Extra-nodal NK/T-cell lymphoma (ENKTL) is a form of highly malignant non-Hodgkin's lymphoma. There are two types: nasal forms primarily affecting the oropharyngeal sphere and so-called nasal-type extra-nasal forms in which primary skin involvement is the most common feature enabling diagnosis. Herein, we report a case of systemic nasal-type ENKTL (ENKTL-NT) that was diagnosed based on skin involvement associated with ocular involvement.

Systemic sclerosis is a rare connective tissue disease characterized by skin and several internal organ fibrosis, systemic vasculopathy and immune abnormalities. Even if fibroblasts and endothelial cells dysfunction, as well as lymphocytes and other immune cells implication are now well described, the exact origin and chronology of the disease pathogenesis remain unclear. Oxidative stress, influenced by genetic and environmental factors, seems to play a key role. Indeed, it seems to be implicated in the early phases of fibrosis development, vasculopathy and in immune tolerance abnormalities shared by all patients, although disease expression is heterogeneous. To date, no curative treatment is available. Even if immunosuppressive treatment or drugs acting on vascular system are proposed for some patients, overall, treatment efficiency remains modest. Only autologous hematopoietic stem cells transplantation, reserved for patients with severe or rapidly progressive fibrosis, has recently demonstrated efficiency, with lasting regression of fibrosis. Nevertheless, this treatment can expose to important, life-threatening toxicity. In the last decade, new mechanisms implicated in the pathogenesis of systemic sclerosis have been unraveled, bringing new therapeutic opportunities. In this review, we offer to focus on recent insights in the knowledge of systemic sclerosis pathogenesis and its implication in current and future medical care.

Thyroid hormones (THs) are vital for vertebrate brain function throughout life, from early development to ageing. Epidemiological studies show an adequate supply of maternal TH during pregnancy to be necessary for normal brain development, and this from the first trimester of onwards. Maternal TH deficiency irreversibly affects fetal brain development, increasing the risk of offspring cognitive disorders and IQ loss. Mammalian and non-mammalian (zebrafish, xenopus, chicken) models are useful to dissect TH-dependent cellular and molecular mechanisms governing embryonic and fetal brain development: a complex process including cell proliferation, survival, determination, migration, differentiation and maturation of neural stem cells (NSCs). Notably, rodent models have strongly contributed to understand the key neurogenic roles of TH still at work in adult life. Neurogenesis continues in two main areas, the sub-ventricular zone lining the lateral ventricles (essential for olfaction) and the sub-granular zone in the dentate gyrus of the hippocampus (involved in memory, learning and mood control). In both niches, THs tightly regulate the balance between neurogenesis and oligodendrogenesis under physiological and pathological contexts. Understanding how THs modulate NSCs determination toward a neuronal or a glial fate throughout life is a crucial question in neural stem cell biology. Providing answers to this question can offer therapeutic strategies for brain repair, notably in neurodegenerative diseases, demyelinating diseases or stroke where new neurons and/or oligodendrocytes are required. The review focuses on TH regulation of NSC fate in mammals and humans both during development and in the adult.

The study of gut diseases is often limited by the access to human biological tissues and animal models that do not faithfully mimic the human pathologies. In this context, the development of intestinal organoids from human pluripotent stem cells is paving the way of gastrointestinal physiology and digestive disease study. In this review, we recall the embryonic development of the digestive tract and its translation to human pluripotent stem cell differentiation. We also present the different types of intestinal organoids that can be generated, as well as their applications in research.

Since a few decades, a new invertebrate animal model has emerged in toxicology studies: the planarian. This non-parasitic flatworm, from phylum Platyhelminthes, has an amazing regenerative capacity and has been described as "immortal under the edge of the knife" in 1814 by Dalyell. This formidable capacity is due to the abundance of stem cells called neoblasts, allowing for a tiny fragment equivalent to 1/279th of the size of the planarian to generate a whole animal. The planarian has also a human-like nervous system with several neurotransmitters and has been used to evaluate developmental perturbations and neurotoxicity. This review summarizes the main planarian toxicology studies and highlights the potential of this original animal model for research.

This review focus on kidney organoids derived from pluripotent stem cells, which become a real alternative to the use of in vitro cellular models or in vivo animals models. The comprehension of the key steps involved during kidney embryonic development led to the establishment of protocols enabling the differentiation of pluripotent stem cells into kidney organoids that are highly complex and organized structures, composed of various renal cell types. These mini-organs are endowed with major applications: the possibility to control iPSC genome (by selecting patients with specific disease or by genome editing) allows the generation of kidney organoïds which recapitulate important physiopathological mechanisms such as cyste formation in renal polycystic disease. Kidney organoids can also be used in high-throughput screening to fasten the screening of nephrotoxic/therapeutic compounds. Finally, kidney organoids have a huge interest in the context of tissue repair, which remains for now a challenging goal linked with technological barriers that need still to be overcome.

Allogeneic hematopoietic stem cell transplantation is the only curative therapy for numerous malignant and non-malignant haematological diseases. A sustained engraftment of the donor stem cells is essential for transplant success and overall outcome. Graft failure is a rare but severe event after allogeneic hematopoietic stem cell transplantation. While different risk factors such as underlying disease, graft source or HLA matching have been found to be consistently associated with graft failure, other factors such as ABO mismatch graft-versus-host disease prophylaxis or infections, particularly viral reactivations, are more controversial. In this article, we review the different factors associated with graft failure.

Chronic obstructive pulmonary disease, a disease of increasing incidence, is related mainly to smoking. Although symptoms only appear at adulthood, the disease can develop from early life events. For example, bronchopulmonary dysplasia, which occurs in preterm infants, is characterized by airspace enlargement and could lead to late lung consequences. Once the lesions are established, no curative treatment is available. Stimulating lung regeneration from endogenous stem cells is therefore an exciting research domain, particularly through the activation of the mesenchymal contingent located in the lung stem cell niche.

The corneal limbus is a privileged region on the border between two quite different microenvironments, where corneal epithelial stem cells, numerous melanocytes, and antigen-presenting cells are all concentrated within a richly vascularized and innervated stroma. This situation within the ocular surface confers on it the key functions of barrier, epithelial renewal and defense of the cornea. As an immunological crossroads and since the corneoscleral limbus is directly exposed to external insults such as caustic agents, ultraviolet radiation, microbial agents, and allergens, it is the potential site of many tumoral, degenerative or inflammatory pathologies and may progress under certain conditions to limbal stem cell deficiency.

Congenital aniridia in children. Congenital aniridia is a genetic rare disease that affects the entire eyeball (pan-ocular disease). The disease is characterized by partial or complete absence of iris. Clinical signs in children are essentially photophobia and nystagmus. The prevalence was reported range from 1:40,000 births to 1:100,000 but may be underestimated. It can also be associated with other systemic disorders then constituting a syndromic aniridia. These different syndromes are to be detected rapidly at risk of nephroblastoma in WAGR syndrome (Wilms' tumor, aniridia, genitourinary anomalies, mental retardation) or cerebellar ataxia in Gillespie syndrome. The diagnosis is mostly performed in infants. Congenital aniridia combines several types of ocular disorders, such as aniridia, foveal hypoplasia, glaucoma, cataract, and progressive corneal opacification. Preventive therapies should be instituted and all ocular aspects of the disease should be treated. This disease often leads to major visual impairment or even long-term blindness and requires UV protection optical correction. Clinical research is active with corneal stem cells and gene therapy.

Abdominal and pelvic irradiations play a major place in the management of patients with cancer and present a risk of acute and late side effects. Radiation-induced lesions can affect kidney or urological structures. These side effects can have an impact in the quality of life of patients. The aim of this article is to describe the physiopathology, the symptomatology, and the principles of management of radiation-induced nephropathy, uretheritis, cystitis, and urethritis.

The use of lipostructure to treat burn sequelae is more and more common today. The regeneration capacities of mesenchymal stem cells appear promising on this sequelae skin, which is poorly vascularized, retractile and often painful. The aim of our study is to establish the analgesic properties, and the functional and aesthetic improvements gained by using lipostructure to treat burn sequelae. Forty-three patients who received lipostructure for burn sequelae according to the Coleman method between 2005 and 2017 were selected. Results regarding aesthetic, analgesic and mobility gain were recorded, with a minimum follow-up of one year postoperatively. Our patients consisted of 32 women and 11 men, with a mean age of 31.7 years (15 to 64 years). The mean follow-up during the study was 49.8 months (2 to 205 months). Patients received an average of 1.3 (1 to 3) sessions of lipostructure with an average of 153 cc (10 to 1040 cc) per session. Sequela sites were the face for 13 patients, the upper limb for 13 patients, the lower limb for 16 patients and the trunk for 4 patients. Twelve patients had lesions on multiple locations. Twenty patients benefited from this surgery for purely aesthetic or functional reasons, and 23 for painful sequelae. A significantly lower EVA was observed after surgery and a functional gain thanks to the restoration of no longer painful amplitudes. An aesthetic gain was also reported in more than three quarters of cases. In two cases, the analgesic effect decreased after one year and required a second lipostructure. The use of lipostructure in burn sequelae has already proved its efficiency with regard to the functional aspect, aesthetics and also analgesia. However, the evaluation of results is based on scales that are still imperfect. Lipostructure is not the only type of surgery used in burn sequelae. Local plasty or skin grafts are also used, but they are more invasive and have no direct analgesic effect. Lipostructure is only possible on mature, soft and non-adherent scars in order not to traumatize adipose cells. Post-burn skin is defined by retractions and adhesions to deep planes, requiring heavy rehabilitation work beforehand. Finally, the effect is not always sustainable and the duration of efficiency remains unknown. Lipostructure has its place in the treatment of hyperalgic and unsightly burn sequelae that are responsible for a functional and social disability in the patient.

For more than a decade, the existence of ovarian stem cells that can contribute to neo-oogenesis in the adult ovary is reported by some teams, challenging the dogma according to which mammalian females are born with a fixed and non-renewed germinal cell pool. The presence of germinal stem cells with mitotic activity suggests the possibility of potential postnatal oogenesis. These cells have both germ-line and stem cell markers in culture. They have been isolated using different strategies and their ability to differentiate into oocytes has been demonstrated since after reintroduction in an ovarian somatic environment, these cells generate follicles capable of producing healthy offspring in rodents. However, many scientists remain skeptical and question the reliability of the methods used. Despite that there is no consensus on the origin of these ovarian stem cells, private companies are now proposing to use their stem cell potential to treat human infertility.

Careful sequencing studies on small samples of normal oesophageal epithelium reveal the presence of very abundant cellular clones harbouring mutations in known cancer genes (and elsewhere). The number and size of these clones increases with age. This surprising finding confirms previous studies on sun-exposed epidermis. It has important implications for the understanding of cancer initiation and will hopefully lead to conceptual and clinical advances.

Therapeutic progress in primary cutaneous lymphomas continues to be largely dominated by the T-cell lymphomas, towards which the great majority of recent therapeutic innovations have been directed. The latter include local treatments consisting either of relatively classical but "revamped" approaches involving different pharmaceutical forms (example: chlormethine gel) or else lower but seemingly equally effective dosages (electron therapy), or of more innovative approaches (example: UVA-1, dynamic phototherapy, imiquimod, resimiquimod). However, significant progress has been made chiefly in terms of systemic treatments with the emergence of "targeted" drugs that directly and specifically target tumour cells (monoclonal antibodies directed against CD30, CCR4 or CD158k) and the further development of "small" molecules such as histone deacetylase inhibitors and new cytostatics. Immunotherapies, which have proven so effective in other areas of oncodermatology, are also of great interest, while allogeneic haematopoietic stem-cell transplantation has clearly shown its superiority over autologous transplantation and now constitutes a significant component of the therapeutic arsenal in advanced disease. While the innovations in terms of B-cell lymphomas are certainly less significant, mention must also be made of the value of rituximab combined with polychemotherapy (CHOP) and of lenalidomide (as second-line therapy) in primary cutaneous diffuse large B-cell lymphoma, leg type, along with the development of localized (very) low-dose radiotherapy in unilesional or paucilesional indolent forms.

The prognosis for acute lymphoblastic leukemia (ALL) in adults remains poor in refractory or relapsed (R/R) situations. Among the immunotherapy strategies that have recently been developed, CAR-T cells (chimeric antigen receptor modified T-cells) represent a major technological and therapeutic advance in the management of adult and pediatric patients with such resistant diseases. The first CAR-T trials targeting the ubiquitous B-cell antigen CD19 showed very encouraging results with complete remission rates of approximately 80%. Cytokine release syndrome (CRS) and neurotoxicity are two major and potentially life-threatening adverse events, that require coordinated management with intensive care units and graduated use of IL-6 pathway blocking antibodies and steroids. In addition to immediate toxicity, many clinical issues arise such as ALL treatment from apheresis to CAR-T infusion, the role of allogeneic hematopoietic stem cell transplant (HSCT) before or after CAR-T therapy, or the reduction of escape mechanisms mostly driven by the loss of target expression. The development of these strategies in other subtypes of acute leukemias, including myeloid acute leukemia, is confronted with the expression of antigenic targets by healthy tissues and the potential risk of prolonged cytopenias. This review adopts a clinical perspective to detail the main results of CD19 CAR-T in ALL and the challenges raised by this new therapeutic approach. Cet article fait partie du numéro supplément Les cellules CAR-T : une révolution thérapeutique ? réalisé avec le soutien institutionnel des partenaires Gilead : Kite et Celgene.