Annexin II can be recognized by antibodies in serum from patients with systemic autoimmune disorders. Further studies are required to determine the clinical significance of anti-annexin II antibodies in rheumatoid arthritis and to determine their diagnostic value in discriminating clinical subgroups of patients with antiphospholipid syndrome.

Although hepatocellular carcinoma (HCC) is one of the most common malignancies and constitutes the third leading cause of cancer-related deaths, the underlying molecular mechanisms are not fully understood. In the present study, we demonstrate for the first time that hepatocytes express signalling lymphocytic activation molecule family member 3 (SLAMF3/CD229) but not other SLAMF members. We provide evidence to show that SLAMF3 is involved in the control of hepatocyte proliferation and in hepatocellular carcinogenesis. SLAMF3 expression is significantly lower in primary human HCC samples and HCC cell lines than in human healthy primary hepatocytes. In HCC cell lines, the restoration of high levels of SLAMF3 expression inhibited cell proliferation and migration and enhanced apoptosis. Furthermore, SLAMF3 expression was associated with inhibition of HCC xenograft progression in the nude mouse model. The restoration of SLAMF3 expression levels also decreased the phosphorylation of MAPK ERK1/2, JNK and mTOR. In samples from resected HCC patients, SLAMF3 expression levels were significantly lower in tumorous tissues than in peritumoral tissues. Our results identify SLAMF3 as a specific marker of normal hepatocytes and provide evidence for its potential role in the control of proliferation of HCC cells.

In this study, we investigated the capacity of chronic lymphocytic leukemia (CLL) B cells to undergo terminal differentiation into Ig-secreting plasma cells in T cell-independent and T cell-dependent responses. We used a two-step model involving stimulation with phorbol myristate acetate (PMA) and CD40L, together with cytokines (PMA/c and CD40L/c), for 7 days. We describe immunophenotypic modifications, changes in the levels of mRNA and protein for transcription factors and morphological and functional events occurring during the differentiation of CLL B cells into antibody-secreting cells (ASCs). The induction of differentiation differed significantly between the CD40L/c and PMA/c culture systems. The PMA/c culture system allowed CLL B cells to differentiate into IgM-secreting cells with an immunophenotype and molecular profile resembling those of preplasmablasts. By contrast, CD40L/c-stimulated cells had a phenotype and morphology similar to those of activated B cells and resembling those of the CLL B cells residing in the lymph node and bone marrow. These data suggest that the CLL B cells are not frozen permanently at a stage of differentiation and are able to differentiate into ASCs as appropriate stimulation are provided. The data presented here raise questions about the molecular processes and stimulation required for CLL B-cell differentiation and about the inability of CD40 ligand to induce differentiation of the CLL B cells.

The interaction of the synthetic serum thymic factor (FTS, "facteur thymique serique") with human T lymphocytes from two established T The thymus gland has been shown to produce a number of factors or "hormones" that promote the differentiation of thymus-derived cells (T cells) and induce the appearance of their specific markers. We showed in 1971 that thymic extracts induce the appearance of the best-characterized of these markers, the 0 (Thy-i) antigen, on 0-negative bone marrow rosette-forming cells (1). It was ultimately demonstrated that there exists in normal serum an active principle with activity on rosette-forming cells identical to that of thymic extracts. The absence of this principle in serum from thymectomized or nude (athymic) mice demonstrated the strict thymic dependence of this factor (2).The molecule responsible for this activity has been isolated from pig serum and called "facteur thymique senique" (FTS). FTS is a nonapeptide whose amino acid sequence has been determined. FTS has been synthesized, and the synthetic material shows full biological activity and displays chromatographical characteristics identical to those of biological FTS in several chromatography systems (3, 4).The recent observation of the localization of antibodies directed against synthetic FTS on the thymic epithelium has provided direct demonstration of its thymic origin.tThe binding to specific receptors on its target cell is the first step in the action of a polypeptide hormone. It is thus of utmost importance for the understanding of the cellular mode of action of FTS to search for and characterize FTS receptors on lymphoid cells. With this in view, we have applied the methodology now well established for polypeptide hormones (5). This effort was significantly helped by the finding of two lymphoblastoid cell lines that showed high levels of FTS binding. MATERIALS AND METHODSLymphoblastoid Cell Lines. The initial lymphoblastoid T cell line (1301) was given by S. M. Fu and M. Fellous. It was derived from a leukocyte culture of a patient with acute lymphoblastic leukemia. Lymphocytes were maintained at 370C in RPMI 1640 essential medium, supplemented with 10% fetal calf serum, 1% glutamine, antibiotics and, Fungizone. The cells were used in the binding studies when they were in the stationary phase of growth. Their viability was determined by their capacity to exclude trypan blue dye. The T cell nature of the cell line was established by the study of its markers (6, 7). Results of these studies are presented in Table 1. Methods used for marker evaluation have been previously reported (6, 7). Other cell lines were also studied in less detail. The origin, nature and characteristics of these various cell lines are presented in Table 1.FiTS. Labeled [3H]FTS was prepared according to a method consisting of lysine methylation by use of 3H-labeled sodium borohydride and formaldehyde (8). Briefly, 1 mg of synthetic FTS (Choay, Paris, France) was incubated for 1 hr at 40C with 100 mCi of NaB3H4 and 1 mmol of formaldehyde...

B-cell chronic lymphocytic leukemia (CLL) is the most frequent adult leukemia in the Western world. It is a heterogeneous disease characterized by clonal proliferation and the accumulation of CD5+ mature B lymphocytes. However, the normal counterpart from which the latter cells arise has not yet been identified. CD27 expression and gene expression profiling data suggest that CLL cells are related to memory B-cells. In vitro, memory B-cells differentiate into plasma cells when stimulated with CpG oligodeoxynucleotide (CpG). The objective of the present study was therefore to investigate the ability of CpG, in the context of CD40 ligation, to induce the differentiation of CLL B-cells into antibody-secreting cells (ASCs). CD20+CD38− CLL B-cells were stimulated with a combination of CpG, CD40 ligand and cytokines (CpG/CD40L/c) in a two-step, 7-day culture system. We found that the CpG/CD40L/c culture system prompted CLL B-cells to differentiate into CD19+CD20+CD27+CD38−ASCs. These cells secreted large amounts of IgM and had the same shape as plasma cells. However, only IgMs secreted by ASCs that had differentiated from unmutated CLL B-cells were poly/autoreactive. Class-switch recombination (CSR) to IgG and IgA was detected in cells expressing the activation-induced cytidine deaminase gene (AICDA). Although these ASCs expressed high levels of the transcription factors PRDM1 (BLIMP1), IRF4, and XBP1s, they did not downregulate expression of PAX5. Our results suggest that CLL B-cells can differentiate into ASCs, undergo CSR and produce poly/autoreactive antibodies. Furthermore, our findings may be relevant for (i) identifying the normal counterpart of CLL B-cells and (ii) developing novel treatment strategies in CLL.

We have previously shown that Fas-induced apoptosis is markedly enhanced by IL-7 in human pre-B but not pro-B cell lines. In addition, pre-B cell receptor (pre-BCR) ligation significantly potentiates the IL-7 effects on Fas-triggered pre-B cell death. We show herein that transforming growth factor (TGF)-g 1 sharply reduces Fas-induced death rate of pre-B but not pro-B cells. TGF-g 1 causes inhibition of Fas-mediated disruption of mitochondrial transmembrane potential and cleavage of caspase 8, Bid and caspase 3. Bcl2 expression is markedly increased in TGF-g 1-treated pre-B cells, whereas cellular FLICE-like inhibitory protein long (c-FLIPL), Bcl-XL, Bax, and Bad expression remains unchanged. TGF-g 1 causes a selective growth arrest of pre-B cells in G0/G1 phase of the cell cycle and induces a partial down-modulation of both Fas and pre-BCR expression. All TGF-g 1-mediated effects, but Bcl2 up-regulation, can be reproduced by the LY294002 phosphatidylinositol 3-kinase (PI3K)/Akt inhibitor but not by inhibitors of the MAPK/ERK (MEK) and Janus kinase (Jak)/STAT pathways, which promote cell death. Akt phosphorylation is strongly inhibited by TGF-g 1 in pre-B but not pro-B cells and is not modified by Fas engagement. Altogether, our findings suggest that TGF-g 1 prevents Fas-induced apoptosis of pre-B lines by inhibiting PI3K pathway and by enhancing expression of Bcl2. They also suggest that the PI3K/Akt pathway is involved in the control of Fas and pre-BCR expression, a checkpoint in B cell development.

The transcription factors STAT5A and STAT5B (STAT: signal transducer and activator of transcription) play a major role in the signaling events elicited by a number of growth factor and cytokine receptors. In this work, we aimed to investigate the role of STAT5 in human precursor B cell survival by introducing dominant-negative (DN) forms of STAT5A or STAT5B in the 697 pre-B cell line. All clones expressing DN forms of either transcription factor exhibited a higher spontaneous apoptotic rate that was massively enhanced upon interleukin-7 (IL-7) stimulation. This was associated with caspase 8 cleavage, mitochondrial transmembrane potential disruption and caspase 3 activation. However, the DN forms of STAT5 did not alter the expression of Bcl-2, Bax, Bcl-x, Bim, A1 and Mcl1 proteins in IL-7-stimulated cells. The pancaspase inhibitor Z-Val-Ala-Asp-fluoromylmethyl ketone partially suppressed IL-7-mediated mitochondrial transmembrane potential disruption and cell death, suggesting that IL-7 induced the death of DN STAT5 expressing 697 cells through caspase-dependent and -independent mechanisms that both require mitochondrial activation.

Marked polyclonal immunoglobulin (Ig)G4 hypergammaglobulinemia has exceptionally been reported. Here we report on two Algerian patients who presented a syndrome characterized by anemia, plasmacytic lymphadenopathy, renal manifestations, and a marked polyclonal IgG4 hypergammaglobulinemia leading to a hyperviscosity syndrome in one case. The IgG4-expressing cell percentage was significantly increased in the peripheral blood lymphocytes collected from the two patients upon diagnosis. Moreover, in contrast with normal sera, both patients' sera significantly increased the percentage of IgG4-expressing cells when incubated with CD40-stimulated normal B lymphocytes. Similar effects were obtained with the culture supernatants of the patients' activated T cells. Anti-interleukin (IL) 4 and/or anti-IL-13 antibodies were unable to antagonize the IgG4 production. IL-4 and IL-13 serum concentrations were found to be normal in the two patients. The increased IgG4 production was found to be mediated by soluble factor(s), most probably secreted by activated T cells, which did not require the signal transducer and activator of transcription 6 signaling pathway.