Expression of proliferation and differentiation antigens in response to modulation of membrane fluidity in chronic lymphocytic leukemia lymphocytes

Isolated lymphocytes from patients with chronic lymphocytic leukemia (CLL) and from healthy controls were investigated for cell membrane fluidity and lipid phase separation. Expression of surface immunoglobulins, OKB7 and HLA-DR antigen, transferrin and interleukin-2 receptor was determined in relation to modulation of membrane lipid composition in each individual case. Structural and functional changes of membrane lipids and impaired lipid-protein interactions could be demonstrated in CLL lymphocytes. However, there is no simple correlation of membrane fluidity and receptor expression. This interaction poses a complex physicochemical problem, which must consider the original structural and functional state of the lipid bilayer. Disturded lipid-protein interactions are discussed in terms of defective transmembrane signalling and cell-cell interaction, allowing uncoupling of the leukemic cell from the network of growth and differentiation factors.

Small lymphocytic lymphoma: a clinicopathologic analysis of 268 cases

We analyzed specimens from 268 patients with small lymphocytic lymphoma (SL) to identify prognostic factors significant for survival. These patients were staged and treated according to the protocols of the Cancer and Leukemia Group B, Eastern Cooperative Oncology Group, Southeastern Cancer Study Group, and the Southwest Oncology Group. Univariate analysis showed that a large-cell grade greater than I, WBC greater than 10,000/microL, hemoglobin (Hgb) less than 11 g/dL, age greater than or equal to 55 years, and failure to respond to treatment were all poor prognostic factors. Multivariate analysis showed that large-cell grade, age, degree of capsular invasion, and symptom type were independently associated with survival. Separate analyses of cases with and without leukocytosis indicated differences in survival. In patients without leukocytosis, age, presence or absence of anemia, and treatment response were significant prognostic variables; in patients with leukocytosis, large-cell grade, presence or absence of anemia, symptom type, and treatment response were significantly related to survival. Multivariate analysis showed that age was the only significant independent prognostic variable in patients without leukocytosis; in patients with leukocytosis, symptom type, large-cell grade, and bone marrow involvement were independently associated with survival. We conclude that several parameters, both clinical and pathologic, should be assessed at the initial diagnosis of SL to predict prognosis better.

Cross-linking of membrane IgM on B CLL cells: dissociation between intracellular free Ca2+ mobilization and cell proliferation

It has been shown previously that chronic lymphocytic leukemia (CLL) B cells are frozen at different stages of activation with unique requirements for proliferation. Although most B CLL cells express surface IgM, anti-mu antibodies are able to trigger only some of them to proliferate and/or respond to B cell growth factor (BCGF) or interleukin 2 (IL2), as normal B cells. In this report we extend these observations using three different monoclonal antibodies (mAb) to human mu chain (one mitogenic in soluble form for normal B cells, the two others mitogenic only when coupled on Sepharose 4B beads). Cells from only 3 out of 11 B CLL patients proliferated in the presence of either mitogenic anti-mu. When the early events following surface Ig cross-linking, such as calcium mobilization (by flow cytometry on indo-1-labeled cells), were studied all three mAb in soluble form were able to induce a similar increase in the intracellular free calcium concentration ([Ca2+]i); analogous to [Ca2+]i rise after the mitogenic F(ab')2 anti-mu stimulation. This response was seen only in 8 out of the 12 CLL B cells studied. All B CLL cells, however, proliferate in response to a combination of phorbol ester 12,13-dibutyrate (PBt2) and ionomycin. Therefore, three patterns of response to sIg cross-linking by anti-mu could be distinguished: cells from 4 out of 12 cases proliferate and mobilize Ca2+ upon anti-mu triggering (behaving like resting B lymphocytes); in 4 other cases anti-mu lead to Ca2+ mobilization without cell proliferation; in the last 4 cases neither Ca2+ mobilization, IP3 generation (in the one case studied) nor cell proliferation are observed although these cells do proliferate directly in response to growth factors. Moreover, anti-mu stimulation in this group leads to increased proliferation in response to BCGF and IL2 suggesting an anti-Ig signaling independent of inositol phosphate metabolism. These results are interpreted in terms of differential anti-mu signaling on B cells at different stages of activation.

[Effects of cranial radiotherapy on growth and hypothalamo-hypophyseal function]

Aiming at evaluating the possible adverse effects of the use of radiotherapy on the CNS in children, we studied fourteen patients in whom it was used: seven as part of the conventional prophylaxis we use in malignant lymphoproliferative processes (group I) and the remaining seven as a treatment for primary cerebral tumors (group II). We evaluated growth during periods ranging from 1.5 to 11 years, and also hypothalamic-pituitary function by RIA. We comment on the results and confirm the endocrine alterations, especially the deficit of growth hormone.