Cutibacterium acnes (Propionibacterium acnes) and acne vulgaris: a brief look at the latest updates

While the commensal bacterium Propionibacterium acnes (P. acnes) is involved in the maintenance of a healthy skin, it can also act as an opportunistic pathogen in acne vulgaris. The latest findings on P. acnes shed light on the critical role of a tight equilibrium between members of its phylotypes and within the skin microbiota in the development of this skin disease. Indeed, contrary to what was previously thought, proliferation of P. acnes is not the trigger of acne as patients with acne do not harbour more P. acnes in follicles than normal individuals. Instead, the loss of the skin microbial diversity together with the activation of the innate immunity might lead to this chronic inflammatory condition. This review provides results of the most recent biochemical and genomic investigations that led to the new taxonomic classification of P. acnes renamed Cutibacterium acnes (C. acnes), and to the better characterisation of its phylogenetic cluster groups. Moreover, the latest data on the role of C. acnes and its different phylotypes in acne are presented, providing an overview of the factors that could participate in the virulence and in the antimicrobial resistance of acne-associated strains. Overall, this emerging key information offers new perspectives in the treatment of acne, with future innovative strategies focusing on C. acnes biofilms and/or on its acne-associated phylotypes

TCR Analyses of Two Vast and Shared Melanoma Antigen-Specific T Cell Repertoires: Common and Specific Features

Among Immunotherapeutic approaches for cancer treatment, the adoptive transfer of antigen specific T cells is still a relevant approach, that could have higher efficacy when further combined with immune check-point blockade. A high number of adoptive transfer trials have been performed in metastatic melanoma, due to its high immunogenic potential, either with polyclonal TIL or antigen-specific polyclonal populations. In this setting, the extensive characterization of T cell functions and receptor diversity of infused polyclonal T cells is required, notably for monitoring purposes. We developed a clinical grade procedure for the selection and amplification of polyclonal CD8 T cells, specific for two shared and widely expressed melanoma antigens: Melan-A and MELOE-1. This procedure is currently used in a clinical trial for HLA-A2 metastatic melanoma patients. In this study, we characterized the T-cell diversity (T-cell repertoire) of such T cell populations using a new RNAseq strategy. We first assessed the added-value of TCR receptor sequencing, in terms of sensitivity and specificity, by direct comparison with cytometry analysis of the T cell populations labeled with anti-Vß-specific antibodies. Results from these analyzes also confirmed specific features already reported for Melan-A and MELOE-1 specific T cell repertoires in terms of V-alpha recurrence usage, on a very high number of T cell clonotypes. Furthermore, these analyses also revealed undescribed features, such as the recurrence of a specific motif in the CDR3α region for MELOE-1 specific T cell repertoire. Finally, the analysis of a large number of T cell clonotypes originating from various patients revealed the existence of public CDR3α and ß clonotypes for Melan-A and MELOE-1 specific T cells. In conclusion, this method of high throughput TCR sequencing is a reliable and powerful approach to deeply characterize polyclonal T cell repertoires, and to reveal specific features of a given TCR repertoire, that would be useful for immune follow-up of cancer patients treated by immunotherapeutic approaches

Double Positive CD4CD8 αβ T Cells: A New Tumor-Reactive Population in Human Melanomas

BACKGROUND: Double positive (DP) CD4CD8 Talphabeta cells have been reported in normal individuals as well as in different pathological conditions including inflammatory diseases, viral infections and cancer, but their function remains to be elucidated. We recently reported the increased frequency of DP Talphabeta cells in human breast pleural effusions. This manuscript addresses the question of the existence and above all the role of this non-conventional DP sub-population among tumor associated lymphocytes in melanomas. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the intratumoral cell infiltrate in solid metastasis (n = 6) and tumor invaded lymph nodes (n = 26) samples from melanomas patients by multiparametric cytometry. Here we documented for the first time significant increased frequency of DP T cells in about 60% of melanoma tumors compared to blood samples. Interestingly, a high proportion of these cells produced TNF-alpha in response to autologous melanoma cell lines. Besides, they are characterized by a unique cytokine profile corresponding to higher secretion of IL-13, IL-4 and IL-5 than simple positive T cells. In deep analysis, we derived a representative tumor-reactive DP T cell clone from a melanoma patient's invaded lymph node. This clone was restricted by HLA-A*2402 and recognized both autologous and allogeneic tumor cells of various origins as well as normal cells, suggesting that the target antigen was a ubiquitous self antigen. However, this DP T cell clone failed to kill HLA-A*2402 EBV-transformed B cells, probably due to the constitutive expression of immunoproteasome by these cells. CONCLUSIONS/SIGNIFICANCE: In conclusion, we can postulate that, according to their broad tumor reactivity and to their original cytokine profile, the tumor associated DP T cells could participate in immune responses to tumors in vivo. Therefore, the presence of these cells and their role will be crucial to address in cancer patients, especially in the context of immunotherapies

Value of large scale expansion of tumor infiltrating lymphocytes in a compartmentalised gas-permeable bag: interests for adoptive immunotherapy

<p>Abstract</p> <p>Background</p> <p>Adoptive cell therapy (ACT) has emerged as an effective treatment for patients with metastatic melanoma. However, there are several logistical and safety concerns associated with large-scale <it>ex vivo </it>expansion of tumour-specific T lymphocytes for widespread availability of ACT for cancer patients. To address these problems we developed a specific compartmentalised bag allowing efficient expansion of tumour-specific T lymphocytes in an easy handling, closed system.</p> <p>Methods</p> <p>Starting from lymph nodes from eight melanoma patients, we performed a side-by-side comparison of Tumour-Infiltrating Lymphocytes (TIL) produced after expansion in the compartmentalised bag versus TIL produced using the standard process in plates. Proliferation yield, viability, phenotype and IFNγ secretion were comparatively studied.</p> <p>Results</p> <p>We found no differences in proliferation yield and cell viability between both TIL production systems. Moreover, each of the cell products complied with our defined release criteria before being administered to the patient. The phenotype analysis indicated that the compartmentalised bag favours the expansion of CD8+ cells. Finally, we found that TIL stimulated in bags were enriched in reactive CD8+ T cells when co-cultured with the autologous melanoma cell line.</p> <p>Conclusions</p> <p>The stimulation of TIL with feeder cells in the specifically designed compartmentalised bag can advantageously replace the conventional protocol using plates. In particular, the higher expansion rate of reactive CD8+ T cells could have a significant impact for ACT.</p

Characterisation of Cutibacterium acnes phylotypes in acne and in vivo exploratory evaluation of Myrtacine®

OBJECTIVE : Our main objective was to compare Cutibacterium acnes (C. acnes) skin colonisation in patients with mild to moderate acne versus healthy controls and secondly, to evaluate a Myrtacine® -based cream on C. acnes total population and antibioresistant Cutibacteria in patients with acne. METHODS:In 60 acne patients (Global Acne Severity Scale, GEA grades 2-3), of mean age 20 [15-30] years and in 24 age- and sex- matched healthy controls, forehead strips samplings were performed for microbiological analysis of comedones by colony forming unit (CFU) counts of global C. acnes and erythromycin (EryR) or clindamycin-resistant (ClnR) populations of Cutibacterium and determination of phylotypes by MALTI-TOF. Clinical evaluations of acne patients (GEA, lesion count, porphyrin fluorescence) were performed at baseline and after 56 days of twice-daily application of a Myrtacine® -based cream. RESULTS : We first showed (i) high and similar levels of C. acnes colonisation in superficial pilosebaceous follicles and detection of EryR and ClnR strains in both acne and control groups; (ii) different repartition of phylotypes in acne patients versus healthy control, with a predominance of phylotype IA in acne patients and a link between phylotype IA and erythromycin resistance. Besides, after treatment with the Myrtacine® -based cream in acne patients, there was no change in C. acnes total load, but a significant decrease of EryR Cutibacteria, reduced porphyrin production by C. acnes, a decrease in acne severity (GEA), associated with reduced retentional and inflammatory lesions. CONCLUSION : Cutibacterium acnes colonisation was not significantly different in acne versus control groups. Phylotype IA was predominant in acne patient and in EryR C. acnes. A Myrtacine® -based cream significantly reduced the level of EryR Cutibacteria in vivo and improved acne lesions

Clinical Study Adoptive TIL Transfer in the Adjuvant Setting for Melanoma: Long-Term Patient Survival

Two first analyses of our clinical trial on TIL as adjuvant therapy for melanoma were published in 2002 and 2007. We present here an update of the clinical results after a 17-year median followup. In this trial, disease-free patients were randomly assigned to receive either TIL/IL-2 or IL-2. The relapse-free survival (RFS) was the primary objective. Eighty-eight patients were enrolled. A new analysis performed in May 2013 did not show significant changes in RFS or OS duration. However, our first finding on the association between the number of invaded lymph nodes and TIL effectiveness was strengthened. The Cox model adjusted on this interaction showed for the first time a significant treatment effect when considering the overall population, both on the RFS and OS. Patients treated with TIL had a longer RFS ( = 0.023) or OS ( = 0.020). This study being with a very long followup (17 years), confirmed the association between TIL effectiveness and the number of invaded lymph nodes, indicating that a low tumor burden could be a crucial factor enhancing the curative effect of TIL in possible microscopic residual disease. Moreover, we confirmed that a prolonged survival was associated with the presence of specific TIL and a decrease in Foxp3 expression

Ultrafast electron microscopy study of irreversible transformations in nanosystems

Le travail de la thèse a pour but d'étudier des transitions irréversibles dans des nano-systèmes qui changent leurs structures, leurs dimensions ou leurs phases en nanosecondes sous des impulsions laser. Les expériences ont été réalisées à l’aide d’un microscope électronique ultrarapide (UTEM). La première série d'expériences a étudié une réaction chimique rapide, à savoir la réduction des nanocristaux d'oxyde de nickel en nickel élémentaire avec une seule impulsion laser infrarouge de quelques nanosecondes. Une image détaillée de ce mécanisme irréversible a été obtenue avec une résolution spatiale nanométrique et une résolution temporelle nanoseconde. La morphologie microscopique, la structure cristalline, la composition élémentaire ainsi que l’évolution temporelle du système ont été étudiées en imagerie, en diffraction électronique et en spectroscopie perte d'énergie des électrons. Une deuxième étude a été faite où on a montré que la formation des phases métal-carbone amorphes est possible en exposant des nanocristaux de fer et de cobalt encapsulés dans des coquilles graphitiques à des impulsions laser IR nanoseconde.The aim of the thesis is the study of irreversible transitions in nanosystems that change their structure, dimension, or phase within nanoseconds under laser irradiation. The experiments were realized by using an ultrafast electron microscope (UTEM). In the first set of experiments, a fast-chemical reaction was studied, namely the reduction of nickel oxide nanocrystals to elemental nickel with a single nanosecond infrared laser pulse. A detailed picture of this irreversible reaction has been obtained with nanometer spatial and nanosecond temporal resolution. The microscopic morphology, the crystal structure, the elemental composition as well as the temporal evolution of the system were studied by imaging, electron diffraction and electron energy-loss spectroscopy. A second study followed where it was shown that the formation of amorphous metal-carbon phases is possible by exposing nanocrystals of iron and cobalt encapsulated in graphitic shells to nanosecond infrared laser pulses

Ultrafast electron microscopy study of irreversible transformations in nanosystems

Le travail de la thèse a pour but d'étudier des transitions irréversibles dans des nano-systèmes qui changent leurs structures, leurs dimensions ou leurs phases en nanosecondes sous des impulsions laser. Les expériences ont été réalisées à l’aide d’un microscope électronique ultrarapide (UTEM). La première série d'expériences a étudié une réaction chimique rapide, à savoir la réduction des nanocristaux d'oxyde de nickel en nickel élémentaire avec une seule impulsion laser infrarouge de quelques nanosecondes. Une image détaillée de ce mécanisme irréversible a été obtenue avec une résolution spatiale nanométrique et une résolution temporelle nanoseconde. La morphologie microscopique, la structure cristalline, la composition élémentaire ainsi que l’évolution temporelle du système ont été étudiées en imagerie, en diffraction électronique et en spectroscopie perte d'énergie des électrons. Une deuxième étude a été faite où on a montré que la formation des phases métal-carbone amorphes est possible en exposant des nanocristaux de fer et de cobalt encapsulés dans des coquilles graphitiques à des impulsions laser IR nanoseconde.The aim of the thesis is the study of irreversible transitions in nanosystems that change their structure, dimension, or phase within nanoseconds under laser irradiation. The experiments were realized by using an ultrafast electron microscope (UTEM). In the first set of experiments, a fast-chemical reaction was studied, namely the reduction of nickel oxide nanocrystals to elemental nickel with a single nanosecond infrared laser pulse. A detailed picture of this irreversible reaction has been obtained with nanometer spatial and nanosecond temporal resolution. The microscopic morphology, the crystal structure, the elemental composition as well as the temporal evolution of the system were studied by imaging, electron diffraction and electron energy-loss spectroscopy. A second study followed where it was shown that the formation of amorphous metal-carbon phases is possible by exposing nanocrystals of iron and cobalt encapsulated in graphitic shells to nanosecond infrared laser pulses

Conception et mise en place d'un dossier médical informatisé en dermato-cancérologie

Dans le domaine du mélanome, l'utilisation de nouvelles thérapies ciblées révolutionne la prise en charge des patients et suppose de disposer d'informations cliniques précises exhaustives à la fois dans le cadre des soins au patient mais également pour la recherche translationnelle. Le dossier médical personnel (DMP) et le dossier communiquant de cancérologie (DCC) ne remplissent pas ces exigences. L'objectif de ce travail est de concevoir un dossier clinique informatisé pour l'unité de dermato-cancérologie du CHU de Nantes. Dans une première partie, nous avons mené une enquête sur l'avancée de l'informatisation à 3 échelles (locale, nationale et européenne). Dans un second temps, nous avons défini l'ensemble des items nécessaires et pertinents pour ce dossier informatisé. Le projet à terme est de construire à partir de ce dossier une base de données clinico-biologique initialement nantaise puis française dans le cadre du réseau Mélanome afin de pouvoir améliorer la prise en charge médicale des patients atteints de mélanome mais aussi promouvoir la recherche translationnelle dans ce domaine.NANTES-BU Médecine pharmacie (441092101) / SudocSudocFranceF

Is antigen specificity the key to efficient adoptive T‑cell therapy?

International audienceAdoptive transfer of T cells remains a promising approach in melanoma. Initial clinical trials performed with polyclonal tumor-infiltrating lymphocyte gave limited clinical results. Nonetheless, encouraging results have been reported in adjuvant setting (stage III melanoma), and when tumor-infiltrating lymphocytes were associated with lymphodepleting regimens. Specificity of adoptive cell therapy has been achieved with the infusion of antigen specific cytotoxic T-lymphocyte clones, associated with some clinical responses. Antigen specificity can also be obtained by the allogeneic transfer of high-avidity T-cell receptors into autologous T cells. We propose an alternative strategy based on the selection of antigen-specific T cells with magnetic beads coated with HLA-peptide multimers. Future improvements of adoptive melanoma immunotherapy may be achieved by its association with other therapeutic strategies such as targeted therapy against signaling pathways