Culture of leukemic progenitor cells in acute non-T lymphoid leukemia

A preliminary study of the culture of leukemic progenitor cells (CFU-L) from acute non-T lymphoblastic leukemia was undertaken for 25 patients (19 were considered in complete remission and 6 in the acute phase of the disease). Two culture systems were tested; a double layer agar-liquid phase and a single layer of methylcellulose. The major problem was the characterization of the colonies: immunological labelling coupled with cytofluorometry, as well as cytomorphology, cytogenetic and more recently molecular biology may allow the characterization of the CFU-L. The culture of CFU-L appears to be an efficient method for detecting residual leukemic cells which can be used to evaluate the quality of both the remission obtained and that of autologous bone marrow after purging.     

Chronic lymphocytic leukemia cells induce non-T cells to produce IgE in the presence of interleukin-4

Mononuclear cells from peripheral blood and bone marrow from patients with chronic lymphocytic leukemia (CLL) were cultured with interleukin-4 (IL-4) alone or with IL-4 and hydrocortisone (HC) in order to induce IgE synthesis. From a total of 29 experiments with the cells of 17 different donors an IgE secretion was observed only twice. Even in those two cases the IgE was found to be not monoclonal. The additional stimulation of CLL cells by polyclonal B cell activators induced IgM but not IgE production. When CLL cells were cocultured with monocyte-enriched cell preparations (M) in the presence of IL-4 and HC, a substantial IgE secretion could be obtained, which again consisted of both IgE and IgE. Since the irradiation of the M but not of the CLL cells abolished the formation of IgE, it is likely that the IgE production resided in the contaminating B cell population of the M. When the M were replaced by T cell-depleted peripheral blood mononuclear cells (non-T cells), irradiated as well as formaldehyde fixed CLL cells were able to stimulate non-T cells to secrete IgE in the presence of IL-4 or to potentiate IL-4- and HC-induced IgE formation. Furthermore, the coculture of irradiated pure CLL cells and purified B cells induced not only IgE but also IgG and IgM production and B cell proliferation in the presence of lymphokines. Our findings suggest that CLL cells, contrary to current opinion, cannot be induced to produce IgE. However, they are able to replace T cells in their role for the noncognate activation of B cells, implicating the existence of a common surface determinant on T and B CLL cells for this function.     

Density separation of chronic lymphocytic leukemia cells: Low-density non-T cells are efficient stimulator cells in allogeneic and autologous mixed leukocyte reaction

Unseparated mononuclear cells and E rosette-depleted non-T cells from a majority of patients with chronic lymphocytic leukemia (CLL) were found to be weak stimulators in the allogeneic mixed-leukocyte reaction (MLR). However, a minor population (1–5%) of highly active stimulator cells could be isolated from all patients studied by buoyant density centrifugation using discontinuous gradients of Percoll. The same low-density non-T-cell fraction also stimulated autologous T-cell proliferation in the autologous mixed-leukocyte reaction (AMLR). In contrast, Percoll-separated high-density non-T cells, including the leukemic B-cell pool, were completely inactive as stimulators in AMLR. These results suggest that the presence of efficient stimulator cells among CLL mononuclear cells may be masked by the large number of nonstimulating leukemic B cells.     

Chromosomes in acute lymphocytic leukemia

Results of chromosome analysis in acute lymphocytic leukemia are reviewed. Emphasis is placed on so-called specific translocations and their association with cytology, immunology, and prognosis. Data presently available suggest that chromosomes in acute lymphocytic leukemia are not only an important, independent prognostic factor, but also contribute to a new understanding of leukemic cell origin and pathway, which may enable us to overcome the limitations of present classification schemes.     

Immunoelectron-microscopic localization of Tac antigen in adult T-cell leukemia/lymphoma.

The localization of Tac antigen in adult T-cell leukemia-associated antigen (ATLA)-positive lymphomas was studied ultrastructurally with the use of the immunoperoxidase technique. The antigen was observed on the plasma membranes of a portion of the characteristic cells with convoluted nuclei and a majority of the cells with less irregular nuclei, which were larger than the former. In addition, the cisternae of the rough endoplasmic reticulum, perinuclear cisternae, and Golgi cisternae of the latter cells were also positively stained with anti-Tac antibody. It is thought that the positive reaction of the plasma membranes may correspond to interleukin 2 (IL 2) receptors, the cytoplasmic and perinuclear reaction sites may well correspond to the precursor of IL 2 receptors, and Tac antigen may be produced in the cytoplasm of the ATLA-positive lymphoma cells.     

Giant mitochondria in acute lymphocytic leukemia

Giant mitochondria were observed in 2 cases among 28 cases of ALL by electron microscopy. The cristae of the giant mitochondria in the leukemic cells were irregularly arranged, decreased in number, and formed concentric circles. Several morphological abnormalities were also observed in the normal mitochondria. Morphometric analysis of the mitochondria in the 2 patients disclosed that the sizes of mitochondria were well distributed from small to large and thus, the mitochondria could not be divided into different populations. Also, there were no clear differences in the distribution of shape between normal and giant mitochondria. These results suggest that the giant mitochondria were derived from normal mitochondria. Since they were observed before the initial treatment, they did not developed as a result of drug action.     

Ultrastructural study of lymphocytic interaction with hepatocytes and endothelial cells in acute non-A, non-B hepatitis

In the liver biopsy specimens of all six patients with acute non-A, non-B hepatitis, the lymphocytic interaction with hepatocytes and sinusoidal endothelial cells was observed by electron microscopic study. Lymphocytes were in a close contact with damaged hepatocytes and interrupted endothelial cells, and the microvilli on the surface of these damaged hepatocytes were degenerated and lost. These findings pointed out the possibility that the lymphocyte may play one of the important roles in hepatocytic damage and endothelial cell damage in acute non-A, non-B hepatitis.     

Interleukin-3-treated non-B, non-T cells switch activated B cells to IgG1/IgE synthesis.

The switch of activated B cells to IgE synthesis is an interleukin (IL)-3-dependent process. It is currently thought that specific T cells activated by antigen presented in the context of class II major histocompatibility complex are the major source of IL-4. Recently it has been demonstrated that a splenic non-T non-B cell population (termed NBNT) has the capacity to produce IL-4 following IgE and IgG receptor cross-linkage. In this study we demonstrate that IL-4 producing NBNT cells can induce the switch of lipopolysaccharide-activated B cells to the synthesis of IgG1 and IgE antibodies. Furthermore, it was found that not only IgE receptor cross-linkage but IL-3 was able to stimulate NBNT cells to produce IL-4 and induce the switch of B cells to IgE synthesis. NBNT cells derived from the spleen and bone marrow of SCID mice were able to produce IL-4 on exposure to IL-3. This suggested that the ability of IL-3 to stimulate IL-4 production was not dependent on prior exposure of the NBNT cells to antibody complexes in vivo. Taken together these findings represent the first observation that enough IL-4 is produced by NBNT cells to actually influence a B cell IgG/Ig response. The findings also clearly demonstrate that B cells do not need high concentrations of IL-4 to be directed to switch to IgG1 and IgE synthesis.     

Therapeutic considerations in acute lymphocytic leukemia.

Evidence that the first human neoplasm systematically explored with chemotherapeutic treatments has apparently been cured in a palpable segment of affected patients evokes optimism for other types of cancer. The application of similar effort, similar logic, and quantitative experimental therapeutic approaches to the common cancers augurs well for cancer research and clinical medicine.     

T6 monoclonal antibody reacts with blasts from cases of common antigen acute lymphocytic leukemia

The expression of the T6 antigen on malignant lymphoid cells has been considered strong evidence in support of T-cell lineage and thymic stage of differentiation of the neoplastic cells. Thus, the authors have used the T6 monoclonal antibody for the last three years in the immunophenotyping of blasts from 60 consecutive cases of acute lymphocytic leukemia (ALL) and 8 cases of T-cell lymphoma. Blasts from 12 of 46 (26%) cases of common type ALL, 4 of 7 (57%) cases of T-cell ALL, 2 of 3 (66%) cases of lymphoblastic lymphoma, and 1 of 5 (20%) cases of peripheral (postthymic) T-cell lymphoma were positive for the T6 antigen. The authors conclude that the expression of T6 antigen on malignant lymphoid cells may not always indicate T-cell lineage.     

Clinical importance of myeloid antigen expression in adult acute lymphoblastic leukemia

To determine the clinical importance of immunophenotypes in adult acute lymphoblastic leukemia (ALL), we prospectively studied 76 patients with this condition. Before treatment, lymphoblasts were tested for reactivity with monoclonal antibodies to B-cell, T-cell, and myeloid (My) antigens. Unexpectedly, myeloid antigens (MCS-2 or MY9) were identified in 25 patients (33 percent), usually in conjunction with B-cell or T-cell antigens. Among My+ patients, 15 (60 percent) expressed B-cell antigens (B+T-My+); all 6 tested had rearranged immunoglobulin genes. Five patients (20 percent) expressed T-cell antigens (B-T+My+), and one My+ patient expressed both B-cell and T-cell antigens. Only myeloid antigens (B-T-My+) were expressed in four patients (16 percent); three who were tested had germ-line immunoglobulin and T-cell-receptor gene configurations. Although no significant differences in presenting clinical features were found, My+ patients had fewer complete remissions than My- patients (35 vs. 76 percent, P less than 0.01). No differences in response or survival were observed between My+ and My- patients expressing T-cell antigens. However, among those expressing B-cell antigens, My+ patients had fewer complete remissions (29 vs. 71 percent, P = 0.02) and shorter survival (P = 0.03; median, 8.1 vs. greater than 26 months). These findings indicate that expression of myeloid antigen identifies a high-risk group of patients with adult ALL for whom alternative forms of treatment should be investigated.     

Intracellular cytokine expression in T cells from patients with chronic lymphocytic leukemia

Functional disorders of T lymphocytes play an essential role in abnormal immune response in patients with chronic lymphocytic leukemia. The aim of this study was to assess the profile of cytokines expressed by T cells derived from patients with CLL. We have demonstrated that the intracellular levels of IL-2, IL-4, IFN-γ, TNF, IL-6 and IL-10 were significantly higher in T cells of CLL patients than in healthy donors. Moreover, the percentages of CD4+/CD3+/TNF+, CD4+/CD3+/IFN-γ+, and CD4+/CD3+/IL-2+ cells were significantly higher in ZAP-70-positive patients compared with ZAP-70-negative ones. Likewise, significantly higher percentages of CD4+/CD3+/TNF+, CD4+/CD3+/IFN-γ+ cells were observed in CD38-positive than in CD38-negative cases. What is more, there was a significant difference in median percentage of CD3+/CD4+ cells expressing TNF, IL-4, IFN-γ, IL-2 or IL-6 between patients carrying the 11q22.3 deletion and/or the 17p13.1 deletion and patients without these genetic aberrations. Our results confirm the functional disorders of T cells in CLL and their influence on the clinical course of the disease.