Existence of tartrate-resistant acid phosphatase activity in differentiated lymphoid leukemic cells

Hairy Cell Leukemia: Diagnostic Pathology

The pathology of HCL has been reviewed with a focus on the diagnostic hematopathology of this rare, but fascinating, disease. The discrimination of HCL from other B-cell lymphoproliferations, particularly HCL-V and SMZL, has been emphasized. The unique responsiveness of HCL to 2-CdA and other chemotherapeutic agents makes this distinction critical. Fortunately, HCL has consistent cytologic, histologic, cytochemical, and immunologic features that make classification reliable and reproducible. Less straightforward is the differential diagnosis of SMZL and HCL-V, problematic because of the rarity of both disorders, lack of discriminating evidence-based criteria, and perhaps a biologic kinship between these two disorders that share many clinical and pathologic features. Fortunately, this is not a clinically critical distinction.

High Specificity of Combined TRAP and DBA.44 Expression for Hairy Cell Leukemia

Because of marrow fibrosis, bone marrow aspirations are often nonconclusive in patients with hairy cell leukemia (HCL). Therefore, histologic examination is important in HCL but often difficult in cases with low numbers of tumor cells. A combined immunohistochemical positivity for DBA.44 and tartrate-resistant phosphatase was previously found in 100% of HCL and suggested to be specific for this diagnosis. To further assess the diagnostic specificity and sensitivity of this immunohistochemical approach in a higher number of cases, we analyzed 56 HCLs and lymphoma tissue microarrays, including 840 cases of the most frequent non-Hodgkin lymphomas. All HCLs showed combined positivity for these two proteins (100% sensitivity). Both antibodies were often positive in other lymphoma types. DBA.44 reactivity was especially frequent in follicular lymphomas (46%), whereas tartrate-resistant acid phosphatase (TRAP) expression was often seen in mantle cell lymphomas (57%), primary mediastinal large B-cell lymphomas (54%), and chronic lymphocytic leukemia/small lymphocytic lymphoma (41%). A combined DBA.44/TRAP positivity was seen in only 3% of non-HCL non-Hodgkin lymphomas, including cases of diffuse large B-cell lymphomas, follicular lymphomas, chronic lymphatic leukemia/small lymphocytic leukemias, and mantle cell lymphomas. Overall, these data confirm the utility of combined immunohistochemical DBA.44/TRAP expression analysis in confirming the diagnosis of HCL. However, combined positivity for these markers is highly sensitive but not absolutely specific for HCL.

CD11c gene expression in hairy cell leukemia is dependent upon activation of the proto-oncogenes ras and junD

Hairy cell leukemia (HCL) is a chronic lymphoproliferative disease, the cause of which is unknown. Diagnostic of HCL is abnormal expression of the gene that encodes the beta2 integrin CD11c. In order to determine the cause of CD11c gene expression in HCL the CD11c gene promoter was characterized. Transfection of the CD11c promoter linked to a luciferase reporter gene indicated that it is sufficient to direct expression in hairy cells. Mutation analysis demonstrated that of predominant importance to the activity of the CD11c promoter is its interaction with the activator protein-1 (AP-1) family of transcription factors. Comparison of nuclear extracts prepared from hairy cells with those prepared from other cell types indicated that hairy cells exhibit abnormal constitutive expression of an AP-1 complex containing JunD. Functional inhibition of AP-1 expressed by hairy cells reduced CD11c promoter activity by 80%. Inhibition of Ras, which represents an upstream activator of AP-1, also significantly inhibited the CD11c promoter. Furthermore, in the hairy cell line EH, inhibition of Ras signaling through mitogen-activated protein kinase/extracellular signal-regulated kinase kinases 1 and 2 (MEK1/2) reduced not only CD11c promoter activity but also reduced both CD11c surface expression and proliferation. Expression in nonhairy cells of a dominant-positive Ras mutant activated the CD11c promoter to levels equivalent to those in hairy cells. Together, these data indicate that the abnormal expression of the CD11c gene characteristic of HCL is dependent upon activation of the proto-oncogenes ras and junD.

Pathology of hairy-cell leukaemia

Hairy-cell leukaemia (HCL) is a low grade B-cell lymphoproliferative process that presents either with lymphocytosis or neutropenia/monocytopenia. It is a disease predominantly of bone marrow and spleen, although it can also involve other organs and sites. Recent advances including multi-parameter flow cytometry and the development of antibodies with high specificity for HCL have permitted precise distinction of typical HCL from other lymphoproliferative diseases that can morphologically mimic the appearance of HCL. Although there is a commonly held belief that HCL is associated with a significant increase in second neoplasms, several recent studies have not supported this notion. The development of extremely effective therapy for HCL results in a high incidence of complete remission. However, a significant percentage of patients continue to harbour minimal residual disease that can be revealed with immunohistochemical and flow cytometric studies.

T-ALL with monoclonal gammopathy and hairy cell features

The presented case is a boy with T-cell acute lymphoblastic leukemia (ALL) with hairy cell (HC) features and monoclonal gammopathy. The disease process had an acute onset and followed a rapid, progressive course. The patient had minimal splenomegaly and bicytopenia, but the bone marrow displayed increased numbers of reticulin fibers. The blasts were positive for tartrate-resistant acid phosphatase (TRAP) and CD11c. Molecular analysis revealed rearrangement of immunoglobulin heavy chain genes and a rearranged T-cell receptor (TcRbeta) beta gene. The patient responded to conventional ALL therapy. Acute T-cell ALL with HC features in childhood has not been reported previously, either alone or in association with monoclonal gammopathy. We propose "T-ALL with hairy cell features" to describe this case.

Occurrence of particular isoenzymes in fresh and cultured leukemia-lymphoma cells. I. Tartrate-resistant acid phosphatase isoenzyme

The cells from 87 leukemia-lymphoma cell lines, 14 B-lymphoblastoid cell lines, 459 cases of leukemia-lymphoma, normal specimens, 22 leukemia-lymphoma cell lines treated with 12-O-tetradecanoylphorbol 13-acetate (TPA) and 14 cases of chronic lymphocytic leukemia (CLL) and chronic myelocytic leukemia (CML) treated with TPA were analyzed for the expression of tartrate-resistant acid phosphatase (TracP) isoenzyme separated by isoelectric focusing. The TracP isoenzyme was seen in the following leukemia-lymphoma cell lines: 4 of 30 T-cell, 2 of 35 B-cell, 1 of 6 non-T/non-B-cell, 1 of 8 myelomonocytic, 3 of 4 erythroleukemia, and 3 of 4 Hodgkin's disease-derived cell lines. The expression of the TracP band could be induced by treatment with TPA in 3 myelomonocytic leukemia cell lines. Among the different types of leukemia-lymphoma cells freshly obtained from patients, the TracP isoenzyme was detected at a high incidence in cases of B-CLL, hairy cell leukemia (HCL), and B-lymphoma. Of the myeloid leukemias, 10% to 20% displayed the TracP isoenzyme. TracP positivity was detected in the peripheral blood, tonsil, bone marrow, spleen, and liver obtained from healthy donors, but not in the thymus. The expression of the TracP band could be newly induced by TPA in cases of CLL and in cases of CML. It is concluded that TracP activity is not specific for HCL, but is found at high incidences in cases of HCL, B-CLL and B-lymphoma. The TracP isoenzyme is not expressed by very immature lymphoid leukemia cells, but by cells arrested at later stages of differentiation of the T- or B-cell lineage, and by some myeloid cells.

Monocyte-associated acid phosphatase isoenzyme profiles as determined in acute myeloid leukaemia cells

The acid phosphatase (acP) isoenzymes from the blast cells of 102 cases of acute myeloid leukaemia were separated by isoelectric focusing on horizontal polyacrylamide gels. The cases were classified on the basis of the FAB cooperative group criteria. Several single bands were combined into groups (I-IV). An increase in the number of acP isoenzymes was noted which paralleled the assumed maturation along the granulocytic cell lineage from FAB M1 to FAB M3 and along the monocytic cell lineage from FAB M4 to FAB M5. One isoenzyme which was resistant to tartrate inhibition was found in 40% of the monocytic variants FAB M4 and M5, but not in the nonmonocytic cases FAB M1-M3 and M6. This particular isoenzyme, which has been described as being characteristic for hairy cell leukaemia, also appears to be a marker of the monocyte/macrophage system and the respective neoplastic counterparts. The FAB M4 and M5 patients expressed a characteristic profile of group I isoenzymes which allows for the discrimination between monocytic and nonmonocytic cells.

Isoenzyme studies in human leukemia-lymphoma cells lines--II. Acid phosphatase

This report describes the qualitative acid phosphatase (acP) isoenzyme profiles detected in permanent human hematopoietic cell lines. The acP activity was separated into its isoenzymes by isoelectric focusing on horizontal thin-layer polyacrylamide gels. The pattern of acP isoenzyme was investigated in a total of 86 cell lines. These cell lines were classified into five groups on the basis of their phenotypes characterized in the multiple marker analysis: 74 leukemia-lymphoma cell lines (26 T-, 34 B-, 6 myelomonocytic, 8 Non-T, Non-B cell lines) and 12 so-called 'normal' Epstein-Barr virus transformed B-lymphoblastoid cell lines. Their immunological features had been analysed in detail by use of a large panel of poly- and monoclonal antibodies which led to a further subclassification into stages of differentiation. A progressive increase in number and staining intensity of the isoenzymes which paralleled the expression of surface markers at different stages of differentiation along their developmental pathway was seen in the T- and B-leukemia-lymphoma cell lines. Some cell lines whose isoenzyme profiles did not correspond to the stage of differentiation as evidenced by surface antigen analysis might represent good examples of deranged gene expression in otherwise normally programmed malignant cells, i.e. in our study a mismatch between the isoenzymatic and immunological phenotypes. The tartrate-resistant isoenzyme was detected in 9 out of 74 leukemia-lymphoma cell lines (4 T-, 2 B-, 1 myelomonocytic, 2 Non-T, Non-B cell lines) and in 10 out of 12 normal B-lymphoblastoid cell lines; the only one studied hairy cell leukemia cell line did not express this isoenzyme. The relative specificity of the tartrate-resistant acP is discussed in detail. No leukemia-lymphoma specific isoenzyme or an additional isoenzyme which was not seen in normal hematopoietic cells could be observed. Nor did we find an isoenzyme or isoenzyme pattern characteristic for a certain cell lineage. This underlines the necessity of a combined analysis using markers from different disciplines in the 'multiple marker analysis' in order to accurately characterize normal and malignant blood cells. Furthermore, our results support the concept of maturation arrest at particular stages of differentiation together with the theory of normal gene expression in leukemic cells equivalent to that in their normal counterparts.

Acid phosphatase and acid esterase activity in neoplastic and non-neoplastic lymphoid cells. A semiquantitative evaluation related to immunological markers in 112 cases

Acid phosphatase (AcP) and acid alpha-naphthylacetate esterase (ANAE) were examined in lymphoid cells from 104 patients suffering from various lymphoproliferative disorders and from 8 healthy controls. Enzyme activities were evaluated by means of a scoring system. Scores of AcP and ANAE were higher in normal T cells than non-T cells. In comparison, the activated T cells in infectious mononucleosis showed increased AcP and decreased ANAE reaction. Malignant T lymphoblasts had a distinct granular AcP positivity in contrast to the faint reactivity observed in cALL blasts, whereas ANAE showed negative or weak reaction in both subsets. High scores and distinct staining patterns for both enzymes were found in T CLL and T prolymphocytic leukaemia, clearly different from the weak activities seen in B CLL, B PLL and some B cell lymphomas. The latter, too, could be distinguished by mutual differences in enzyme reactions. High AcP and ANAE scores were also found in hairy cell leukaemia, and the staining patterns together with the tartrate resistance firmly established the diagnosis. Thus, simultaneous determinations of AcP and ANAE can be of great value in the diagnosis of lymphoid malignancies.

Analysis of isoenzyme patterns of acid phosphatase in acute leukemias

The status of acid phosphatase isoenzymes was evaluated in cells of patients with acute lymphocytic leukemias or lymphomas by analytical isoelectric focusing in polyacrylamide gels (IEF) on horizontal thin-layer slabs. The isoenzyme patterns were correlated with routine immunological cell surface markers and the relationship of enzyme activity to specific immunological subclasses of ALL is discussed. By isoelectric focusing up to five isoenzyme groups (I-V) containing several isoenzyme were observed. No leukemia specific or additional isoenzyme could be demonstrated. This biochemical characterization showed a marked heterogeneity within two major immunologic subgroups indicating that various differentiation stages of cell maturation could be involved in cALL and T-ALL. According to their degree of maturation along T-cell differentiation axis the leukemic cells displayed no enzyme activity, weak isoenzyme bands or the incomplete or complete isoenzyme pattern seen with normal lymphocytes from human tonsils which were used as controls. The investigation of specific enzymatic patterns can lead to a further definition of subsets of acute leukemias and give insight into lymphopoietic differentiation.