Establishment and Characterization of a Stromal Cell Line Derived From a Patient With Thoracic Endometriosis.

Thoracic endometriosis (TE) syndrome is a clinical condition known as an extrapelvic form of endometriosis with the presence of functioning endometrial tissue involving lung parenchyma, pleura, chest wall, or diaphragm. In an effort to obtain an endometriosis ex vivo model, we established the spontaneously growing TH-EM1 cell line from endometriotic implants in lung parenchyma from a woman with TE. Maintained in long-term culture, the cells grew as large mesenchymal-like cells with a doubling time between 5 and 6 days. Treatment with medroxyprogesterone acetate (10-7 mol/L) inhibited the TH-EM1 cells growth and induced morphological changes to an epithelial-like cells. Strong expression of the nuclear estrogen receptors, progesterone receptors, and erytropoietin receptors were found in both the pulmonary implant and the TH-EM1 cells by immunohistochemical analysis. Consistent immunoreactivity of TH-EM1 cells for CD9, CD13, CD73, CD90, CD105, and CD157 was revealed by flow cytometry. Likewise, the embryonic markers, SRY-box 2 (SOX-2) and the Nanog molecules, were detected in 76% and 52% of the cells, while fetal hemoglobin and a-globin were detected in 76% and 65% of TH-EM1 cells, respectively. By RHG banding, normal metaphases were observed, while the microarray chromosomal analysis showed gains of DNA sequences located on the segments 8p23.1, 11p15.5, and 12p11.23. The described in vitro cellular model can serve as a useful tool to study the pathogenesis of endometriosis and to improve the knowledge of molecular mechanisms controlling the endometriotic cell dissemination potential.

Establishment and Characterization of a Stromal Cell Line Derived From a Patient With Thoracic Endometriosis.

Thoracic endometriosis (TE) syndrome is a clinical condition known as an extrapelvic form of endometriosis with the presence of functioning endometrial tissue involving lung parenchyma, pleura, chest wall, or diaphragm. In an effort to obtain an endometriosis ex vivo model, we established the spontaneously growing TH-EM1 cell line from endometriotic implants in lung parenchyma from a woman with TE. Maintained in long-term culture, the cells grew as large mesenchymal-like cells with a doubling time between 5 and 6 days. Treatment with medroxyprogesterone acetate (10-7 mol/L) inhibited the TH-EM1 cells growth and induced morphological changes to an epithelial-like cells. Strong expression of the nuclear estrogen receptors, progesterone receptors, and erytropoietin receptors were found in both the pulmonary implant and the TH-EM1 cells by immunohistochemical analysis. Consistent immunoreactivity of TH-EM1 cells for CD9, CD13, CD73, CD90, CD105, and CD157 was revealed by flow cytometry. Likewise, the embryonic markers, SRY-box 2 (SOX-2) and the Nanog molecules, were detected in 76% and 52% of the cells, while fetal hemoglobin and α-globin were detected in 76% and 65% of TH-EM1 cells, respectively. By RHG banding, normal metaphases were observed, while the microarray chromosomal analysis showed gains of DNA sequences located on the segments 8p23.1, 11p15.5, and 12p11.23. The described in vitro cellular model can serve as a useful tool to study the pathogenesis of endometriosis and to improve the knowledge of molecular mechanisms controlling the endometriotic cell dissemination potential.

[Telomeres and telomerase: relevance and future prospects in systemic lupus erythematosus]. / Télomères et télomérase : intérêts et perspectives dans le lupus érythémateux systémique.

Telomeres are specialized structures that cap and protect the end of chromosomes. Telomeres progressively shorten after each cellular division unless an enzyme, the telomerase, counteracts. Telomeres are implicated in cellular senescence, acting like a biological clock. Telomere length and telomerase activity are important in the physiopathology of cancer. In the past years, research has focused on them in order to find new therapeutic targets. Yet, oxidative stress, inflammation and increased leucocytes renewal are major environmental factors associated with telomeres shortening acceleration and thus in concordance with biological age. Thus, telomeric erosion induces cell apoptosis; indeed, apoptotic cell clearance is impaired in systemic lupus. Considering these elements and data resulting from oncology, telomere/telomerase couple was studied during the last decade in systemic lupus erythematosus. The objective was to know if this couple could have an implication in the physiopathology of this disease. A systematic review of literature is proposed about telomere and/or telomerase in systemic lupus erythematosus in order to discuss their physiopathological implication. Among 273 tested patients, telomere seems to be eroded and telomerase activity insufficiently increased but correlated to the activity of the disease. The analysis of telomere length and telomerase activity could be useful as prognosis factor or disease activity index. Telomere erosion could reflect an accelerated replicative senescence of the immune system. The role of the regulator T lymphocytes has not yet been precised. Standardized studies on larger population could be realized in systemic lupus and open new avenues of research and/or therapy based upon the telomere/telomerase biology.

[Current concepts and treatment advances in systemic mastocytosis]. / Actualités sur la compréhension et le traitement des mastocytoses systémiques.

PURPOSE: Mast cell disorders are defined by an abnormal accumulation of tissue mast cells in one or more organ systems. Clinical symptoms in mastocytosis result from mast cells derived mediators and, less frequently, from destructive infiltration of mast cells. Systemic mastocytosis is regressive among children, whereas the disease is persistent among adults. A clonal haematological non-mast cell lineage disease can be associated. The clinical course in these patients is variable ranging from asymptomatic for years to highly aggressive and rapidly devastating. Until recently, the only treatment of this incurable disease was symptomatic. CURRENT KNOWLEDGE AND KEY POINTS: Recent advances were done in understanding the physiopathology of this myeloproliferative syndrome which results from an activating mutation of the stem cell factor receptor: C-Kit. A somatic C-Kit mutation is usually detectable in mast cells and their progenitors. Different mutations were found and the mutation D816V is the most frequent. Their specific transduction paths were also studied. Diagnosis of systemic mastocytosis does not only rest upon pathological examination but also on molecular as well as immunological and immunochemical tools. FUTURE PROSPECTS AND PROJECTS: Physiopathological advancements led to suggest new treatments in order to directly inhibit proliferative paths of masts cells such as tyrosine kinase inhibitors and rapamycin.

Recent advances in adult T-cell leukemia therapy: focus on a new anti-transferrin receptor monoclonal antibody.

HTLV-I is an endemic retrovirus responsible for the adult T-cell leukemia/lymphoma (ATLL). This aggressive lymphoid proliferation is associated with a bad prognosis due to the resistance of HTLV-I-infected cells to most classical chemotherapeutic agents. Here we review recent advances in ATLL immunotherapy. We particularly focus on promising data from our group, characterizing a new mouse monoclonal antibody (mAb A24) against the human transferrin receptor (TfR-1). Monoclonal antibodies to target cell differentiation markers on ATLL cells have already been proposed as therapeutic agents. However, in clinical trials acute forms of ATLL were resistant to these immunotherapies. A24 binds TfR-1 (K(d) 2.7 nM) and competes with transferrin for receptor binding. It blocks the proliferation of malignant cells (TfR-1(high)), such as HTLV-I-infected T cells but not of resting cells. A24 induces TfR-1 endocytosis in lysosomal compartments where the receptor is degraded leading to intracellular iron deprivation. In HTLV-I-infected cells, A24 targets and induces apoptosis of both chronic and acute ATLL forms, independent of antibody aggregation, antibody-dependent cellular cytotoxicity and/or complement addition. The antibody efficacy was confirmed in animal models. We are currently developing strategies to use A24 in clinical trials.

Differentiation of Langerhans cells in Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) consists of lesions composed of cells with a dendritic Langerhans cell (LC) phenotype. The clinical course of LCH ranges from spontaneous resolution to a chronic and sometimes lethal disease. We studied 25 patients with various clinical forms of the disease. In bone and chronic lesions, LCH cells had immature phenotype and function. They coexpressed LC antigens CD1a and Langerin together with monocyte antigens CD68 and CD14. Class II antigens were intracellular and LCH cells almost never expressed CD83 or CD86 or dendritic cell (DC)-Lamp, despite their CD40 expression. Consistently, LCH cells sorted from bone lesions (eosinophilic granuloma) poorly stimulated allogeneic T-cell proliferation in vitro. Strikingly, however, in vitro treatment with CD40L induced the expression of membrane class II and CD86 and strongly increased LCH cell allostimulatory activity to a level similar to that of mature DCs. Numerous interleukin-10-positive (IL-10(+)), Langerin(-), and CD68(+) macrophages were found within bone and lymph node lesions. In patients with self-healing and/or isolated cutaneous disease, LCH cells had a more mature phenotype. LCH cells were frequently CD14(-) and CD86(+), and macrophages were rare or absent, as were IL-10-expressing cells. We conclude that LCH cells in the bone and/or chronic forms of the disease accumulate within the tissues in an immature state and that most probably result from extrinsic signals and may be induced to differentiate toward mature DCs after CD40 triggering. Drugs that enhance the in vivo maturation of these immature DCs, or that induce their death, may be of therapeutic benefit.

A subset of human dendritic cells expresses IgA Fc receptor (CD89), which mediates internalization and activation upon cross-linking by IgA complexes.

Immature dendritic cells (DC) sample Ags within nonlymphoid tissues and acquire exogenous proteins/pathogens via scavenger receptors or Ig FcR such as Fc gamma R and Fc epsilon R. IgA is present in a significant proportion among serum Ig and is the main isotype in mucosae, where DC are numerous. We found that a functional Fc alpha R (CD89) was expressed in situ and in vitro on interstitial-type DC but not on Langerhans cell-type DC. Interstitial-type DC expressed CD89 as a 50- to 75-kDa glycoprotein with a 32-kDa protein core, which was down-regulated upon addition of TGF-beta 1. DC, Fc alpha R specifically, bound IgA1 and IgA2. Cross-linking of CD89 on DC triggered endocytosis in time-dependent manner. In addition, internalization of polymeric IgA complexes induced the production of IL-10 and DC activation, as reflected by up-regulation of CD86 costimulatory molecules, class II MHC expression, and increased allostimulatory activity. Therefore, interstitial-type DC may use Fc alpha R-mediated Ag sampling in the subepithelium to check tissue integrity while Langerhans cells inside epithelial layers may neglect IgA immune complexes.

Langerhans cell deficiency in reticular dysgenesis.

Reticular dysgenesis is a rare inherited immunodeficiency characterized by the lack of blood monocytes and neutrophils and low lymphocyte counts, contrasting with normal red blood cell counts and normal or decreased platelet counts. Whether dendritic cells or macrophages, both of which derive primarily from blood monocytes, are affected in this condition remains unknown. We studied 7 patients with reticular dysgenesis. Macrophages were present in normal numbers in the dermis and in the atrophic lymphoid tissues of these patients, proving that at least some subsets of macrophages can differentiate despite very low monocyte counts. By contrast, Langerhans cells, which are CD1a-positive epidermal dendritic cells, were absent in all (n = 5) patients before bone marrow transplantation. After bone marrow transplantation, Langerhans cells were present (n = 2), suggesting that the defect is not related to keratinocyte dysfunction. A split chimeric reconstitution, characterized by the presence of autologous blood monocytes able to differentiate in vitro into CD1a-positive dendritic cells, was observed in a patient who underwent successful engraftment. These results suggest that an intrinsic cell defect is unlikely and that a bone marrow-derived factor may be defective in reticular dysgenesis; it may be responsible for the Langerhans cell defect but not involved in macrophage differentiation.

TGF-beta 1 prevents the noncognate maturation of human dendritic Langerhans cells.

TGF-beta 1 is critical for differentiation of epithelial-associated dendritic Langerhans cells (LC). In accordance with the characteristics of in vivo LC, we show that LC obtained from human monocytes in vitro in the presence of TGF-beta 1 1) express almost exclusively intracellular class II Ags, low CD80, and no CD83 and CD86 Ags and 2) down-regulate TNF-RI (p55) and do not produce IL-10 after stimulation, in contrast to dermal dendritic cells and monocyte-derived dendritic cells. Surprisingly, while LC exhibit E-cadherin down-regulation upon exposure to TNF-alpha and IL-1, TGF-beta 1 prevents the final LC maturation in response to TNF-alpha, IL-1, and LPS with respect to Class II CD80, CD86, and CD83 Ag expression, loss of FITC-dextran uptake, production of IL-12, and Ag presentation. In sharp contrast, CD40 ligand cognate signal induces full maturation of LC and is not inhibited by TGF-beta 1. The presence of emigrated immature LCs in human reactive skin-draining lymph nodes provides in vivo evidence that LC migration and final maturation may be differentially regulated. Therefore, due to the effects of TGF-beta 1, inflammatory stimuli may not be sufficient to induce full maturation of LC, thus avoiding potentially harmful immune responses. We conclude that TGF-beta 1 appears to be responsible for both the acquisition of LC phenotype, cytokine production pattern, and prevention of noncognate maturation.