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We selected a series of 63 primary diffuse large B-cell lymphomas (DLBCLs) of bone collected in tissue microarrays from centers in France and Brazil. These cases were classified according to the expression of antigens associated with germinal center (GC; n = 42) or non-GC (n = 21) stages of B-cell differentiation. By fluorescence in situ hybridization, we found a substantial number of cases with a rearrangement of BCL2 (9/32) and c -MYC (n = 3), whereas the PAX5, BCL6, BCL1 cyclin D1, and ALK genes were in germline configuration. It is interesting that 1 case, with a GC phenotype, showed dual BCL2 and c -MYC rearrangement. The majority of the cases with rearrangements were of the GC phenotype. These results, associated with the lack of BCL6 rearrangement, suggest that bone DLBCL represents a specific group within extranodal B-cell lymphomas. [ABSTRACT FROM AUTHOR]

We studied the distribution of lymphoid cells in the bone marrow of 10 follicular lymphoma (FL) cases in complete response after immunochemotherapy but with nodular lymphoid infiltrates mimicking persistent lymphoma nodules. Immunohistochemical analysis showed that most of these cells displayed a T-cell phenotype with important proportions of regulatory T cells (CD3+/CD4+/FOXP3+) and mast cells. These populations were also present before treatment. Whereas no CD20+ cells were observed, immature B cells (CD79a+/terminal deoxynucleotidyl transferase+/CD20-) were detected. These cells were scarce before immunochemotherapy, suggesting that immunochemotherapy enabled their expansion. Fluorescence in situ hybridization and quantitative polymerase chain reaction failed to detect residual lymphoma cells in 5 cases with the t(14;18) translocation. Our study describes 2 important features in bone marrow in FL following immunochemotherapy. It is probable that the accumulation of regulatory T cells has some role in the control of FL. The expansion of nonmalignant B cells reflects the regeneration of B-cell lineage following immunochemotherapy. [ABSTRACT FROM AUTHOR]

Abstract  Hepatitis E virus is a ribonucleic acid (RNA) enterically transmitted virus that causes both epidemics and sporadic cases of acute hepatitis E in many countries of Asia and Africa. Domestically acquired (non-travel-associated) hepatitis E has been reported recently in many industrialized countries including the USA, Europe, and Japan. There is little information available on liver histology in these patients. We report a series of 11 patients with sporadic acute hepatitis E and needle liver histology in South-West France. Hepatitis E was diagnosed based on elevated transaminases (>10 upper limit normal) and the presence of specific serum antibodies (immunoglobulin-G class, present in all 11 patients) and/or viral RNA detection in serum and/or stools. Acute hepatitis lesions were observed in all cases with marked necro-inflammatory activity in nine patients. Confluent necrosis was present in five cases. Anisocaryosis and Kupffer’s cell aggregates with siderosis were observed in most of the 11 patients. Cholangitis was frequent (9/11 cases). Cholestasis was observed in eight cases. Pseudo-glandular pattern was present in only one case but without zonal repartition. Characteristic pathological signs of acute hepatitis E were severe intralobular necrosis, polymorph inflammation, and acute cholangitis with numerous neutrophils. [ABSTRACT FROM AUTHOR]

Summary 1.A human glioma cell line, NG97, was established by Grippo et al. in 2001 from tissue obtained from a grade III astrocytoma (WHO, 2000). In this first study, the cell line grew as two morphologically distinct subpopulations: dendritic/spindle cells and small round cells. The injection of NG97 cells into nude mice induced an aggressive tumor characterized by: severe cytological atypia, vascular proliferation and pseudopalisading necrosis (glioblastoma multiforme features).2.The purpose of the present study was to characterize the immunophenotype and ultrastructural aspects of this cell line, using the parental tumor, cultured cells and the xenotransplant, in order to assess its glial nature and possible divergent differentiation.3.NG97 cells and xenotransplant expressed the main neuroglial markers (GFAP, S-100 protein, NSE and Leu-7) and showed no aberrant expression of other histogenetic markers. GFAP was similarly expressed in the parental tumor and in the cells in culture, but decreased in the xenotransplant. NSE expression was reduced in NG97 cells, but substantially recovered in the xenotransplant. This variability in expression of GFAP and NSE was interpreted as either a phenomenon of dedifferentiation or to microenvironmental selection of specific subclones. S-100 was equally expressed in the three contexts. The xenotransplant’s ultrastructural features were those of a highly undifferentiated tumor. No significant immunophenotypic or ultrastructural differences between the two morphologically distinct populations were found.4.Thus, our data demonstrate that NG97 cells constitute a pure glial-committed cell line, which may prove useful as a malignant glioma model in studies addressing pathophysiological, diagnostic and therapeutic issues. [ABSTRACT FROM AUTHOR]

Abstract Germinal centers (GCs) are the main site of T cell-dependent antibody responses. Upon antigen challenge, GCs comprise mostly B cells undergoing proliferation, somatic hypermutation and antigen-affinity selection. GC B cells down-modulate the expression of Bcl-2 protein and are highly sensitive to apoptosis to eliminate autoreactive or low-affinity cells. Bcl-2 is still expressed in a few GC cells, whose identity remains unclear. To address this issue, we examined by confocal microscopy the expression of Bcl-2 by different GC lymphocyte subsets in hyperplastic tonsils. We found that the vast majority of Bcl-2+ GC cells are T lymphocytes. Conversely, while in the mantle zone and in the interfollicular areas T cells are almost exclusively Bcl-2+, in the GC, most T lymphocytes are Bcl-2-. In addition, most of the CD4+ GC T cells are Bcl-2-, while nearly 100% of the CD8+ GC T cells are Bcl-2+. The Bcl-2 downregulation by both B and CD4+ T GC cells supports the concept that these two subsets may undergo a selection process in this microenvironment. [ABSTRACT FROM AUTHOR]