LMO2-associated clonal T cell proliferation in two patients after gene therapy for SCID-X1

We have previously shown correction of X-linked severe combined immunodeficiency [SCID-X1, also known as gamma chain (gamma(c)) deficiency] in 9 out of 10 patients by retrovirus-mediated gamma(c) gene transfer into autologous CD34 bone marrow cells. However, almost 3 years after gene therapy, uncontrolled exponential clonal proliferation of mature T cells (with gammadelta+ or alphabeta+ T cell receptors) has occurred in the two youngest patients. Both patients' clones showed retrovirus vector integration in proximity to the LMO2 proto-oncogene promoter, leading to aberrant transcription and expression of LMO2. Thus, retrovirus vector insertion can trigger deregulated premalignant cell proliferation with unexpected frequency, most likely driven by retrovirus enhancer activity on the LMO2 gene promoter.

Immunological classification of acute lymphoblastic leukaemias: evaluation of its clinical significance in a hundred patients

The use of T and B lymphocyte markers and of different antisera raised against malignant B cells and fetal thymocytes allowed the classification of 100 patients with acute lymphoblastic leukemia (ALL) into three groups. (I) Patients with non-T non-B ALL whose cells were devoid of conventional B and T markers but characterized by a leukaemia associated antigen (69 cases). (2) Patients with T-derived ALL (28 cases). (3) Patients with ALL of B cell origin (three cases). The search for haematological and clinical correlations showed that those patients with T-derived ALL tended to have a higher leucocyte count (P=0.05) and acid phosphatase positivity of blast cells (P= 0.01), a higher incidence of tumour presentation (P=0.05) and a thymic mass. Survival curves for the two main groups of patients are similar at 36 months but meningeal relapses were more frequent in patients with T-derived ALL (P=0.02).

Splenic lymphoma with villous lymphocytes: clinical presentation, biology and prognostic factors in a series of 100 patients. Groupe Francais d'Hématologie Cellulaire (GFHC)

The diagnosis of splenic lymphoma with villous lymphocytes (SLVL) was assessed by a panel of cytologists in a series of 100 patients. Clinical and biological characteristics were analysed in relation to prognosis. SLVL is a chronic B-cell lymphoproliferative disorder characterized by splenomegaly and the presence, in peripheral blood, of lymphocytes with "villous' projections. The cytological diagnosis can be difficult in patients without an absolute lymphocytosis which was observed in 24% of cases. B-cells expressed CD19+, CD20+, CD22+, CD24+ and DBA44+, whereas the expression of CD5, CD10 and CD25 was usually negative. SLVL is a disease of the elderly with a relatively benign clinical course. In the present series the 5-year overall survival was 78%. Deaths in 15 patients were related to disease progression or treatment (nine cases). Patients with a leucocyte count > 30 x 10(9)/1 or lymphocyte count < 4 x 10(9)/1 or initially treated with chemotherapy had significantly (P < 0.001) lower overall survival than other patients. From these findings, treatment abstention should be considered in patients with favourable prognostic factors; on the other hand, the efficacy of conventional chemotherapy remains to be evaluated in patients with unfavourable prognostic factors.

Cytogenetic studies on 519 consecutive de novo acute nonlymphocytic leukemias

Cytogenetic studies were performed in the same laboratory on 519 untreated cases of de novo acute nonlymphocytic leukemia (ANLL) between 1977 and 1985. The overall incidence of clonal chromosome abnormalities was 54.3%; higher in children (67.5%) than in adults (50.4%). The distribution of chromosome abnormalities was uneven, according to the categories of the FAB nomenclature. The highest frequency of chromosome changes was observed in ANLL-M3 and the lowest in M1 and M6. The frequency of specific chromosome abnormalities and of their associated changes were also estimated. Monosomy 7 was detected in three patients with acute megakaryocytic leukemia (M7). Six cases with two abnormal chromosomally unrelated clones were observed and six constitutional chromosome abnormalities were detected. A clearer knowledge of the incidence of various chromosomal changes in ANLL seems necessary for better differentiation between the so-called primary and secondary chromosome abnormalities and for prognostic evaluation.

Transforming growth factor inhibits erythropoiesis by blocking proliferation and accelerating differentiation of erythroid progenitors

Erythropoiesis is positively regulated by stem cell factor, interleukin 3, and erythropoietin, which synergize to allow the production of hemoglobinized red blood cells from erythroid progenitors. In contrast, interferon gamma, tumor necrosis factor alpha, and transforming growth factor B(1), (TGF-beta(1)) are powerful inhibitors of erythropoiesis. Interferon gamma and alpha act principally by inducing apoptosis. The aim of this study was to elucidate the mechanisms by which TGF-beta(1) inhibits erythropoiesis. We used an in vitro serum-free system of human red blood cell production. From a virtually pure population of CD36(+) erythroid progenitors, stem cell factor, interleukin 3, and erythropoietin allowed massive proliferation (x300) and promoted terminal red blood cell differentiation. We show here that TGF-beta(1) (2 ng/mL) inhibited the growth of CD36(+) cells by 15-fold. TGF-beta(1) markedly accelerated and increased erythroid differentiation as assessed by hemoglobin and glycophorin expression. Furthermore, May-Grünwald-Giemsa staining and ultrastructural analysis revealed that TGF-beta(1) induced full differentiation toward normal enucleated red cells even in the absence of macrophages. This acceleration of erythroid differentiation did not modify the pattern of hemoglobin chains expression from adult or fetal erythroid progenitors. Analysis of apoptosis, cell cycle and Ki-67 expression showed that TGF-beta(1) inhibited cell proliferation by decreasing the cycle of immature erythroid cells and accelerating maturation toward orthochromatic normoblasts that are not in cycle. We showed that TGF-beta(1) is a paradoxical inhibitor of erythropoiesis that acts by blocking proliferation and accelerating differentiation of erythroid progenitors.

Sequential chemotherapy by CHOP and DHAP regimens followed by high-dose therapy with stem cell transplantation induces a high rate of complete response and improves event-free survival in mantle cell lymphoma: a prospective study

Mantle cell lymphoma (MCL) is a distinct clinico-pathological entity with a poor prognosis. We have conducted a prospective study in patients with MCL to evaluate a therapeutic strategy in which CHOP polychemotherapy was followed by DHAP if CHOP failed to induce complete remission. Responding patients then proceeded to an intensification therapy with autologous peripheral blood stem cell transplantation (APBSCT). Twenty-eight consecutive patients with newly diagnosed aggressive MCL were included. After four cycles of CHOP regimen, two complete responses (CR) were obtained (7%) and 14 (50%), five (18%) and seven (25%) patients achieved partial (PR), minor (MR) and no response, respectively (one patient died from septic complications during CHOP induction). The two patients in CR after CHOP underwent intensification with TBI, high-dose cyclophosphamide-etoposide and APBSCT. The other twenty-five patients received DHAP and in this group a response rate of 92% (21 CR (84%), two PR (8%)) was observed. Two patients had progressive disease. The twenty-three responding patients received high-dose therapy (TAM8 regimen: TBI-cytarabine-melphalan) followed by APBSCT. One of the two partial responding patients achieved CR after TAM8. After a median follow-up of 47.6 months (range, 14-70), seven patients have relapsed. Our data confirm that: (1) CHOP regimen induces a low CR rate in MCL; (2) CHOP plus DHAP appears to be much more efficient and allows a large proportion of patients to proceed to high-dose therapy in CR; (3) consolidation therapy including TBI and high-dose Arac-C followed by APBSCT may improve event-free survival.

Blastic variant of mantle cell lymphoma: a rare but highly aggressive subtype

The blastic variant (BV) form of mantle cell lymphoma (MCL) is considered to be a very aggressive subtype of non-Hodgkin's lymphoma (NHL). In order to determine its clinico-biological features and response to therapy we studied 33 patients (17%) out of 187 suffering from MCL who were diagnosed with a BV of MCL. Blastic variant was diagnosed according to histopathological patterns, immunophenotyping, and bcl1 gene rearrangement and/or cyclin D1 overexpression. Three patients initially diagnosed with large cell NHL were classified as BV. Patients received front-line therapy including CHOP-like regimen or CVP (n = 29), or chlorambucil (n = 4) and CHOP or ESAP as second-line therapy. High-dose intensification with stem cell transplantation (SCT) was performed in 11 cases (autoSCT, n = 8; alloSCT, n = 3). All but two patients were in complete remission (CR) at the time of transplant (CR1, n = 5; CR2, n = 4). Clinical and biological characteristics did not differ from those of the common form of MCL. The median age was 62 years (29-80), with a sex ratio (M/F) of 2.6:1. Of the 33 patients, 66% had extranodal site involvement, 85% had an Ann Arbor stage IV, and 82% had peripheral lymphadenopathy. Circulating lymphomatous cells were seen in 48% of cases. Twelve patients (36%) entered a CR1 with a median duration of 11 months. Fifteen patients (46%) failed to respond and rapidly died of progressive disease. Second-line therapy led to a 26% (6/23) CR2 rate. Nine patients relapsed after high-dose therapy. Twenty-two of the 33 patients (66%) died of refractory or progressive disease. Median overall survival (OS) time was 14.5 months for the 33 BV patients as compared to 53 months for the 154 patients with a common form of MCL, P <0.0001. In the univariate analysis, OS was influenced by age, extranodal site involvement, circulating lymphomatous cells, and international prognosis index (IPI). In the multivariate analysis, only IPI affected OS: patients with IPI > or =2 had 8 months median OS as compared to 36 months median OS for patients with IPI <2, P = 0.003. Blastic variant is one of the worst forms of NHL. An improved recognition of BV of MCL is required, particularly in high-grade CD5+ NHL using immunophenotyping and bcl1 molecular study. Standard therapy using anthracycline or even high-dose intensification produce poor results and an alternative treatment should be proposed to such patients.

Molecular detection of t(8;21)/AML1-ETO in AML M1/M2: correlation with cytogenetics, morphology and immunophenotype

The t(8;21) identifies a subgroup of acute myeloid leukaemia (AML) with a relatively good prognosis which may merit different treatment. It is associated predominantly, but not exclusively, with AML M2, and corresponds to rearrangements involving the AML1 and ETO genes. AML1-ETO positive, t(8;21) negative cases are well recognized but their incidence is unknown. In order to determine optimal prospective AML1-ETO RT-PCR screening strategies, we analysed 64 unselected AML M1 and M2 cases and correlated the results with other biological parameters. Molecular screening increased the overall detection rate from 8% to 14%. AML1-ETO was found in 3% (1/32) of AML M1 and 25% (8/32) of M2, including three patients without a classic (8;21) but with chromosome 8 abnormalities. It was more common in younger patients. Correlation with morphology enabled development of a scoring system which detected all nine AML1-ETO-positive cases with a false positive rate of 7% (4/55). Although certain AML1-ETO-positive cases demonstrated characteristic immunological features (CD19 and CD34 expression, CD33 negativity), each of these markers was insufficiently specific to permit prediction in an individual case. We conclude that initial routine prospective molecular screening for AML1-ETO in all AMLs, combined with standardized morphological and immunological analysis, is desirable in order to produce improved prognostic stratification and to determine whether screening can ultimately be restricted to appropriate subgroups.

Acute monocytic leukemia chromosome studies

Cytogenetic studies have been performed on 34 acute monocytic leukemia (M5) patients, 24 of the a type and 10 of the b type. No chromosomal abnormalities were found in 12 cases, in spite of the fact that the mitoses concerned monocytes. Different chromosomal aberrations were present in the other cases. In 12 of them, an abnormality of the chromosome 11 long arm was observed (mainly in the poorly differentiated type of M5), on bands q22-q24 in nine cases and on band q14 in three cases. The chromosome 11 long arm thus appears preferentially rearranged in M5 although this is not apparent in every case. Concomitant study of the mitoses with cytological and cytogenetic techniques suggests that erythroblasts may not be involved in the M5 leukemic process.

Prognostic significance of chromosomal abnormalities in acute nonlymphocytic leukemia: a study of 343 patients

Clonal chromosome abnormalities of 343 patients with de novo acute nonlymphocytic leukemia (ANLL) have been tentatively correlated with prognosis. All the patients were treated according to therapeutic protocols in the same hospital. The complete remission rate and median survival were generally lower in AA-ANLL (ANLL with only karyotypically abnormal metaphases) when compared with NN- and AN-ANLL. Similarly, AA-ANLL had the poorest prognosis in the majority of the classes of the French-American-British nomenclature. ANLL with inversion and/or deletion of chromosome #16 had the best prognosis, and ANLL with t(8;21) was not particularly favorable, nor was acute promyelocytic leukemia with t(15;17). ANLL with complex chromosomal abnormalities had the poorest prognosis. The conclusion is that chromosomal aberrations do have a prognostic significance in ANLL, but that this significance is dependent on the types of chromosomal aberrations.

Human herpes virus 8 (Kaposi's sarcoma herpes virus) and malignant lymphoproliferations in France: a molecular study of 250 cases including two AIDS-associated body cavity based lymphomas

The new human herpes virus 8 (HHV8) was recently detected in cases of body cavity based lymphoma (BCBL), a rare B cell lymphoma, mostly AIDS-associated. We investigated for HHV8 DNA sequences a series of 250 B or T cell lymphoproliferative malignancies, as seen in France, including 126 leukemias and 124 lymphomas (232 non-AIDS-associated and 18 AIDS-associated tumors). HHV8 sequences were detected in only three patients. The first two were homosexual males, HIV-infected since 1985 who suffered from a BCBL initially characterized in one case by a pleural lymphomatous effusion and a peritoneal one in the other case. A high level of HHV8 copies was detected in the tumoral cells of these two BCBL. In contrast, in the third positive patient who had an AIDS-associated immunoblastic lymphoma, the HHV8 sequences level was quite low. In the two BCBL patients, the HHV8-infected clonal B cells had a large immunoblastic feature with an indeterminate phenotype and were also infected by Epstein-Barr virus. In one BCBL case, a semiquantitative PCR analysis revealed that the HHV8 sequences were much more abundant in the effusion tumor cells than in the cutaneous Kaposi's biopsy while no HHV8 sequence was detectable in the peripheral blood lymphocytes. This study reports HHV8-associated BCBL in European AIDS patients and confirms that HHV8 is present at a high copy number in the tumoral B cells of this malignancy. Furthermore, HHV8 does not seem to play a pathogenic role in any of the other T or B malignant lymphoid neoplasias studied so far. This study also stresses the necessity for quantification studies in interpretation of a positive PCR analysis for HHV8 sequences, especially in patients at risk for HIV infection or Kaposi's sarcoma.

Genetic analysis of splenic lymphoma with villous lymphocytes: a Groupe Français d'Hématologie Cellulaire (GFHC) study

In order to characterize the genetic diversity in splenic lymphoma with villous lymphocytes (SLVL), we have undertaken cytogenetic and molecular analyses of CCND1 expression and BCL1-IgH PCR rearrangement in 76 cases diagnosed predominantly on morphological criteria. Cytogenetic abnormalities were detected in 19/44 (43%) of cases, including in 16/25 (64%) of cases with an absolute lymphocytosis. Abnormalities included those involving chromosome 14q32 (9/19, 47%), predominantly t(11;14)(q13;q32) (5/19, 26%), chromosome 3 (26%), predominantly 3q, chromosome 17p (26%) and trisomy 12 (3/19, 16%) and were thus suggestive of pathogenetic diversity. CCND1 was expressed in 8/30 (27%) cases, including in all t(11;14) cases, 5/10 (50%) CD5-positive cases and also in 3/20 (15%) CD5-negative cases. Three CCND1-positive SLVL demonstrated immunophenotypic features similar to mantle cell lymphoma (MCL) but the majority differed in their CD5 negativity or CD23 positivity. BCL1-IgH rearrangement was only seen in 1/62 (2%) of cases overall and in none of the t(11;14) cases, which demonstrated FISH breakpoints both centromeric and telomeric to the BCL1/MTC, suggesting that, if genomic clustering exists in t(11;14) SLVL, it differs from MCL. Although CCND1 expressing SLVL more commonly had marked lymphocytosis, they did not demonstrate a more aggressive clinical course than their negative counterparts, demonstrating that the detection of CCND1 expression or of a t(11;14) should not suffice to alter diagnostic classification in the absence of other criteria.

Fludarabine: an effective treatment in patients with splenic lymphoma with villous lymphocytes

Splenic lymphoma with villous lymphocytes (SLVL) is a B cell chronic lymphoproliferative disorder. Splenectomy and/or chlorambucil are usually regarded as the most effective treatment in SLVL patients. However, a few patients relapse and the second-line treatment remains questionable. In a retrospective study, we evaluated the efficacy and toxicity of fludarabine (FDR) in 10 SLVL patients. The median duration between diagnosis and treatment was 17 months (range, 1-30). Two patients were previously untreated. The patients received FDR 25 mg/m2/day by venous infusion for 5 days with a median of four cycles of chemotherapy (range, 2-6). All patients were assessable: five patients achieved a good and persistent response after a median follow-up of 14 months (5-31), two achieved a good response but relapsed after a follow-up of 15 and 36 months. One out of the three partial responders have a persistent response. The treatment was well tolerated. FDR appears to be an efficient therapy with a favorable toxicity profile for patients in relapse after splenectomy or resistant to CLB. Furthermore it could constitute an alternative to splenectomy in older patients. A longer follow-up and the study of a larger group of patients are warranted to confirm our findings.

Rapid, multifluorescent TCRG Vgamma and Jgamma typing: application to T cell acute lymphoblastic leukemia and to the detection of minor clonal populations

Detection of clonal T cell receptor gamma (TCRG) gene rearrangements by PCR is widely used in both the diagnostic assessment of lymphoproliferative disorders and the follow-up of acute lymphoblastic leukaemia (ALL), when residual positivity in excess of 10(-3) at morphological complete remission is increasingly recognised to be an independent marker of poor prognosis. This is largely based on specific detection of V-J rearrangements from childhood cases. We describe rapid, multifluorescent Vgamma and Jgamma PCR typing of multiplex amplified diagnostic samples, as applied to 46 T-ALL. These strategies allow selected analysis of appropriate cases, immediate identification of Vgamma and Jgamma segments in over 95% of alleles, improved resolution and precision sizing and a sensitivity of detection at the 10(-2)-10(-3) level. We demonstrate preferential V-J combinations but no difference in V-J usage between children and adults, nor between SIL-TAL1-negative and -positive cases. A combination of fluorescent multiplex and Vgamma-Jgamma-specific monoplex follow-up, as described here, will allow detection of both significant clonal evolution and of the diagnostic clone at a level of prognostic significance, by techniques which can readily be applied to large-scale prospective studies for which real-time analysis is required.

The majority of myeloid-antigen-positive (My+) childhood B-cell precursor acute lymphoblastic leukaemias express TEL-AML1 fusion transcripts

The t(12:21) translocation fuses the TEL and AML1 genes and has been found in up to 28% of paediatric B-cell precursor acute lymphoblastic leukaemias (BCP-ALL). The AML1 gene is a transcription factor which regulates expression of several myeloid differentiation associated genes. A molecular analysis of TEL-AML1, E2A-PBX1, MLL-AF4, BCR-ABL expression and an immunophenotypic study of CD13/CD33 myeloid antigen expression have been performed prospectively on tumour cells from 96 paediatric BCP-ALL patients. Percentages of CD13 or CD33 expressing leukaemic cells were found to be higher in TEL-AML1 positive cases (n = 22) than in TEL-AML1 negative (n = 74) cases (P<0.001). In 22/96 cases (23%) >10% of neoplastic cells were found to express at least one of the two markers. In 14 of these cases (63%), TEL-AML1 expression was detected, whereas t(4;11), t(11;19) and t(9;22) translocations were found by molecular methods in only three cases (14%). In four cases (18%) no molecular marker was found. These data show that TEL-AML1 expression is significantly associated with myeloid antigen expression by leukaemic cells and suggests that the prognostic significance of myeloid antigen expression in paediatric ALLs should be re-evaluated in the light of molecular cytogenetic markers.

Persistent polyclonal B lymphocytosis with binucleated lymphocytes: a study of 25 cases. Groupe Français d'Hématologie Cellulaire

Persistent and polyclonal lymphocytosis of B lymphocytes (PPBL) with binucleated lymphocytes is an entity characterized by a polyclonal lymphocytosis. The lymphocytosis is stable for years and binucleated lymphocytes are detected on peripheral blood smears. We previously described +i(3q) as a recurrent chromosomal abnormality in seven PPBL patients. In this study we report a large series of 25 PPBL patients and demonstrated that PPBL was associated with +i(3q) in 77% of cases, premature chromosome condensation (PCC) in 50% and both abnormalities in 41% of cases. Furthermore, we demonstrated that i(3q) was present in a minority of B cells, restricted to B lymphocytes independently of the kappa or lambda light Ig chain expression, and exclusively observed in non-binucleated cells. The benign clinical course of PPBL and the lack of biological evolution in the majority of cases suggest that recognition of these disorders is so important that aggressive therapy in PPBL has to be avoided. Whether this syndrome represents a premalignant or benign disease remains unclear. The persistence of cytogenetic abnormalities after stopping tobacco use suggests no association with cigarette smoking.

Cytological types of mitoses and chromosome abnormalities in acute leukemia

In order to determine the nature of the cells in mitosis in acute leukemia, a parallel study was conducted by cytological and cytogenetic methods on the same marrow and blood samples. On direct marrow examination, erythrocyte precursors in mitosis are usually observed but ordinarily disappear following in vitro culture. In APL (M3) characterized by t(15;17) translocation, the comparison between the proportions of the different categories of cells in mitosis and of karyotypically normal and abnormal cells suggests that erythroblasts do not belong to the leukemic clone. An analogous situation is observed in AML (M2) with t(8;21) and in monocytic leukemia (M5) with chromosome abnormalities. Erythroleukemia could be divided into two categories, one with chromosome abnormalities and persistence of erythroblast mitoses after culture, and another with no detectable chromosome abnormality and with disappearance of erythroblast mitoses following culture. Other examples of blood malignancies demonstrate the importance of the method used in determining which cell categories belong to the leukemic clone. An interpretation of the results in terms of commitment 'level' of the involved stem cells and a distinction between 'primary' and 'secondary' chromosome abnormalities is proposed.

A multicentric study of 41 cases of B-prolymphocytic leukemia: two evolutive forms

B-prolymphocytic leukemia (B-PLL) is an infrequent disease with a poor prognosis. We present the clinical and biological features of 41 patients. Median age was 67 years [42-89] and male-female sex ratio was 2.4. The immunophenotyping revealed B-cell phenotype, with a high level expression of surface IgM and/or IgD in all cases, FMC7+ in 76 % of cases and CD5+ in 67%. Marked spontaneous in-vitro apoptosis was observed in most cases tested (n = 12). The median overall survival time was 5 years and the event-free survival time was 37 months. As detected by univariate and multivariate analysis, the only variables associated with a poor prognosis were advanced age and anemia. No significant difference was observed between de novo PLL (n = 27) and prolymphocytoid transformation of chronic lymphocytic leukemia (n = 14). Two groups of patients were individualized according to their clinical course: patients who died within one year of diagnosis (n = 14) and patients who had a prolonged survival (n = 23) without any treatment in some cases. The comparison between the 2 groups showed that they differed in age (p = 0.01) and anemia (p = 0.02). We also observed that the patients with p53 mutations had a worse clinical outcome. Taken together these data confirm that B-PLL should be regarded as a distinct form of chronic lymphoproliferative disorder and suggest the existence of two patterns of clinical evolution.

Human T-cell leukaemia/lymphoma virus type 1-associated infective dermatitis in Africa: a report of five cases from Senegal

BACKGROUND

Infective dermatitis (ID) is a rare dermatological condition of childhood that has been linked to human T-cell leukaemia/lymphoma virus type 1 (HTLV-1). Most cases have been reported in the Caribbean. Although several million people are estimated to be infected by HTLV-1 in sub-Saharan Africa, no case of ID has been reported in this area.

OBJECTIVES

To identify and to describe cases of HTLV-1-associated ID in Senegal, West Africa.

METHODS

Over a 3-year period, a serological test for HTLV-1 was performed at a dermatological centre in Dakar, Senegal, in children who presented with a picture suggestive of ID. Complementary haematological, immunological and virological investigations were performed in infected children and in their mothers.

RESULTS

Five patients with typical HTLV-1-associated ID were identified, of ages 17, 5, 4, 3 and 3 years; two patients belonged to the same family. They all presented with repeated flares of superinfected dermatitis involving typical sites of ID (mainly the scalp, external ears, nares and eyelids), associated with nasal discharge, and less commonly with a nonspecific papular rash on the face or trunk. Although oral antibiotic therapy always gave effective control of the symptoms, recurrences were constant. A persisting dry dermatitis of the retroauricular folds was common between flares. Infection in the oldest patient was associated with a chronic adult T-cell leukaemia/lymphoma. The mothers of three patients, and the grandmother of another, were all infected by HTLV-1 strains belonging to the Cosmopolitan molecular subtype, with a perfect nucleotide identity of long-terminal repeat and env gp21 genomic regions within each family.

CONCLUSIONS

We present the clinical and virological features of the first reported African cases of HTLV-1-associated ID. When compared with data from the Caribbean, infectious features seemed particularly prominent. ID appears to be overlooked in sub-Saharan Africa, where it might be easily confused with common pyoderma. Breast feeding appears to be the origin of HTLV-1 contamination of the children.

Persistent polyclonal lymphocytosis with binucleated B lymphocytes: a genetic predisposition

Persistent lymphocytosis is usually associated with a malignant lymphoproliferative disease (MLPD). We report six female patients presenting a chronic, moderate lymphocytosis of 2-16 years duration with atypical binucleated lymphocytes on peripheral blood smears. Further investigation showed a polyclonal increase in serum IgM and HLA-DR7 phenotype in all patients. The B cells were polyclonal because Southern hybridization of DNA and polymerase chain reaction failed to demonstrate a clonal rearrangement of immunoglobulin heavy chain genes. Peripheral blood examination showed binucleated lymphocytes in a family member of two of the cases; taken together with the association with HLA-DR7 these data suggest a genetic predisposition. The identification of this benign syndrome is important in order to prevent its misdiagnosis as a MLPD.

DEK-CAN molecular monitoring of myeloid malignancies could aid therapeutic stratification

The t(6;9)(p23;q34) is a recurrent chromosomal abnormality observed in 1% of acute myelogenous leukemia (AML), which generates a fusion transcript between DEK and CAN/NUP214 genes. We used a DEK-CAN real-time quantitative (RQ)-PCR strategy to analyze 79 retrospective and prospective samples from 12 patients. Five patients reached DEK-CAN negativity (sensitivity 10(-5)); all underwent early allogeneic hematopoietic stem cell transplantation (median 5.5 months from diagnosis) with some demonstrating molecular positivity at the time of allograft. All four cases in CCR with adequate follow-up (median 18.5 months, range 13--95) demonstrate persistent molecular negativity, whereas all seven patients with persistent DEK-CAN positivity died at a median of 12 months from diagnosis (range 7--27). We conclude that DEK-CAN molecular monitoring by RQ-PCR in t(6;9) malignancies is a useful tool for individual patient management and that molecular negativity is indispensable for survival, but should not be a prerequisite for allografting in this rare, poor prognosis, subset of AML.

Simultaneous SIL-TAL1 RT-PCR detection of all tal(d) deletions and identification of novel tal(d) variants

Site-specific deletions of the 5' part of the TAL1 gene (tal(d)) are among the most frequent non-random genetic abnormalities in T-cell acute lymphoblastic leukaemia (T-ALL). They are usually detected by PCR from DNA with several primer pairs or by Southern blot analysis. Since tal(d) lead to expression of a SIL-TAL1 fusion transcript, irrespective of the genomic breakpoint, we have used a single monoplex RT-PCR reaction to screen 55 T-ALL patients at diagnosis. SIL-TAL1 transcripts were demonstrated in 12 (22%) cases, including 7/27 (26%) children <15 years of age, 2/8 (25%) adolescents and 2/17 (12%) adults aged >20 years. SIL-TAL1 RT-PCR was preferrable to tal(d) DNA PCR since it allowed the simultaneous detection of tal(d), tal(d2) and two previously undescribed tal(d) variants. SIL-TAL1 RT-PCR screening should therefore increase the detection rate of tal(d) by approximately 15-20%, with an at least comparable sensitivity to tal(d) genomic PCR, and represents a more practical and economic alternative to multiple DNA PCRs or Southern blotting when incorporated into molecular screening for multiple transcripts at diagnosis.

Lack of efficacy of 2-chlorodeoxyadenoside in the treatment of splenic lymphoma with villous lymphocytes

Splenic lymphoma with villous lymphocytes (SLVL) is a B-cell chronic lymphoproliferative disorder. Splenectomy and/or chlorambucil (CLB) are usually regarded as the most effective treatment in SLVL patients. However, a few patients relapse and the second line therapy remains questionable. Although 2-Cda has been evaluated in patients with chronic lymphoid leukemia (CLL) and hairy cell leukemia (HCL), it has been reported as the treatment of SLVL in only one case report. Therefore, we have evaluated its efficacy and toxicity in 7 SLVL patients. The median duration between diagnosis and treatment was 18 months (range, 1 to 59). The patients received 2-CdA (0.1 mg/kg/d) by venous infusion for 7 days with a median number of 1 cycle (range, 1 to 2) either as a first line therapy (one patient) or after a failure of other therapies (splenectomy, chemotherapy). Two patients achieved a complete response. The first one maintained his CR during a follow-up of 9 months and then relapsed; the second patient remained in CR after a follow-up of 20 months. Four patients achieved a partial response and relapsed after a median follow-up of 3.5 months (range, 1 to 4). One patient had no response. The treatment was not well tolerated with many infectious events. In the limits of our study, 2-Cda does not appear to be efficient therapy for SLVL and is not well tolerated for patients in relapse after splenectomy or resistant to CLB.

NG2 expression in MLL rearranged acute myeloid leukaemia is restricted to monoblastic cases

Expression of NG2 has been reported in the majority of paediatric acute leukaemia (AL) cases with MLL rearrangement. We demonstrated 7. 1 positivity in 2/3 paediatric and 4/11 adult MLL rearranged acute myeloid leukaemia (AML) but in 0/28 adult AML without MLL rearrangement, thus extending the 100% specificity to adult cases. Positivity correlated with stage of maturation arrest since it was found in 0/6 immature AML but in 6/8 monoblastic cases. These data demonstrate that, if NG2 expression in AL is the (in)direct result of MLL rearrangement, such activation is restricted to a monoblastic population in AML. They also have practical implications for NG2 diagnostic screening strategies.