Hairy cell leukemia: a specific 17-gene expression signature points to new targets for therapy

Background

Hairy cell leukemia (HCL) is a rare chronic B cell malignancy, characterized by infiltration of bone marrow, blood and spleen by typical “hairy cells” that bear the BRAFV600E mutation. However, in addition to the intrinsic activation of the MAP kinase pathway as a consequence of the BRAFV600E mutation, the potential participation of other signaling pathways to the pathophysiology of the disease remains unclear as the precise origin of the malignant hairy B cells.

Materials and methods

Using mRNA gene expression profiling based on the Nanostring technology and the analysis of 290 genes with crucial roles in B cell lymphomas, we defined a 17 gene expression signature specific for HCL.

Results

Separate analysis of samples from classical and variant forms of hairy cell leukemia showed almost similar mRNA expression profiles apart from overexpression in vHCL of the immune checkpoints CD274 and PDCD1LG2 and underexpression of FAS. Our results point to a post-germinal memory B cell origin and in some samples to the activation of the non-canonical NF-κB pathway.

Conclusions

This study provides a better understanding of the pathogenesis of HCL and describes new and potential targets for treatment approaches and guidance for studies in the molecular mechanisms of HCL.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-022-04010-4.

Identification of driver genes for critical forms of COVID-19 in a deeply phenotyped young patient cohort

[Figure: see text].

Prolonged in-hospital stay and higher mortality after Covid-19 among patients with non-Hodgkin lymphoma treated with B-cell depleting immunotherapy

Prolonged Covid-19 is an emerging issue for patients with lymphoma or immune deficiency. We aimed to examine prolonged length of in-hospital stay (LOS) due to Covid-19 among patients with lymphoma and assess its determinants and outcomes. Adult patients with lymphoma admitted for Covid-19 to 16 French hospitals in March and April, 2020 were included. Length of in-hospital stay was analyzed as a competitor vs death. The study included 111 patients. The median age was 65 years (range, 19-92). Ninety-four patients (85%) had B-cell non-Hodgkin lymphoma. Within the 12 months prior to hospitalization for Covid-19, 79 patients (71%) were treated for their lymphoma. Among them, 63 (57%) received an anti-CD20 therapy. Fourteen patients (12%) had relapsed/refractory disease. The median LOS was 14 days (range, 1-235). After a median follow-up of 191 days (3-260), the 6-month overall survival was 69%. In multivariable analyses, recent administration of anti-CD20 therapy was associated with prolonged LOS (subdistribution hazard ratio 2.26, 95% confidence interval 1.42-3.6, p < 0.001) and higher risk of death (hazard ratio 2.17, 95% confidence interval 1.04-4.52, p = 0.039). An age ≥ 70 years and relapsed/refractory lymphoma were also associated with prolonged LOS and decreased overall survival. In conclusion, an age ≥ 70 years, a relapsed/refractory lymphoma and recent administration of anti-CD20 therapy are risk factors for prolonged LOS and death for lymphoma patients hospitalized for Covid-19. These findings may contribute to guide the management of lymphoma during the pandemic, support evaluating specific therapeutic approaches, and raise questions on the efficacy and timing of vaccination of this particular population.

Disentangling molecular and clinical stratification patterns in beta-galactosidase deficiency

INTRODUCTION

This study aims to define the phenotypic and molecular spectrum of the two clinical forms of β-galactosidase (β-GAL) deficiency, GM1-gangliosidosis and mucopolysaccharidosis IVB (Morquio disease type B, MPSIVB).

METHODS

Clinical and genetic data of 52 probands, 47 patients with GM1-gangliosidosis and 5 patients with MPSIVB were analysed.

RESULTS

The clinical presentations in patients with GM1-gangliosidosis are consistent with a phenotypic continuum ranging from a severe antenatal form with hydrops fetalis to an adult form with an extrapyramidal syndrome. Molecular studies evidenced 47 variants located throughout the sequence of the GLB1 gene, in all exons except 7, 11 and 12. Eighteen novel variants (15 substitutions and 3 deletions) were identified. Several variants were linked specifically to early-onset GM1-gangliosidosis, late-onset GM1-gangliosidosis or MPSIVB phenotypes. This integrative molecular and clinical stratification suggests a variant-driven patient assignment to a given clinical and severity group.

CONCLUSION

This study reports one of the largest series of b-GAL deficiency with an integrative patient stratification combining molecular and clinical features. This work contributes to expand the community knowledge regarding the molecular and clinical landscapes of b-GAL deficiency for a better patient management.

Abstract S09-02: High incidence of persistent COVID-19 among patients with lymphoma treated with B-cell depleting immunotherapy

Introduction Treatment of B-lineage lymphoma with B-cell depleting immunotherapy causes B-cell aplasia and impairs immune response. Case studies have reported patients treated with anti-CD20 therapy who suffered from persistent Covid-19. We aimed to assess the incidence, risk factors and long-term outcomes of persistent Covid-19 in patients with lymphoma. Patients and methods This retrospective multicentric study was conducted in 16 French hospitals. All adult patients with lymphoma who were admitted for Covid-19 in March and April 2020 were included. Persistent Covid-19 was defined as persisting severe Covid-19 symptoms requiring in-hospital stay for &gt;30 days. Patients who re-experienced severe Covid-19 symptoms after initial improvement, requiring repeated hospitalizations for a total in-hospital length of stay &gt;30 days were added to the persistent Covid-19 cases. Results One hundred eleven patients were included. Thirty days after admission for Covid-19, 24 patients had died, 55 had been definitively discharged from hospital, 31 were still hospitalized and 1 was later rehospitalized for Covid-19 recurrence. The incidence of persistent Covid-19 was 32/111 (29%). Patients with persistent Covid-19 had a median age of 64 years (range, 43-87) and 63% were male. Twenty-two patients (69%) had at least one significant comorbidity. None of the patients with T-cell (n=8) lymphoma or classical Hodgkin’s disease (n=8) experienced persistent Covid-19. In the 32 patients with persistent Covid-19, the median time between first admission and final discharge was 58 days (range, 31-235) and the median duration of Covid-19 symptoms was 83 days (range, 32-237). Eight patients received corticosteroids and 9 convalescent plasma: all patients recovered from their symptoms, except one. Overall, 9 patients with persistent Covid-19 died (27%). After a median follow-up of 191 days (range, 3-260), the 6-month overall survival was 69% (95% CI 60-78%) for the whole cohort. In multivariate analysis, administration of anti-CD20 monoclonal antibody within 12 months before admission to hospital for Covid-19 was both associated with decreased overall survival (HR 2.13, 95% CI 1.03-4.44, p = 0.043) and prolonged in-hospital stay (HR 1.97, 95% CI 1.24-3.13, p = 0.004). The two other significant factors associated with decreased overall survival and prolonged in-hospital stay: age ≥ 70 years and refractory or relapsed lymphoma. Conclusion Patients with B-cell non-Hodgkin lymphoma hospitalized for Covid-19 have a high incidence of prolonged evolution of SARS-CoV-2 infection. Administration of anti-CD20 therapy within the last 12 months is one of the main risk factors for longer in-hospital stay and death of Covid-19. The risk of persistent Covid-19 was also higher in patients older than 70 years or with refractory or relapsed disease. These findings may contribute to guide the management of lymphoma patients during the Covid-19 pandemic.

Citation Format: Sylvain Lamure, Remy Dulery, Marc Delord, Roberta Di Blasi, Adrien Chauchet, Thomas Hueso, Cédric Rossi, Bernard Drenou, Bénédicte Deau-Fischer, Carole Soussain, Pierre Feugier, Nicolas Noel, Sylvain Choquet, Serge Bologna, Bertrand Joly, Laure Philippe, Milena Kohn, Sandra Malak, Guillemette Fouquet, Etienne Daguindau, Sophie Bernard, Yassine Taoufik, Karine Lacombe, Guillaume Cartron, Catherine Thieblemont. High incidence of persistent COVID-19 among patients with lymphoma treated with B-cell depleting immunotherapy [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2021 Feb 3-5. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(6_Suppl):Abstract nr S09-02.

Plasmacytoid dendritic cells proliferation associated with acute myeloid leukemia: phenotype profile and mutation landscape

Neoplasms involving plasmacytoid Dendritic Cells (pDCs) include Blastic pDC Neoplasms (BPDCN) and other pDC proliferations, where pDCs are associated with myeloid malignancies: most frequently Chronic MyeloMonocytic Leukemia (CMML) but also Acute Myeloid Leukemia (AML), hereafter named pDC-AML. We aimed to determine the reactive or neoplastic origin of pDCs in pDC-AML, and their link with the CD34+ blasts, monocytes or conventional DCs (cDCs) associated in the same sample, by phenotypic and molecular analyses (targeted NGS, 70 genes). We compared 15 pDC-AML at diagnosis with 21 BPDCN and 11 normal pDCs from healthy donors. CD45low CD34+ blasts were found in all cases (10-80% of medullar cells), associated with pDCs (4-36%), monocytes in 14 cases (1-10%) and cDCs (2 cases, 4.8-19%). pDCs in pDC-AML harbor a clearly different phenotype from BPDCN: CD4+ CD56- in 100% of cases, most frequently CD303+, CD304+ and CD34+; lower expression of cTCL1 and CD123 with isolated lymphoid markers (CD22/CD7/CD5) in some cases, suggesting a pre-pDC stage. In all cases, pDCs, monocytes and cDC are neoplastic since they harbor the same mutations as CD34+ blasts. RUNX1 is the most commonly mutated gene: detected in all AML with minimal differentiation (M0-AML) but not in the other cases. Despite low number of cases, the systematic association between M0-AML, RUNX1 mutations and an excess of pDC is puzzling. Further evaluation in a larger cohort is required to confirm RUNX1 mutations in pDC-AML with minimal differentiation and to investigate whether it represents a proliferation of blasts with macrophage and DC progenitor potential.

Determinants of outcome in Covid-19 hospitalized patients with lymphoma: A retrospective multicentric cohort study

BACKGROUND

Patients with lymphoma are immunocompromised because of the disease per se and its treatments. We aimed to describe the characteristics of patients with lymphoma hospitalized for Coronavirus Disease 2019 (Covid-19) and to analyze pre-Covid-19 determinants of mortality.

METHODS

This retrospective multicentric cohort study used the Programme de Médicalisation des Systèmes d'Information database to identify all adult patients with lymphoma, hospitalized for Covid-19 in March and April 2020, in 12 hospitals of three French regions with pandemic outbreaks. The characteristics of lymphoma and Covid-19 were collected from medical charts.

FINDINGS

Eighty-nine patients were included. The median age was 67 years (range, 19-92), 66% were male and 72% had a comorbidity. Most patients had B-cell non-Hodgkin lymphoma (86%) and had received a lymphoma treatment within one year (70%). With a median follow-up of 33 days from admission, 30-day overall survival was 71%, (95% confidence interval, 62-81%). In multivariable analysis, having an age ≥ 70 years (hazard ratio 2·87, 1·20-6·85, p = 0·02) and relapsed/refractory lymphoma (hazard ratio 2·54, 1·14-5·66, p = 0·02) were associated with mortality. Recent bendamustine treatment (n = 9) was also pejorative (hazard ratio 3·20, 1·33-7·72, p = 0·01), but was strongly associated with relapsed/refractory lymphoma. Remarkably, 30-day overall survival for patients < 70 years of age without relapsed/refractory lymphoma was 88% (78% - 99%).

INTERPRETATION

Thirty-day mortality was associated with being older and relapsed/refractory lymphoma. Survival of patients younger than 70 years without relapsed/refractory lymphoma was comparable to that of the general population.

FUNDING

There have been no specific funds to run this study.

Multicentric MFI30 study: Standardization of flow cytometry analysis of CD30 expression in non-Hodgkin lymphoma

CD30 transmembrane receptor, a member of the tumor necrosis factor receptor family, is expressed in different lymphomas. Brentuximab vedotin (BV), a CD30 monoclonal antibody (Ab)-drug conjugate, is effective in CD30-positive lymphomas. However, the response to BV is not always correlated to CD30 expression detected by immunohistochemistry (IHC). The objectives of this study were to standardize and evaluate CD30 intensity by flow cytometry (FCM) in non-Hodgkin's lymphomas. Twelve centers analyzed 161 cases on standardized cytometers using normalized median fluorescence intensity (nMFI30) of three different Abs, of which one clone can recognize the same epitope as BV. FCM distinguished four groups of cases: negative group (n = 110) which showed no expression with the three clones; high positive group (n = 13) which gave nMFI30 > 5% with all tested clones; dim positive group (n = 17) which showed nMFI30 > 1% with all tested clones and <5% for at least one; discordant group (n = 21) with positive and negative expression of the different clones. In consistency with the literature, CD30 was positive in all anaplastic large cell lymphomas, in some diffuse large B-cell lymphomas (DLBCL), and in other rare lymphomas. FCM results were concordant with those of IHC in 77% of cases. Discrepancies could be explained by clones-related differences, microenvironment, or intracytoplasmic staining. Interestingly, FCM was more sensitive than IHC in 11% of cases, especially in DLBCL. Multicenter standardized FCM of specific CD30 could improve case detection and extend the treatment of BV to various CD30-positive lymphomas.

Macrophage Activation in COVID-19 Patients in Intensive Care Unit

We report six cases of patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, admitted to intensive care unit (ICU), for whom bone marrow aspirate revealed hemophagocytosis. We compared their clinical presentation and laboratory findings to those that can be encountered during a hemophagocytic lymphohistiocytosis. These observations might evoke a macrophage activation mechanism different from the one encountered in the hemophagocytic lymphohistiocytosis (HLH).

Analysis of a cohort of 279 patients with hairy-cell leukemia (HCL): 10 years of follow-up

In total, 279 patients with hairy-cell leukemia (HCL) were analyzed, with a median follow-up of 10 years. Data were collected up to June 2018. We analyzed responses to treatment, relapses, survival, and the occurrence of second malignancies during follow-up. The median age was 59 years. In total, 208 patients (75%) were treated with purine analogs (PNAs), either cladribine (159) or pentosatin (49), as the first-line therapy. After a median follow-up of 127 months, the median overall survival was 27 years, and the median relapse-free survival (RFS) was 11 years. The cumulative 10-year relapse incidence was 39%. In patients receiving second-line therapy, the median RFS was 7 years. For the second-line therapy, using the same or another PNA was equivalent. We identified 68 second malignancies in 59 patients: 49 solid cancers and 19 hematological malignancies. The 10-year cumulative incidences of cancers, solid tumors, and hematological malignancies were 15%, 11%, and 5.0%, respectively, and the standardized incidence ratios were 2.22, 1.81, and 6.67, respectively. In multivariate analysis, PNA was not a risk factor for second malignancies. HCL patients have a good long-term prognosis. PNAs are the first-line treatment. HCL patients require long-term follow-up because of their relatively increased risk of second malignancies.

The anti-fibrotic role of mast cells in the liver is mediated by HLA-G and interaction with hepatic stellate cells

BACKGROUND & AIMS

We have reported a significant association between HLA-G expression or the number of hepatic mast cells and liver fibrosis. Here, we investigated the role of HLA-G and mast cells in liver fibrosis, focusing, in particular, on interactions between human mast and stellate cells.

METHODS

Human mast cells (HMC cell line, CD34-derived mast cells, or tissue-derived mast cells) were co-cultured with purified human hepatic stellate cells (HSCs), and collagen I production by HSCs was evaluated. Mast cells and HSCs were characterized by immunocytochemistry. Various conditions were tested: different times in direct or indirect contact, presence or absence of cytokines, addition or not of HLA-G, and presence or absence of specific protease inhibitors.

RESULTS

The reciprocal interaction between HSCs and mast cells led to the attraction of mast cells to HSCs in vivo and in vitro, and to a significant decrease in collagen production, at all times of co-culture, following the direct or indirect contact of mast cells with HSCs alone or in the presence of TGF-β, IFN-α or IL-10. We identified the diffusible factors involved in collagen I degradation as mast cell proteases. Moreover, HLA-G expression increased during the co-culture of HSCs and mast cells, with HLA-G acting on both mast cells and HSCs, to enhance collagen I degradation.

CONCLUSIONS

Mast cells play a beneficial, anti-fibrotic role in liver fibrosis, via the HLA-G-mediated decrease of collagen I. These findings are consistent with high levels of cross-communication between mast cells and hepatic stellate cells and the role of HLA-G.

Dyserythropoiesis evaluated by the RED score and hepcidin:ferritin ratio predicts response to erythropoietin in lower-risk myelodysplastic syndromes

Erythropoiesis-stimulating agents are generally the first line of treatment of anemia in patients with lower-risk myelodysplastic syndrome. We prospectively investigated the predictive value of somatic mutations, and biomarkers of ineffective erythropoiesis including the flow cytometry RED score, serum growth-differentiation factor-15, and hepcidin levels. Inclusion criteria were no prior treatment with erythropoiesis-stimulating agents, low- or intermediate-1-risk myelodysplastic syndrome according to the International Prognostic Scoring System, and a hemoglobin level <10 g/dL. Patients could be red blood cell transfusion-dependent or not and were given epoetin zeta 40 000 IU/week. Serum erythropoietin level, iron parameters, hepcidin, flow cytometry Ogata and RED scores, and growth-differentiation factor-15 levels were determined at baseline, and molecular analysis by next-generation sequencing was also conducted. Erythroid response (defined according to the International Working Group 2006 criteria) was assessed at week 12. Seventy patients, with a median age of 78 years, were included in the study. There were 22 patients with refractory cytopenia with multilineage dysplasia, 19 with refractory cytopenia with unilineage dysplasia, 14 with refractory anemia with ring sideroblasts, four with refractory anemia with excess blasts-1, six with chronic myelomonocytic leukemia, two with del5q-and three with unclassifiable myelodysplastic syndrome. According to the revised International Prognostic Scoring System, 13 had very low risk, 47 had low risk, nine intermediate risk and one had high-risk disease. Twenty patients were transfusion dependent. Forty-eight percent had an erythroid response and the median duration of the response was 26 months. At baseline, non-responders had significantly higher RED scores and lower hepcidin:ferritin ratios. In multivariate analysis, only a RED score >4 (P=0.05) and a hepcidin:ferritin ratio <9 (P=0.02) were statistically significantly associated with worse erythroid response. The median response duration was shorter in patients with growth-differentiation factor-15 >2000 pg/mL and a hepcidin:ferritin ratio <9 (P=0.0008 and P=0.01, respectively). In multivariate analysis, both variables were associated with shorter response duration. Erythroid response to epoetin zeta was similar to that obtained with other erythropoiesis-stimulating agents and was correlated with higher baseline hepcidin:ferritin ratio and lower RED score. ClinicalTrials.gov registration: NCT 03598582.

Nationwide survey on the use of eltrombopag in patients with severe aplastic anemia: a report on behalf of the French Reference Center for Aplastic Anemia

Few therapeutic options are available for patients with aplastic anemia who are ineligible for transplantation or refractory to immunosuppressive therapy. Eltrombopag was recently shown to produce trilineage responses in refractory patients. However, the effects of real-life use of this drug remain unknown. This retrospective study (2012–2016) was conducted by the French Reference Center for Aplastic Anemia on patients with relapsed/refractory aplastic anemia, and patients ineligible for antithymocyte globulin or transplantation, who received eltrombopag for at least 2 months. Forty-six patients with aplastic anemia were given eltrombopag without prior antithymocyte globulin treatment (n=11) or after antithymocyte globulin administration (n=35) in a relapsed/refractory setting. Eltrombopag (median daily dose 150 mg) was introduced 17 months (range, 8–50) after the diagnosis of aplastic anemia. At last followup, 49% were still receiving treatment, 9% had stopped due to a robust response, 2% due to toxicity and 40% due to eltrombopag failure. Before eltrombopag treatment, all patients received regular transfusions. The overall rates of red blood cell and platelet transfusion independence were 7%, 33%, 46% and 46% at 1, 3, 6 months and last follow-up. Responses were slower to develop in antithymocyte treatment-naïve patients. In patients achieving transfusion independence, hemoglobin concentration and platelet counts improved by 3 g/dL (interquartile range, 1.4–4.5) and 42×10⁹/L (interquartile range, 11–100), respectively. Response in at least one lineage (according to National Institutes of Health criteria) was observed in 64% of antithymocyte treatment-naïve and 74% of relapsed/refractory patients, while trilineage improvement was observed in 27% and 34%, respectively. We found high rates of hematologic improvement and transfusion independence in refractory aplastic anemia patients but also in patients ineligible for antithymocyte globulin receiving first-line treatment. In conclusion, elderly patients unfit for antithymocyte globulin therapy may benefit from eltrombopag.

Autologous hematopoietic stem cell transplantation in elderly patients (≥ 70 years) with non-Hodgkin's lymphoma: A French Society of Bone Marrow Transplantation and Cellular Therapy retrospective study

INTRODUCTION

Limited data is available on the feasibility of high-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (AHSCT) in elderly patients over 70 years of age with non-Hodgkin's lymphoma (NHL).

MATERIALS AND METHODS

In the setting of the Société Française de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC) group, we retrospectively analyzed 81 consecutive patients with NHL over 70 years of age who received AHSCT.

RESULTS

The median age at AHSCT was 72.3 years [70-80]. Patients' were diagnosed with diffuse large B-cell lymphoma (n=40), follicular lymphoma (n=16), mantle cell lymphoma (n=15), T-cell lymphoma (n=5), and other (n=5). Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI) was 0 in 73% of patients. Main conditionings were BEAM (Carmustine-Etoposide-Cytarabine-Melphalan, n=61) and melphalan alone (n=14). Median delays to reach 0.5×10⁹/L neutrophils and 20 × 10(9)/L platelets were of 12 [9-76] days and 12 [0-143] days, respectively. One hundred day and one year cumulative incidence of NRM was 5.4% and 8.5%, respectively. The main cause of death remains relapse.

CONCLUSION

In conclusion, this study revealed that AHSCT seemed to be acceptable in patients over 70 years of age with NHL. Patient age is not a limiting factor if clinical condition is adequate.

Transdifferentiation of hepatocyte-like cells from the human hepatoma HepaRG cell line through bipotent progenitor

Hepatic tumors, exhibiting mature hepatocytes and undifferentiated cells merging with cholangiocyte and hepatocyte phenotypes, are frequently described. The mechanisms by which they occur remain unclear. We report differentiation and transdifferentiation behaviors of human HepaRG cells isolated from a differentiated tumor developed consecutively to chronic HCV infection. We demonstrate that, in vitro, proliferating HepaRG cells differentiate toward hepatocyte-like and biliary-like cells at confluence. If hepatocyte-like cells are selectively isolated and cultured at high cell density, they proliferate and preserve their differentiation status. However, when plated at low density, they transdifferentiate into hepatocytic and biliary lineages through a bipotent progenitor. In accordance, transplantation of either undifferentiated or differentiated HepaRG cells in uPA/SCID mouse damaged liver gives rise mainly to functional human hepatocytes infiltrating mouse parenchyma. Analysis of the differentiation/transdifferentiation process reveals that: (1) the reversible differentiation fate of HepaRG cells is related to the absence of p21(CIP1) and p53 accumulation in differentiated cells; (2) HepaRG bipotent progenitors express the main markers of in vivo hepatic progenitors, and that cell differentiation process is linked to loss of their expression; (3) early and transient changes of beta-catenin localization and HNF3beta expression are correlated to Notch3 upregulation during hepatobiliary commitment of HepaRG cells.

CONCLUSION

Our results demonstrate the great plasticity of transformed hepatic progenitor cells and suggest that the transdifferentiation process could supply the pool of hepatic progenitor cells. Moreover, they highlight possible mechanisms by which transdifferentiation and proliferation of unipotent hepatocytes might cooperate in the development of mixed and differentiated tumors.

Expression of nine tumour antigens in a series of human glioblastoma multiforme: interest of EGFRvIII, IL-13Ralpha2, gp100 and TRP-2 for immunotherapy

In this study, we investigated the mRNA and protein expression of nine tumour antigens in human glioblastoma multiforme with a view to their possible use in dendritic cell-based immunotherapy. Expression of ALK, EGFRvIII, GALT3, gp100, IL-13Ralpha2, MAGE-A3, NA17-A, TRP-2 and tyrosinase were studied by real-time RT-PCR on frozen tissues using a series of 47 tumour samples from patients with glioblastoma. Results were compared with non-neoplastic brain expression or glioblastoma samples with very low levels of expression near the limits of detection for EGFRvIII and MAGE-A3, as these latter two antigens were not detected in non-neoplastic brain. Tumour antigens showing a 5-fold increase in mRNA expression were considered as positive, and only antigens displaying an mRNA over-expression in a significant number of cases were analysed by immunohistochemistry on paraffin-embedded sections. Using real time RT-PCR, we found EGFRvIII, gp100, IL-13Ralpha2 and TRP-2 to be positive in 64, 38, 32 and 21% of cases, respectively. While we observed no over-expression for ALK, GALT3 and tyrosinase, 3 samples out of 47 were positive for MAGE-3 and 1 sample for NA17-A. More than 25% of tumour cells showed strong protein expression in 13, 34, 85 and 96% of GBM samples for gp100, TRP-2, EGFRvIII and IL-13Ralpha2, respectively. Interestingly, protein expression of at least 3 antigens was observed in 38% of cases. These results point out the importance of EGFRvIII, IL-13Ralpha2 and, to a less extent gp100 and TRP-2, for developing an immunotherapy strategy against glioblastoma.

Administration of rituximab during the first trimester of pregnancy without consequences for the newborn

Rituximab, a chimeric mouse/human monoclonal antibody that binds to the CD20 antigen, is part of current treatment of many B-cell malignancies and several autoimmune diseases. Very few cases of rituximab administration during pregnancy have been described. We report here the case of rituximab administration during the first trimester of pregnancy in a woman with autoimmune hemolytic anemia. No significant effects were observed in B-cell counts or the immune status of the newborn.

Expression of the myeloid-associated marker CD33 is not an exclusive factor for leukemic plasmacytoid dendritic cells

A new entity of acute leukemia coexpressing CD4(+)CD56(+) markers without any other lineage-specific markers has been identified recently as arising from lymphoid-related plasmacytoid dendritic cells (pDCs). In our laboratory, cells from a patient with such CD4(+)CD56(+) lineage-negative leukemia were unexpectedly found to also express the myeloid marker CD33. To confirm the diagnosis of pDC leukemia despite the CD33 expression, we demonstrated that the leukemic cells indeed exhibited pDC phenotypic and functional properties. In 7 of 8 other patients with CD4(+)CD56(+) pDC malignancies, we were able to confirm that the tumor cells expressed CD33 although with variable expression levels. CD33 expression was shown by flow cytometry, reverse transcriptase-polymerase chain reaction, and immunoblot analysis. Furthermore, CD33 monoclonal antibody stimulation of purified CD4(+)CD56(+) leukemic cells led to cytokine secretion, thus confirming the presence of a functional CD33 on these leukemic cells. Moreover, we found that circulating pDCs in healthy individuals also weakly express CD33. Overall, our results demonstrate that the expression of CD33 on CD4(+)CD56(+) lineage-negative cells should not exclude the diagnosis of pDC leukemia and underline that pDC-specific markers should be used at diagnosis for CD4(+)CD56(+) malignancies.

Cytochrome P450-dependent toxicity of environmental polycyclic aromatic hydrocarbons towards human macrophages

Polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene (BP) are potent immunosuppressive environmental contaminants acting on lymphocytes and monocytes. To establish whether differentiated macrophages, which play a crucial role in innate and acquired immunity, can also constitute major cellular targets, we have characterized PAH effects towards primary human macrophages. BP-treatment was found to dramatically alter their functional capacities and to trigger a caspase- and mitochondrion-related apoptosis, associated with down-regulation of the survival factors c-FLIP(L) and Bcl-X(L) and up-regulation of the pro-apoptotic factor p53. Such deleterious effects were associated with BP metabolite production, whose inhibition by the cytochrome P-450 1A1 inhibitor alpha-naphthoflavone fully abolished BP toxicity. In contrast to BP, the related halogenated arylhydrocarbon 2,3,7,8-tetrachlorodibenzo-p-dioxin, known to be poorly metabolized if any, only minimally affected macrophages. Overall, these data provide evidence for a cytochrome P-450-dependent toxicity of PAHs towards human differentiated macrophages, which may contribute to their immunosuppressive effects.

Quinine as a multidrug resistance inhibitor: a phase 3 multicentric randomized study in adult de novo acute myelogenous leukemia

Based on our previous demonstration that quinine could be used clinically to reverse P-glycoprotein-mediated resistance, we designed a multicenter, randomized trial aiming to determine whether quinine would improve the survival of adult patients (15-60 years old) with de novo acute myelogenous leukemia (AML). These patients randomly received (n = 213) or did not receive (n = 212) a 30 mg/kg/day continuous intravenous infusion of quinine in combination with induction chemotherapy combining idarubicine and cytarabine and, depending on bone marrow examination at day 20, an additional course of cytarabine and mitoxantrone. The mean steady-state quinine concentration was 7.8 mg/L and the mean multidrug resistance reversing activity of serum was 1.96. Complete remission (CR) was obtained in 344 patients (80.9%) without significant influence of quinine. Of the patients in complete remission, 82 were assigned to receive HLA-matched bone marrow transplants, whereas 262 were assigned to 2 courses of intensive consolidation chemotherapy, with or without quinine, depending on initial randomization. The 4-year actuarial overall survival (OS) of the 425 eligible patients was 42.0% +/- 2.5%, without significant influence of quinine. Of 160 patients who could be studied, 54 demonstrated rhodamine 123 efflux. In these patients, quinine significantly improved the CR rate from 12 of 25 (48.0%) to 24 of 29 (82.8%) (P =.01). However, there was no significant difference in OS. Neither mdr1 gene nor P-glycoprotein expression influenced the outcome. We conclude that quinine does not improve the survival of adult patients with de novo AML, even though it improves CR rate in a small subgroup of patients defined by rhodamine 123 efflux.

Injection by various routes of melanoma antigen-associated macrophages: biodistribution and clinical effects

Patients' autologous macrophages (AM) were used as antigen-presenting cells (APC) in a vaccination protocol against malignant melanoma. AM were administered by various routes, including intralymphatic, since these cells did not express CCR7, a molecule required for APC migration to lymph nodes. Seven HLA-A2 patients with metastatic melanoma-two classified as M1 and five as M3-were included in the study. AM were produced from leukapheresis-separated mononuclear cells by 7-day culture with granulocyte-macrophage colony-stimulating factor. After separation by elutriation, AM were frozen in aliquots and subsequently thawed at monthly intervals, exposed to MAGE-3(271-279) peptide and injected subcutaneously into lymph nodes or into one peripheral lymph vessel. Intradermal tests were performed before and after treatment to determine peptide reactivity. No acute toxicity was observed following injection. One M1 patient had a 7-mm induration intradermal reaction response and was stabilized for 64 weeks. The M3 patients did not show any immunological or clinical response. In 11 patients, the biodistribution of 111In-labeled AM was investigated. There was no clear evidence that AM injected intradermally or subcutaneously left the site of injection. After injection into a lymph vessel of the foot region, scintigraphs showed five to ten popliteal and inguinocrural lymph nodes. This appeared to be the most efficient way to administer rapidly and safely large amounts of peptide-loaded APC into lymph nodes.

Potassium antimonyl tartrate induces caspase- and reactive oxygen species-dependent apoptosis in lymphoid tumoral cells

The metalloid salt potassium antimonyl tartrate (PAT), previously used as an antiparasitic agent, has recently been shown to exert cytotoxicity towards acute promyelocytic leukaemia cells like arsenical compounds. In this study, we have investigated its effects towards human lymphoid malignant cells and compared them with those of arsenic trioxide (As2O3). Like As2O3, PAT was found to inhibit cell growth of various lymphoid cell lines, deriving from either acute lymphoid leukaemias (Jurkat, Molt-4 and Nalm-6) or lymphomas (Daudi, Raji and Rec1). PAT toxicity was linked, at least in part, to induction of apoptosis in both Daudi and Jurkat cells, which was dependent on caspase activity. This apoptotic process was also associated, similarly to that triggered by As2O3, with loss of mitochondrial potential and enhanced cellular production of reactive oxygen-related species. It was enhanced by co-treatment with the pro-oxidant buthionine sulphoximine and abolished in response to the antioxidant N-acetylcysteine, thus underlining that PAT toxicity, similarly to that of As2O3, is probably modulated by the redox status of the cells. PAT, used at concentrations in the micromolar range that are thought to be clinically achievable, was also demonstrated to markedly decrease the viability of primary cultured tumoral B cells that originated from 18 patients suffering from chronic lymphoid leukaemia whereas normal lymphocytes were less sensitive. These data therefore suggest that PAT may deserve to be evaluated in the treatment of some lymphoid malignancies.

High multidrug resistance protein activity in acute myeloid leukaemias is associated with poor response to chemotherapy and reduced patient survival

Multidrug resistance protein (MRP) activity was investigated in 44 newly diagnosed acute myeloid leukaemia (AML) patients using a functional assay based on efflux of carboxy-2',7'-dichlorofluorescein, an anionic dye handled by both MRP1 and MRP2. Elevated MRP transport was detected in 29% of cases, but was not significantly correlated with sex, age, white blood cell count at diagnosis or karyotype. In contrast, it was associated with secondary AML (P = 0.002), CD34 positivity (P = 0.041) and P-glycoprotein activity (P = 0.01). There was a lower rate of complete remission in MRP-positive patients versus MRP-negative patients (23% versus 81%; P = 0.001); overall survival was also better for MRP-negative patients (P = 0.004). These data indicate a probable role for MRP activity in the clinical outcome of AML.

Treatment of metastatic renal cell carcinoma with activated autologous macrophages and granulocyte--macrophage colony-stimulating factor

Fifteen patients with progressive metastatic renal cell carcinoma were treated with granulocyte-macrophage colony-stimulating factor and intravenous infusions of activated autologous macrophages (AAMs). The latter were prepared from leukapheresis-separated mononuclear cells cultured in the presence of granulocyte-macrophage colony-stimulating factor, exposed to gamma interferon, and submitted to elutriation to separate AAMs. Three intravenous injections of AAMs were performed within a 2-week interval. This treatment cycle was repeated once or twice, in cases of tumor response or stabilization. Ninety-seven preparations containing a mean 3 x 10(9) AAMs were administered and usually well tolerated. One partial response, eight stabilizations and six progressions were observed. The median time to progression and median overall survival time after inclusion were 7 and 9 months, respectively. The cells injected did not accumulate substantially in tumor lesions, as shown by scintigraphic imaging of indium-111-labeled AAMs. Thus, combined granulocyte-macrophage colony-stimulating factor and AAM treatment was well tolerated and resulted in transitory stabilization (n = 8) or partial regression (n = 1) in 9 of 15 patients.

Jumping translocation in acute leukemia of myelomonocytic lineage: a case report and review of the literature

Jumping translocation (JT) is a very rare cytogenetic event, occurring especially in cancer. We describe a case of secondary acute monocytic leukemia (AML5b) with a JT involving the 3q13-3qter segment and leading to a partial trisomy 3. Each clone with JT was associated with trisomy 8 or tetrasomy 8. The literature of JT in AML cases is reviewed: only 13 cases of AML associated with JT have been previously described, seven of which are AML4/5 FAB subtype. Jumping translocation involvement in leukemogenesis is discussed. Leukemia (2000) 14, 119-122.

Use of the anionic dye carboxy-2',7'-dichlorofluorescein for sensitive flow cytometric detection of multidrug resistance-associated protein activity

Multidrug resistance-associated protein (MRP) and P-glycoprotein are drug efflux pumps conferring multidrug resistance to tumor cells and sharing numerous substrates. In order to determine a flow cytometric assay allowing to analyse MRP activity in cancerous cells in a sensitive and specific manner, cellular accumulation and efflux of the anionic fluorescent dye carboxy-2',7'-dichlorofluorescein (CDF) were studied by flow cytometry using mainly MRP-overexpressing lung GLC4/Sb30 cells and parental GLC4 cells. GLC4/Sb30 cells were found to display reduced accumulation and enhanced efflux of the dye when compared to their parental counterparts. Probenecid, a well known blocker of MRP, strongly enhanced CDF accumulation in GLC4/Sb30 cells through inhibiting efflux of the dye; it also increased CDF levels in GLC4 cells, although to a lesser extent, which may likely be linked to the low, but detectable, expression of MRP in these cells. Comparison of CDF retention with that of calcein demonstrated that the former dye was the most efficiently effluxed by GLC4/Sb30 cells. In contrast to MRP overexpression, that of P-glycoprotein was not found to alter cellular CDF labelling whereas it strongly impaired calcein staining. These results indicate that CDF is a substrate for MRP, but not for P-gp, which may likely be useful for sensitive and specific flow cytometric determination of MRP activity in clinical samples.

HLA-G protein expression is not induced during malignant transformation

To evaluate the biological relevance of HLA-G expression during tumoral transformation, we analyzed its expression in different malignant cells and immune effector cells infiltrating solid tumors. Our analysis of 33 tumor cell lines and 53 tumoral biopsies demonstrated that: i) six tumor cell lines display HLA-G transcription with differential alternative splicing patterns and only Jeg3 choriocarcinoma and MCF-7 breast adenocarcinoma cell lines express HLA-G translated products; and ii) HLA-G antigens are not expressed in malignantly transformed cells derived from lung (n=18), liver (n=5), colon (n=5), breast (n=10), kidney (n=5), ovary (n=5), and larynx (n=5) tissues ex vivo. The healthy tissues surrounding these tumor tissues do not express HLA-G molecules either. On the other hand, surprisingly, HLA-G products were detected in activated macrophages and dendritic cells localized in tumoral biopsies of 5 out of 18 different lung carcinomas. No HLA-G labelling was observed in resident mononuclear phagocytes of surrounding healthy tissues. Our observations clearly demonstrate that HLA-G is not a marker of malignant cells but appears as a gene expressed in tumor-associated macrophages and dendritic cells, preferentially in those recruited in lung carcinomas. Our findings suggest that specific environmental factors around lung tumors could be involved in the induction of HLA-G protein expression.

Multidrug resistance analysis in lymphoproliferative disease of large granular lymphocytes

Multi-drug resistance (MDR) phenotype contributes to the ineffectiveness of chemotherapy. P-glycoprotein (PgP) and lung resistance protein (LRP) are proteins implicated in chemoresistance. We analysed the expression of PgP and LRP respectively in 17 and 15 cases of lymphoproliferative disease of granular lymphocytes (LDGL) including 10 cases of clonal large granular lymphocytic (LGL) leukaemia, six cases of oligoclonal (n = 5) and polyclonal (n = 1) CD3+ lymphoproliferation and one case of CD3- NK lymphocytosis. Functional PgP activity, as determined by Rh123 dye efflux assay, was found in all the patients. The mean percentage of effluxing cells was 47 +/- 22%, compared to 35 +/- 8% on normal lymphocytes (P<0.04). The efflux was blocked in the presence of verapamil, a PgP revertant agent. A high proportion of CD57+ cells (66 +/- 10%) from these patients expelled Rh123. Functional PgP activity was associated with expression of MDR1 mRNA. By using immunocytochemistry, LRP expression was detected in 11/15 patients (73%). 7/10 LGL leukaemia patients presented a LRP+/Efflux+ phenotype and 5/7 had LRP+/Efflux+/MDR1 mRNA+ phenotype. These findings suggest that the PgP+/LRP+ phenotype is frequently observed in LDGL. Its clinical relevance in aggressive cases remains to be determined.

Loss of HLA molecules in B lymphomas is associated with an aggressive clinical course

Major histocompatibility complex class I molecule expression is reduced in some malignant tumours permitting escape from immune surveillance and is therefore associated with a poor prognosis. Seven cases of non-Hodgkin lymphomas out of 300 cases of malignant lymphoproliferative disorders totally lacked expression of class I molecules as determined by flow cytometry. Clinical data confirmed a particular aggressiveness of these cases with frequent extra-nodal involvement, a poor international prognostic index, a histological high grade and a poor outcome leading to early death in five of the seven cases. A previous diagnosis of follicular lymphoma characterized by bcl-2 rearrangements was made in four of these cases. HLA-G (class Ib gene), which is reported to bind killer inhibitory receptors on NK cells, was absent from the cell surface. However, it was detected in three out of four cases at the mRNA level with transcripts encoding soluble forms. Additional analysis revealed other abnormalities: class II was negative in four out of the seven NHL cases and decreased expression of beta2 microglobulin was observed in all cases. Peptide transporter proteins (TAP1) were detected in various degrees by immunocytochemistry. These observations showed that total lack of class I or class II molecules is a rare event in NHL and is associated with a poor prognosis. This could support a role for specific autologous T cells in immune surveillance.

Differential expression and activity of P-glycoprotein and multidrug resistance-associated protein in CD34-positive KG1a leukemic cells

CD34+ acute myeloid leukemias generally respond poorly to chemotherapy when compared to CD34- myeloid leukemias. In order to contribute to the analysis of the mechanisms involved in this drug resistance, expression and activity of P-glycoprotein (P-gp) and multidrug resistance-associated protein (MRP), two drug efflux pumps conferring multidrug resistance, have been investigated in the CD34+ KG1a leukemic myeloid cell line and in two CD34- K562 and HL60 leukemic myeloid cell lines. Reverse transcription-polymerase chain reaction and dye efflux assays revealed that KG1a cells express P-gp but not MRP whereas neither P-gp nor MRP were detected in K562 and HL60 cells. In addition, KG1a cells were demonstrated to display resistance to anticancer drug substrates for P-gp such as vincristine and daunorubicin and to poorly accumulate vincristine. These results indicated that P-gp, in contrast to MRP, is expressed and functional in the drug-resistant CD34+ KG1a cell line, that may constitute a useful cellular model to analyze the constitutive chemoresistance of CD34+ acute myeloid leukemias.

Multicentric evaluation of the MDR phenotype in leukemia. French Network of the Drug Resistance Intergroup, and Drug Resistance Network of Assistance Publique-Hôpitaux de Paris

The wide discrepancies in the frequency of 'positive' samples for multidrug resistance (MDR) phenotype within the same type of tumor observed in the literature justified the need for the definition of consensus recommendations. To define standard techniques of MDR phenotype measurement, we ran a large multicentric evaluation of the different methods available. Thirty-six French centers participated in the study, and 742 samples of 2-10 x 10(6) viable cells were sent by overnight express mail between December 1993 and February 1996. The same batches of MRK16, 4E3 and UIC2 were used. Nineteen samples of leukemia (12 AML, 1 ALL, 6 lymphoproliferative syndromes) and six leukemic cell lines with different levels of MDR expression were tested. Five meetings reached agreement concerning the guidelines for each technique, except immunocytochemistry. The 19 fresh samples were tested by each center using one to four techniques among cytofluorometry, immunocytochemistry, functional tests and RT-PCR. Five samples were diagnosed as 'negative' according to local criteria, with few discordant results (0 to 16% of 'positive' results). For all the 14 remaining samples, large discrepancies were observed from center to center, and from one technique to another. No correlations could be found between techniques. Flow cytometric analysis of cells already exposed to MRK16 or control IgG2A, fixed in paraformaldehyde and sent to centers did not reduce the discrepancies between centers in two of the four samples with moderate expression, emphasizing the role of histogram interpretation. The use of alternative monoclonal antibodies (4E3 and UIC2) did not reduce the discrepancies observed. In a second step, the K562 parental cell line, a low resistant subline (K562/HHT100, x7 resistance index to DNR) and a high resistant subline (K562/HHT300, x125 resistance index to DNR) were sent blindly three times, with an increasing level of recommendations for flow cytometry. Dramatic improvements were observed in cytometric results when the result was expressed as the ratio of arithmetic mean of fluorescence of antibody (10 microg of MRK16)/arithmetic mean of fluorescence of control (10 microg IgG2A): the proportion of expected results increased from 61 to 100% for K562, and from 37 to 85% for K562/HHT100. For uptake and drug efflux measurements, the use of 1 h uptake of 0.1 microM of rhodamine, followed by 1 h efflux +/-10 microM of verapamil, permitted an increased reproducibility of the technique from 71 to 100% for K562 and K562/HHT100. Whatever the technique used, concordant results were obtained for K562/HHT300. The immunocytochemistry, using several antibodies (MRK16, JSB1 and C219) gave many non-interpretable results (44%), due to a frequent high background and discordant results between antibodies in the same centers, and discordant conclusions between centers. The group does not recommend this technique for circulating tumoral cells.

CpG methylation patterns in the 5' part of the nonclassical HLA-G gene in peripheral blood CD34+ cells and CD2+ lymphocytes

A dominant goal of research focused on the nonclassical human leukocyte antigen G (HLA-G) gene is to understand the molecular mechanism involved in its limited expression. In the present report, we examined DNA methylation as a potential regulatory mechanism of HLA-G transcription in two cell types of the adult lymphomyeloid lineage: CD2+ lymphocytes express several mRNA isoforms while transcripts are undetectable in CD34+ hematopoietic cells. The methylation status of 63 CpG sites in the promoter and in the 5' CpG island was established using bisulfite-treated genomic DNA sequencing. Methylation was first analyzed by the direct sequencing of bisulfite-treated and amplified products. The general patterns of CpG methylation in the 5' part of the gene were found to be similar for CD34+ cells and CD2+ lymphocytes: the distribution of methylation was not uniform across the 63 CpG sites. In the promoter region, both CpG dinucleotides were partially or fully methylated whereas in the CpG island, several CpG sites were totally demethylated. Unexpectedly, in HLA-G positive CD2+ lymphocytes, a great number of CpG dinucleotides displayed a higher frequency of methylation relative to that found in CD34+ cells. However, the sequence analysis of cloned products revealed that the molecules have different methylation patterns which suggests that the HLA-G gene is differentially expressed in CD2+ cells. Our results suggest that methylation is not the sole mechanism that achieves the repression of HLA-G transcription in immature CD34+ cells.

Inapparent polycythemia vera: an unrecognized diagnosis

PURPOSE

The Polycythemia Vera Study Group (PVSG) has established useful criteria for the diagnosis of polycythemia vera. In some circumstances, an increase of plasma volume (PV) masks that of red cell mass (RCM), with hemoglobin (Hb) and hematocrit (Ht) remaining normal. This defines the concept of inapparent polycythemia.

PATIENTS AND METHODS

One hundred and three patients seen in the hematology unit with the diagnosis of polycythemia vera were studied. There were 55 males and 48 females with a median age of 59 years. Ninety-five patients fulfilled the PVSG criteria. Spontaneous erythroid colonies and low serum erythropoietin level confirmed the diagnosis in the 8 other cases. Patients were classified according to Hb and Ht level.

RESULTS

Group A consisted of 85 patients with increased Hb and Ht defined, respectively, by Hb > 18 g/dl, Ht > 0.52 in males and Hb > 16 g/dL, Ht>0.47 in females. Group B included 18 patients (17%) with inapparent polycythemia vera (IPV) defined by a normal Hb and Ht value at diagnosis. In this group, the reasons to perform RCM were as follows: splenomegaly associated with increased platelets and/or leucocytes counts (n = 8), portal vein thrombosis (n = 5), increased platelets or leucocytes counts without splenomegaly (n = 3), and isolated splenomegaly (n = 2). The two groups were balanced in terms of age, sex, leucocyte, serum iron, and platelet level. Hemoglobin and Ht levels were significantly different between the two groups. The difference between the PV was indeed highly significant. The mean PV increase was + 9.5% (nL < +20%) in group A versus + 36.3% in group B (P < 0.00005). Red cell mass was not different between the two groups.

CONCLUSIONS

Increased Hb or Ht should constitute the sole criteria for RCM determination. In the context of portal vein thrombosis, isolated hyperleucocytosis, thrombocytosis, or splenomegaly, a RCM should be performed. The frequency of IPV remains to be specified but the diagnosis of polycythemia vera is probably underestimated.

Inhibition of P-glycoprotein activity in human leukemic cells by mifepristone

The antiprogestatin drug mifepristone has previously been shown to potentiate anti-cancer drug activity in rodent multidrug-resistant cell lines through inhibition of P-glycoprotein (P-gp) function. In order to characterize P-gp-mifepristone interactions in human tumoral cells, we have studied the effect of the antiprogestatin agent on P-gp activity in human CD34+ leukemic cells known to display high levels of P-gp-related drug efflux. P-gp-mediated transport of the fluorescent dye rhodamine 123 occurring in the CD34+ KG1a myeloid leukemia cell line was found to be strongly inhibited by mifepristone in a dose-dependent manner. Similarly to verapamil, a well-known chemosensitizer agent, the antiprogestatin drug increased doxorubicin cytotoxicity in KG1a cells. Mifepristone, when used at a 10 microM concentration thought to be achievable in vivo without major toxicity, was also able to markedly decrease cellular rhodamine 123 efflux occurring in CD34+ blast cells isolated from six patients suffering from myeloid acute leukemias. These results thus indicate that mifepristone can strongly inhibit P-gp activity in human cells, including tumoral cells freshly isolated from patients, therefore suggesting that the clinical use of this compound may contribute to down-modulate P-gp-mediated drug resistance.

Internalization of human macrophage surface antigens induced by monoclonal antibodies

Drugs intended to be endocytosed by macrophages may be transported by MAbs directed against these cells. Twenty MAbs were investigated for this purpose. The binding of these MAbs to macrophages obtained from a 7 day culture of blood monocytes showed that anti-CD11b and anti-CD14 recognized the highest number of cell surface antigen sites. Further assays determined that anti-CD63, Mo5 and anti-CD33 were the MAbs that induced the strongest modulation of the corresponding antigens, the highest rate being with anti-CD63. Endocytosis of antigen-antibody complexes was evidenced by the presence of MAbs in the cytoplasm. Anti-CD63 MAbs induced the highest internalization in this assay. For most MAbs, however, the density of antigen sites and the intensity of antigen modulation were not predictive of the amount of MAb detected in the cytoplasm.

Quantification and molecular analysis of plasmatic HLA-BCw molecules with a locus B and Cw HLA specific mAb (B1.23.2 mAb)

Plasmatic HLA class I molecules were analysed quantitatively and qualitatively with a B and Cw locus-specific mAb, B1.23.2. sHLA-BCw were detected among all individuals with a wide range of concentration. The HLA-A29(19) allele was significantly associated with an increased sHLA-BCw mean concentration. Three different isoforms of relative molecular weights of 44, 39 and 36kDa were detected. The 39 kDa class I heavy chain was not detected after immunoprecipitation with mAb B1.23.2 in 17% of tested plasma, but was immunoprecipitated with W6/32 mAb.

Multi-drug resistance (MDR) activity in acute leukemia determined by rhodamine 123 efflux assay

We prospectively analyzed MDR functional activity by the Rh123 efflux assay in 84 de novo acute leukemias. Thirty of the 60 AML cases (50%) showed a positive dye efflux (in more than 10% of blast cells). In 19 cases, the dye efflux was superior to 30%. Twenty-four of the 30 efflux positive cases were CD34+ and could be studied in double staining. The mean percentage of effluxing CD34+ blast cells was 54%. There was a high correlation between CD34 expression and MDR activity (P < 10(-4)), MDR activity and PgP expression (P < 10(-6)). All the efflux negative samples were PgP negative. Nine efflux positive cases were PgP negative. Five of the 24 ALL were efflux positive. MDR activity did not correlate with FAB subtype (with the exception of AML3: 1/6 was efflux positive), age, white blood cell count or LDH level. Forty-seven AML patients were treated with conventional chemotherapy including cytarabine and an anthracycline. Thirty-one (66%) entered complete remission (CR). CR rate was statistically lower for efflux positive as compared to efflux negative patients, 46 vs 87% (P = 0.003), for PgP+ as compared to PgP- patients, 40 vs 78% (P = 0.01), for CD34+ as compared to CD34- patients, 45 vs 84% (P = 0.005). There was no correlation between P110 expression (32 AML cases studied) and FAB subtype, MDR status and clinical outcome. Two years survival was 20% for efflux positive patients as compared to 54% for efflux negative patients (P < 0.07), 15% for PgP+ vs 54% for PgP- patients (P < 0.04). The finding of efflux+/PgP- cases suggests the existence of other membrane efflux pumps. Rh123 efflux assay is straightforward in routine and could be included in MDR screening because of its potential interest in clinical outcome in AML.

Expression of p-glycoprotein in multidrug-resistant human leukemia k562 cells during erythroid-differentiation

Expression of P-glycoprotein (P-gp), the multidrug resistance gene product, has previously been shown to be downregulated during differentiation of normal haematopoietic cells. In order to determine whether such a regulation also occurs in leukemic cells, we have investigated the relevance of differentiation levels to P-gp expression in multidrug-resistant leukemia K562R/7 cells and in parental drug-sensitive K562 cells. These leukemic cells were exposed to hemin and sodium butyrate, two known inducers of erythroid differentiation. Analysis of hemoglobin-synthesizing cells indicated that hemin induced both K562R/7 and K562 cells to differentiate into erythroid cells while sodium butyrate led to hemoglobin synthesis in only K562 cells. Northern blotting and immunolabelling experiments revealed elevated levels of MDR1 mRNAs and P-gp in both untreated and hemin-treated K562R/7 cells while P-gp expression was not detected in both uninduced and hemin-induced K562 cells. Flow cytometric analysis of cellular doxorubicin retention demonstrated that K562R/7 cells poorly accumulated the anticancer drug regarless their level of differentiation. These results therefore suggest that erythroid differentiation of leukemic drug-resistant K562R/7 cells in response to hemin treatment did not result in major alteration of P-gp expression and activity.

Multidrug resistance in B-cell chronic lymphocytic leukemia

Multidrug resistance (MDR) was investigated in peripheral blood cells isolated from 40 patients with B cell chronic lymphocytic leukemia (B-CLL) and from 7 healthy volunteers, using a flow cytometric assay that detects cellular efflux of the fluorescent dye rhodamine 123 (Rh 123), which has been demonstrated to be transported from the cell by the P-glycoprotein pump. The proportion of B leukemic cells effluxing Rh 123 and thus displaying MDR was low (14 +/- 17%) in B-CLL and in only 4 cases did the contingent of B leukemic cells showing MDR represent more than 30% of the total leukemic cells. In contrast, a higher proportion of cells effluxing Rh 123 (44 +/- 13%) was demonstrated in normal B lymphocytes. No statistical correlation was found between the number of leukemic B cells displaying MDR and clinical parameters or previous treatment. These results clearly suggest that MDR activity is usually low in B-CLL.

Plasmacytoid CD8 lymphoma: morphologic and immunologic characterization

This study describes a 79 year-old female suffering from fever and lymphadenopathy. A lymph node biopsy showed diffuse infiltration of medium-sized cells with plasmacytoid features. The immunologic phenotype determined by cytometric analysis and immunochemistry showed suppressor T antigen (CD2, CD3, CD7, CD8) expression. Absence of CD5 expression characterized this abnormal T cell proliferation. Gamma T cell receptor rearrangement without immunoglobulin heavy-chain gene rearrangement confirmed the T lineage of these plasmacytoid cells and their clonality. Immunological studies are necessary for identification of this T lymphoma with B microscopic findings.

Improvement of hematologic recovery after high-dose intensification using peripheral blood progenitor cells (PBPC) mobilized by chemotherapy and GM-CSF

We have tested the efficiency of GM-CSF to mobilize peripheral blood progenitor cells (PBPC) and evaluated the hematological reconstitution after GM-CSF primed-PBPC infusion following myeloablative therapy. Twenty three patients suffering from hematological malignancies were included in this study. Starting 24 hours after completion of a standard dose chemotherapy including vindesine, cyclophosphamide, adriblastine, prednisone, (VCAP), 5 micrograms/kg sub-cutaneous daily dose GM-CSF was given for a median time of 14 days followed by three consecutives cycles of leukapheresis. Fifteen of these 23 patients underwent GM-CSF primed-PBPC autotransplantation following high dosed intensification regimen. PBPC collection and hematopoietic recovery were compared with a 15 patients control group who did not receive GM-CSF. No marrow or growth factors were administered after PBPC reinfusion in the two groups. VCAP/GM-CSF mobilization induced significantly higher yields of CFU-GM (3.8 fold) than did VCAP mobilization alone, 19 x 10(4)/kg (2-73) vs 5 x 10(4)/kg (2-27), (p < 0.005). The median number of days to achieve 1.10(9)/l neutrophils, platelet count > 20.10(9)/l and > 50.10(9)/l was significantly lower in the GM-CSF group than in the control group, respectively 13 vs 19 days (p = 0.04), 15.5 vs 27 days (p < 0.02), 19 vs 51 days (p < 0.01). When compared with the control group, transfusion requirements and median of hospital stay were both significantly decreased for the patients receiving GM-CSF primed-PBPC. Our study confirms that infusion of GM-CSF primed-PBPC as a sole source of hematopoietic support improves hematopoietic reconstitution following myeloablative therapy.