Management of Congenital Melanocytic Naevi in Children: A French National Survey Using Clinical Vignettes.

Management of congenital melanocytic naevi in childhood may vary depending on the habits and experience of the treating clinician. The aim of this study was to assess current practice and determinants of surgical excision decision-making among French physicians. A national survey was conducted among dermatologists, paediatricians and surgeons, using clinical vignettes illustrating 29 scenarios. The primary outcome was the decision to perform surgical excision in each vignette. Of the 11,310 decisions made by the 390 participants (257 dermatologists, 35 surgeons, and 98 paediatricians) surgical excision was chosen in 33% of cases. The stated motivations for performing surgical excision were: melanoma risk, aesthetic/psychosocial risk, or both, in 39%, 34% and 27% of cases, respectively. Physicians with a higher level of experience in oncodermatology were more likely to opt for surgical excision. The age of the child, the size of the congenital melanocytic naevi, and the visibility of the lesion had no influence on the decision to perform surgical excision.

Human CD8+ Tregs expressing a MHC-specific CAR display enhanced suppression of human skin rejection and GVHD in NSG mice.

Polyclonal CD8+CD45RClow/- Tregs are potent regulatory cells able to control solid organ transplantation rejection and even induce tolerance. However, donor major histocompatibility complex (MHC)-specific Tregs are more potent than polyclonal Tregs in suppressing T-cell responses and preventing acute as well as chronic rejection in rodent models. The difficulty of identifying disease-relevant antigens able to stimulate Tregs has reduced the possibility of obtaining antigen-specific Tregs. To bypass this requirement and gain the advantage of antigen specificity, and thus improve the therapeutic potential of CD8+ Tregs, we stably introduced a chimeric antigen receptor (CAR) derived from a HLA-A*02 antigen-specific antibody (A2-CAR) in human CD8+ Tregs and developed a clinically compatible protocol of transduction and expansion. We demonstrated that A2-CAR CD8+ Tregs were not phenotypically altered by the process, were specifically activated, and did not exhibit cytotoxic activity toward HLA-A*02+ kidney endothelial cells (ECs). We showed that A2-CAR CD8+ Tregs were more potent suppressors of immune responses induced by HLA-A*02 mismatch than control-CAR CD8+ Tregs, both in vitro and in vivo, in models of human skin graft rejection and graft-versus-host disease (GVHD) in NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice. We showed that integrity of human skin graft was preserved with A2-CAR CD8+ Tregs at least 100 days in vivo after administration, and that interaction between the A2-CAR CD8+ Tregs and HLA-A*02+ kidney ECs resulted in a fine-tuned and protolerogenic activation of the ECs without cytotoxicity. Together, our results demonstrated the relevance of the CAR engineering approach to develop antigen-specific CAR-CD8+ Tregs for clinical trials in transplantation, and potentially in other diseases.

Ten years of myocutaneous flaps for pressure ulcers in patients with spinal lesions: Analysis of complications in the framework of a specialised medical-surgical pathway.

INTRODUCTION: The objective of the study is to analyse complications associated with surgery for pelvic pressure ulcers in terms of their frequency, nature and rate of surgical revisions. The secondary aims are to analyse the rate of recurrence, length of stay and time to healing, and to determine factors associated with complications and recurrence. METHODS: It is a single-centre, retrospective cohort study with a 10-year follow-up setting in Nantes University Hospital, France, a specialist centre for spinal cord injury (SCI). All patients who were admitted to the Neurological Physical Medicine and Rehabilitation (PMR) department for surgery (flap coverage) for pelvic pressure ulcers between 1st of January 2004 and 30th September 2014 were included. The main outcome measures were the rate of complications, rate of recurrence, length of stay and time to healing, as well as factors associated with complications and recurrence. RESULTS: One hundred and sixty-six patients underwent 252 flap procedures in 239 operations. The majority of patients had SCI (78.3%). The ulcer sites were mainly ischial (67%), sacral (20%) and trochanteric (12%). Gluteus maximus was used most often (75.3% of flaps) (ischial and sacral ulcers), followed by tensor fascia lata (16.2%) (trochanteric ulcers). The rate of complications that delayed return to wheelchair at 6 weeks was 34.5%. The factors associated with complications were more than one surgical ulcer and drainage time greater than 10 days. The rate of recurrence was 20.04%. The factors related to recurrence were young age, scoliosis and an oblique pelvis. CONCLUSIONS: Management within a specialised medical-surgical pathway limited post-operative complications and recurrences in this sample of subjects who mostly had SCI.

Generation of Immunodeficient Rats With Rag1 and Il2rg Gene Deletions and Human Tissue Grafting Models.

BACKGROUND: Immunodeficient mice are invaluable tools to analyze the long-term effects of potentially immunogenic molecules in the absence of adaptive immune responses. Nevertheless, there are models and experimental situations that would beneficiate of larger immunodeficient recipients. Rats are ideally suited to perform experiments in which larger size is needed and are still a small animal model suitable for rodent facilities. Additionally, rats reproduce certain human diseases better than mice, such as ankylosing spondylitis and Duchenne disease, and these disease models would greatly benefit from immunodeficient rats to test different immunogenic treatments. METHODS: We describe the generation of Il2rg-deficient rats and their crossing with previously described Rag1-deficient rats to generate double-mutant RRG animals. RESULTS: As compared with Rag1-deficient rats, Il2rg-deficient rats were more immunodeficient because they partially lacked not only T and B cells but also NK cells. RRG animals showed a more profound immunossuppressed phenotype because they displayed undetectable levels of T, B, and NK cells. Similarly, all immunoglobulin isotypes in sera were decreased in Rag1- or Il2rg-deficient rats and undetectable in Rats Rag1 and Il2rg (RRG) animals. Rag1- or Il2rg-deficient rats rejected allogeneic skin transplants and human tumors, whereas animals not only accepted allogeneic rat skin but also xenogeneic human tumors, skin, and hepatocytes. Immune humanization of RRG animals was unsuccessful. CONCLUSIONS: Thus, immunodeficient RRG animals are useful recipients for long-term studies in which immune responses could be an obstacle, including tissue humanization of different tissues.

Ex Vivo Expanded Human Non-Cytotoxic CD8+CD45RClow/- Tregs Efficiently Delay Skin Graft Rejection and GVHD in Humanized Mice.

Both CD4+ and CD8+ Tregs play a critical role in the control of immune responses and immune tolerance; however, our understanding of CD8+ Tregs is limited while they are particularly promising for therapeutic application. We report here existence of highly suppressive human CD8+CD45RClow/- Tregs expressing Foxp3 and producing IFNγ, IL-10, IL-34, and TGFß to mediate their suppressive activity. We demonstrate that total CD8+CD45RClow/- Tregs can be efficiently expanded in the presence of anti-CD3/28 mAbs, high-dose IL-2 and IL-15 and that such expanded Tregs efficiently delay GVHD and human skin transplantation rejection in immune humanized mice. Robustly expanded CD8+ Tregs displayed a specific gene signature, upregulated cytokines and expansion in the presence of rapamycin greatly improved proliferation and suppression. We show that CD8+CD45RClow/- Tregs are equivalent to canonical CD4+CD25highCD127low/- Tregs for suppression of allogeneic immune responses in vitro. Altogether, our results open new perspectives to tolerogenic strategies in human solid organ transplantation and GVHD.

Functional Langerinhigh-Expressing Langerhans-like Cells Can Arise from CD14highCD16- Human Blood Monocytes in Serum-Free Condition.

Langerhans cells (LCs) are epithelial APCs that sense danger signals and in turn trigger specific immune responses. In steady-state, they participate in the maintenance of peripheral tolerance to self-antigens whereas under inflammation LCs efficiently trigger immune responses in secondary lymphoid organs. It has been demonstrated in mice that LC-deprived epithelia are rapidly replenished by short half-life langerin-expressing monocyte-derived LCs (MDLCs). These surrogate LCs are thought to be progressively replaced by langerin(high) LCs arising from self-renewing epithelial precursors of hematopoietic origin. How LCs arise from blood monocytes is not fully understood. Hence, we sought to characterize key factors that induce differentiation of langerin(high)-expressing monocyte-derived Langerhans-like cells. We identified GM-CSF and TGF-ß1 as key cytokines to generate langerin(high)-expressing cells but only in serum-free conditions. These cells were shown to express the LC-specific TROP-2 and Axl surface markers and contained Birbeck granules. Surprisingly, E-cadherin was not spontaneously expressed by these cells but required a direct contact with keratinocytes to be stably induced. MDLCs induced stronger allogeneic T cell proliferations but released low amounts of inflammatory cytokines upon TLR stimulation compared with donor-paired monocyte-derived dendritic cells. Immature langerin(high) MDLCs were responsive to MIP-3ß/CCL20 and CTAC/CCL27 chemokine stimulations. Finally, we demonstrated that those cells behaved as bona fide LCs when inserted in a three-dimensional rebuilt epithelium by becoming activated upon TLR or UV light stimulations. Collectively, these results prompt us to propose these langerin(high) MDLCs as a relevant model to address LC biology-related questions.

Coverage of clavicular area by a pectoralis minor pedicle flap: anatomical study and description of three clinical cases.

As the data in the literature concerning the vascularization of the pectoralis minor were conflicting, we conducted a new anatomic study on cadavers preliminary to clinical application of a pedicle flap for clavicular coverage in 3 patients. Twenty flaps were dissected, yielding numerous anatomic variations. In all cases, the principal arteries penetrated the muscle in its upper part, either posteriorly or posterolaterally. This anatomic study justified the use of the pectoralis minor as a pedicle flap, with turnover just below the coracoid process. Accordingly, 3 cases of clavicular defects were treated successfully. Reports in the literature propose an adipofascial turnover flap or a pectoralis major flap for clavicular coverage. The pectoralis minor pedicle flap is easy to dissect and reproducible, involving minor esthetic sequelae and no functional complications. This flap, which has never been described in this application, would appear to be suitable for first-line treatment in this indication.