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P Brousset

Publications and source records attributed to P Brousset.

At least 37 records · Page 2Linked to original sources
PubMed2001

The role of Epstein-Barr virus in neoplastic transformation.

In this review, we focus on new data from basic, translational and clinical research relating to the Epstein-Barr virus (EBV). Beside its well-known tropism for B lymphocytes and epithelial cells, EBV also infects T lymphocytes, monocytes and granulocytes. After primary infection, EBV persists throughout the life span in resting memory B cells, from where it is reactivated upon breakdown of cellular immunity. In the process of neoplastic transformation, the EBV-encoded latent membrane protein 1 (LMP1) oncogene represents the major driving force. LMP1 acts like a constitutively activated receptor of the tumor necrosis factor receptor family and allows the amplification or bypassing of physiological regulatory signals through direct and indirect interactions with proteins of the tumor necrosis factor receptor-associated factor (TRAF) family. TRAF2-mediated NF-kappaB activation, AP-1 induction and JAK3/STAT activation may result in sustained proliferation leading to lymphoma. The ability of LMP1 to suppress germinal center formation and its capacity to mediate its own transcriptional activation shed new light on the pathogenesis of EBV-associated latency type II lymphoproliferations like Hodgkin's disease and angioimmunoblastic lymphadenopathy. The carboxy terminus of LMP1 is also a reliable marker for individual EBV strain identification and thus offers new possibilities in tracing the molecular events leading to posttransplant lymphoproliferative disorders (PTLDs). Cytotoxic T lymphocytes directed against well-characterized epitopes of EBV latency genes represent an already successful and promising therapeutic approach to EBV-associated lymphomas, in particular PTLDs.

Apoptosis↗
PubMed2001

Increased yield of PCR products by addition of T4 gene 32 protein to the SMART PCR cDNA synthesis system.

Under certain conditions, T4 gene 32 protein is known to increase the efficiency of different enzymes, such as Taq DNA polymerase, reverse transcriptase, and telomerase. In this study, we compared the efficiency of the SMART PCR cDNA synthesis kit with and without the T4 gene 32 protein. The use of this cDNA synthesis procedure, in combination with T4 gene 32 protein, increases the yield of RT-PCR products from approximately 90% to 150%. This effect is even observed for long mRNA templates and low concentrations of total RNA (25 ng). Therefore, we suggest the addition of T4 gene 32 protein in the RT-PCR mixture to increase the efficiency of cDNA synthesis, particularly in cases when low amounts of tissue are used.

DNA, Complementary↗
PubMed2001

[Gene expression profiling by suppression subtractive hybridization (SSH): a example for its application to the study of lymphomas].

Suppression subtractive hybridization (SSH) was used to isolate genes that were differentially expressed in anaplastic lymphoma kinase (ALK)-positive and ALK-negative anaplastic large cell lymphoma. In addition, this approach was applied to Hodgkin's disease cases with different clinical outcomes. SSH combines a normalization step that equalizes the abundance of cDNAs within the sequences to be tested and a subtraction step that excludes the common sequences between the target and the control. In a model system, the SSH technique enriches for rare sequences up to 5,000-fold in one round. We have isolated several genes whose expression varied significantly with regard to the tumour subtypes. There were different genes with known or unknown functions. We aim to compare the results of the SSH approach with those obtained with high density filters. In a near future, we would like to design DNA chips specific of each pathology that could be used for clinical purposes (evaluation of prognosis and therapeutic response).

Gene Expression Profiling↗
PubMed2000

PCR analysis of immunoglobulin heavy chain (IgH) and TcR-gamma chain gene rearrangements in the diagnosis of lymphoproliferative disorders: results of a study of 525 cases.

This report summarizes a cumulative 4-year experience in polymerase chain reaction (PCR) analysis of immunoglobin heavy chain (IgH) and TcR-gamma chain gene rearrangements in 525 cases of lymphoproliferative disorders. Because the sensitivity of the PCR methodology was found to be tissue dependent, in the study of the presence of clonal cell population in tissues containing a small number of polyclonal lymphocytes, such as skin and gastrointestinal biopsy specimens, we used the multiple-PCR run approach. In this latter methodology, we repeat the PCR reaction from the same sample at least three times to confirm the reproducibility of the results. In the study of 273 cases of B- or T-cell lymphomas with characteristic immunomorphological and clinical features, a clonal IgH or TcR-gamma chain gene rearrangement was detected in approximately 80% of cases. A clonal rearrangement involving both IgH and TcR-gamma chain genes was found in 10% of cases of both B-cell and T-cell lymphomas. The study of 167 cases of nonneoplastic lymphoid tissue samples showed the presence of clonally rearranged cell populations for IgH or TcR-gamma genes in 3 and 9% of cases, respectively. We also applied PCR for the study of 85 cases of lymphoproliferations with no definite diagnosis (i.e., benign versus malignant) after immunomorphological analysis. In 65 cases (76%), the correlation of immunomorphological features with the presence (48 cases) or the absence (17 cases) of clonal lymphoid cell populations led to a definite diagnosis. In almost all these cases, the final diagnosis was found to be in agreement with the clinical course. In the 20 remaining cases (24%), no definite diagnosis could be made. We also assessed the value of PCR in detecting bcl-2/J(H) gene rearrangement as an additional clonal marker in the diagnosis of follicular lymphoma. Bcl-2/J(H) rearrangement and/or IgH gene rearrangement was found in approximately 85% (71/85) of follicular lymphoma cases studied.

Adolescent↗
PubMed2000

High concentration of leptin stimulates myeloid differentiation from human bone marrow CD34+ progenitors: potential involvement in leukocytosis of obese subjects.

OBJECTIVE AND DESIGN: As well as its involvement in control of adipose mass and body energy balance, several reports suggest a link between leptin and hemopoiesis. To test its putative role in human hemopoiesis, we developed a homologous system, ie recombinant human leptin treatment of purified CD34+ progenitors from adult human bone marrow. RESULTS: Leptin (50-100 ng/ml) significantly stimulated the appearance of granulocyte-macrophage colonies in the presence or absence of erythropoietin. The concentration of leptin required for this effect was rather high but within the range of plasma leptin levels observed in obesity. Two results further support the hypothesis that leptin may be involved in the leukocytosis associated with obesity: (i) leptin concentrations in bone marrow and plasma of subjects studied were highly correlated; (ii) leptin and leukocyte count were correlated only in obese subjects. Paracrine effects of locally released leptin from bone marrow adipocytes could also be involved in the regulation of hemopoiesis, a hypothesis supported by marrow immunocytochemistry revealing the close association of CD34+ cells with adipocytes and by previous demonstration that leptin is secreted at a high level by these cells. CONCLUSION: These results indicate that leptin acts on human multilineage CD34+ cells and that high plasma leptin levels associated with obesity could participate in the differentiation of granulocytes from hemopoietic progenitors.

Adult↗
PubMed2000

Variation in the histological pattern of nodal involvement by gamma/delta T-cell lymphoma.

AIMS: Gamma-delta (gammadelta) T-cell non-Hodgkin's lymphomas (NHLs) usually present with liver, spleen and marrow infiltration. Lymph node involvement by gammadelta T-cell NHL has been rarely documented so far; its histological pattern needs to be further defined. METHODS AND RESULTS: Two cases of nodal gammadelta T-cell NHL are reported: case 1, a 44-year-old man, presented with cytomegalovirus retinitis and superficial lymphadenopathies. Histological analysis of an inguinal lymph node showed complete destruction by a diffuse pleomorphic lymphoid proliferation, which was positive for CD2, CD3, CD43, CD45, TIA-1 and granzyme B, and displayed a gammadelta phenotype (deltaTCR1+, Vdelta1+, Vdelta2-, Vdelta3-, betaF1-). Bone marrow was normal. Case 2, a male 24-year-old patient with a history of renal transplantation, presented with hepatosplenomegaly and supraclavicular lymph node enlargement. Lymph node architecture was globally preserved. Peripheral sinuses contained scattered nests of medium-sized irregular lymphoid cells. Bone-marrow was infiltrated. Phenotype showed positivity for CD2, CD3, CD45 and TIA1 and expression of gammadelta TCR (deltaTCR1+, deltaV1+, deltaV2-, deltaV3-, betaF1-). Both patients died a short time after diagnosis. CONCLUSIONS: These observations suggest that at least two forms of nodal gammadelta T-cell NHL may be encountered: one mimicking classical alphabeta T-cell NHL, with diffuse pleomorphic cell proliferation, and one displaying sinusoidal neoplastic infiltration suggesting a close relationship with hepatosplenic gammadelta T-cell NHL.

Adult↗
PubMed1999

Spontaneous apoptosis and the expression of p53 and Bcl-2 family proteins in locally advanced head and neck cancer.

BACKGROUND: Apoptotic cell death plays a key role in the pathogenesis, aggressiveness, and therapy responsiveness of cancer. The suicidal machinery of apoptosis is genetically controlled. Proteins of the Bcl-2 family as well as p53 are important regulators of apoptosis. OBJECTIVE: To assess the rate of spontaneous apoptosis and the expression of p53 and Bcl-2 family proteins in locally advanced squamous cell carcinomas of the head and neck. DESIGN: Twenty-six patients with locally advanced squamous cell carcinoma of the head and neck were included in the study. The expression of p53, Bcl-2, Mcl-1, Bax, and Bak was assessed by immunohistochemical analysis. The terminal deoxytransferase-mediated deoxyuridine nick end-labeling assay was used to quantify apoptosis by flow cytometry. RESULTS: Tumor cells containing immunostaining for the antiapoptotic proteins Bcl-2 and Mcl-1 were present in 4 (15%) and 24 (92%) of the cases evaluated, respectively, whereas immunopositivity for the proapoptotic proteins Bax and Bak was found in 9 (35%) and 24 (92%) of the samples. Immunoreactivity to p53 was detected in 20 (77%) of the samples. There was a positive correlation between the expression of Bcl-2 and Bax and between Mcl-1 and Bak. A low fraction of apoptotic cells (<2.5%) in the pretreatment tumor samples was significantly correlated with increased 2-year survival in these patients. CONCLUSIONS: Our results establish the frequent expression of the Bcl-2 family proteins Bcl-2, Mcl-1, Bax, and Bak in locally advanced head and neck cancer. In addition, this study suggests that the apoptotic fraction in pretreatment tumor samples might be of prognostic importance for the outcome in these patients.

Adult↗
PubMed1999

High Epstein-Barr virus serum load and elevated titers of anti-ZEBRA antibodies in patients with EBV-harboring tumor cells of Hodgkin's disease.

Hodgkin's disease is commonly associated with EBV latent infection. The incidence of EBV reactivation (active infection or EBV infection with replicative cycle) was evaluated in a series of 30 patients with untreated Hodgkin's disease (except for one case with chronic lymphocytic leukemia) by quantitation of EBV DNA and titration of anti-ZEBRA antibodies in serum samples. DNA was detected in serum (>2.5 x 10(2) genomes/ml) in 15 of 30 patients and was more frequent in Hodgkin's disease with EBV-positive Reed-Sternberg cells (10/12) than in EBV-negative cases (5/18), (P< 0.01). Of interest was the demonstration that viremia correlated well with increased titers of anti-ZEBRA IgG and/or standard serological profiles of EBV reactivation (12/15), (P < 0.05). However the lack of EBV replicative cycle in Reed-Sternberg cells (negative for ZEBRA antigen and early antigen BHLF1) suggests that the viral replication occurs in a nonneoplastic cell compartment rather than in tumor cells. The measurement of EBV DNA loads and the titration of anti-ZEBRA antibodies shed new lights on the link between activation of EBV replication and Hodgkin's disease: these serological markers together with the determination of the EBV status of the tumor suggest that replication of the viral genome occurs with a decreased efficiency of the immune system, thus allowing progression of the tumor.

Adolescent↗
PubMed1999

In vivo patterns of Bcl-2 family protein expression in breast carcinomas in relation to apoptosis.

The expression of the pro-apoptotic proteins (Bax, Bak) and anti-apoptotic proteins (Bcl-2, Bcl-X, Mcl-1) was studied by immunohistochemistry in 110 invasive ductal breast carcinomas. The results were correlated with tumour grade, expression of oestrogen receptor (ER) and p53 protein, and the apoptotic index by combined morphology, immunohistochemistry, and a terminal UTP nick end labelling (TUNEL) procedure. Overall, Bcl-2, Bcl-X, Mcl-1, Bax, Bak, ER, and p53 were detected in 62, 75, 68, 75, 60, 68 and 26 per cent of the cases respectively, but at different levels in each case. A high apoptotic index was correlated with high tumour grade (p<0.001), overexpression of p53 (p<0.001), Bak expression (p<0.001), and low expression of Bcl-2 (p<0.001) and ER (p<0.001). No correlation was found between the apoptotic index and Bax, Bcl-X, and Mcl-1 immunostaining results. The expression of Bcl-2 and Bcl-X was correlated to that of ER. Overall, the results of this study strongly suggest that Bcl-2 and Bak expression is critical in regulating apoptosis in breast carcinomas.

Apoptosis↗
PubMed1999

Acquisition of a stimulatory activity for Vgamma9/Vdelta2 T cells by a Burkitt's lymphoma cell line without loss of HLA class I expression.

Daudi Burkitt's lymphoma cells activate Vgamma9/Vdelta2 T cells through TCR ligation by an unknown antigen. This activity is for a large part revealed by their lack of HLA class I antigen expression, allowing their escape from KIR downregulation. We characterize here a culture variant of the Burkitt's lymphoma line Raji, RJ-A3, which is able to promote as efficiently as Daudi cells the outgrowth of Vgamma9/Vdelta2 T cells in cocultures in spite of unchanged HLA class Ia/Ib antigen expression. RJ-A3 is resistant to lysis by most Vgamma9/Vdelta2 lines and clones, even those lacking CD9-4/NKG2 and p58, p70 p140 KIR molecules. However, one Vgamma9/Vdelta2 line which can efficiently kill RJ-A3 do so in a TCR-dependent manner since killing is modulated by anti-TCR antibodies. The CDR3 sequences of the T cell clones amplified with Daudi and RJ-A3 reveal that some clones can be expanded with both lines while others are expanded preferentially with one or the other but not both. This indicates differences in the antigenic determinants of the two Burkitt's lines. The occurrence of this Raji variant line demonstrates that the stimulatory phenotype for Vgamma9/Vdelta2 cells can be acquired by some tumors independently of the loss of class I antigens and comforts the hypothesis of an anti-tumoral function for the Vgamma9/Vdelta2 T cell population.

Burkitt Lymphoma↗
PubMed1999

Inflammatory neutrophils secrete annexin 1 during experimentally induced colitis in rats.

Immunoblotting and immunohistochemical analysis were performed to identify the cells expressing and secreting annexin 1 during experimental rat colitis induced by trinitrobenzene sulfonic acid. Annexin 1 expression was increased during the inflammation. Likewise, annexin 1 secretion was induced in inflamed colons at one, three, six, and nine days after trinitrobenzene sulfonic acid treatment but was not detected in colons from controls and rats at 12 days. Immunohistochemistry showed that the rise in annexin 1 expression resulted from the infiltration of two types of leukocytes highly positive for annexin 1: neutrophils (the most abundant) and macrophages. At day 1 after treatment, neutrophils of the inflammatory site, in mucosa and submucosa, are the only cells expressing annexin 1. Immunoblotting showed that they secreted annexin 1 whereas neutrophils from blood or tunica muscularis did not. This indicates that, during this colitis, annexin 1 can be secreted by neutrophils located in the inflammatory site.

Animals↗
PubMed1999

Expression of apoptosis regulatory proteins of the Bcl-2 family and p53 in primary resected non-small-cell lung cancer.

Proteins of the Bcl-2 family as well as p53 are important regulators of apoptosis. Alterations in the expression of these proteins can contribute to the formation of cancer, as well as influence tumour response to chemo- and radiotherapy. We used antibodies specific for the human Bcl-2, Mcl-1, Bax, Bak and p53 proteins to examine the expression of these apoptosis-regulating genes in 49 archival specimens of patients with radically resected non-small-cell lung cancer (NSCLC). Tumour cells containing immunostaining for the antiapoptotic proteins Bcl-2 and Mcl-1 were present in 31% and 58% of the cases evaluated, respectively, whereas immunopositivity for the proapoptotic proteins Bax and Bak was found in 47% and 58% of the samples. p53 immunopositivity was detected in 61% of the samples. The expression of Bcl-2 and p53 and the expression of Mcl-1 and Bax showed a positive association (P = 0.02 and P = 0.06 respectively), whereas the expression of Bax was inversely related to p53 (P = 0.008). The expression of Bcl-2 had a negative influence on relapse-free survival in this population of primary resected NSCLC patients (P = 0.02). The expression of p53 and Bcl-2 was significantly associated with metastasis-free survival (P < 0.01). Only patients with p53-positive tumours developed metastases during the follow-up period. Our results establish the frequent expression of the Bcl-2 family proteins Bcl-2, Mcl-1, Bax and Bak in NSCLC. It can be expected that Bcl-2 family members have no straightforward impact on clinical outcome in this disease because their interactions in the regulation of apoptosis are complex.

Apoptosis↗
PubMed1999

Detection of the cell death-inducing protein BAK in Reed-Sternberg cells of Hodgkin's disease.

The expression of the cell death-inducing protein, Bak, was investigated in 41 cases of Hodgkin's disease and was correlated with Epstein-Barr virus (EBV) status. Overall, Bak immunostaining was observed in 35/41 cases (85%). Among the 22 EBV-positive cases, 20 cases (91%) expressed Bak while 15/19 EBV-negative cases (79%) contained Bak-positive Reed-Sternberg cells. The expression of Bak, as assessed by the staining intensity and the numbers of positive tumor cells, varied greatly from case to case but was high in 6 cases (15%). Our findings show that, similar to Bax, a second apoptosis-inducing gene Bak is frequently expressed in Hodgkin's disease. Whilst Bak is suspected to protect cells immortalized by EBV from apoptosis, its expression in Hodgkin's disease appears to be unrelated to the EBV status of Reed-Sternberg cells. Moreover, the potential pro-apoptotic functions related to Bak and Bax in Hodgkin's disease might be surpassed by a stronger expression of anti-apoptotic molecules thus explaining tumor progression.

Adolescent↗
PubMed1999

[CD30 positive pilotropic lymphoma].

BACKGROUND: We report an unusual case of cutaneous CD30-positive lymphoma with pilar tropism and circulating Sezary cells which had a rapidly fatal course. CASE REPORT: A 78-year-old man presented erythematous infiltration of the face, a pruriginous eruption on the trunk and proximal portions of the limbs with small erythematopurpuric follicular papulae, and node enlargement in the inguinal and axillary areas. The rest of the clinical examination was normal. Circulating Sezary cells were found in significant numbers on two different blood smears. Histologic and immunohistochemistry examination of a skin biopsy evidenced medium to large sized lymphoid cell infiltration in a perifollicular localization. A few small cells penetrated the pilar apparatus. There was no follicular mucinosis. The tumoral cells expressed CD2, CD3, CD4 and 75 p. 100 were positive for CD30. Node aspiration showed lymphomatous cells and CD3+ and CD30+ lymphomatous infiltration was found on marrow smears. A T clone was evidenced both in blood and bone marrow leading to the diagnosis of pilotropic CD30-positive lymphoma. Chlorambucil and prednisone were given. The patient died 5 months later. DISCUSSION: The cytology findings suggest medium to large cell pleomorphic lymphoma. The circulating Sezary cells, the pilotropic eruption, and the rapidly fatal outcome suggest transformation of a Sezary syndrome into CD30-positive large cell lymphoma which has been described in fungoid mycosis.

Aged↗