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To study the results and complications of Traditional Growing Rods (TGR) for the treatment of Early-Onset Scoliosis (EOS) in patients with Ehlers-Danlos syndrome (EDS).This is a retrospective study of patients with EDS treated for EOS between 2012 and 2018 by TGR. For each patient, we evaluated the evolution of the Cobb angle of the main coronal curve before the first surgery, postoperatively and at the last follow-up. We also noted every complication.Four patients have been evaluated. Age at the index surgery ranged from 3- to 6-year-old. All the patients had a Kyphoscoliosis. The preoperative Cobb angle of the main coronal curve ranged from 70° to 104°. Prior to surgery, a progressive correction of the spinal deformity by Halo-gravity traction was performed for all patients. One patient had several complications with a poor result after final fusion. Three patients did not sustain any complication and presented good results. Follow-up ranged from 3 to 8 years. For two of our patients, further lengthening procedures are still needed.TGR is a good surgical option for the treatment of EOS in EDS. A progressive preoperative correction is recommended. Anchor-related complications must be minimized in these patients with an important kyphosis. Level of evidence Level IV.

Cockayne syndrome (CS) is a rare disease caused by mutations in ERCC6/CSB or ERCC8/CSA. We report here the clinical, genetic, and functional analyses of three unrelated patients mutated in ERCC6/CSB with a severe phenotype. After clinical examination, two patients were investigated via next generation sequencing, targeting seventeen Nucleotide Excision Repair (NER) genes. All three patients harbored a novel, c.3156dup, homozygous mutation located in exon 18 of ERCC6/CSB that affects the C-terminal region of the protein. Sanger sequencing confirmed the mutation and the parental segregation in the three families, and Western blots showed a lack of the full-length protein. NER functional impairment was shown by reduced recovery of RNA synthesis with proficient unscheduled DNA synthesis after UV-C radiations in patient-derived fibroblasts. Despite sharing the same mutation, the clinical spectrum was heterogeneous among the three patients, and only two patients displayed clinical photosensitivity. This novel ERCC6 variant in Tunisian patients suggests a founder effect and has implications for setting-up prenatal diagnosis/genetic counselling in North Africa, where this disease is largely undiagnosed. This study reveals one of the rare cases of CS clinical heterogeneity despite the same mutation. Moreover, the occurrence of an identical homozygous mutation, which either results in clinical photosensitivity or does not, strongly suggests that this classic CS symptom relies on multiple factors.

Background Co-occurrence of two genetic diseases is challenging for accurate diagnosis and genetic counseling. The recent availability of whole exome sequencing (WES) has dramatically improved the molecular diagnosis of rare genetic diseases in particular in consanguineous populations. Methods We report here on a consanguineous family from Southern Tunisia including three members affected with congenital ichthyosis. The index case had a hearing loss (HL) and ichthyosis and was primarily suspected as suffering from keratitis-ichthyosis-deafness (KID) syndrome. WES was performed for the index case, and all members of the nuclear family were sequenced (Sanger method). Results The WES approach allowed the identification of two strong candidate variants in two different genes; a missense mutation c.1334T>G (p.Leu445Trp) in exon 11 of SLC26A4 gene, associated with isolated HL and a novel missense mutation c.728G>T (p.Arg243Leu) in exon 8 of CYP4F22 gene likely responsible for ichthyosis. These two mutations were predicted to be pathogenic by three pathogenicity prediction softwares (Scale-Invariant Feature Transform [SIFT], Polymorphism Phenotyping [PolyPhen], Mutation Taster) to underlie the HL and ichthyosis, respectively. Conclusions The present study raises awareness about the importance of familial history for accurate diagnosis of syndromic genetic diseases and differential diagnosis with co-occurrence of two distinct clinical entities. In addition, in countries with limited resources, WES sequencing for a single individual provides a cost effective tool for molecular diagnosis confirmation and genetic counseling.

Escobar syndrome is a rare, autosomal recessive disorder that affects the musculoskeletal system and the skin. Mutations in the CHRNG and TPM2 genes are associated with this pathology. In this study, we conducted a clinical and genetic investigation of five patients and also explored via in silico and gene expression analysis their phenotypic variability. In detail, we identified a patient with a novel composite heterozygous variant of the CHRNG gene and two recurrent mutations in both CHRNG and TPM2 in the rest of the patients. As for the clinical particularities, we reported a list of modifier genes in a patient suffering from myopathy. Moreover, we identified decreased expression of IGF-1, which could be related to the short stature of Escobar patients, and increased expression of POLG1 specific to patients with TPM2 mutation. Through this study, we identified the genetic spectrum of Escobar syndrome in the Tunisian population, which will allow setting up genetic counseling and prenatal diagnosis for families at risk. In addition, we highlighted relevant biomarkers that could differentiate between patients with different genetic defects.

Background Cockayne syndrome (CS) is a rare autosomal recessive disorder caused by mutations in ERCC6/CSB or ERCC8/CSA that participate in transcription-coupled nucleotide excision repair (TC-NER) of UV-induced DNA damage. CS patients display a large heterogeneity of clinical symptoms and severities, the reason of which is not fully understood, and little data is available for affected siblings. CS is largely undiagnosed in North Africa. Methods We report here the clinical description as well as genetic and functional characterization of eight North African CS patients, including siblings. These patients, who belonged to six unrelated families, underwent complete clinical examination and biochemical analyses. Sanger sequencing was performed for the recurrent mutation in five families, and targeted gene sequencing for one patient of the other family. We also performed RRS (Recovery RNA Synthesis) to confirm the functional impairment of DNA repair in the identified mutations. Results Six out of eight patients carried a homozygous indel mutation (c.598_600delinsAA) in exon 7 of ERCC8, and displayed a variable clinical spectrum, including between siblings, despite sharing the same mutation. The other two patients were Tunisian siblings who carried a homozygous splice-site variant in ERCC8 (c.843 + 1 G > C). They presented more severe clinical manifestations, which are in general rarely associated with CSA mutations, leading to gastrostomy and hepatic damage. Impaired TC-NER was confirmed by RRS in six tested patients. Conclusions This study provides the first deep characterization of case series of rare CS-A patients in North Africa. They carry mutations described to date only in this region and the Middle-East. We also provide the largest characterization of unrelated patients, as well as siblings, with the same mutation, providing a framework for dissecting elusive genotype-phenotype correlations in CS.

Annual Meeting of the British-Society-for-Investigative-Dermatology, Univ Bradford, Bradford, ENGLAND, APR 01-03, 2019; International audience; International Symposium on Xeroderma Pigmentosum and other Nucleotide Excision Repair Disorders Downing College, University of Cambridge, Cambridge, UK. 20–22 March 2019

Background: Horizontal Gaze Palsy with Progressive Scoliosis (HGPPS) is a rare autosomal recessive congenital disorder characterized by the absence of conjugate horizontal eye movements, and progressive debilitating scoliosis during childhood and adolescence. HGPPS is associated with mutations of the ROBO3 gene. In this study, the objective is to identify pathogenic variants in a cohort of Tunisian patients with HGPPS and to further define ROBO3 genotype-phenotype correlations. Methods: Thirteen Tunisian patients from six unrelated consanguineous families all manifesting HGPPS were genetically investigated. We searched for the causative variants for HGPPS using classical Sanger and whole exome sequencing. Results: Four distinct homozygous mutations were identified in ROBO3 gene. Two of these were newly identified homozygous and non-synonymous mutations, causing effectively damage to the protein by in silico analysis. The other two mutations were previously reported in Tunisian patients with HGPPS. Mutations were validated by Sanger sequencing in parents and affected individuals. Conclusion: To the best of our knowledge, this is the largest ever reported cohort on families with HGPPS in whom ROBO3 mutations were identified. These molecular findings have expanded our knowledge of the ROBO3 mutational spectrum. The relevance of our current study is two-fold; first to assist proper management of the scoliosis and second to protect families at risk.

International audience; Background: Co-occurrence of two genetic diseases is challenging for accurate diagnosis and genetic counseling. The recent availability of whole exome sequencing (WES) has dramatically improved the molecular diagnosis of rare genetic diseases in particular in consanguineous populations.Methods: We report here on a consanguineous family from Southern Tunisia including three members affected with congenital ichthyosis. The index case had a hearing loss (HL) and ichthyosis and was primarily suspected as suffering from keratitis-ichthyosis-deafness (KID) syndrome. WES was performed for the index case, and all members of the nuclear family were sequenced (Sanger method).Results: The WES approach allowed the identification of two strong candidate variants in two different genes; a missense mutation c.1334T>G (p.Leu445Trp) in exon 11 of SLC26A4 gene, associated with isolated HL and a novel missense mutation c.728G>T (p.Arg243Leu) in exon 8 of CYP4F22 gene likely responsible for ichthyosis. These two mutations were predicted to be pathogenic by three pathogenicity prediction softwares (Scale-Invariant Feature Transform [SIFT], Polymorphism Phenotyping [PolyPhen], Mutation Taster) to underlie the HL and ichthyosis, respectively.Conclusions: The present study raises awareness about the importance of familial history for accurate diagnosis of syndromic genetic diseases and differential diagnosis with co-occurrence of two distinct clinical entities. In addition, in countries with limited resources, WES sequencing for a single individual provides a cost effective tool for molecular diagnosis confirmation and genetic counseling.

cited By 0; International audience; In this study, we carried out whole exome sequencing (WES) analysis in one Libyan patient in order to identify the molecular aetiology of hereditary epidermolysis bullosa (HEB).

Marielle Saclier and Houda Yacoub-Youssef : Both should be considered as first author; International audience; Macrophages (MPs) exert either beneficial or deleterious effects on tissue repair, depending on their activation/polarization state. They are crucial for adult skeletal muscle repair, notably by acting on myogenic precursor cells. However, these interactions have not been fully characterized. Here, we explored both in vitro and in vivo, in human, the interactions of differentially activated MPs with myogenic precursor cells (MPCs) during adult myogenesis and skeletal muscle regeneration. We showed in vitro that through the differential secretion of cytokines and growth factors, proinflammatory MPs inhibited MPC fusion while anti-inflammatory MPs strongly promoted MPC differentiation by increasing their commitment into differentiated myocytes and the formation of mature myotubes. Furthermore, the in vivo time course of expression of myogenic and MP markers was studied in regenerating human healthy muscle after damage. We observed that regenerating areas containing proliferating MPCs were preferentially associated with MPs expressing proinflammatory markers. In the same muscle, regenerating areas containing differentiating myogenin-positive MPCs were preferentially coupled to MPs harboring anti-inflammatory markers. These data demonstrate for the first time in human that MPs sequentially orchestrate adult myogenesis during regeneration of damaged skeletal muscle. These results support the emerging concept that inflammation, through MP activation, controls stem cell fate and coordinates tissue repair.

Aims: Xeroderma pigmentosum (XP, OMIM 278700-278780) is one of the most severe genodermatoses and is relatively frequent in Tunisia. In the absence of any therapy and to better manage the disease, we aimed to develop a molecular tool for DNA-based prenatal diagnosis. Methods: Six consanguineous Tunisian XP families (4 XP-A and 2 XP-C) have benefited from a prenatal diagnosis. Screening for mutations was performed by direct sequencing, while maternal-foetal contamination was checked by genotyping. Results: Among the 7 prenatal diagnoses, 4 foetuses were heterozygous for the screened mutation. Exclusion of contamination by maternal cells was checked. Mutations were detected at a homozygous state in the remaining cases, and the parents decided to terminate pregnancy. Conclusion: Our study illustrates the implementation of prenatal diagnosis for better health support of XP in Tunisia.

Xeroderma Pigmentosum(XP) is a rare recessive autosomal cancer prone disease, characterized by UV hypersensitivity and early appearance of cutaneous and ocular malignancies. We investigated four unrelated patients suspected to be XP-C. To confirm linkage toXPCgene, genotyping and direct sequencing ofXPCgene were performed. Pathogenic effect of novel mutations was confirmed by reverse Transciptase PCR. Mutation screening revealed the presence of two novel mutations g.18246G>A and g.18810G>T in theXPCgene (NG_011763.1). The first is present in one patient XP50NEF, but the second is present in three unrelated patients (XP16KEB, XP28SFA, and XP45GB). These 3 patients are from three different cities of Southern Tunisia and bear the same haplotype, suggesting a founder effect. Reverse Transciptase PCR revealed the absence of theXPCmRNA. In Tunisia, as observed in an other severe genodermatosis, the mutational spectrum of XP-C group seems to be homogeneous with some clusters of heterogeneity that should be taken into account to improve molecular diagnosis of this disease.

Background Skin cancers (SC) are complex diseases that develop from complex combinations of genetic and environmental risk factors. One of the most severe and rare genetic diseases predisposing to SC is the Xeroderma pigmentosum (XP) syndrome. Objectives First, to identify the genetic etiology of XP and to better classify affected patients. Second, to provide early molecular diagnosis for pre-symptomatic patient and finally to offer genetic counseling for related individuals. Methods Whole Exome Sequencing (WES) and Run Of Homozygosity (ROH) were performed for two patients belonging to two different multiplex consanguineous families. The identified mutations were confirmed by Sanger sequencing and researched in ten Tunisian families including a total of 25 affected individuals previously suspected as having XP group V (XP-V) form. All patients had mild dermatological manifestations, absence of neurological abnormalities and late onset of skin tumors. Results Screening for functional variations showed the presence of the ERCC2 p.Arg683Gln in XP14KA-2 patient and a novel mutation, DDB2 p. (Lys381Argfs*2), in XP51-MAH-1 patient. Sanger sequencing and familial segregation showed that the ERCC2 mutation is present at a homozygous state in 10 affected patients belonging to 3 families. The second mutation in DDB2, is present at a homozygous state in 5 affected cases belonging to the same family. These two mutations are absent in the remaining 10 affected patients. The ERCC2 c.2048G > A mutation is present in a medium ROH region (class B) suggesting that it mostly arises from ancient relatedness within individuals. However, the c.1138delG DDB2 mutation is present in a large ROH region (class C) suggesting that it arises from recent relatedness. Conclusion To our knowledge, this is the first study that identifies XP-D and XP-E complementation groups in Tunisia. These two groups are very rare and under-diagnosed in the world and were not reported in North Africa.

Macrophages have been shown to be essential for muscle repair by delivering trophic cues to growing skeletal muscle precursors and young fibers. Here, we investigated whether human macrophages, either proinflammatory or anti-inflammatory, coinjected with human myoblasts into regenerating muscle of Rag2(-/-) γC(-/-) immunodeficient mice, could modify in vivo the kinetics of proliferation and differentiation of the transplanted human myogenic precursors. Our results clearly show that proinflammatory macrophages improve in vivo the participation of injected myoblasts to host muscle regeneration, extending the window of proliferation, increasing migration, and delaying differentiation. Interestingly, immunostaining of transplanted proinflammatory macrophages at different time points strongly suggests that these cells are able to switch to an anti-inflammatory phenotype in vivo, which then may stimulate differentiation during muscle regeneration. Conceptually, our data provide for the first time in vivo evidence strongly suggesting that proinflammatory macrophages play a supportive role in the regulation of myoblast behavior after transplantation into preinjured muscle, and could thus potentially optimize transplantation of myogenic progenitors in the context of cell therapy.

Introduction: Duchenne Muscular Dystrophy (DMD) is characterized by the lack of dystrophin that leads to severe myofiber degeneration. We have shown that endomysial fibrosis is correlated with age at ambulation loss in DMD patients. However, the dystrophin-deficient mdx mouse does not have fibrotic lesions in adult limb muscles. Here, we describe a model of chronic mechanical muscle injury that triggers chronic lesions in mdx hindlimb muscle. Methods: Micromechanical injuries were performed daily in tibialis anterior muscles for 2 weeks. Results: Endomysial fibrosis appeared beginning 1 week post-injury, remained stable for 3 months and was associated with loss of specific maximal force. Fibrosis was associated with an increased expression of factors involved in fibrogenesis including α-smooth muscle actin, connective tissue growth factor, and lysyl oxidase, which colocalized with collagen deposits. Conclusions: This induced fibrotic dystrophic model may be useful to study mechanisms of fibrosis in dystrophinopathies and to evaluate antifibrotic treatments. Muscle Nerve 45: 803–814, 2012

International audience; Macrophages are necessary for skeletal muscle regeneration after injury. Muscle recruits inflammatory monocytes/macrophages that switch toward an anti-inflammatory profile upon phagocytosis of debris. In vitro, proinflammatory macrophages stimulate myoblast proliferation, whereas anti-inflammatory macrophages stimulate their differentiation. Thus, macrophages are involved in both phases of skeletal muscle regeneration: first, inflammation and cleansing of necrosis, and then myogenic differentiation and tissue repair.

Rodents have been widely used for studies in transplantation immunology because of their short reproduction period and the relative ease of generating inbred mutant or transgenic strains. However, although many biological mechanisms are similar between rodents and humans, several features clearly distinguish the immune system in these species. Consequently, it is rarely possible to extrapolate observations from rodent models directly into clinical practice. In vitro studies with human cells are useful for elucidation of basic mechanisms, but in order to study complex biological phenomena, in vivo studies are indispensable. In later years, a number of interesting models have been described where immunodeficient mice have been reconstituted with human cells, so-called humanized mice, in order to study human immune responses in vivo. This has opened a new field of experimental immunology that has been applied to areas such as cancer, autoimmunity, allergy, infections, and transplantation biology. In this review, we shall concentrate on the use of severe combined immunodeficient mice reconstituted with human immune or stem cells for studies of human alloreaction in vivo.

Xeroderma pigmentosum Variant (XP-V) form is characterized by a late onset of skin symptoms. Our aim is the clinical and genetic investigations of XP-V Tunisian patients in order to develop a simple tool for early diagnosis. We investigated 16 suspected XP patients belonging to ten consanguineous families. Analysis of thePOLHgene was performed by linkage analysis, long range PCR, and sequencing. Genetic analysis showed linkage to thePOLHgene with a founder haplotype in all affected patients. Long range PCR of exon 9 to exon 11 showed a 3926 bp deletion compared to control individuals. Sequence analysis demonstrates that this deletion has occurred between two Alu-Sq2 repetitive sequences in the same orientation, respectively, in introns 9 and 10. We suggest that this mutationPOLHNG_009252.1: g.36847_40771del3925 is caused by an equal crossover event that occurred between two homologous chromosomes at meiosis. These results allowed us to develop a simple test based on a simple PCR in order to screen suspected XP-V patients. In Tunisia, the prevalence of XP-V group seems to be underestimated and clinical diagnosis is usually later. Cascade screening of this founder mutation by PCR in regions with high frequency of XP provides a rapid and cost-effective tool for early diagnosis of XP-V in Tunisia and North Africa.

International audience; BACKGROUND: Hypercholesterolemia could inhibit the immune response against various pathogens. No information is available about its impact on the immune response toward Chlamydophila pneumoniae. METHODS: Apolipoprotein E (apoE)-deficient and wild-type mice fed a normal diet were infected with a single intranasal inoculation of viable C. pneumoniae. RESULTS: Whereas interferon gamma concentrations (T helper 1 response) were similar in the lungs and spleen of apoE-deficient and wild-type mice, increased concentrations of interleukin 10, interleukin 6, and interleukin 4 (T helper 2 response) were found in the lungs of apoE-deficient mice. The spleen B lymphocyte percentage and interleukin 4 levels and serum specific antibody titers were higher in apoE-deficient mice. C. pneumoniae infection was facilitated neither in the lungs nor in the aorta of these mice. On the contrary, the number of apoE-deficient mice with detectable levels of bacterial DNA in the aorta was clearly decreased. When low-density lipoprotein receptor-deficient mice fed a normal diet were similarly infected, no difference in the interleukin 4 concentration and infection level was observed in the lungs and no protection was found in the aorta. CONCLUSIONS: Mild hypercholesterolemia in mice does not facilitate C. pneumoniae persistence in the vascular wall. ApoE deficiency, rather than mild hypercholesterolemia, probably favors the development of an unusual anti-C. pneumoniae T helper 2 response and protects against vascular infection.

International audience; BACKGROUND: Chronic vascular rejection (CVR) is characterized by an intimal thickening in the arteries of allografts due to immunoinflammatory reactions and smooth muscle cell proliferation. Interleukin 6 (IL-6) levels are increased in patients with graft rejection, however the role of IL-6 in CVR is not known. We investigated if IL-6 deficiency in the recipient could prevent CVR after an aortic allograft. METHODS: Donor aortas from wild-type DBA/2 mice were transplanted into C57BL/6 recipients, either wild-type mice or mice deficient for IL-6 (IL-6(-/-)), apolipoprotein E (ApoE(-/-)), or both (IL-6(-/-)ApoE(-/-)). Alloantibody titers were determined at Day 30, 60, or 90 after grafting. The grafts were examined for CVR lesions by morphometry and immunohistology. RESULTS: All recipient allografts displayed lesions typical for CVR. The lesions were larger in IL-6-deficient strains, and significantly so in IL-6(-/-)ApoE(-/-) recipients. Early immunoglobulin (Ig) G1 alloantibody deposits were observed in the grafts of ApoE-deficient strains and late IgG2a deposits in the grafts of IL-6-deficient strains. A rapid and sustained type 1 helper T cell (Th1; IgG2a) alloresponse in IL-6(-/-) mice, and a strong type 2 helper T cell (Th2; IgG1) response in ApoE(-/-) mice were observed. IL-6(-/-)ApoE(-/-) mice displayed the highest alloantibody titer, with a Th1 dominance. CONCLUSIONS: Unexpectedly, IL-6 deficiency in the recipient mice did not prevent CVR lesions but even aggravated them in IL-6(-/-)ApoE(-/-) recipients. This was associated with increased local and systemic alloresponses.

BACKGROUND Lumen loss in graft arteriosclerosis is the consequence of the development of a thick neointima and constrictive arterial remodeling. The latter is due to adventitial chronic inflammation and excessive perivascular collagen deposition. We reasoned that blockade of the portal of entry of inflammatory effectors may constitute a strategy to prevent constrictive arterial remodeling. METHODS AND RESULTS We found that an anti-angiogenic therapy (ABT-510 nonapeptide), devoid of direct immunomodulatory properties, dramatically reduced adventitial angiogenesis by 66% (P\textless0.0001) in the rat aortic interposition model of graft arteriosclerosis. The associated decreased entry of inflammatory cells (44%; P\textless0.00001) resulted in drastic reduction of collagen deposition (57%; P\textless0.0001) thereby preventing subsequent adventitial constrictive remodeling and reduction of lumen surface area (5.26+/-0.74 vs. 8.58+/-2.48 microm2; Control vs. ABT-510-treated rats; P\textless0.0001). ABT-510 had no effect on the development of the neointima. CONCLUSION This work supports the idea that targeting angiogenesis may act synergistically with conventional immunosuppressive therapy in preventing graft arteriosclerosis, a crucial feature of chronic graft rejection.

Introduction Le xeroderma pigmentosum est la photo-genodermatose la plus connue. Elle est due a un defaut de reparation des lesions UV-induites. La forme XP-C est la plus repandue dans le monde. Cette forme se caracterise par une morbidite et une mortalite precoce en raison du nombre eleve de cancers cutanes developpes. Nous rapportons dans cette etude, notre experience comme centre de reference pour la maladie de XP en Tunisie. Nous avons recueilli les donnees cliniques, genealogiques et genetiques concernant tous les patients XP-C tunisiens recrutes entre 2006 et 2013. Patients et methodes Soixante-quatre patients appartenant a 44 familles non apparentees ont ete etudies. Un suivi clinique retrospectif et prospectif de ces patients a ete assure. Pour tous les patients, la recherche mutationnelle a ete faite pour le gene XP-C par sequencage direct. Resultats L’etude genealogique des familles montrait un taux de consanguinite de 48,1 %, 27 patients presentant une histoire familiale positive de XP-C. L’atteinte cutanee se caracterisait par une pigmentation specifique, de couleur differente avec contours et tailles irregulieres. Les tâches achromiques precedaient et s’installaient meme dans les zones non photo-exposees. Les carcinomes basocellulaires (CBC, 62,50 %) etaient plus frequents que les carcinomes spinocellulaires (CSC, 48,43 %) et les melanomes cutanes (MC, 23,4 %). Aux cancers cutanes s’ajoutaient d’autres pathologies comme les problemes thyroidiens, les nodules des seins, le sarcome uterin et la leucemie. L’exploration genetique montrait que 91,48 % des patients XP-C tunisiens portaient la mutation fondatrice c.1642-1643 del TG, celle-ci etant la plus frequente dans toute la region maghrebine. Nous avons rapporte aussi deux autres mutations, la c.850G > T et la mutation privee c.779 + 1G > A. Discussion Chez les patients XP-C l’atteinte est generalement limitee a la peau sans qu’il y ait d’atteinte neurologique. Les CSC constituent la premiere cause de deces chez les XP-C. Pour les MC, des regressions spontanees ont ete observees. La resistance a la chimiotherapie est tres frequente chez les XP-C. Le traitement a la bleomycine semble plus efficace contre les CSC et les keratoacanthomes. Par ailleurs, les patients sont predisposes a developper d’autres pathologies associees et des cancers internes. Les problemes thyroidiens sont les plus frequents meme pour d’autres cas de XP-C decrits dans le monde. Ceci explique le role du gene XP-C dans d’autres voies que celles du systeme NER. La mutation c.1642-1643 del TG reste la plus frequente dans la region Nord africaine et en Tunisie. Conclusion Nous presentons la plus grande cohorte de patients XP-C dans le monde. La protection contre les UV est le facteur preventif le plus efficace contre les cancers de la peau, mais elle ne previent pas la survenue de cancers internes.

Background Chronic vascular rejection (CVR) is a major problem in clinical transplantation. Studies in experimental animals have been important to understand some of its mechanisms, but they are hampered by the difficulty of extrapolating the results into clinical practice. Methods We created a new experimental model for the study of human CVR by grafting multiple human mesenteric arteries from the same human donor into different SCID/beige mice in the infrarenal aortic position. Twenty-seven different mice were successfully grafted with a human artery from 6 donors. One week later, 23 of the mice received an intraperitoneal injection of 40 million human spleen cells, either from the same donor (autologous) or from another donor (allogeneic). Results In 81% of the mice an immune reconstitution was obtained, shown by the presence of human T, B and NK cells and IgG in circulating blood. At the time of sacrifice, 5 weeks after the arterial transplantation, a typical CVR with infiltration of human immune cells and deposit of human immunoglobulin was observed in the reconstituted mice that received allogeneic cells, whereas only minor lesions were noted in autologous combinations. No CVR was observed without injection of human splenocytes. We did not observe lymphoma or graft-vs-host reactions during the experiment. Conclusions We show that it is feasible to graft multiple human arteries from the same donor into SCID/beige mice, and that a specific and typical CVR is observed after reconstitution with allogeneic spleen cells. Our method allows for pre-clinical testing of new therapeutics in controlled series.

Background We developed an original experimental model to study chronic vascular rejection (CVR) consisting of a graft of human mesenteric artery followed by human immune reconstitution into CB.17 SCID/Beige mice. Human immune reconstitution achieved after human PBMC injection has often been variable and incomplete. The aim of this work was to develop an alternative method to achieve a complete, functional human immune reconstitution. Method After institutional authorizations, spleen cells were recovered from cadaveric organ donors. Single intraperitoneal injections of various doses of spleen cells were made into 70 CB.17 SCID/Beige mice. Reconstitution of the human immune system was monitored by flow cytometry (circulating human cells) and ELISA (human IgG). Colonization of murine lymphoid organs by human cells was studied by immunohistochemistry and flow cytometry. Evaluation of the immune function consisted of examination of CVR lesions in human arterial grafts. The animals were humanely killed at day 28. Results After injection of 30 to 40 × 106 spleen cells, the mice showed significant human CD3+, CD19+, and CD56+ populations in peripheral blood. The mean human cells levels were, respectively, 8.2% ± 5.4%, 2.9% ± 1.2%, and 5.3% ± 5.1%. Murine spleen and mesenteric lymph nodes were colonized by human T and B cells, while the murine thymus was only colonized by human T cells. Human IgG was detected in murine serum (65.9 ± 63.3 mg/L) and typical CVR lesions were observed within the allogeneic grafts. Conclusion Intraperitoneal injection of 30 to 40 × 106 human spleen cells into CB.17 SCID/Beige mice induces complete and functional human immune reconstitution allowing the study of CVR under human allogeneic conditions.

We wanted to establish a preclinical model of chronic vascular rejection (CVR) by transplanting small arteries from the mesentery of cadaveric organ donors by the rapid "sleeve" technique into SCID/beige mice reconstituted with human allogeneic spleen cells. After institutional authorization and with informed consent from relatives, we obtained tissues and cells from cadaveric organ donors. A piece of mesentery was recovered from the donor and kept in buffered solution at 4 degrees C until use. After dissection of the mesentery, small arteries of suitable size were transplanted in place of the infrarenal aorta of the mice. Cells for the immunological reconstitution of the mice were spleen cells from the same or other organ donors. Twenty-three suitable arterial segments were obtained from the mesentery of three cadaveric donors. Ten of the mice received 3 x 10(7) human spleen cells intraperitoneally 1 week after the arterial graft and they all showed circulating human CD3+ and CD19+ cells 2 weeks after injection. The mice were sacrificed 5 weeks after the arterial graft. SCID/beige mice reconstituted with allogeneic spleen cells showed a typical CVR, whereas mice that received no cells had a normal vascular anatomy. We believe our model is well suited for the study of treatment of CVR under human allograft conditions.