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A Cosson

Publications and source records attributed to A Cosson.

At least 37 records · Page 2Linked to original sources
PubMed1999

The French haemovigilance system.

Haemovigilance is a national system of surveillance and alarm, from blood collection to the follow-up of the recipients, gathering and analysing all untoward effects of blood transfusion in order to correct their cause and prevent recurrence. In France haemovigilance was created by law and notification of transfusion incidents is a legal obligation. The haemovigilance network associates local correspondents in each hospital and blood centre with regional co-ordinators and is centralised by the Agence Française du Sang. After 4 years the incident reporting rate is 2.3 per 1,000 allogeneic blood components transfused, justifying for example increased efforts in the prevention of bacteria-associated transfusion reactions, haemolytic transfusion reactions or vascular overload. However, haemovigilance still has to be strenghtened by improved information management or further progress in standardisation from one region to the other. The most important factor of success is collaboration between blood centres and hospitals. Haemovigilance clearly is the ultimate quality indicator of a transfusion service.

Blood Banks↗
PubMed1999

p190 bcr-abl rearrangement: a secondary cytogenetic event in some chronic myeloid disorders?

BACKGROUND AND OBJECTIVE: A small number of chronic myeloproliferative disorders with hematologic features of chronic myelomonocytic leukemia (CMML) or atypical chronic myeloid leukemia and Ph1 chromosome with m-BCR rearrangement have been reported (p190 CMPD). We report here 3 new cases of p190 CMPD that had unusual features. In 2 of the cases the m-BCR rearrangement appeared to be a secondary event. DESIGN AND METHODS: Patients were studied by cytogenetic, FISH, and molecular biology analyses and followed-up clinically. RESULTS: The first patient initially had typical 5q- syndrome, without m-BCR rearrangement. Five years later, she developed hematologic features of CMML, with t(9;22) translocation, m-BCR rearrangement and high levels of p190 BCR-ABL transcript. The second patient initially had hematologic characteristics of chronic myeloid leukemia (CML) with t(9;22) translocation and m-BCR rearrangement but also other complex cytogenetic findings including 17p rearrangement. Monocytosis developed during the course of the disease. The third patient initially had agnogenic myeloid metaplasia (AMM). Five years later, while the hematologic characteristics were still those of AMM, a first karyotype showed a t(9;22) translocation and molecular analysis showed a very low level of p190 BCR-ABL transcript. Four years later, the patient developed hematologic features of atypical CML with blood monocytosis, t(9;22) and much greater (100 fold) p190 BCR-ABL transcript levels. INTERPRETATION AND CONCLUSIONS: Our 3 cases and review of the previously published cases show the variability of clinical features of p190 positive CMPD. Our results also suggest that, at least in some cases, p190 BCR-ABL rearrangement could be a secondary event in the course of a myeloid disorder.

Chromosomes, Human, Pair 22↗
PubMed1998

The French haemovigilance system.

Haemovigilance was part of the reform of the French transfusion system. The haemovigilance network is now operational with approximately 4600 transfusion incidents reported annually. Immediate incidents observed within 8 days after transfusion account for 85% of the reports. A cause cannot be identified in 41% of these, usually concerning minor clinical incidents with transient fever and/or shivers. An allergic reaction is described in 31% of transfusion reactions. Immunological conflicts account for 18% and bacteria associated transfusion reactions for 6%. The importance of bacteria associated transfusion reactions, the first identified cause of death associated with transfusion is one of the findings of haemovigilance. Improvement in the haemovigilance systems aims at obtaining better descriptions of transfusion incidents, standardisation of severity and imputability assessment and definitions of denominators such as the actual number of recipients. Delayed incidents will ultimately provide a true vision of post transfusion immunisation and infection The improvement of haemovigilance now considered as part of transfusion medicine practice is a continuous process.

Bacteremia↗
PubMed1998

Expression of lung resistance protein and correlation with other drug resistance proteins and outcome in myelodysplastic syndromes.

The major vault lung resistance protein LRP is a cytoplasmic protein involved in drug resistance, especially in acute myeloid leukemia. We looked for LRP overexpression, using immunocytochemistry with LRP 56 monoclonal antibody, on marrow slides from 41 cases of myelodysplastic syndromes (MDS). LRP overexpression (LRP+) was defined by expression of LRP 56 in at least 20% of marrow blasts. LRP overexpression was seen in 19 (46%) cases. Concordant results between LRP overexpression and P-glycoprotein (PGP) expression were seen in 66% of the cases (p = 0.03), and discordant results (LRP+ and PGP-, or LRP- and PGP+) in 33% of the cases. No correlation was seen between LRP overexpression and FAB type, karyotype, CD34, p53 expression and bcl2 overexpression in blasts. Furthermore, in the 18 cases treated with anthracycline-AraC intensive chemotherapy and the 7 cases treated with low dose AraC, the response rate was not significantly different in LRP+ and LRP- patients. Survival was also similar in LRP+ and LRP- patients. In conclusion, LRP overexpression is probably more frequent in MDS than in de novo AML and, as in AML, is only partially correlated with PGP expression. In our experience, however, LRP was not a prognostic factor for response to chemotherapy and survival in MDS.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Fas/APO-1 (CD95) expression in myelodysplastic syndromes.

Increased apoptosis of myeloid precursors appears to contribute to the pathophysiology of cytopenias in myelodysplastic syndromes (MDS). Fas /APO-1(CD95) is a cell surface protein inducing an apoptotic signal after its binding to Fas ligand or to a functional anti-Fas antibody. Here we studied Fas expression by immunocytochemistry on marrow slides from 30 cases of MDS. Increased Fas expression in erythroblasts and/or immature granulocytes, compared to controls, was seen in 12 (40%) of the cases. In addition, in 16 of the 18 cases with > or = 5% marrow blasts, a variable proportion of blasts expressed Fas. Increased apoptosis was found by morphological analysis and/or TUNEL technique in marrow cells from 8 of the 26 cases analyzed (31%) The ability of Fas antigen to trigger apoptosis was studied after addition of a functional anti Fas antibody in 5 of the patients with Fas overexpression. Addition of this antibody, however, only lead to mild increase of apoptosis in immature granulocytes (but not other myeloid cells) in 2 of the 5 cases. Thus, increased Fas expression is seen in myeloid and/or blast cells in the majority of MDS cases. However, the relationship between this finding and increased apoptosis in MDS still remains to be established.

Adult↗
PubMed1997

Several cytogenetic subclones may be identified within plasma cells from patients with monoclonal gammopathy of undetermined significance, both at diagnosis and during the indolent course of this condition.

Monoclonal gammopathy of undetermined significance (MGUS) is a frequent condition in patients over 50 years old, that ultimately leads to multiple myeloma (MM) in 20% of patients after 20 to 35 years of follow-up. Little is known about cytogenetic changes associated with this condition. We studied 19 MGUS patients both at diagnosis and after 12 to 35 months of follow-up (mean = 26), using DNA content measurement of bone marrow plasma cells (BMPC), and a new interphase fluorescence in situ hybridization technique (FISH) allowing the simultaneous identification of monotypic BMPC (fluorescent anti light-chain antibodies) and the determination of the number of copies for two different chromosomes within the same PC nucleus (one biotin-labeled probe coupled next to texas red avidin and one FITC-labeled probe). At diagnosis of the MGUS, single interphase FISH showed at least one numeric chromosome change in 13 of 19 patients, after the use of centromeric probes directed against chromosomes no. 3, no. 7, no. 9, and no. 11. At follow-up, abnormalities found at diagnosis in 13 patients were still shown. Moreover, abnormalities occurred in three of the last six patients (trisomy for one to three different chromosomes), although no patient evolved into MM. Dual interphase FISH showed that some BMPC bore numeric changes with both probes tested whereas other BMPC bore abnormality with only one of the probes tested. In patients who showed trisomy for at least three different chromosomes, distribution of numeric changes within BMPC defined significant numbers of up to seven different BMPC clones. All these various clones were shown both at diagnosis and at follow-up. In every patient, these various clones differed only for the number of abnormalities they exhibited, and could be related to each other in a model of gradual acquisition of chromosome changes. Eventually, data reported here show that MGUS patients acquire slowly, gradually, but ineluctably chromosome changes, distributed within several related subclones. However, these changes are not related to transformation into MM: among the various clones coexisting within the same patient, a peculiar change, still to demonstrate, might develop and lead to overt MM.

Adult↗
PubMed1997

Effects of coronary angioplasty on monocyte tissue factor response in patients with stable or unstable angina.

Balloon coronary angioplasty is a revascularization procedure which increases the luminal diameter at a site of arterial stenosis, leading to mechanical disruption of the atherosclerotic plaque and to stretching of the vascular wall (1). This procedure can be complicated by thrombosis or restenosis, which occur in 5% and 30% of the cases respectively (2). These complications probably result from exposure of blood to components of atherosclerotic plaque, subendothelium and components of vascular wall, leading to activation of coagulation (thrombin generation) and platelets (3,4). Recent data point to simultaneous increase of leukocyte adhesive receptors, indicating an additional process of leukocyte activation, which could play a key role in the vascular healing process after angioplasty (5). These elements could also play a role in the thrombotic and stenotic complications.

Aged↗
PubMed1997

Interest of immunomodulation as a mean to improve the preparation of polyclonal and monoclonal antibody reagents.

Immunomodulation by monoclonal antibodies (mAbs) was investigated in mice in order to improve the preparation of antibody reagents. Three different types of representative immunogens were chosen: a human soluble protein (secretory immunoglobulin A, SIgA), a bacterial polysaccharide from E. coli K1 and an envelope protein from the hepatitis B virus. These Ag are all of importance for diagnosis and exhibit different levels of immunogenicity. Antibody-mediated enhancement was observed against restricted and defined regions of each immunogen i.e.: the Fab epitopes of SIgA, the preS1 domain of the HBV envelope and associated cell wall components of the capsular PS. The epitopes which were enhanced appeared to be different from those recognized by the modulating mAb. Negative modulations were also observed. Moreover, new epitopes seemed to be generated. In both cases the level and direction of the modulation were irrespective of isotypy and affinity of the mAbs. Interestingly the positive modulatory effect was found to be correlated with an in vitro assay based on the binding of immune complex to antigen-presenting cells.

Animals↗
PubMed1997

[Impact of a quality approach for transfusion safety on prescription, circuit optimization, traceability].

The Quality Assessment Program undertaken at the Regional University Hospital of Lille benefits from previous experience making management of this project possible: continuing education, preliminary initiation into the quality approach, and existing reference systems. The aims are to master the rates of outdated and no longer efficient red cell concentrates, to control red cell concentrate delivery time, to validate the refrigeration line integrity and to ensure a flawless marking out process. The process studied is transverse, with those taking part in it belonging to several professional categories. The method will consist in a process identification, its description and characterization according to FMECA (Failure Mode Effects and Criticality Analysis), the creation of a new process and its improvement. Thus failures should be identified and classified hierachically. The corrective actions will consist in communication aids, an education program, blood product transport and blood depot reorganization, data processing improvement and medical equipment acquisition. Quality indicators are developed according to the objectives of the study, and progress indicators are developed as a periodical assessment of blood transfusion practice. This ambitious project relies on the involvement of Hospital Management and referent network. These referents facilitate the improvement processes for those taking part in this process.

Blood Transfusion↗
PubMed1997

Good correlation between RT-PCR analysis and relapse in Philadelphia (Ph1)-positive acute lymphoblastic leukemia (ALL).

We sequentially performed cytogenetic analysis and RT-PCR analysis of BCR-ABL transcripts in 17 cases of Ph1-positive ALL who had achieved hematological complete remission (CR) with intensive chemotherapy (CT). Sixteen cases were studied prospectively. All but one of the patients had reached cytogenetic CR, but cytogenetic has low sensitivity in predicting relapse. Twelve patients relapsed, three died in first CR and two were alive in first CR. Two of five, two of four, and five of nine patients who were allografted (in first or second CR), autografted and received consolidation CT, respectively, achieved negative two-round PCR in the bone marrow (BM): three died in CR, three remained in CR with negative two-step PCR in the BM and three relapsed after 22 to 28 months. In all cases, relapse was preceded by switch to PCR positivity in the BM by 4 to 6 months. The remaining nine patients remained PCR-positive in the BM and relapsed after 2 to 16 months. In the four autografted cases, PCR was positive at the time of bone marrow harvest. The two patients who received a purged transplant achieved negative PCR and prolonged CR, whereas the two patients who received an unpurged transplant remained PCR positive and relapsed. In 34% of the samples where analysis was concomitant, sensitivity of PCR proved lower in the blood than in the BM. These findings show that RT-PCR is a useful tool in the monitoring of MRD in Ph1 positive ALL.

Adult↗
PubMed1997

Involvement of peripheral blood cells in multiple myeloma: chromosome changes are the rule within circulating plasma cells but not within B lymphocytes.

The mononuclear cells in the peripheral blood are implicated in the myeloma process especially with the presence of peripheral blood plasma cells (PBPC) and clonal B lymphocytes found using phenotypic or gene rearrangement techniques. The purpose of this study was to look for aneuploidy in the two main B cell components of the peripheral blood: PBPC and CD20-positive B lymphocytes. Conventional cytogenetics (CC) or DNA content analysis and fluorescence in situ hybridization (FISH) with centromeric probes were performed on bone marrow plasma cells (BMPC) of 21 patients with multiple myeloma and peripheral blood cells were studied as follows: immunostaining to look for PBPC and to assess their number, image analysis cytometry for the determination of their DNA content, and FISH chromosomes analysis. FISH was performed using probes against the chromsomes that were lost or gained in BMPC and was coupled with immunostaining of the relevant light chain or CD20 antigen to study PBPC or B lymphocytes, respectively. Monotypic PBPC were found in 16 patients. Their DNA content was the same or nearly the same as for BMPC and they exhibited the same monosomies or trisomies as those found within their BM counterpart. By contrast, DNA content of mononuclear cells other than PBPC was within normal ranges, and in 13 of 15 patients CD20-positive B lymphocytes failed to show chromosomal changes by FISH analysis. In two patients however, a few CD20+ cells with lymphoid morphology exhibited chromosome changes, hypothesizing that a few cytogenetically abnormal B cells without plasmocytic morphology may circulate. From these data, we conclude that PBPC share the same genetic abnormalities as BMPC and thus belong to the malignant clone, whereas most peripheral blood B lymphocytes are unrelated to the tumor clone.

Aged↗
PubMed1996

Is apoptosis a massive process in myelodysplastic syndromes?

We looked for increased apoptosis in fresh bone marrow aspirates in 40 cases of myelodysplastic syndrome (MDS), by detection of DNA fragmentation using TdT incorporation of nucleotides on 3' ends of DNA (TUNEL technique). No DNA laddering was seen. In six cases (15%) the TUNEL technique showed a moderate increase in the percentage of apoptotic cells (2.5-5% in comparison with < 2% in controls). In seven of the 34 patients with normal findings by TUNEL analysis, apoptosis was reanalysed after short-term (18 h) bone marrow culture without inducers of apoptosis. Increased apoptosis was shown in four of the seven cases by morphological analysis and/or the TUNEL technique. Increased apoptosis predominated on erythroblasts in three of them. The percentage of apoptotic cells, however, was < 40% in all samples. Our findings suggest that increased apoptosis can be detected in one half of MDS cases after cell culture. Furthermore, the precise relationship between increased apoptosis of myeloid precursors and cytopenias will have to be more precisely explored in MDS.

Apoptosis↗
PubMed1996

Laboratory evaluation of the Abbott Cell DYN 3500 5-part differential.

The study reports the performance of the Abbott CD3500 automated hematology analyzer for the enumeration and delineation of leukocyte populations for both adult and pediatric samples, and the ability of this instrument to detect the presence of abnormal cells. Samples from 542 individual patients either attending medical practitioners or during hospitalization were examined and then subdivided for the purposes of this study into 106 samples from newborn infants (< days), 145 samples from older children (15 days to 14 years) with non-oncologic disorders, 100 samples from normal adults, and 191 samples from oncology patient (97 adults and 94 children). The leukocyte differentials provided by both the Abbott CD3500 and the Coulter STKS were compared with those obtained from conventional morphology (two observers, total of 400 leukocytes). The sensitivities and specificities of the blast, immature granulocyte (IG) and NRBC "flags" were also determined. For the non-oncology adult (n=100) and pediatric (n=145) cohorts, automated differentials were given in all samples with the CD3500, whereas the STKS did not provide a differential analysis for 20 of the 145 (14%) pediatric samples, 11 of these were absent for no obvious reason. However, for the evaluable cases, the performances of the CD3500 and the STKS were broadly similar and generally correlated well with the manual reference procedure. The results for the newborn samples were less consistent with wider 95% confidence intervals (CI) noted. For example, the CD3500 (which reported a differential for all 106 samples studied) gave CI values of +/-14.4% for neutrophils, +/-14.6% for lymphocytes and +/-8.1% for monocytes. For comparison, the STKS (which did not provide a differential in 15% of 79 samples analyzed; insufficient material being available from the remaining 27 of 106 newborn samples) gave CI values of +/-21.9% for neutrophils, +/-23.5% for lymphocytes and +/-8.2% for monocytes. For all samples, the sensitivity of the blast flag on the CD3500 was 85% with a specificity of 91% (STKS: sensitivity, 75%; specificity, 85%); the sensitivity of the CD3500 IG flag was 72% with a specificity of 76% (STKS: sensitivity, 75%: specificity, 73%); and the sensitivity of the NRBC flag was 43% with a specificity of 94%(STKS sensitivity, 37%; specificity, 88%). This study confirms competitive performance levels for the CD3500 in the analysis of normal adult samples and suggests positive performance advantages in the study of neonatal, pediatric, and leukopenic samples.

Adolescent↗
PubMed1996

Molecular analysis of the modulatory factors of the response to HBsAg in mice as an approach to HBV vaccine enhancement.

Mice were injected with immune complexes containing the recombinant hepatitis B surface antigen (HBsAg) vaccine (S + preS2) bound to different monoclonal antibodies (mAbs), in order to determine whether an enhancement of the response to a human vaccine could be obtained and observed. Enhancement and indifference were observed, as well as a decrease in immunogenicity. No relationship could be established between any effect and affinity or isotype of the bound mAbs. The preS2 region was rendered more immunogenic when an IgG2a mAb was bound to the S region of the HBsAg. The response to the S region was not modulated, whereas immunogenicity of the preS2 colinear region was decreased by antibody shielding. The mAb which was the most efficient as an enhancer of the antibody response also increased binding of the complexed immunogen to antigen presenting cells. The binding of a human mAb to the sole S region, but not to the preS2 region, should be tested as a potentiating agent of the anti-preS2 human immune response.

Adjuvants, Immunologic↗
PubMed1995

Detection of monocyte tissue factor after endotoxin stimulation: comparison of one functional and three immunological methods.

Monocyte procoagulant activity is mainly due to tissue factor (TF) expression, but functional assays may not be sufficiently accurate in clinical use, making useful a determination of TF antigen level. The aim of this study was to compare the results of one functional and three immunological TF assays (ELISA, immunocytochemical staining on slides and flow immuno cytometric analysis), in normal monocytes, after standardized stimulation by endotoxin. TF expression was determined in blood mononuclear cells isolated by gradient centrifugation and cultured, with or without various concentrations of endotoxin. On lysed cells, TF activity was determined by amidolytic assay and TF antigen level was determined, after triton extraction, by ELISA (Imubind, American Diagnostica). Mouse monoclonal antibody against TF (4508, American Diagnostica) was used for 1) immunocytochemical (ICC) staining on cytocentrifuge slides (Avidine-Biotine-peroxidase-Complex revelation) and 2) flow cytometric analysis using indirect labeling (Fab'2 Fluoresceine Isothyocyanate revelation). The determination of TF activity and TF antigen by ELISA method were equally sensitive to low concentration of endotoxin (0.005 EU/ml) and well correlated in the presence of higher concentrations of endotoxin. ICC led to a qualitative detection with a similar sensitivity to endotoxin stimulation. Flow cytometric analysis was poorly sensitive to increasing stimulation of monocytes. Of note, the functional, ELISA and immunocytochemical assays for monocyte TF expression were sensitive to endotoxin concentrations as low as 0.005 EU/ml.

Adult↗
PubMed1995

Combined immunophenotyping and in situ hybridization (FICTION): a rapid method to study cell lineage involvement in myelodysplastic syndromes.

We present a study in which we used a recently described method combining fluorescence in situ hybridization (FISH) and immunophenotyping, i.e. FICTION, to assess the involvement of different cell lineages in myelodysplastic syndrome (MDS) with monosomy 7 (-7), trisomy 8 (+8) or loss of Y chromosome (-Y). Blood or marrow smears or cytocentrifuge preparations were stained both by antibodies to granulocytes (CD15), monocytes (CD14), T lymphocytes (CD3), B lymphocytes (CD20) and by probes specific for chromosomes 7, 8 or Y. Of nine cases of MDS with -7, four with +8 and two with -Y studied, none showed lymphocytic involvement by the chromosome abnormality. In contrast, -7, +8 and -Y were found in granulocytes and monocytes in all patients studied, but they involved a variable proportion of those cells. The partial involvement by -7 and +8 seen in some cases suggests that myelopoïesis was only partially clonal in those cases, or that the chromosome abnormality was a secondary event in the MDS process. FICTION therefore appears to be a simple and easily reproducible method that can be used for the assessment of lineage involvement in MDS and other haematological malignancies.

Adolescent↗
PubMed1995

CD19 and immunophenotype of bone marrow plasma cells in monoclonal gammopathy of undetermined significance.

AIMS: To determine whether a particular phenotype or antigen is preferentially related to monoclonal gammopathies of undetermined significance (MGUS). METHODS: Bone marrow specimens from 56 patients with MGUS were stained immunocytochemically (ABC peroxidase) for CD38, CD56, CD9, CD10, CD19, CD20, CD22, and MB2. Specimens from patients recently diagnosed with multiple myeloma and reactive bone marrow samples were studied in parallel. RESULTS: CD38 was expressed on all plasma cells from all MGUS samples tested, while 36% were positive for CD56, CD9 and MB2 were both expressed strongly; CD20 was moderately expressed, and staining for CD10 and CD22 was uncommon. For these five B cell antigens there was no clear difference between their expression in MGUS and in multiple myeloma. A great difference was found for CD19: in MGUS this antigen was expressed on 2-91% of plasma cells (mean 35%) and 77% patients had > 10% positive plasma cells; in multiple myeloma its expression was low and only 12% patients had > 10% positive plasma cells. When these results were converted to numbers of CD19 positive plasma cells per 100 nucleated bone marrow cells, reactive bone marrow and MGUS specimens had a similar number of positive plasma cells. There was no correlation between expression of any of the antigens tested. CONCLUSIONS: Many of the so-called pre-B, B or activation antigens are present on plasma cells from MGUS specimens, and expression of CD9, CD10, CD20, CD22, MB2, and CD38 in MGUS was very similar to that in multiple myeloma. CD56 was frequently expressed in MGUS. In this series CD19 was highly expressed in MGUS but not in multiple myeloma. Plasma cells bearing this antigen could represent the non-neoplastic process and determination of its expression could be useful for the diagnosis of MGUS.

Antigens, CD↗