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Biomedical subjects

F Guilhot

Publications and source records attributed to F Guilhot.

At least 73 records · Page 4Linked to original sources

Cell-mediated cytotoxicity can be regulated by p53 tumor suppressor gene activity in vitro.

The wild-type human p53 tumor suppressor gene was tested for its ability to modulate cytotoxic activity of in vitro activated peripheral blood lymphocytes. Peripheral blood mononuclear cells (PBMCs) were stimulated by phytohemagglutinin (PHA), interferon alpha 2b (IFN alpha 2b), interleukin 2 (IL-2) or their combinations to induce cytotoxicity. This stimulation significantly increased the percentage of cells expressing p53, which was at its maximum when induced by IL-2 combined with IFN alpha 2b. The role of p53 in the modulation of different aspects of cytotoxic activity of these cells was analyzed by studying the effects of p53 abrogation by antisense oligonucleotide (p53 AS) treatment in comparison with p53 sense or scrambled (missense) oligonucleotide (p53 S or p53 MS) treatment. We show that p53 plays a key role through induction of apoptosis in target cells (tumor necrosis factor pathway) rather than through osmolytic degeneration (perforin pathway) which is only slightly increased by p53 abrogation. Meanwhile, in vitro abrogation of p53 expression in PBL was found to be accompanied by an increase of CD8+ lymphocytes and an important increase of the CD56 'bright' NK cell sub-population.

Antigens, CD↗

Changes of cerebral biopterin and biogenic amine metabolism in leukemic children receiving 5 g/m2 intravenous methotrexate.

Acute or subacute neurologic disorders can be observed in patients receiving high-dose methotrexate therapy for lymphoblastic leukemia or malignant tumor. Impairment of biopterin metabolism leading to decreased availability of monoamine neurotransmitters has been suggested to explain methotrexate neurotoxicity. To investigate such a mechanism, we have measured prospectively by HPLC the concentrations of total biopterin, homovanillic acid, and 5-hydroxyindolacetic acid in cerebrospinal fluid of 57 children with acute lymphoblastic leukemia. A sequential analysis of cerebrospinal fluid was performed for each patient: cerebrospinal fluid samples were obtained before therapy and after each of the four high-dose methotrexate infusions during the CNS prophylaxis phase. A significant increase of total biopterin concentrations in cerebrospinal fluid was observed after high-dose methotrexate therapy compared with the pretreatment values. No cumulative effect was noted. In contrast, no significant variation of the homovanillic acid and 5-hydroxyindolacetic acid levels was observed in cerebrospinal fluid. However, individual analysis revealed a transient decrease of homovanillic acid and 5-hydroxyindolacetic acid concentrations in cerebrospinal fluid of six children. The increase of total biopterin mimicking that observed in inherited dihydropteridine reductase deficiencies suggests that methotrexate inhibits the regenerating system of biopterin in the brain of patients undergoing high-dose methotrexate therapy.

Adolescent↗

Recombinant alpha-interferon as treatment for chronic myelogenous leukemia in relapse after allogeneic bone marrow transplantation: a report from the Société Française de Greffe de Moelle.

Thirty three patients with Philadelphia chromosome positive (Ph+) chronic myelogenous leukemia (CML) in relapse after allogenic bone marrow transplantation (BMT) were treated with recombinant alpha-interferon (IFN). Ten patients received IFN for cytogenetic relapse (group I) and 23 (group II) for hematologic relapse. The starting dose of IFN varied from 1.7 to 6 million units/m2/day (median 3 x 10(6) U/m2/day). Among the 10 group I patients, 3 subsequently developed hematologic relapse. Of the other 7, a cytogenetic response was observed in 6 (complete 4, minor 2). Three of these responders are alive in complete cytogenetic remission. Of the 23 group II patients, 3 did not respond to IFN but 20 achieved a complete (CHR) (n = 14) or a partial hematologic response (PHR) (n = 6). Thirteen of the 14 CHR patients subsequently achieved a cytogenetic response (complete 7, minor 6). Seven of the latter 13 patients are still alive in complete cytogenetic remission (CCR). Thus, for the entire group of 33 patients, IFN was followed by CCR in 11 cases (33%); all these patients are still alive and the median follow-up in CCR is now 60.7 months (range 35.3-72.5 months). The BCR-ABL rearrangement was not detected by RT-PCR in 5 of the 10 patients analyzed. Eleven other patients developed either blast crisis or acceleration. The 3-year probability of survival from the start of IFN therapy probability of survival from the start of IFN therapy was 70 +/- 16% (95% CI) and was statistically higher for patients who achieved CCR than for the others.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Allogeneic bone marrow transplantation remains an efficient consolidation for adults with acute myeloid leukemia even when performed very soon after diagnosis (< 100 days). The SFGM (Société Française de Greffe de Moelle.

Allogeneic BMT is presently recognized as one of the reference anti-leukemic treatments for AML patients. It could be a very useful therapy in CR1 AML if it is efficient as an early form of consolidation after induction therapy. Later procedures may be of lesser importance since they concern a population which may have already been cured by chemotherapy. Alternatively it is not solved if very early BMT gives patients sufficient therapy and provides lower toxicity. To answer this question we analyzed data from the Société Française de Greffe de Moelle (SFGM) on a sub-group of patients according to the following criteria: (1) Allogeneic BMT carried out on patients with AML in CR1; (2) after January 1985; (3) conditioning with CyTBI; (4) GVHD prophylaxis with MTX-CsA; (5) interval between diagnosis and BMT < 100 days. Forty-two fulfilled all criteria. Age was 31 +/- 8 years and M/F ratio was 19/23. WBC at diagnosis were 36 +/- 49 x 10(9)/l and four patients needed two induction courses to achieve CR1. Median follow-up is now 51 (24-116) months. Twenty-two patients developed a grade > or = 2 acute GVHD. Early transplant mortality at 1 year is no higher than 14%. Two patients died of secondary malignancies at 3.5 and 6.5 years after BMT. Finally 5-year (and 7-year) probabilities for relapse, survival, leukemia and event-free survival are respectively 17% (17%), 71% (62%), and 71% (71%) and 68% (59%). These data indicate the feasibility of such an approach with low mortality and low relapse rates providing a good long-term outcome. This should prompt an invitation to initiate the search for an HLA-identical sibling when AML is diagnosed in a young patient eligible for allo-BMT.

Adult↗

Pregnancy occurring during complete cytogenetic response after interferon therapy in chronic myeloid leukaemia.

A 25 year old woman with chronic myelogenous leukaemia was treated for 27 months with alpha-interferon, leading to complete haematological and cytogenetic remission. One year after interruption of treatment, she became pregnant and delivered a healthy full term infant. This case provides further evidence in support of the safety of alpha-interferon with respect to the fertility of women of childbearing age.

Adult↗

Trisomy 8q due to i(8q) or der(8) t(8;8) is a frequent lesion in T-prolymphocytic leukaemia: four new cases and a review of the literature.

Cytogenetic abnormalities found in four cases of T-cell prolymphocytic leukaemia (T-PLL) are described. An isochromosome 8q was found in three patients and a t(8;8) in one. In the four cases, karyotypes were complex and showed a high degree of instability. In addition, we reviewed 27 published cases of cytogenetically studied T-PLL. On the whole, the most frequently recurring anomalies in T-PLL are 14q lesions with nonrandom breakpoints, inversion (14)(q11q32) or tandem translocations (14;14) (not seen in any of our cases) and trisomy for 8q. mainly due to i(8q), found in more than 40% of patients each. Similar structural anomalies were found almost as frequently among the 23 cytogenetically studied cases of so-called T-chronic lymphocytic leukaemia (T-CLL) reported prior to 1989. It is now accepted that the T-cell counterpart of B-CLL either does not exist or is exceedingly rare and thus previously reported cases of T-CLL sharing the chromosomal characteristics of T-PLL may well have been misdiagnosed examples of T-PLL. Isochromosomes 8q are exceptionally found in other types of haematological malignancies. However, i(8q) could not be shown to be the primary lesion in any case in T-PLL and the role of trisomy for 8q, as well of the associated monosomy 8p, is entirely unknown.

Adult↗

Unclassifiable high grade malignant T-cell lymphoma with clonal evolution.

We report a case of leukemic malignant T-cell lymphoma with mixed small and large cells. The small cells displayed a mature CD8-positive phenotype, a diploid DNA distribution by cell cycle analysis, and structural karyotypic abnormalities. Large cells were near triploid, showed additional structural cytogenetic abnormalities and a more immature membrane phenotype without CD8 expression. Altogether, these data provide suggestive evidence for a clonal evolution from a mature small cell T-cell lymphoma to a more immature large cell proliferation.

Aged↗

Effects of alpha-interferon on MHC unrestricted cytotoxicity in chronic myelogenous leukemia.

The capacity of alpha-interferon (alpha-IFN) to induce lymphokine activated killer (LAK) cytotoxicity in the absence of interleukin-2 (IL2) has prompted us to test whether its ability to reduce dramatically the number of Ph1+ clones in chronic myelogenous leukemia (CML) patients is in part mediated through the generation of natural killer (NK) or LAK activity. The latter were tested using NK-sensitive (K562) and NK-resistant (Raji) cell lines in a target-cell colony-growth inhibition assay. Effector cells (E) were patient blood mononuclear cells (MC) without in vitro activation prior to their coculture with targets (T). Here we report that cytogenetic remission in alpha-IFN-treated patients is associated with significantly enhanced NK and LAK activities. Nevertheless, some patients under alpha-IFN therapy were found to develop lymphoid blast crisis despite high levels of NK and LAK activities, and partial or total cytogenetic remission. In contrast, most of the patients who developed nonlymphoid blast crisis presented 100% Ph1+ cells and displayed defective NK and/or LAK activity. These observations could favor the hypothesis that there is an indirect but complex effect of alpha-IFN on leukemic cells, mediated by cells involved in immune surveillance; and also that lymphoid blast cells may actually escape LAK cytotoxicity.

Adolescent↗

The role of interferon in the treatment of chronic myelogenous leukemia in chronic phase.

Several studies have shown that interferon IFN-alpha can produce durable complete hematological remission and in some patients complete cytogenetic remission. This latter result is never achieved by standard monochemotherapy. The hematologic and cytogenetic response rates are dependent on the phase of the chronic myelogenous leukemia, the patient risk group, and the dose of IFN-alpha. The expected median survival of patients with early chronic phase is 60 months. A significant association between cytogenetic response and survival is now reported by several groups. Thus new trials are now under way in order to improve these results.

Antineoplastic Combined Chemotherapy Protocols↗

Molecular remission after allogeneic bone marrow transplantation for chronic lymphocytic leukemia.

A 51-year-old man with previously treated CLL received an allogeneic sex mismatched BMT after total body irradiation and high dose chemotherapy. Residual disease was studied at phenotypic and molecular levels including Y chromosome DNA amplification by PCR assay. The patient was clinically disease-free 20 months after BMT with disappearance of the leukemic clone assessed by the most sensitive methods of detection. Long-term follow-up is necessary to ascertain the relevance of Y DNA amplification in predicting outcome in this patient.

Antineoplastic Agents↗

Detection of monosomy 7 and trisomies 8 and 11 in myelodysplastic disorders by interphase fluorescent in situ hybridization. Comparison with acute non-lymphocytic leukemias.

Cells from 50 patients with myelodysplastic syndrome (MDS) and 20 patients with acute non-lymphoblastic leukemia (ANLL) were studied by fluorescent in situ hybridization (FISH) using alphoid biotinylated probes to detect numerical chromosome 7, 8 and 11 aberrations in interphase nuclei. FISH data were compared with cytogenetic results. Both methods were in agreement in 25/50 MDS and 20/20 ANLL cases. Trisomy 11 was found neither by cytogenetic study nor by FISH. In 11 MDS patients the percentage of abnormal cells was higher by FISH than by classical cytogenetic analysis. FISH revealed monosomy 7 which was undetectable by karyotypic study in 5-22% cells from 15 MDS patients. It also allowed the identification of two small markers and a ring chromosome in two MDS cases. FISH hence appears to be useful for the detection of minor abnormal clones and is a convenient complement to conventional cytogenetic analysis in the study of MDS.

Aged↗

Effects of sCD23 on proliferation of leukemic cells from a patient with chronic myelogenous leukemia during blast crisis.

The present study has attempted to further delineate the growth factor requirements of peripheral blasts of a patient with CML in acute phase. Phenotypic analysis of leukemic blasts from this patient before culture has shown a homogenous population of CD34+ cells at the onset of blast crisis. In the second and third samples the percentage of CD34+ DR+ blast cells decreased slightly and up to 32% of cells in the third sample expressed the CD19 antigen. Optimal proliferation of cells derived from the first sample required the presence of exogenous sCD23 and to a lesser extent IL7. The stimulatory effects of sCD23 and IL7 were clearly reduced 4 months later and no longer detected after 6 months. This variability in growth factor response along with disease progression may be related to phenotypic differentiation. There was no evidence for lymphoid or myeloid maturation after 4 days of liquid culture. Our results in conjunction with previous studies are in agreement with sCD23-involvement in the complex control of proliferative processes at both normal and leukemic stages, demonstrating that cytokines are critical in determining CML cell proliferation.

Acute-Phase Reaction↗

Endogenous lymphokine activated killer cell activity and cytogenetic response in chronic myelogenous leukaemia treated with alpha-interferon.

The capacity of alpha-interferon (alpha-IFN) to induce lymphokine activated killer (LAK) cytotoxicity in the absence of interleukin-2 (IL2) has prompted us to test whether or not its ability to reduce dramatically the number of Ph1+ clones in chronic myelogenous leukaemia (CML) patients is in part mediated through the generation of natural killer (NK) or LAK activity. The latter were tested using NK-sensitive (K562) and NK-resistant (Raji) cell lines in a target-cell colony-growth inhibition assay. Effector cells (E) were patient blood mononuclear cells (MC) without in vitro activation prior to their coculture with targets (T). Out of 16 patients tested so far, three failed to undergo cytogenetic remission under alpha-IFN therapy. No NK nor LAK cells could be detected in the MC from two of them while the other displayed NK activity within upper normal limits. 13 patients underwent complete (eight) or partial (five) cytogenetic remission together with significantly high NK and/or LAK activity as compared to normal controls. These observations could favour the hypothesis of an indirect effect of alpha-IFN on leukaemic cells, mediated by cells involved in immune surveillance.

Adolescent↗

A multicentric randomised study of alpha 2b interferon (IFN) and hydroxyurea (HU) with or without cytosine-arabinoside (Ara-c) in previously untreated patients with Ph+ chronic myelocytic leukemia (CML): preliminary cytogenetic results.

The CML 88 study was designed to evaluate the efficacy of maintenance therapy in a multicentric randomised protocol using IFN combined with low-dose Ara-C versus IFN alone, following an induction with IFN + HU. Between April 1988 and February 1991, 237 patients from 36 French Hematology Centres were entered in the study. Preliminary cytogenetic results show a slightly higher, although not statistically significant, proportion of major chromosomal responses, including complete cytogenetic remissions, in the IFN + Ara C arm.

Adolescent↗

[Interferons. Treatment of malignant hemopathies with interferons].

Interferons (INF) are glycoproteins with protean antiviral, immunomodulator, and antiproliferative actions. In Haematology, IFN-alpha is the most widely used. Diffusion into the spleen, bone marrow and liver is good. Hairy cell leukemia is probably the malignant blood disorder which responds best to IFN. At some time during their treatment, nearly 90% of the patients require IFN. Treatment initiation is indicated when pancytopenia (polynuclear neutrophils below 1 x 10(9)/L) develops or in case of a very voluminous spleen. IFN-alpha 2a, 2b and 2c are active (leukocyte IFN is used less often, as is IFN-beta; IFN-gamma is ineffective). The standard dose is 3 x 10(6) U, three times a week for 12 weeks. Smaller doses and maintenance treatment is sometimes proposed. Haematological remission occurs in almost all cases, if not a misdiagnosis must be considered (villous lymphocyte lymphoma). Relapse usually occurs at the end of treatment, but sensitivity to IFN is not altered and final survival is improved. Nearly 90% of the patients are alive at 4 years. Although IFN is active in chronic myeloid leukemia, research in this area continues. Clinical trials have reported haematologic relapse in 90% and complete cytogenetic response in 15 to 35% of the patients. The effect on Ph+ cells is not observed with classical chemotherapies. Initial dose is generally 5 x 10(6) U/m2/day. High doses are not always well tolerated, but cytogenetic response is only seen in patients in haematologic and cytopenic remission. IFN therapy improves survival over classical treatments (median 62 versus 39 months). Survival is better after good cytogenetic response or complete remission. Combined chemo-IFN therapy is currently under study in an attempt to improve cytogenetic response. In terms of the molecular biology however, residual disease is almost always present and relapse is frequent.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗