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Normal ageing is associated with an impaired systemic immune response contributing to an increased susceptibility to infectious diseases. The aim of this study was to compare the lymphocyte phenotype in human skin from old and young healthy subjects. Skin samples from donors were used for explant cultures before flow cytometric analysis. Our results depicted a higher proportion of CD4+ and a lower proportion of CD8+ among CD3+ T cells, a decreased proportion of CD45RA+ naive T cells (3.5 ± 1.9% vs 22.9 ± 11.1%, P ≤ 0.007) and an upregulation of the expression of CD39 and PD1 on CD3+ CD4+ T cells (25.1 ± 8.5% vs 12.5 ± 8.5%, P ≤ 0.003, 68.8 ± 11.6% vs 50.0 ± 11.3%, P ≤ 0.01, respectively) in the skin of old subjects. These findings could explain a reduced generation of long-lived memory T cells and an impaired antitumoral response in the skin of the elderly.

Introduction: Cancer-associated fibroblasts (CAFs), a component of tumor microenvironment, play a key role in oncogenesis and promote growth, invasion, metastasis and chemo-resistance of tumor cells. Our previous RNAseq results brought evidence of the contribution of dermal fibroblasts obtained from cutaneous T-cell lymphoma (CTCL) lesions to support tumor growth. Here, we further go on by analyzing the alteration of protein production by dermal fibroblasts obtained from CTCL lesions versus control fibroblasts. Materials and methods: Secretome and proteome was performed on fibroblast primary cultures skin biopsies of 6 cutaneous T-cell lymphoma (CTCL[GD1]) versus fibroblasts from healthy mammary skin controls (age-paired). The fibroblasts of the two groups were studied at the 3rd passage, after stimulation or not with 5 ng/ml TGF-β for 24 h. The supernatants and lysates collected underwent enzymatic digestion with trypsin before peptide analysis by HLPC/Mass spectrometry Results: The comparison of the secretomes from the CTCL groups (± TGF-s) and the control donors showed a global significant differential expression (fold >2, p-value 2, p-value Conclusion: The present data demonstrate the potent proteomic alteration of CTCL-associated dermal fibroblasts, confirming the involvement of mesenchymal cells on the behavior of CTCL.

Sezary syndrome (SS) is a rare, aggressive leukemic form of cutaneous T-cell lymphoma characterized by generalized erythroderma, lymphadenopathy and circulating malignant CD4+ T cells (Sezary cells). Sezary syndrome evolves very quickly, patients are severely immunocompromised and their quality of life is drastically impaired. SS prognosis remains dismal despite recent therapeutic advances. AAC-11 (Anti-Apoptosis Clone 11, also known as Api5) is a survival scaffold protein that is widely expressed in cancer cells. Recent data indicate that AAC-11 might to be one of the central molecules involved in cancer cell progression and survival. Therefore, its inactivation might constitute an attractive approach for developing novel cancer therapeutics. AAC-11 contains a heptad leucine repeat domain that constitutes a protein-protein interaction motif, allowing its interaction with several apoptosis regulatory proteins. Loss-of-function mutations of the heptad leucine repeat motif are responsible for a defect in the interaction with its binding partners and associated with an abolition of the survival properties of AAC-11. We have recently described cell penetrating peptides based on the fusion of penetratin and a portion of the heptad leucine repeat region of AAC-11 that can induce cancer cells death. This effect is not observed in normal cells, suggesting high therapeutic indices. Here we evaluated the anti-tumor effect of a novel AAC-11-derived peptide, termed RT39, in the context of Sezary syndrome. Our results demonstrate that RT39 exerts an efficient and specific cytotoxic activity towards Sezary cells, while sparring the other immune cell populations, both ex vivo on primary patient cells and in vivo in preclinical Sezary syndrome murine models. Mechanistic studies revealed that RT39 induces membranolysis of Sezary cells by means of binding to p21-activated kinase 1 (PAK1) in the context of Sezary cells plasma membrane, where PAK1 is overexpressed. Preliminary pharmacokinetic studies in mice indicated that, after intravenous, subcutaneous or intraperitoneal administration, the half-life of the peptide is of the order of 30 minutes, but the elimination phase is very prolonged with high AUCs, indicative of durable exposure. Along with excellent tolerability in mice, our preclinical results support the development of RT39 as a new therapeutic strategy in Sezary syndrome.

To the editor: Sezary syndrome (SS) is a rare, aggressive leukemic form of primary cutaneous T-cell lymphoma.[1][1] The diagnostic criteria associate a clonal T-cell receptor (TCR) rearrangement with peripheral Sezary cell (SC) counts of ≥1 G/L, an increased CD4/CD8 ratio of ≥10, CD4+CD7−

Purpose: KIR3DL2 is a recently discovered marker of the malignant clonal cell population in Sézary syndrome. We intended to evaluate the expression of KIR3DL2 on blood T cells as a diagnostic, prognostic, and follow-up marker of Sézary syndrome. Experimental Design: Sixty-four patients diagnosed with Sézary syndrome were included in this monocentric study. We collected the percentage of KIR3DL2+ cells among CD3+ T cells, obtained by flow cytometry, and other classical diagnostic criteria for Sézary syndrome at diagnosis and during the follow-up. Results: Compared with the classical diagnostic factors, KIR3DL2 was the most sensitive diagnostic factor for Sézary syndrome. Univariate and multivariate analyses established that an eosinophil cell count >700/mm3 and a percentage of KIR3DL2+ cells within the CD3+ T cells >85% at diagnosis were associated with a significantly reduced disease-specific survival. Moreover, KIR3DL2 immunostaining allowed the assessment of treatment efficiency and specificity toward tumor cells, the detection of the residual disease following treatment, and the occurrence of relapse, even though patients clinically experienced complete remission and/or undetectable circulating Sézary cells by cytomorphologic analysis. Conclusions: We show that KIR3DL2 expression is the most sensitive diagnostic criterion of Sézary syndrome when compared with all other available biological criteria. It also represents the best independent prognostic factor for Sézary syndrome–specific death and the most relevant feature for the follow-up of Sézary syndrome, showing the invasion of the functional lymphocytes pool by Sézary cells. KIR3DL2 therefore represents a valuable tool for routine use as a clinical parameter at diagnosis, for prognosis and during patient follow-up. Clin Cancer Res; 23(14); 3619–27. ©2017 AACR.

Background Embryo implantation remains the main limiting factor in IVF/ICSI program. Endometrial immune remodeling events begin before implantation and are a vital process for pregnancy, preparing future maternal immune tolerance and regulating the placentation process. Methods Between 2012 and 2014, 193 patients (analyzed group) enrolled in our IVF program benefitted of an endometrial immune profiling to determine if their uterus was immunologically ready to accept an embryo and, if not, the specific immune mechanisms involved. Subsequently, they had an effective embryo transfer (ET) with personalization of their treatments if an immune deregulation has been diagnosed. Each analyzed patient was paired to the closest patient included in the IVF program according to biological criteria (age, number of mature oocytes, stage and number of transferred embryo), which had no endometrial immune profiling (193 patients, non-analyzed group). Finding 78% of analyzed patients had a uterine immune dysregulation and therefore care personalization. Their corresponding live birth rate (LBR) was twice higher than observed in the matched control group with conventional cares (30.5% versus 16.6%, OR: 2.2 [1.27–3.83] p = 0.004) with a simultaneous drastic reduction of miscarriages per initiated pregnancy (17.9% versus 43.2%, OR: 0.29 [0.12–0.71], p = 0.005). 22% of analyzed patients had no dysregulation. They did not differ from their matched controls for LBR and miscarriages. Conclusion Uterine immune profiling enables an integrated approach of infertility that includes endometrial immunity as a key factor in planning personalized IVF/ICSI treatments. Personalization of treatment according to the woman’s uterine immune balance produced a very significantly higher LBR.

Psoriasis is a frequent inflammatory disease that involves mostly the skin and sometimes the joints. This chronic disease is rarely life-threatening but impairs significantly the patient's quality of life. It is characterized, in its typical form, by erythematous and squamous plaques with well-defined borders, associated with increased proliferation of the keratinocytes, inflammation and greater number of dilated blood vessels in the upper dermis. A role of Th1 CD4 T cells was initially suspected. More recently, Th17 CD4 T cells have been shown to play a major role in the disease. It has led to the development of Th17 inhibitors, such as anti-IL-23 (cytokine that induces Th17 CD4 T cell differentiation), anti-IL-17, anti-IL-17RA (IL-17 receptor) and anti-IL-22 (cytokines that are notably produced by Th17 CD4 T cells).

Purpose Anti-angiogenic agents stand first in the treatment of neovascular diseases of the retina. CD160 appeared in several experimental studies as a marker of activated endothelial cells, suggesting it could represent a promising target for novel anti-angiogenic therapies. The aim of the present study was to assess the distribution of CD160 in the human eye, and to search for a possible correlation with retinal neovascular diseases. Methods The physiological distribution of CD160 in the normal eye was assessed with immunolabeling in 10 human donor eyes. Then, in a retrospective cohort of 75 surgical retinal specimens, the density of CD160+ microvessels was evaluated, along with immunolabeling on serial sections against ERG (pan-endothelial cell marker), CD105 (activated endothelial cell marker), and α-SMA (pericyte cell marker). The cohort was divided into two groups: 29 patients with neovascular disease (NV+) and 46 control patients (NV-). Results CD160 was physiologically expressed by several cell types: endothelial cells of retinal blood vessels, ganglion cells, macrophages, epithelial cells of the conjunctiva, ciliary body, and retinal pigment epithelium. In the patient cohort, the percentage of CD160+ vessels in the retina was significantly and independently higher in patients suffering from neovascular diseases (P = 0.04). On the contrary, the expression of CD105 was correlated neither with retinal neovascular diseases, nor with CD160 expression. Conclusions CD160 was expressed in some retinal vessels in both normal and pathologic eyes. CD160 expression by endothelial cells of retinal vessels was correlated with ocular neovascular diseases. CD160 could therefore represent an interesting target for novel anti-angiogenic therapies.

Introduction Corticotherapy is the leading medication worldwide for patients with history of repeated implantation failures (RIF) after IVF/ICSI. Nevertheless, we still do not know its local mechanism of action, hence its precise indication. Our objective is to document the impact of prednisone on the endometrial expression of immune biomarkers (CD56 cells count, IL-18/TWEAK, IL-15/Fn-14 mRNA ratio) at the time of uterine receptivity in a RIF population. Materials and method An endometrial biopsy was realized in the mid luteal phase for immune profiling: IL-15/Fn-14 and IL-18/TWEAK mRNA ratios were determined by quantitative RT-PCR and CD56 mobilization per IHC. Fifty-five patients with a RIF history were diagnosed to have local over-immune activation [high IL-18/TWEAK mRNA ratio, and/or high IL-15/Fn-14 mRNA ratio] likely to impair the implantation process. They underwent a second immune profiling with supplementation of prednisone. A paired comparison of the immune profile before and under prednisone was performed in the subset of patients subsequently pregnant under prednisone. Finding In 54.5% of the cases, both immune biomarkers were normalized and in 16.5%, only one was normalized under prednisone. In 29% we observed a paradoxical increase of both immune biomarkers. The IL-18/TWEAK mRNA ratio reflecting the Th-1/Th-2 local equilibrium was significantly reduced (0.29 versus 0.10, p = .004), through very significant increase of TWEAK expression, in patients who were subsequently pregnant under prednisone. Conclusion Testing the response to prednisone in a RIF context may be very useful. Less than half of RIF patients with immune deregulation may be prednisone responders and would benefit from its administration.

Reproductive immunology applies general immunology principles to specialised targets, reproduction and development. The involvement of colony-stimulating factors (CSFs) in reproduction illustrates this. The CSF family includes CSF-1 or macrophage CSF (M-CSF), CSF-2 or granulocyte macrophage CSF (GM-CSF), and CSF-3 or granulocyte CSF (G-CSF). Each member has a specific localisation and timed expression in the reproductive tract with specific functions involving them in ovulation, embryo implantation, placentation and further embryonic development. They are used in reproductive medicine, either as biomarkers of oocyte quality and competence (follicular G-CSF), or to supplement embryo culture media with human recombinant GM-CSF, or they are used as an innovative therapy by using human recombinant G-CSF for infertile patients. Given fundamental considerations on CSFs and their strong implication in reproduction, this review aimed to detail the current knowledge for each member of the family to improve our understanding of their implication in the maternal–foetal cytokinic dialogue and in possibly preventing reproductive disorders.

The ectonucleotidases CD39 and CD73 hydrolyze extracellular adenosine triphosphate (ATP) and adenosine diphosphate (ADP) to generate adenosine, which binds to adenosine receptors and inhibits T-cell and natural killer (NK)–cell responses, thereby suppressing the immune system. The generation of adenosine via the CD39/CD73 pathway is recognized as a major mechanism of regulatory T cell (Treg) immunosuppressive function. The number of CD39+ Tregs is increased in some human cancers, and the importance of CD39+ Tregs in promoting tumor growth and metastasis has been demonstrated using several in vivo models. Here, we addressed whether CD39 is expressed by tumor cells and whether CD39+ tumor cells mediate immunosuppression via the adenosine pathway. Immunohistochemical staining of normal and tumor tissues revealed that CD39 expression is significantly higher in several types of human cancer than in normal tissues. In cancer specimens, CD39 is expressed by infiltrating lymphocytes, the tumor stroma, and tumor cells. Furthermore, the expression of CD39 at the cell surface of tumor cells was directly demonstrated via flow cytometry of human cancer cell lines. CD39 in cancer cells displays ATPase activity and, together with CD73, generates adenosine. CD39+CD73+ cancer cells inhibited the proliferation of CD4 and CD8 T cells and the generation of cytotoxic effector CD8 T cells (CTL) in a CD39- and adenosine-dependent manner. Treatment with a CD39 inhibitor or blocking antibody alleviated the tumor-induced inhibition of CD4 and CD8 T-cell proliferation and increased CTL- and NK cell–mediated cytotoxicity. In conclusion, interfering with the CD39–adenosine pathway may represent a novel immunotherapeutic strategy for inhibiting tumor cell–mediated immunosuppression. Cancer Immunol Res; 3(3); 254–65. ©2014 AACR.

We previously identified the NK cell receptor KIR3DL2 as a valuable diagnostic and prognostic marker for the detection of the tumoral T cell burden of Sezary syndrome (SS) patients. However, the function of this receptor on the malignant T lymphocyte population remained unexplored. We here demonstrate that engagement of KIR3DL2 by its recently identified ligand CpG oligodeoxynucleotide (ODN) induces the internalization of the receptor and leads to a caspase-dependent apoptosis of malignant T cells. This process of cellular death is correlated to a dephosphorylation of the transcription factor STAT3 (signal transducer and activator of transcription 3), which is found constitutively phosphorylated and activated in Sezary cells. Our results indicate that KIR3DL2 can directly promote SS malignant cell death through the use of CpG ODN.

To the editor: KIR3DL2, a killer immunoglobulin-like receptor normally expressed by a subset of natural killer (NK) cells, is aberrantly expressed in Sezary syndrome (SS), an aggressive cutaneous T-cell lymphoma (CTCL). In SS patients, the detection of KIR3DL2 expression on circulating tumor cells

BACKGROUND: Male androgenetic alopecia (AGA) is the most common form of hair loss in men and is characterized by a distinct pattern of progressive hair loss starting from the frontal area and the vertex of the scalp. Although several genetic risk loci have been identified, relevant genes for AGA remain to be defined. OBJECTIVES: Herein, molecular biomarkers associated with premature AGA were identified through gene expression analysis using cDNA generated from scalp vertex biopsies of hairless/bald men with premature AGA and healthy volunteers. RESULTS: This monocentric study reveals that genes encoding mast cell granule enzymes, inflammatory and immunoglobulin-associated immune mediators were significantly over-expressed in AGA. In contrast, under-expressed genes appear to be associated with the Wnt/β-catenin and BMP/TGF-β signaling pathways. Although involvement of these pathways in hair follicle regeneration is well-described, functional interpretation of the transcriptomic data highlights different events that account for their inhibition. In particular, one of these events depends on the dysregulated expression of proopiomelanocortin (POMC), as confirmed by RT-qPCR and immunohistochemistry. In addition, lower expression of CYP27B1 in AGA subjects supports the notion that changes in vitamin D metabolism contributes to hair loss. CONCLUSION: This study provides compelling evidence for distinct molecular events contributing to alopecia that may pave way for new therapeutic approaches. This article is protected by copyright. All rights reserved.

Allogeneic human cardiac-derived stem/progenitor cells (hCPC) are currently under clinical investigation for cardiac repair. While cellular immune response against allogeneic hCPC could be part of their beneficial-paracrine effects, their humoral immune response remains largely unexplored. Donor-specific HLA antibodies (DSA-HLA-I/DSA-HLA-II), primary elements of antibody-mediated allograft injury, might present an unidentified risk to allogeneic hCPC therapy. Here we established that the binding strength of anti-HLA monoclonal antibodies delineates hCPC proneness to antibody-mediated injury. In vitro modeling of clinical setting demonstrated that specific DSA-HLA-I of high/intermediate binding strength are harmful for hCPC whereas DSA-HLA-II are benign. Furthermore, the Luminex-based solid-phase assays are suitable to predict the DSA-HLA risk to therapeutic hCPC. Our data indicate that screening patient sera for the presence of HLA antibodies is important to provide an immune-educated choice of allogeneic therapeutic cells, minimize the risk of precipitous elimination and promote the allogeneic reparative effects.

Advanced cutaneous T-cell lymphoma (CTCL) remains an unmet medical need, which lacks effective targeted therapies. In this study, we report the development of IPH4102, a humanized monoclonal antibody that targets the immune receptor KIR3DL2, which is widely expressed on CTCL cells but few normal immune cells. Potent antitumor properties of IPH4102 were documented in allogeneic human CTCL cells and a mouse model of KIR3DL2+ disease. IPH4102 antitumor activity was mediated by antibody-dependent cell cytotoxicity and phagocytosis. IPH4102 improved survival and reduced tumor growth in mice inoculated with KIR3DL2+ tumors. Ex vivo efficacy was further evaluated in primary Sézary patient cells, sorted natural killer–based autologous assays, and direct spiking into Sézary patient peripheral blood mononuclear cells. In these settings, IPH4102 selectively and efficiently killed primary Sézary cells, including at unfavorable effector-to-target ratios characteristic of unsorted PBMC. Together, our results offer preclinical proof of concept for the clinical development of IPH4102 to treat patients with advanced CTCL. Cancer Res; 74(21); 6060–70. ©2014 AACR.

Human T cell clones and a cDNA probe specific for constant regions of the beta subunit of the antigen/major histocompatibility complex (MHC) receptor, TiC beta 1 and TiC beta 2, were employed to determine whether these genes were differentially used by functional classes of T lymphocytes. DNA from 10 interleukin-2-dependent T cell clones including class I and class II MHC-specific cytotoxic T lymphocytes (n = 6), T4+ inducer T lymphocytes (n = 2), and T8+ suppressor T lymphocytes (n = 2) showed rearrangement of the TiC beta 1 gene on Southern blot analysis with or without deletion of the other TiC beta 1 allele. In contrast, TiC beta 2 always remained in germline configuration. Moreover, the finding that one additional suppressor clone deleted both TiC beta 1 alleles, maintained a germline TiC beta 2 configuration, and yet actively transcribed TiC beta 2 message suggested that TiC beta 2 is not a pseudogene. Rather, it appeared to be used less frequently than the TiC beta 1 gene and in the absence of detectable DNA rearrangements. Together, these results demonstrate that the functional repertoire (or isotype) of a given subclass of T cells is not encoded within the Ti beta genes.

By using several monoclonal antibodies (mAb) reacting either with the constant or variable regions of the T cell receptors (TcR) αβ and γδ or various CD molecules, differences between two clinically related entities e.g. T cell acute lymphoblastic leukemia (T-ALL) and lymphoblastic lymphoma (T-LL) have been demonstrated. We studied a panel of fifteen T-ALL and fifteen T-LL because of their cell surface expression of the CD3-TcR molecules. The results indicated that TcR γδ is more frequently expressed in T-ALL (10 out of the 15 patients tested) than TcR αβ. This is in contrast to the results obtained with T-LL where the vast majority showed TcR αβ (13 out of the 15 patients). We discuss the significance of these findings which may imply that the leukemic cells are of a different origin in these two diseases. In addition analysis of TcR variable regions expressed by the leukemic blasts showed that in most cases they had rearranged functional Vδ1 gene to Jδ1 or Jδ2 segments (8 out of 11 patients) whereas in a unique case Vδ2 gene segment was evident. Taken together these results and those showing that T-ALL cells coexpress the CD1a, b and c molecules strengthen the possibility that despite the fact that these leukemic cells express the CD3-TcR complex at their surface their normal counterparts are not found in peripheral blood.

Regulatory T cells (Tregs) are a subpopulation of CD4(+) T cells that are essential for maintaining the homeostasis of the immune system, limiting self-reactivity and excessive immune responses against foreign antigens. In cancer, infiltrated Tregs inhibit the effector lymphocytes and create a favorable environment for the growth of the tumor. Although Tregs mediate immunosuppression through multiple, non-redundant, cell-contact dependent and independent mechanisms, a growing body of evidence suggests an important role for the CD39-CD73-adenosine pathway. CD39 ectonucleotidase is the rate-limiting enzyme of a cascade leading to the generation of suppressive adenosine that alters CD4 and CD8 T cell and natural killer cell antitumor activities. Here, we review the recent literature supporting CD39 as a promising therapeutic target in oncology. In vitro and in vivo experiments involving knockout models and surrogate inhibitors of CD39 provide evidence in support of the anticancer activity of CD39 inhibition and predict a favorable safety profile for CD39 inhibitory compounds. In addition, we report the ongoing development of CD39-blocking monoclonal antibodies as potential anticancer drugs. Indeed, CD39 antagonistic antibodies could represent novel therapeutic tools for selectively inhibiting Treg function without depletion, a major limitation of current Treg-targeting strategies.

PIGA mutations in paroxysmal nocturnal hemoglobinuria (PNH) patients lead to a glycosylphosphatidylinositol (GPI)-linked membrane proteins expression deficiency. Herein, we report the constitutive expression of the transmembrane CD160 (CD160-TM) activating receptor on non PIGA-mutated PNH patients circulating NK cells. In healthy individuals, only the GPI-anchored isoform of CD160 receptors is expressed on the circulating NK lymphocytes, while the transmembrane isoform appears after ex vivo activation. Similarly to CD160-GPI, we identified CD160-TM as a receptor for the MHC class I molecules. We demonstrate that PNH patients NK lymphocytes spontaneously produce significant amounts of IFN-γ that is inhibited by anti-CD160-TM or anti-MHC class I mAbs. These results indicate that circulating NK cells from PNH patients exhibit a self-MHC class I molecule reactive effector function, which could be mediated through the recruitment of CD160-TM receptor. Our data provide new insights regarding the possible role of CD160-TM on PNH patients NK lymphocytes and in the pathogenesis of the disease.

Labeled problem Embryo implantation remains the main limiting factor in assisted reproductive medicine (20% success rate). Methods of study An endometrial immune profiling was performed among 394 women with the previous history of repeated embryo implantation failures (RIF). The endometrial immune profile documented the ratio of IL‐15/Fn‐14 mRNA as a biomarker of uNK cell activation/maturation (together with the uNK cell count) and the IL‐18/TWEAK mRNA ratio as a biomarker of both angiogenesis and the Th1/Th2 balance. According to their profile, we recommended personalized care to counteract the documented dysregulation and assessed its effects by the live birth rate (LBR) for the next embryo transfer. Results Endometrial immune profiles appeared to be dysregulated in 81.7% of the RIF patients compared to control. Overactivation was diagnosed in 56.6% and low activation in 25%. The LBR among these dysregulated/treated patients at the first subsequent embryo transfer was 39.8%. Conclusion Endometrial immune profiling may improve our understanding of RIF and subsequent LBR if treated.

The natural cytotoxicity receptors NKp30, NKp44, and NKp46 were identified as activating receptors mainly expressed by natural killer (NK) lymphocytes. In this study we show that peripheral blood malignant CD4(+) T lymphocytes from patients with Sézary syndrome, an aggressive form of cutaneous T-cell lymphoma, express NKp46 at their cell surface. Although NKp46 does not behave as an independent functional receptor, its engagement provides a strong inhibiting signal on the malignant T lymphocyte CD3-induced proliferation. We show that this inhibition is correlated with a decreased phosphorylation of the CD3ζ chain associated with NKp46 and/or the TCR/CD3 complexes. Our results reveal that in addition to KIR3DL2/CD158k expression, NKp46 could represent an additional marker on the circulating malignant T lymphocytes of Sézary patients, where it displays an as yet unreported function of inhibitory co-receptor able to interfere with the processes governing their CD3-dependent proliferation.

Objective.It was recently reported that CD101 surface expression discriminates potency among CD4+CD25+ FoxP3+ regulatory T cells in the mouse. We investigated whether CD101 may also have a role in the suppressor function of regulatory T cells in humans given that the latter population may affect the autoimmune response in patients with rheumatoid arthritis (RA).Methods.Sorted T cells and monocyte/macrophage cell populations were analyzed by flow cyto metry using conjugated antibodies specific for cell-surface markers. T cell proliferation assays were conducted by [3H]thymidine incorporation and CD8highcytotoxicity measurements by Cyto-Scan-LDH cytotoxicity assays. ELISA were used to measure cytokines in cell culture supernatants and Western blotting was performed for profiling mitogen-activated protein (MAP) kinase activation using specific antiphospholipid antibodies.Results.CD101 expression coincided with PMA-induced monocyte/leukocyte lineage differentiation. CD8highCD101− T cells exhibited greater cytotoxic activity than CD8highCD101+ T cells, while no difference was observed between CD4CD25highCD101+ and CD4CD25highCD101− Treg inhibitory activity through responder T cells. LPS-induced proinflammatory cytokine production and p38 MAP kinase activation were made possible by ligation of CD101 with an anti-CD101 antibody F(ab’)2fragment.Conclusion.These results suggested a modulatory/coregulatory function of CD101 in the human immune system, in contrast to murine models, in which CD101 surface expression discriminates potency among FoxP3+ regulatory T cells. Cytotoxic CD8highCD101+ T cells were markedly less cytotoxic than CD8highT cells negative for the CD101 antigen and were conspicuously downregulated in patients with RA, suggesting a possible role for CD101 expression and function in the control of certain manifestations of RA pathology.

Background CD158k/KIR3DL2 is a specific marker for Sezary cells which can be used to diagnose Sezary syndrome (SS) in erythrodermic patients with abnormal circulating T cells. Objectives To evaluate the suitability of CD158k/KIR3DL2 for detecting and evaluating blood tumour load during the follow up of patients with SS. Methods The absolute CD3+ CD158k+ lymphocyte count was compared with the absolute count of cytomorphological Sezary cells and was correlated with clinical flares in a cohort of patients with SS. Twenty-five patients were included in the study and 48 blood samples were analysed. Results The absolute count of CD3+ CD158k+ cells strongly correlated with the absolute count of atypical circulating cells (r = 0.97, P < 10(-15)). The CD3+ CD158k+ lymphocyte cell count was in eight cases more sensitive than cytomorphology for detecting atypical circulating cells especially for small-sized tumour cells. The tumour burden evaluated by CD3+ CD158k+ immunostaining was significantly associated with clinical flare (P < 10(-4)). Conclusions CD3+ CD158k+ phenotyping is a reliable and objective test to monitor the blood tumour burden in patients with SS under systemic therapy.

Notre systeme de defense immunitaire est extremement sophistique… Et il est aise de s’egarer dans le dedale des multiples sous-populations cellulaires dont il dispose pour nous defendre des agressions exterieures ou d’un dysfonctionnement interieur, sous-populations qu’il est possible aujourd’hui d’identifier grâce aux progres de l’analyse en cytometrie de flux associee a l’utilisation des anticorps monoclonaux specifiques de marqueurs de surface cellulaires. L’expression simultanee de differents antigenes a la surface d’une meme cellule permet d’etablir un phenotype caracteristique d’une population cellulaire. Mais il faut se mefier des apparences, et en l’absence de recepteurs indiscutables comme le TCR (T cell receptor) pour les lymphocytes T ou le BCR (B cell receptor ) pour les lymphocytes B, classer une cellule dans telle ou telle population sur le seul phenotype peut etre hasardeux. Ceci d’autant que, pour compliquer le tout, le phenotype des effecteurs du systeme immunitaire varie selon qu’ils sont au repos ou actives.

Natural killer (NK) cells are part of the innate immune system and help to protect against infections and tumour transformation by eliminating affected cells. NK cells become activated upon target cell recognition through the integration of signals provided by both activating and inhibitory receptors. Ligands recognized by these receptors include major histocompatibility complex class I, stress-induced molecules, adhesion proteins and other molecules that are used by NK cells to identify cells to be killed. This recognition constitutes the basis of NK immunosurveillance, and its full understanding is important for therapeutic purposes, such as haploidentical bone marrow transplantation for haematological malignancies. Human NK cells are also found abundantly in the uterine decidua during early pregnancy. Besides a detrimental role in reaction to the semi-allogeneic fetus, these uterine NK cells help to create a balanced environment for the conceptus, influencing important processes such as blastocyst implantation, trophoblast invasion and spiral artery development. This review summarizes the different aspects of human NK cell biology implicated in immunosurveillance.

Pathogenesis of allergic inflammatory disorders is characterized by allergen-induced IgE stimulated by Th2 cytokines including mainly IL-4 overproduction. To counteract IL-4 effects in sensitized-BALB/c mice, we prepared an IL-4 derivative immunogen, made of KLH and murine IL-4 heterocomplex, termed mIL-4 kinoid. Murine IL-4 kinoid immunized mice produced high titer of anti-IL-4 neutralizing Abs. In contrast to KLH control immunization kinoid immunization reversed the allergic IgE:IgG ratio hallmark in rBet v 1a sensitized mice and reduced pulmonary eosinophil recruitment and bronchial hyperreactivity in Ova-sensitized mice. These data pave the way to alternative therapies to combat allergic conditions.

CD160 is a glycosylphosphatidylinositol-anchored cell surface molecule expressed by human circulating cytotoxic lymphocytes that correspond to the majority of natural killer cell (NK) expressing CD56 dim , TCR γδ lymphocytes, and to a minor CD8 T-cell subset. CD160 engagement by major histocompatibility complex class I molecules triggers by itself both cytotoxic function and cytokine production in NK lymphocytes, whereas it provides co-activating signals to TCR-induced proliferation in T CD8+ lymphocytes. In this study, we analyzed by immunohistochemistry the phenotype of lymphocytes infiltrating normal skin and inflammatory skin lesions of atopic dermatitis, contact dermatitis, and psoriasis. We identified a minor original subset of CD4 + CD160 + T cells infiltrating inflammatory lesions. We found that this lymphocyte subset localization is not restricted to the skin, as we demonstrated that CD160 transcripts could be induced in IL-2 or IL-15-activated CD4 + peripheral blood lymphocytes. Finally, we report that CD160 acts as a co-activator receptor for CD3-induced proliferation of CD4 + CD160 + T cells isolated from inflammatory skin lesions. Thus, we hypothesize that the unique CD4 + CD160 + lymphocyte subset plays a role in the pathogenesis of skin inflammation.

Dermal fibroblasts play a key role in maintaining skin homoeostasis by synthesizing and degrading extracellular matrix components. During ageing, they are subjected to changes, such as the loss of type I collagen expression and an increased synthesis of metalloproteinase I, leading to fragmentation of collagen fibrils with consequent reduction of the mechanical tension and defects of skin wound healing. Most information about fibroblast ageing was obtained from experiments performed on replicative-senescent dermal fibroblasts in vitro. However, the senescence status of fibroblasts isolated from intrinsically aged skins and its consequences on functionality need to be deeper investigated. Herein, we studied age-related phenotypic and functional alteration of fibroblasts from 'young' (35 years) and 'old' (50 years) donors. Our results brought evidence of the senescent status of 'old' fibroblasts by senescence associated β-galactosidase (SA-βgal) positive staining and p16 expression. A PCR array focusing on senescence highlighted a subset of downregulated genes including cell cycle progression and ECM genes in 'old' fibroblasts as well as a subset of upregulated genes involved in senescence features. In 'old' fibroblasts, we measured a downregulation of proliferative and contractile capacities of migratory potential under PDGF stimulation and activation into myofibroblasts under TGFβ. Old fibroblasts were also more sensitive to oxidative stress than 'young' ones. Of interest, downregulation of p16 expression partially reversed the senescent phenotype of 'old' fibroblasts but failed to restore their functional properties. In conclusion, our data brought evidence of phenotypic and functional differences between fibroblasts from young and intrinsically aged skin that may contribute to the alterations observed with ageing.

Identification of malignant Sézary cells by T-cell receptor (TCR) clonality studies is routinely used for the diagnosis of Sézary syndrome, but T-cell clones expressed in a single patient have never been accurately characterized. We previously reported that CD158k expression delineates Sézary syndrome malignant cells, and, more recently, we identified vimentin at the surface membranes of Sézary cells and normal activated lymphocytes. In the present study, T-cell clones from 13 patients with Sézary syndrome were identified by immunoscopy and further characterized in the blood according to their TCR Vβ, CD158k, and vimentin cell-surface expression. We found in most patients a unique malignant T-cell clone that coexpressed CD158k and vimentin and that, when patients were tested, was also present in the skin. However, in some patients we detected the presence of a nonmalignant circulating clone expressing high amounts of vimentin and lacking CD158k. These results indicate that clonal expansion may originate from circulating malignant and nonmalignant CD4+ T cell populations in patients with Sézary syndrome. Identification of the malignant cells in Sézary syndrome cannot be achieved by T-cell clonality studies or by TCR Vβ monoclonal antibody (mAb) analysis alone; it also relies on CD158k phenotyping.

Human decidual NK cells are massively recruited at the site of embryonic implantation ( decidua basalis ). They differ in many ways from their peripheral blood NK cell counterparts in terms of gene expression, phenotype and functionality. The major subpopulation of decidual NK cells is CD56 bright whereas the minor subset is CD56 dim , contrasting with the peripheral blood NK cells whose major subpopulation is CD56 dim . Decidual NK cell cytolytic function is much reduced despite the presence of several activating receptors and the essential machinery required for lysis. Decidual NK cells produce a number of cytokines that are not normally secreted by peripheral blood NK cells. Human decidual NK cell potential functions at the maternal–fetal interface are not yet clearly established but several hypotheses are being evaluated, including control of extravillous invasion, control of uterine vascular remodeling, and local anti-viral activity.

Les lymphomes T cutanés sont liés à l’accumulation, dans la peau, de lymphocytes T matures mémoires à tropisme cutané. La forme la plus fréquente est le mycosis fongoïde, le syndrome de Sézary représentant la forme disséminée avec cellules tumorales circulantes. La physiopathologie et la progression tumorale restent mal comprises, mais plusieurs découvertes récentes suggèrent le développement possible de nouvelles possibilités thérapeutiques : mise en évidence de plusieurs antigènes exprimés par les lymphocytes T tumoraux, voies de signalisation impliquées dans la résistance à l’apoptose, possibilités de stimulation de l’immunité innée. La mise en évidence récente de signatures moléculaires devrait également permettre de mettre au point de nouveaux marqueurs diagnostiques et pronostiques., Primary cutaneous T cell lymphomas (CTCL) represent the most frequently occurring group of extra-nodal T cell lymphomas, originating from skin-homing memory T cells. Sezary syndrome (SS) is a leukemic variant of CTCL that presents with erythroderma, lymphadenopathies and presence of malignant T cells in peripheral blood. SS has an unfavourable prognosis, and is refractory to current treatments. Progress in understanding the pathogenesis and tumor progression of SS is limited. In the past few years, we have identified and reported several CTCL-associated antigens, CD158k/KIR3DL2, CD85j/ILT2, and SC5/vimentin. KIR3DL2 is the first phenotypic marker of Sezary cells that can be used for the diagnostic and follow-up of Sezary syndrome. The SC5 antibody is the only monoclonal antibody reacting with vimentin on the surface of viable Sezary cells. CTCL are characterized by a predominance of Th2 cytokines. The recent suggestion that CTCL cells could be regulatory T (Tr) cells remains controversial. Gene expression studies suggest that in the future we may develop new diagnostic and prognostic tools, and identify subsets of patients who would benefit from more appropriate treatment protocols. Future challenges are to render tumor cells sensitive to apoptosis by inhibiting specific signalling pathways such as the constitutively activated NF-KB pathway, to identify specific surface kinase receptors and to develop specific inhibitors, to develop humanized monoclonal antibodies directed against tumor specific antigens, able to kill tumor cells via complement-dependent and antibody-dependent cytotoxicity, and to stimulate innate immunity.

We investigated the circulating cytotoxic CD160+ CD8(high) subset in correlation to antiviral immunity and response to highly active antiretroviral therapy (HAART) in HIV+ subjects. The study included 45 treatment-naive patients receiving HAART for 18 months, retrospectively defined as good (n=29) and transient (n=16) responders. HIV-specific CD8 T lymphocyte levels were measured by IFNgamma production in response to p17 Gag, in the presence of immobilized anti-CD160 mAb. We report a significantly increased baseline level of CD160+ CD8(high) subset in good therapy responders. CD160+ CD8(high) subset correlates with CD4+ T cell count, immune activation, and viral load. CD160+ CD8(high) lymphocytes contain a high amount of Granzyme B and include virus-specific T lymphocytes in HIV-1+ subjects. Co-stimulation through CD160 molecules enhances IFNgamma production in response to p17 Gag. Therefore, the CD160+ CD8(high) subset may be useful for monitoring of virus-specific cellular immunity and predicting response to antiretroviral therapy in chronic HIV-1 infection.

CD158k molecules belong to the family of killer cell immunoglobulin-like receptors (KIR) that are expressed on a minor population of circulating NK and CD8+ T lymphocytes. Here, we report a strong positive correlation between the percentage of CD158k+ blood lymphocytes analyzed by flow cytometry and the percentage of atypical circulating cells (Sezary cells) determined by cytomorphology in a large group of patients with Sezary syndrome. Moreover, we show that circulating CD4+CD158k+ lymphocytes correspond to the malignant clonal cell population. Our findings suggest that the CD158k marker could be a useful tool for the evaluation of the circulating tumoral burden and the follow-up of patients with Sezary syndrome.

Circulating malignant Sezary cells are a clonal proliferation of CD4 + CD45RO + T lymphocytes primarily involving the skin. To study the biology of these malignant T lymphocytes, we tested their ability to migrate in chemotaxis assays. Previously, we had shown that the neuropeptide neurotensin (NT) binds to freshly isolated Sezary malignant cells and induces through NT 1 receptors the cell migration of the cutaneous T cell lymphoma cell line Cou-L. Here, we report that peripheral blood Sezary cells as well as the Sezary cell line Pno fail to migrate in response to neurotensin although they are capable of migrating to the chemokine stromal-cell-derived factor 1α. This is in contrast with normal circulating CD4 + or CD8 + lymphocytes, which respond to both types of chemoattractants except after ex vivo short-time anti-CD3 monoclonal antibody activation, which abrogates the neurotensin-induced lymphocyte migration. Furthermore, we demonstrate that neurotensin-responsive T lymphocytes express the functional NT 1 receptor responsible for chemotaxis. In these cells, but not in Sezary cells, neurotensin induces recruitment of phosphatidylinositol-3 kinase, and redistribution of phosphorylated cytoplasmic tyrosine kinase focal adhesion kinase and filamentous actin. Taken together, these results, which show functional distinctions between normal circulating lymphocytes and Sezary syndrome cells, contribute to further understanding of the physiopathology of these atypical cells.

Extensive phenotype analysis of cutaneous T-cell lymphoma (CTCL) malignant cell lines revealed surface expression of receptors usually not detected on normal circulating CD4+CD45RO+lymphocytes. We previously found that CTCL malignant cells express the killer cell immunoglobulinlike receptor (KIR) KIR3DL2/CD158k, whereas they fail to express the other KIRs. In the present study, we report for the first time that the CD85j/immunoglobulin (Ig)–like transcript 2 (ILT2) receptor is found on Sézary cell lines and on circulating Sézary malignant CD4+ cells, while it is hardly detectable on circulating CD4+ lymphocytes from healthy individuals. We demonstrate that ILT2 is functional on CTCL cells, as its triggering leads to the recruitment of Src homology 2 domain-containing tyrosine phosphatase (SHP-1) and to the specific inhibition of CTCL malignant cell proliferation induced by CD3/T-cell receptor (TCR) stimulation. Interestingly, we found that separated CD4+ILT2+ circulating malignant Sézary cells are less susceptible to anti-CD3 monoclonal antibody (mAb)–induced cell death than autologous CD4+ILT2− lymphocytes. Therefore, the resistance to apoptosis of Sézary cells may result from distinct mechanisms including cytokine-induced high levels of bcl-2 and specific expression of inhibitory receptors involved in lymphocyte survival.

Toxic epidermal necrolysis is an extremely severe drug reaction, manifesting itself by widespread apoptosis of keratinocytes, generally considered to result from Fas/CD95-FasLigand interaction, but of unknown primary mechanism. We looked at the role of cells present in the skin blisters as probable effectors of this immune reaction. In a patient suffering from cotrimoxazole-induced toxic epidermal necrolysis, blister fluid cells were phenotyped by FACS and tested without prior restimulation for cytotoxicity on autologous and allogeneic cells in the presence of the drug. Blister fluid lymphocytes were predominantly CD8+, DR+, CLA+, CD56+ T lymphocytes, perforin positive and expressing preferentially two Vbeta chains of the T cell receptor repertoire. These lymphocytes were cytotoxic only in the presence of the drug towards autologous EBV transformed lymphocytes and towards allogeneic cells sharing HLA-Cw4. Cytotoxicity occurred in the presence of either cotrimoxazole, sulfamethoxazole, or the nitroso metabolite of sulfamethoxazole, but not with the hydroxylamine metabolite of sulfamethoxazole. The lysis was blocked by an anti-MHC class I monoclonal antibody. It was abolished by EGTA and CMA, but neither by anti-fas, brefeldin A, nor by anti-TRAIL receptor monoclonal antibodies, strongly suggesting perforin/granzyme-mediated cytotoxicity, without implication of Fas or TRAIL at this stage. This is direct evidence that T lymphocytes present within the lesions of toxic epidermal necrolysis may exhibit, without any re-stimulation, a drug-specific cytotoxicity against autologous cells. Harboring the markers of classical CTL and MHC class I restriction these lymphocytes reacted against the parent drug and one of its reactive metabolites. These results challenge several current concepts and could support new therapeutic approaches.

One part of the human placenta in early pregnancy is particularly important for local immunity: the decidua basalis, which is transformed endometrium located at the site of embryo implantation. This placental bed tissue contains both maternal uterine immune cells, including decidual natural killer (NK) cells, the dominant leukocyte population exhibiting a unique phenotype, and fetal extravillous trophoblast which comes into direct contact with maternal decidual cells. To establish a successful placental development and healthy pregnancy outcome, the maternal immune system must tolerate paternal antigens expressed by trophoblast cells yet remain efficient for clearing any local pathogen infection. This review deals mainly with decidual NK cells. A key element, among others, to achieve such dual functions is the direct interaction between activating and inhibitory receptors expressed by decidual NK cells and their specific ligands presented by trophoblast or other decidual cells. Depending whether maternal decidual cells and trophoblast are infected by viruses, the balance between activating and inhibitory receptor signals mediated by decidual NK cell–trophoblast cross-talk results in tolerance (healthy pregnancy) or specific killing (pathogen-infected cells).

Cutaneous wound healing requires keratinocyte proliferation, migration and differentiation to restore the barrier function of the skin. The calcineurin/nuclear factor of activated-T-cell (NFAT) signaling pathway has been recently shown to be involved in keratinocyte growth, differentiation and migration. It is induced by an increased intracellular calcium rate and its inhibition results in decreased capacities of keratinocytes to migrate. Nevertheless, the link between calcineurin activation and keratinocyte migration remains unknown. Recently, Orai1, a pore subunit of a store-operated calcium channel that favors calcium influx, was shown to play a critical role to control proliferation and migration of basal keratinocytes. Of interest, the actin-bundling T-plastin is crucial in cell motility through cross-linking to actin filament and its synthesis was shown to be induced by calcium influx and regulated by the calcineurin/NFAT pathway in tumor Sezary cells. We investigated herein the role of the calcineurin/NFAT pathway-dependent T-plastin in keratinocyte migration, by quantifying T-plastin expression in keratinocytes and by analyzing their migration under calcineurin inhibition or knockdown of NFAT2 or T-plastin. We did confirm the role of the calcineurin/NFAT pathway in keratinocyte migration as shown by their decreased capacities to migrate after FK506 treatment or siNFAT2 transfection in both scratching and Boyden assays. The expression of NFAT2 and T-plastin in keratinocytes was decreased under FK506 treatment, suggesting that T-plastin plays a role in keratinocyte migration downstream to the calcineurin/NFAT pathway. Accordingly, siRNA knockdown of T-plastin expression also decreased their migration capacities. Actin lamellipodia formation as well as FAK and β6-integrin expression were also significantly decreased after treatment with FK506 or siRNA, reinforcing that NFAT2-dependent T-plastin expression plays a role in keratinocyte migration. These results indicate that T-plastin might be considered as a major actor in the mechanisms underlying calcineurin/NFAT-dependent keratinocyte migration and may explain wound-healing defects observed in patients under calcineurin inhibitor long-term treatment.

IntroductionRecombinant human Granulocyte-Colony Stimulating Factor (rhG-CSF) supplementation seems to be a promising innovative therapy in reproductive medicine, used in case of recurrent miscarriage, embryo implantation failure or thin endometrium, although its mechanisms of action remain unknown. Our aim was to identify possible endometrial pathways influenced by rhG-CSF.Materials and methodsHypothetical molecular interactions regulated by G-CSF were designed through a previous large scale endometrial microarray study. The variation of endometrial expression of selected target genes was confirmed in control and infertile patients. G-CSF supplementation influence on these targets was tested on an endometrial ex-vivo culture. Middle luteal phase endometrial biopsies were cultured on collagen sponge with or without rhG-CSF supplementation during 3 consecutive days. Variations of endometrial mRNA expression for the selected targets were studied by RT-PCR.ResultsAt the highest dose of rhG-CSF stimulation, the mRNA expression of these selected target genes was significantly increased if compared with their expression without addition of rhG-CSF. The selected targets were G-CSF Receptor (G-CSFR), Integrin alpha-V/beta-3 (ITGB3) implicated in cell migration and embryo implantation, Plasminogen Activator Urokinase Receptor (PLAUR) described as interacting with integrins and implicated in cell migration, Thymidine Phosphorylase (TYMP) implicated in local angiogenesis, CD40 and its ligand CD40L involved in cell proliferation control.ConclusionRhG-CSF seems able to influence endometrial expressions crucial for implantation process involving endometrial vascular remodelling, local immune modulation and cellular adhesion pathways. These variations observed in an ex-vivo model should be tested in-vivo. The strict indications or counter indication of rhG-CSF supplementation in reproductive field are not yet established, while the safety of its administration in early pregnancy on early embryogenesis still needs to be demonstrated. Nevertheless, rhG-CSF appears as a promising therapy in some difficult and unsolved cases of reproductive failure. Indications of pre-conceptual rhG-CSF supplementation may derive from a diagnosed lack of endometrial expression of some target genes.

International audience; We have previously reported that a subset of breast tumors are infiltrated with IL-17A-producing tumor-associated lymphocytes and that IL-17A cytokine is principally associated with estrogen receptor negative (ER-) and triple negative, basal-like tumors. We established that IL-17A producing lymphocytes induced cancer cell proliferation, chemoresistance, and invasion, indicating that IL-17A is a potential therapeutic target for breast malignancies.

We tested the immunosuppressive effect of cord blood (CB) natural killer (NK) cells using highly purified CB NK cells in mixed lymphocyte cultures (MLC) containing autologous CB T cells as responders. Control cultures were done without NK cells. Our findings revealed that CB NK cells induced a dose-dependent inhibition of T lymphocyte proliferation as evidenced by decreased 3H-thymidine incorporation in MLC. The T cell alloproliferation was significantly decreased in the presence of an NK cell to responder cell ratio of 0.1, 0.2 or 0.4 compared with control cultures done without NK cells (p=0.02, 0.003 and 0.0002, respectively). T lymphocyte inhibition was also achieved using irradiated CB NK cells and still demonstrable on addition of disparate CB NK and T cells to the MLC. In agreement with previous reports, adult blood NK cells inhibited the alloreactive T cells in the MLC using adult T lymphocytes as responders. Compared to control cultures done without NK cells, statistically significant inhibition of 3H-thymidine incorporation in MLC was observed at a ratio of NK cells to responder cells ratio of 0.2 or 0.4 (p=0.02). To investigate the mechanism whereby CB NK cells can interfere with the development of alloreactive T cells in MLC, we measured the tumour necrosis factor-alpha (TNF-alpha) concentrations in MLC supernatants using NK cell-depleted or unseparated CB mononuclear cells (MNC) as responders. The results revealed significantly high levels of TNF-alpha in the absence of NK cells (p=0.007). We conclude that CB NK cells suppress alloreactive T lymphocytes as do their counterparts in adult blood. However, the high NK to T cell ratio in CB could contribute to a more marked suppressive potential compared to that in adult blood. The mechanism of NK-mediated inhibition is likely related to disruption of the TNF-alpha pathway of T-lymphocyte activation.

CD100 is a human 150-kDa homodimer expressed at the surface of most hemopoietic cells, and its gene belongs to the Ig and semaphorin gene families. Semaphorin genes encode soluble and membrane-bound proteins, most of which have been shown to act as chemorepellents on growth cone guidance. CD100 is discrete, as it is a transmembrane leukocyte surface molecule that can also exist in a soluble form. While our previous studies using mAbs suggested that the transmembrane form of CD100 plays a role in lymphocyte activation, no function was shown for its soluble form. Here, we investigated the effect of soluble CD100 in a cell migration assay; both CD100 spontaneously shed from a stable transfectant and soluble recombinant CD100 inhibited spontaneous and chemokine-induced migration of human monocytes. Interestingly, only the dimeric form of CD100 exerted an effect. Moreover, soluble CD100 inhibited migration of cells from monocytic and B cell lineages. A similar inhibitory effect on migration was observed with H-SemaIII, but not H-SemaIV, semaphorins. In addition, both CD100 and H-SemaIII were recognized by two CD100 mAbs in an ELISA, and one of these mAb abolished the inhibitory effect of each of these semaphorins. We also provide evidence that CD100 and H-SemaIII act through the same receptor on immune cells, which is not neuropilin-1. Furthermore, we describe a function on immune cells for H-SemaIII, a semaphorin to date only studied in the nervous system.

Tumor cells of patients with cutaneous T-cell lymphoma (CTCL) have the cell surface phenotype of mature T-helper lymphocytes, and it may be impossible to differentiate them from nonmalignant lymphocytes in skin and blood. Until now, no specific cell membrane marker of CTCL has been reported. In the current study, it is reported for the first time that CTCL cells express the major histocompatibility complex class I binding p140–killer cell immunoglobulin-like receptor, which has been described on a minor subset of natural killer lymphocytes and on a marginal circulating CD8+ T lymphocyte subset. Interestingly, the molecular characterization of this KIR expressed by CTCL allowed us to isolate a novel allelic form of p140–KIR3DL, resulting in 4 amino acid substitutions, 3 in the extracellular immunoglobulin-like domain of the protein and one in the cytoplasmic region. This finding is likely to be important both for the pathophysiology and for the clinical treatment of patients with CTCL.