (WST-1) assay, flow cytometry, alkaline phosphatase activity and histochemical staining were used to evaluate the results of the different methods. The hUCM cells were successfully isolated by all methods but the isolation method used profoundly altered the cell number and proliferation capacity of the isolated cells. The cells were successfully differentiated into adipogenic and osteogenic lineages and alkaline phosphatase activity was detected in the hUCM cell colonies of all groups. Flow cytometry analysis revealed that CD44, CD73, CD90 and CD105 were expressed in all groups, while CD34 and CD45 were not expressed. The expression of C-kit in the enzymatic groups was higher than in the explant group, while the expression of Oct-4 was higher in the CT group compared to the other groups. We concluded that the collagenase/trypsin method of cell isolation yields a higher cell density than the others. These cells expressed a higher rate of pluripotent cell markers such as C-kit and Oct-4, while the explant method of cell isolation resulted in a higher cell proliferation rate and activity compared to the other methods.