Marie-France Sotto

Effects of two sex steroids (17β estradiol and testosterone) on proliferation and clonal growth of the human monoblastic leukemia cell line, U937

We investigated the effects of two sex steroids (17beta estradiol and testosterone) on five human leukemia cell lines. We observed a statistically significant inhibition of proliferation, dose and time dependent, of the human monoblastic leukemia cell line U937. This inhibition was associated with a dose dependent decrease in the number of CFU-blasts in clonogenic cultures. Cytostatic effect was obtained with doses of 5 microM for estrogen and 10 microM for androgen and was not due to a non-specific cytotoxic effect, some cell viability remained high (> 90%) even after 6 days of incubation. More accurately, we demonstrated that growth inhibition was associated with a cell cycle arrest, U937 cells accumulating in G2/M phase. This blockade was dose related with a maximum number of cells accumulating at day 4. Sensitivity of these cells to an S-phase specific agent (hydroxyurea) was not increased, suggesting that these cells were blocked in G2/M and did not undergo mitosis. Expression in U937 cells of high affinity nuclear receptors for estrogen and androgen was negative which was in favour of a type II estrogen binding site, mediated mechanism. Moreover, a small fraction of these cells underwent apoptosis or differentiation with about 12% apoptotic cells and a significant increase (more than 30%) of two myelomonocytic markers (CD13 and CD64). These results demonstrate that the proliferation of some leukemic cells may be inhibited by micromolar concentrations of sex steroids, independently of nuclear receptor expression. The main mechanism seems to be a block in cell cycle associated with modulation of apoptosis and differentiation. It provided additional evidence for the potential value of sex steroids and their analogues in the treatment of leukemias.

Autotumour reactive T-cell clones among tumour-infiltrating T lymphocytes in B-cell non-Hodgkin's lymphomas.

Summary. Seventy‐three T‐cell clones (TCC) were established from tumour‐infiltrating lymphocytes‐T (TIL‐T) derived from lymph nodes involved by B‐cell non‐Hodgkins lymphomas (B‐NHL) in nine patients with different histological subtypes and clinical stages. 40 TCC (55%) expressed the CD25 Ag and were also able to proliferate in the presence of irradiated autologous B‐NHL cells. Among them, 23 autotumour (AuTu) proliferative TCC were found not to proliferate to autologous EBV‐transformed B‐cell lines, indicating that the proliferative reactivity of these TCC was preferentially directed at autologous B‐NHL cells. Tested against autologous B‐NHL cells, only three AuTu prolifera‐ tive TCC (CD8 +) showed a significant level of cytotoxicity (specific lysis > 15%). In blocking experiments, the AuTu proliferative reactivity of three TCC from one patient was strongly inhibited by anti‐DR and anti‐DQ mAbs, whereas that of three TCC from another patient was not affected by either anti‐MHC class I or class II (DR., DP, DQ) mAbs. These findings suggest that the recognition of autologous B‐NHL cells by AuTu proliferative TCC may occur through MHC‐restricted as well as MHC‐unrestricted mechanisms.

Splenectomy during chronic lymphocytic leukemia

The combination of discontinuous high‐dose chlorambucil therapy with splenectomy greatly increased the prognosis of aggressive forms of chronic lymphocytic leukemia (CLL). The median survival for 43 patients was 84 months from diagnosis and 48 months from splenectomy. For 15 stage 0, according to Rai classification, obtained after splenectomy, duration ranged from 3 to 105 months. The median survival of a group of patients showing “nodular splenic infiltration” was 104 months and superior to that of a group of patients showing “diffuse splenic infiltration” (72 months). In four of 15 cases studied, the peripheral blood lymphocytic clone disappeared after splenectomy.

Deletion 7q in B-Cell Low-Grade Lymphoid Malignancies: A Cytogenetic/ Fluorescence In Situ Hybridization and Immunopathologic Study

Ten cases presenting a simple karyotype and del(7q) as a primary event were selected out of 353 patients referred as B-cell low-grade malignant lymphoproliferative disorders. Chromosome 7-specific painting probes confirmed the deletion that was tentatively assigned to bands q31q35. Chromosome 7 was involved in an interstitial deletion in seven cases, in an unbalanced translocation in two cases, and in a ring chromosome in one case. Common clinical/hematological features included advanced age, marked splenomegaly, and peripheral blood monoclonal IgM(D) lymphocytosis. Regardless of morphologic entity, most cases shared lymphoplasmacytoid features. Deletion 7q may delineate a variety of low-grade B-cell lymphoid disorders characterized by a common clinical history and immunopathologic similarities. The cytogenetic pattern and the ongoing work on molecular mapping of this deletion suggest that the loss of a putative tumor-supressor gene at 7q31q32 may constitute an early event in their pathogenesis.

Production of granulopoiesis-stimulating and-inhibiting activities by T cells associated with malignant cells in lymphomas

The possible role of T lymphocytes in the formation of granulomatous reactions seen in certain malignant lymphoid tumours was investigated by measuring the granulopoietic colony‐stimulating activity (CSA) and granulopoietic‐inhibiting activity (IA) produced by stimulated T‐lymphocytes isolated from peripheral blood, spleen and lymph nodes of patients and normal subjects.

Phenotypic, morphologic changes and Ig secretion induced on B-NHL cells in vitro by interferon alpha and all-trans-retinoic acid: possible progression toward a more differentiated state

Abstract: Twenty‐five B‐cell‐nonHodgkins lymphomas (B‐NHL): 6 lymphocytic, 2 centrocytic, 13 follicular, centrocytic/centroblastic, 2 lymphoplasmocytoid and 2 centroblastic were tested for their ability to acquire features of mature plasma cells under the effect of interferon alpha (final concentration, 600 Ul/ml), all‐trans‐retinoic‐acid (ATRA) (final concentration, 10−6 mol/1) and the association of both. B‐NHL cells were negatively purified (>99%) by an immunomagnetic method, cultured for 7 d with or without interferon and ATRA, then stained with anti‐CD 19, CD20, surface Ig, DR, CD38 and with anti‐CD138 (syndecan‐1) antibody‐recognizing plasma cells. Ig production was estimated in culture supernatants by an ELISA method and changes in cell morphology were investigated on May–Grünwald–Giemsa‐stained cytospin preparations. In all cases interferon and ATRA, alone or in association, were able to induce changes in the immunophenotypic profile, associated or not with morphologic changes and induction of Ig secretion. All changes were greatly variable from one to the other B‐NHL sample and no relationship could be found between a particular pattern of change and the histological subtype. Interferon alpha was more potent than ATRA in inducing changes. In favour of a differentiation process, we observed a concomitant decrease of DR expression and increase of CD38 expression in 8 cases with interferon alpha, and in 4 cases with ATRA. Although interferon‐ or ATRA‐treated cells did not display cytologic, functional features and changes of the immunophenotypic profile fully compatible with those of terminally differentiated cells, these results suggest a possible transition toward more differentiated elements, especially with interferon alpha.