Chronological age estimation for medico-legal expertise-based on sternoclavicular joint CT images using a deep neural network

The aim of this study was to develop and validate fully automated deep learning models to estimate chronological age from sternoclavicular CT images to help forensic age estimation and understand its limitations. A total of 742 whole-body CT and 164 pediatric chest-abdomen-pelvis CT scans (age: 1–60y, 437 m and 469f) were collected as a training dataset. A deep learning pipeline was implemented to segment the clavicle volume of interest, train an age estimation model, and finally fine-tune the network. The predictive performance of nine deep learning models was assessed and compared using 5-fold cross-validation. A transfer learning experiment was designed to evaluate the generalizability of the pre-trained models, using a fine-tuning group (age: 15–35y, 6 m and 4f) and a validation group (age: 16–35y, 6 m and 4f). Clinical age assessment based on clavicle bone was conducted on 5 thorax CT scans (4 m and 1f, age: 16–32y) and 5 sternoclavicular joint CT scans (unknown age) by one radiologist and two forensic pathologists. The intra- and inter-observer agreement of experts was assessed. A mean absolute error (MAE) of 4.23 ± 4.49 years, an area under the receiver operating characteristic (AUC) of 0.99 for age classification (&gt;14 years and &gt;18 years) and an accuracy of 0.97 for classification of ossification stages were achieved in the cross-validation. An MAE of 3.30 ± 3.58 years and an accuracy of 0.90 for ossification stage classification were achieved after fine-tuning. The three experts disagreed on the images that met the diagnostic requirements in 2 cases. Intra-observer agreement varied between experts. This study concluded that a fully automated deep neural network, employing a transfer learning strategy, exhibits potential for estimating chronological age from clavicular CT images.</p

Regulatory T-cell dysfunctions are associated with increase in tumor necrosis factor α in autoimmune hemolytic anemia and participate in Th17 polarization

Warm autoimmune hemolytic anemia (wAIHA) is a rare acquired autoimmune disease mediated by antibodies targeting red blood cells. The involvement of CD4 T-helper cells has been scarcely explored, with most findings extrapolated from animal models. Here, we performed quantification of both effector T lymphocytes (Teff) and regulatory T cells (Treg), associated with functional and transcriptomic analyses of Treg in human wAIHA. We observed a shift of Teff toward a Th17 polarization concordant with an increase in serum interleukin-17 concentration that correlates with red blood cell destruction parameters, namely lactate dehydrogenase and bilirubin levels. A decrease in circulating Treg, notably effector Treg, associated with a functional deficiency, as represented by their decrease capability to inhibit Teff proliferation, were also observed. Treg deficiency was associated with a reduced expression of Foxp3, the master transcription factor known to maintain the Treg phenotype stability and suppressive functions. Transcriptomic profiling of Treg revealed activation of the tumor necrosis facto (TNF)-α pathway, which was linked to increased serum TNF-α concentrations that were twice as high as in controls. Treg transcriptomic profiling also suggested that post-translational mechanisms possibly accounted for Foxp3 downregulation and Treg dysfunctions. Since TNF-α participates in the rupture of immune tolerance during wAIHA, its inhibition could be of interest. To this end, the effects of fostamatinib, a SYK inhibitor, were investigated in vitro, and we showed that besides the inhibition of erythrocyte phagocytosis by monocytes, fostamatinib is also able to dampen TNF-α production, thus appearing as a promising multitargeting therapy in wAIHA (clinicaltrials gov. Identifier: NCT02158195)

HuMoSC, une nouvelle thérapie pour le traitement des maladies dysimmunitaires et fibrosantes

Our team has developed an experimental method to generate immunosuppressive cells of monocyte origin called Human Monocyte-derived Suppressor Cells (HuMoSC). Although their immunosuppressive properties have already been shown, no study had yet evaluated their interest in tissue remodeling.The objective of this thesis was to evaluate the therapeutic potential of HuMoSCs and their supernatant for the treatment of tissue remodeling. On the other hand, we sought to identify the mechanisms of action involved in the functions of the supernatant of HuMoSC. The effect of HuMoSCs was first evaluated in giant cell arteritis using an ex vivo temporal artery culture model, and then in an in vitro and in vivo fibrosis model, similar to that described in Systemic Scleroderma.Our results showed that HuMoSC supernatant decreased the expression of matrix proteins and pro-fibrosing factors as well as cell proliferation.In conclusion, this thesis work has highlighted the anti-remodeling properties of HuMoSC supernatant thus representing a new hope in the treatment of fibrosing diseases.Notre équipe a développé une méthode expérimentale pour générer des cellules immunosuppressives d’origine monocytaire baptisées les Human Monocyte-derived Suppressor Cells (HuMoSC). Si leurs propriétés immunosuppressives ont déjà été montrées, aucune étude n’avait encore évalué leurs intérêts sur le remodelage tissulaire.L'objectif de cette thèse était d’une part, d'évaluer le potentiel thérapeutique des HuMoSC et de leur surnageant pour le traitement du remodelage tissulaire. D’autre part, nous avons cherché à identifier les mécanismes d’action impliqués dans les fonctions du surnageant. L’effet des HuMoSC a d’abord été évalué dans l'artérite à cellules géantes en utilisant un modèle de culture d’artères temporales ex vivo, puis dans un modèle de fibrose in vitro et in vivo, similaire à celle décrite dans la Sclérodermie Systémique.Nos résultats ont montré que le surnageant de HuMoSC diminuait l’expression des protéines matricielles et des facteurs pro-fibrosants ainsi que la prolifération cellulaire.En conclusion, ce travail de thèse a mis en avant les propriétés anti-remodelage du surnageant de HuMoSC, représentant ainsi un nouvel espoir dans le traitement des maladies fibrosantes

HuMoSC, a new therapy for the treatment of auto-immune diseases and fibrosis

Notre équipe a développé une méthode expérimentale pour générer des cellules immunosuppressives d’origine monocytaire baptisées les Human Monocyte-derived Suppressor Cells (HuMoSC). Si leurs propriétés immunosuppressives ont déjà été montrées, aucune étude n’avait encore évalué leurs intérêts sur le remodelage tissulaire.L'objectif de cette thèse était d’une part, d'évaluer le potentiel thérapeutique des HuMoSC et de leur surnageant pour le traitement du remodelage tissulaire. D’autre part, nous avons cherché à identifier les mécanismes d’action impliqués dans les fonctions du surnageant. L’effet des HuMoSC a d’abord été évalué dans l'artérite à cellules géantes en utilisant un modèle de culture d’artères temporales ex vivo, puis dans un modèle de fibrose in vitro et in vivo, similaire à celle décrite dans la Sclérodermie Systémique.Nos résultats ont montré que le surnageant de HuMoSC diminuait l’expression des protéines matricielles et des facteurs pro-fibrosants ainsi que la prolifération cellulaire.En conclusion, ce travail de thèse a mis en avant les propriétés anti-remodelage du surnageant de HuMoSC, représentant ainsi un nouvel espoir dans le traitement des maladies fibrosantes.Our team has developed an experimental method to generate immunosuppressive cells of monocyte origin called Human Monocyte-derived Suppressor Cells (HuMoSC). Although their immunosuppressive properties have already been shown, no study had yet evaluated their interest in tissue remodeling.The objective of this thesis was to evaluate the therapeutic potential of HuMoSCs and their supernatant for the treatment of tissue remodeling. On the other hand, we sought to identify the mechanisms of action involved in the functions of the supernatant of HuMoSC. The effect of HuMoSCs was first evaluated in giant cell arteritis using an ex vivo temporal artery culture model, and then in an in vitro and in vivo fibrosis model, similar to that described in Systemic Scleroderma.Our results showed that HuMoSC supernatant decreased the expression of matrix proteins and pro-fibrosing factors as well as cell proliferation.In conclusion, this thesis work has highlighted the anti-remodeling properties of HuMoSC supernatant thus representing a new hope in the treatment of fibrosing diseases

New Insights into the Pathogenesis of Giant Cell Arteritis: Mechanisms Involved in Maintaining Vascular Inflammation

The giant cell arteritis (GCA) pathophysiology is complex and multifactorial, involving a predisposing genetic background, the role of immune aging and the activation of vascular dendritic cells by an unknown trigger. Once activated, dendritic cells recruit CD4 T cells and induce their activation, proliferation and polarization into Th1 and Th17, which produce interferon-gamma (IFN-γ) and interleukin-17 (IL-17), respectively. IFN-γ triggers the production of chemokines by vascular smooth muscle cells, which leads to the recruitment of additional CD4 and CD8 T cells and also monocytes that differentiate into macrophages. Recent data have shown that IL-17, IFN-γ and GM-CSF induce the differentiation of macrophage subpopulations, which play a role in the destruction of the arterial wall, in neoangiogenesis or intimal hyperplasia. Under the influence of different mediators, mainly endothelin-1 and PDGF, vascular smooth muscle cells migrate to the intima, proliferate and change their phenotype to become myofibroblasts that further proliferate and produce extracellular matrix proteins, increasing the vascular stenosis. In addition, several defects in the immune regulatory mechanisms probably contribute to chronic vascular inflammation in GCA: a defect in the PD-1/PD-L1 pathway, a quantitative and qualitative Treg deficiency, the implication of resident cells, the role of GM-CSF and IL-6, the implication of the NOTCH pathway and the role of mucosal-associated invariant T cells and tissue-resident memory T cells.</jats:p

New Insights into the Pathogenesis of Giant Cell Arteritis: Mechanisms Involved in Maintaining Vascular Inflammation

The giant cell arteritis (GCA) pathophysiology is complex and multifactorial, involving a predisposing genetic background, the role of immune aging and the activation of vascular dendritic cells by an unknown trigger. Once activated, dendritic cells recruit CD4 T cells and induce their activation, proliferation and polarization into Th1 and Th17, which produce interferon-gamma (IFN-&gamma;) and interleukin-17 (IL-17), respectively. IFN-&gamma; triggers the production of chemokines by vascular smooth muscle cells, which leads to the recruitment of additional CD4 and CD8 T cells and also monocytes that differentiate into macrophages. Recent data have shown that IL-17, IFN-&gamma; and GM-CSF induce the differentiation of macrophage subpopulations, which play a role in the destruction of the arterial wall, in neoangiogenesis or intimal hyperplasia. Under the influence of different mediators, mainly endothelin-1 and PDGF, vascular smooth muscle cells migrate to the intima, proliferate and change their phenotype to become myofibroblasts that further proliferate and produce extracellular matrix proteins, increasing the vascular stenosis. In addition, several defects in the immune regulatory mechanisms probably contribute to chronic vascular inflammation in GCA: a defect in the PD-1/PD-L1 pathway, a quantitative and qualitative Treg deficiency, the implication of resident cells, the role of GM-CSF and IL-6, the implication of the NOTCH pathway and the role of mucosal-associated invariant T cells and tissue-resident memory T cells

Forensic age estimation at the University Center of Legal Medicine Lausanne-Geneva: a retrospective study over 12 years.

With the undeniable increase in asylum requests from unaccompanied alleged minors, age estimation of living individuals has become an essential part of the routine work in European forensic centers. This study aims to review the forensic age estimations performed in our center since 2010, to evaluate the state-of-the-art of this practice in Switzerland with the evolution of the methodology according to upcoming recommendations. Our institute's expert reports performed between 2010 and 2022 were retrospectively analyzed. We gathered the following parameters: demographic data, morphological characteristics, alleged age compared with the assessed minimum age, sexual maturation, dental and bone age. When available, we collected personal and family history, medical history, records of torture-related/self-inflicted injuries, and information about eating habits that might affect skeletal development. Data collection amounted to 656 cases. Forensic age estimations ordered by the Swiss Secretariat for Migration (SEM) represented 76.4% of cases, with 23.6% of them ordered by the Court/Public Prosecutor. Most alleged minors were male (94.5%) and came from Afghanistan (53.4%). Adjunction of CT scans of the sternoclavicular joints was necessary in 86.4% of cases. Only 25.2% of our reports concluded on most probable minority, with 55.6% of definite majors; in 19.2% of our cases, minority could not be excluded. This study aspires to further broaden our expertise regarding forensic age estimations. Given the increasing migratory flows, we can expect a notable increase in the frequency of these requests. Consequently, this study aims to promote a multidisciplinary approach and the international standardization of the methodology of these estimations

Single-cell mapping of leukocyte immunoglobulin-like receptors in kidney transplant rejection

International audienceLeukocyte immunoglobulin-like receptors (LILRs) are a family of inhibitory or stimulatory receptors expressed by immune cell types belonging to both myeloid and lymphoid lineage. Several members of the LILR family recognize major histocompatibility complex class I and thus play important roles in a range of clinical situations including pregnancy. Moreover, paired immunoglobulin-like receptors (PIRs), the murine orthologs of LILRs, are implicated in experimental transplant allorecognition by monocytes and contribute to the induction of donor-specific monocyte-memory. After non-self recognition, activating PIRs are transiently overexpressed at the surface of monocytes and participate in donor-specific monocyte recruitment, leading to graft rejection in vivo . In the present study, we mapped LILR expression and also their respective reported ligands at single cell level in the renal allograft and circulating cells in the context of kidney transplant rejection. Recipient-derived monocytes were shown to infiltrate the donor tissue and to differentiate into macrophages. We thus also investigate LILR expression during in vitro monocyte-to-macrophage differentiation in order to characterize the myeloid population that directly contribute to allorecognition. Altogether our results emphasize non-classical monocytes and CD68+ M1 macrophages as key players in LILRs-ligand interaction in kidney transplantation

Alteration of microbiota antibody‐mediated immune selection contributes to dysbiosis in inflammatory bowel diseases

International audienceHuman secretory immunoglobulins (SIg) A1 and SIgA2 guide mucosal responses toward tolerance or inflammation, notably through reverse-transcytosis, the apical-to-basal transport of IgA2 immune complexes via M cells of gut Peyer's patches. As such, the maintenance of a diverse gut microbiota requires broad affinity IgA and glycan-glycan interaction. Here, we asked whether IgA1 and IgA2-microbiota interactions might be involved in dysbiosis induction during inflammatory bowel diseases. Using stool HPLC-purified IgA, we show that reverse-transcytosis is abrogated in ulcerative colitis (UC) while it is extended to IgA1 in Crohn's disease (CD). 16S RNA sequencing of IgA-bound microbiota in CD and UC showed distinct IgA1- and IgA2-associated microbiota; the IgA1+ fraction of CD microbiota was notably enriched in beneficial commensals. These features were associated with increased IgA anti-glycan reactivity in CD and an opposite loss of reactivity in UC. Our results highlight previously unknown pathogenic properties of IgA in IBD that could support dysbiosis