Comparison of bone marrow and peripheral blood ZAP-70 status examined by flow cytometric immunophenotyping in patients with chronic lymphocytic leukemia

BACKGROUND

: The mutational status of the immunoglobulin heavy chain variable gene in patients with chronic lymphocytic leukemia correlates with prognosis. Patients with mutated IgVH genes fare better than those with unmutated genes. Gene expression profiling studies identified the tyrosine kinase ZAP-70 to be expressed in unmutated CLL samples. Flow cytometric examination of ZAP-70 expression in tumor cells has been proposed to be a convenient surrogate marker for IgVH mutational status. However, a few studies have shown a small number of discordant results between ZAP-70 positivity, IgVH mutational status, and clinical outcome. There have been no reported studies comparing bone marrow samples with peripheral blood for ZAP-70 expression in CLL patients.

METHODS

: We searched our flow cytometry files from October 2004 through April 2006 and identified CLL in 311 bone marrow and peripheral blood specimens from 256 patients. We defined ZAP-70 positivity as greater than 30% of the CD19(+) B-cells above the isotype control value that coexpress ZAP-70. Statistical analyses were performed using the Fisher exact test and student t-test.

RESULTS

: A significantly greater number of bone marrow specimens were positive for ZAP-70 when compared with the number of peripheral blood specimens. Of all the ZAP-70 negative specimens, CLL cells from bone marrow had a greater mean percentage of ZAP-70 positive cells when compared with the CLL cells from peripheral blood. Finally, six patients were identified who were ZAP-70 positive in the bone marrow but ZAP-70 negative in the peripheral blood.

CONCLUSIONS

: These results may be due to either an increase in the false positive rate in bone marrow specimens or to an intrinsic feature of CLL cells in the compartment that is biologically distinct from peripheral tumor cells. As prognosis and treatment decisions may be based on ZAP-70 results from either specimen type, it is prudent to further examine this observation. (c) 2006 International Society for Analytical Cytology.

Flow cytometric immunophenotypic profiles of mature gamma delta T-cell malignancies involving peripheral blood and bone marrow

BACKGROUND

In this study we compared clinical findings with flow cytometric immunophenotypic results in a series of patients with aggressive and indolent gamma delta T-cell malignancies with peripheral blood and/or bone marrow involvement.

METHODS

Gamma delta T-cell malignancies were detected based on flow cytometric demonstration of an abnormal T-cell population staining positive with T-cell receptor gamma delta and confirmed by morphologic and clinical reviews. Clinical data were obtained through chart review and discussion with the patients' physicians.

RESULTS

Blood or bone marrow involvement was present in all patients. Hepatosplenic and cutaneous gamma delta T-cell lymphomas had an aggressive clinical course, whereas the gamma delta T-cell large granular lymphocyte (LGL) leukemias had an indolent course. Expressions of CD5, CD8, CD16, and CD57 differed in gamma delta T-cell LGL leukemia compared with hepatosplenic and cutaneous gamma delta T-cell lymphomas.

CONCLUSIONS

Gamma delta T-cell malignancies have a poor prognosis with the exception of gamma delta T-cell LGL leukemia (indolent process). Because CD57 expression is specific for gamma delta T-cell LGL leukemias, expression of this antigen may be associated with a more indolent clinical course. Because cutaneous gamma delta T-cell lymphoma can present with peripheral blood involvement, flow cytometric evaluation of peripheral blood is important in staging these patients.

Semiquantitation of polycyclic aromatic hydrocarbon-DNA adducts in human esophagus by immunohistochemistry and the automated cellular imaging system

It has been suggested that ingestion of polycyclic aromatic hydrocarbons (PAHs) may contribute to the high incidence and mortality of esophageal cancer in Linxian, China. To explore this relationship a semiquantitative immunohistochemical staining method was developed for localization of PAH-DNA adducts. Nuclear color intensity (bright field average pink intensity per nucleus for >1000 cells) was measured using the ChromaVision Automated Cellular Imaging System (ACIS). Paraffin-embedded sections of cultured human keratinocytes exposed to increasing concentrations of 7beta,8alpha-dihydroxy-9alpha,10alpha-epoxy-7,8,9,10-tetrahydro-benzo[a]pyrene (BPDE) were incubated with BPDE-DNA antiserum and served as an internal positive control (standard curve). Values for nuclear staining intensity correlated directly with BPDE exposure concentration (r(2) = 0.99) and were reproducible. DNA adduct levels determined by BPDE-DNA chemiluminescence immunoassay in DNA from BPDE-exposed keratinocytes, correlated with BPDE exposure concentrations (r(2) = 0.99), showing that nuclear staining intensity determined by ACIS correlated directly with BPDE-DNA adduct levels determined by chemiluminescence immunoassay. The ACIS methodology was applied to 5 human samples from Linxian, and significantly positive nuclear PAH-DNA adduct staining was observed in this group when compared with esophageal tissue from 4 laboratory-housed monkey controls and 6 samples obtained at autopsy from smokers and nonsmokers in the United States. Nuclear PAH-DNA staining was absent from Linxian samples when serial sections were incubated with normal rabbit serum (negative control) and was significantly reduced on incubation with BPDE-DNA antiserum absorbed previously with the immunogen BPDE-DNA. These results appear to support the hypothesis that high PAH exposure levels may be etiologically associated with the development of esophageal cancer in Linxian.

HIV Nef increases T cell ERK MAP kinase activity

The human immunodeficiency regulatory protein Nef enhances viral replication and is central to viral pathogenesis. Although Nef has displayed a capacity to associate with a diverse assortment of cellular molecules and to increase T cell activity, the biochemical activity of Nef in T cells remains poorly defined. In this report we examine the bioactivity of Nef in primary CD4 T cells and, in particular, focus on the biochemical pathways known to be central to T cell activity. The extracellular signal-regulated kinase (ERK) mitogen-activated protein (MAP) kinase pathway was dramatically affected by Nef expression with increases in ERK, MEK, and Elk induction. The capacity of Nef to increase the MAP kinase pathway activity was dependent on T cell receptor stimulation. By increasing ERK MAP kinase activity, Nef is functionally associated with a kinase known to affect T cell activity, viral replication, and viral infectivity.

HIV Nef-mediated cellular phenotypes are differentially expressed as a function of intracellular Nef concentrations

Nef is a regulatory protein encoded by the genome of both human and simian immunodeficiency virus. Its expression in T cells leads to CD4 and major histocompatibility complex class I modulation and either enhancement or suppression of T cell activation. How this viral protein achieves multiple and at times opposing activities has been unclear. Through direct measurements of Nef and the Nef-GFP fusion protein, we find that these events are mediated by different Nef concentrations. Relative to the intracellular concentration that down-modulates surface CD4, an order of magnitude increase in Nef-GFP expression is required for a comparable modulation of major histocompatibility complex class I, and a further 3-fold increase is necessary to suppress T cell activation.

HIV-1 Nef increases T cell activation in a stimulus-dependent manner

Lentiviral Nef increases viral replication in vivo, plays a direct role in pathogenesis, and increases viral particle infectivity. We now find that HIV Nef also increases the activation of T cells, a cellular state required for optimal viral replication. This enhancement is stimulant-dependent. As defined by IL-2 generation, activation of T cells stimulated with classical mitogens [phorbol 12-myristate 13-acetate (PMA) + anti-CD3, PMA + phytohemagglutinin, and PMA + ionomycin] is unaffected by the expression of Nef. However, Nef increases IL-2 secretion when cells are stimulated through the T cell receptor and the costimulus receptor (CD28). This increase in activation, which depends on Nef myristylation, is caused by an increase in the number of cells reaching full activation and not by an increase in the amount of IL-2 secreted per cell. These findings demonstrate that Nef lowers the threshold of the dual-receptor T cell activation pathway. The capacity of Nef to increase T cell activity may be very important in vivo when Nef is the predominant or the only viral gene product expressed.

A cell surface chondroitin sulfate proteoglycan, immunologically related to CD44, is involved in type I collagen-mediated melanoma cell motility and invasion

The metastatic spread of tumor cells occurs through a complex series of events, one of which involves the adhesion of tumor cells to extracellular matrix (ECM) components. Multiple interactions between cell surface receptors of an adherent tumor cell and the surrounding ECM contribute to cell motility and invasion. The current studies evaluate the role of a cell surface chondroitin sulfate proteoglycan (CSPG) in the adhesion, motility, and invasive behavior of a highly metastatic mouse melanoma cell line (K1735 M4) on type I collagen matrices. By blocking mouse melanoma cell production of CSPG with p-nitrophenyl beta-D-xylopyranoside (beta-D-xyloside), a compound that uncouples chondroitin sulfate from CSPG core protein synthesis, we observed a corresponding decrease in melanoma cell motility on type I collagen and invasive behavior into type I collagen gels. Melanoma cell motility on type I collagen could also be inhibited by removing cell surface chondroitin sulfate with chondroitinase. In contrast, type I collagen-mediated melanoma cell adhesion and spreading were not affected by either beta-D-xyloside or chondroitinase treatments. These results suggest that mouse melanoma CSPG is not a primary cell adhesion receptor, but may play a role in melanoma cell motility and invasion at the level of cellular translocation. Furthermore, purified mouse melanoma cell surface CSPG was shown, by affinity chromatography and in solid phase binding assays, to bind to type I collagen and this interaction was shown to be mediated, at least in part, by chondroitin sulfate. Additionally we have determined that mouse melanoma CSPG is composed of a 110-kD core protein that is recognized by anti-CD44 antibodies on Western blots. Collectively, our data suggests that interactions between a cell surface CD44-related CSPG and type I collagen in the ECM may play an important role in mouse melanoma cell motility and invasion, and that the chondroitin sulfate portion of the proteoglycan seems to be a critical component in mediating this effect.