Melanoma tumour-derived glycans hijack dendritic cell subsets through C-type lectin receptor binding.

Dendritic cell (DC) subsets play a crucial role in shaping anti-tumour immunity. Cancer escapes from the control immune system by hijacking DC functions. Yet, bases for such subversion are only partially understood. Tumour cells display aberrant glycan motifs on surface glycoproteins and glycolipids. Such carbohydrate patterns can be sensed by DCs through C-type lectin receptors (CLRs) that are critical to shape and orientate immune responses. We recently demonstrated that melanoma tumour cells harboured an aberrant 'glyco-code,' and that circulating and tumour-infiltrating DCs from melanoma patients displayed major perturbations in their CLR profiles. To decipher whether melanoma, through aberrant glycan patterns, may exploit CLR pathways to mislead DCs and evade immune control, we explored the impact of glycan motifs aberrantly found in melanoma (neoglycoproteins [NeoGP] functionalised with Gal, Man, GalNAc, s-Tn, fucose [Fuc] and GlcNAc residues) on features of human DC subsets (cDC2s, cDC1s and pDCs). We examined the ability of glycans to bind to purified DCs, and assessed their impact on DC basal properties and functional features using flow cytometry, confocal microscopy and multiplex secreted protein analysis. DC subsets differentially bound and internalised NeoGP depending on the nature of the glycan. Strikingly, Fuc directly remodelled the expression of activation markers and immune checkpoints, as well as the cytokine/chemokine secretion profile of DC subsets. NeoGP interfered with Toll like receptor (TLR)-signalling and pre-conditioned DCs to exhibit an altered response to subsequent TLR stimulation, dampening antitumor mediators while triggering pro-tumoral factors. We further demonstrated that DC subsets can bind NeoGP through CLRs, and identified GalNAc/MGL and s-Tn/ C-type lectin-like receptor 2 (CLEC2) as potential candidates. Moreover, DC dysfunction induced by tumour-associated carbohydrate molecules may be reversed by interfering with the glycan/CLR axis. These findings revealed the glycan/CLR axis as a promising checkpoint to exploit in order to reshape potent antitumor immunity while impeding immunosuppressive pathways triggered by aberrant tumour glycosylation patterns. This may rescue DCs from tumour hijacking and improve clinical success in cancer patients.

Molecularly matched targeted therapy: a promising approach for refractory metastatic melanoma.

BACKGROUND: Only a fraction of patients with metastatic melanoma derive durable benefit from approved treatments. The clinical impact of personalized medicine strategies for melanoma, apart from BRAF, NRAS, or CKIT targeting, has rarely been reported. MATERIALS AND METHODS: By means of the Group of Cutaneous Oncology of the French Society of Dermatology, we retrospectively included all patients with advanced melanoma aged 18 years and older for whom molecular testing identified one or more actionable molecular alterations and who accordingly received molecularly matched therapy. We excluded patients with only BRAF, NRAS, or CKIT alterations and patients who received molecularly matched therapy for less than 15 days. RESULTS: We included 26 patients with a median follow-up of 8 months (1-54), a median age of 63 years (24-89), and a sex ratio of 2.7. These patients had been heavily pretreated, and 64% had elevated LDH levels. The disease control rate was 38%, with 4 cases of partial response (overall response rate: 15%) and 6 of stable disease for at least 6 months. The median duration of treatment was 3.1 months (0.9-13.5). Among patients with disease control, the median duration of control was 6.6 months (2.6-13.5) and 3 cases were ongoing at the end of the study. Patients with controlled disease had GNA11, MAP2K1, FYCO1-RAF1, HRAS, ATM, CCND1, MDM2/CDK4, and CDKN2A/NRAS alterations. CONCLUSIONS: High-throughput sequencing followed by matched targeted therapy is a promising approach for patients with advanced melanoma refractory to approved treatments.

Late-onset adverse events of anti-PD1 therapy in melanoma patients: An observational study from MELBASE, a nationwide prospective cohort.

BACKGROUND: Late-onset adverse events (AEs) of anti-programmed cell death 1 (anti-PD1) antibodies have not been systematically described. OBJECTIVES: The purpose was to evaluate late-onset AEs in melanoma patients treated with anti-PD1 administered for at least 2 years in a real-life setting. METHODS: Patients were screened from MelBase, a French multicentric biobank dedicated to the prospective follow up of unresectable stage III or IV melanoma. The study included 119 patients who received anti-PD1 during at least 2 years from January 2013 to November 2019. Median follow up was 41.7 months (range, 25.2-57.5 months). Fifty-three patients received nivolumab and 66 patients received pembrolizumab. RESULTS: AEs occurred in 99 patients (83%) with a median time of 13.3 months (range, 0-53.9 months), including severe AEs (grade 3 or 4) in 30 patients (30%). Late-onset AEs, mostly grades 1 or 2, occurred in 51 (43%) patients and led to 5 (4%) hospitalizations, of which 4 were severe. Factors associated with late-onset AEs in multivariate analysis were early-onset AEs (within the first 2 years of treatment) and treatment duration (P = .02 and P = .03, respectively). CONCLUSIONS: Our data demonstrate the possibility of late-onset AEs occurring after 2 years of anti-PD1 therapy. Late-onset AEs appear frequently and were mostly mild or moderate. Early-onset AEs and prolonged anti-PD1 treatment may increase the risk of late-onset AEs.

Contribution of phototesting in the diagnosis of photodermatoses: Retrospective study of 100 cases.

BACKGROUND: Photodermatoses are sun-related inflammatory skin diseases. They usually require phototesting in diagnosis. However, fewer and fewer medical centers in France are equipped with photobiological equipment. OBJECTIVES: The main purpose was to evaluate the relevance of phototesting in photodermatosis diagnosis. The second goal was to study the proportions of the different kinds of photodermatosis found in this particular study. METHODS: This study was descriptive, retrospective, and mono-centric. It was based on 100 consecutive patients, who have been phototested in a French University Hospital from 2014 to 2018. Phototesting included determination of the minimal erythematous dose (MED), UVA and UVB phototests, and photopatch testing. RESULTS: The use of phototesting led to 60% of photodermatosis diagnosis and formally eliminated the latter in 13% of the cases. The diagnosis remained undetermined in 27% of the cases. Nineteen cases of polymorphous light eruption (PLE), 14 cases of photocontact dermatitis (PCD), 10 cases of solar urticaria, 8 cases of photo-aggravated atopic eczema, 5 cases of chronic actinic dermatitis, and 2 cases of systemic photosensitization were diagnosed. The allergens involved in PCD were topical non-steroidal anti-inflammatory drug (NSAID) in 9 cases, sunscreens in 3 cases, and fragrance in 2 cases. The average amount of time between the first symptoms and actual phototesting was about 7,5 years. CONCLUSION: This study confirms phototesting is truly useful. PLE was the most common form of photodermatosis, followed by PCD and solar urticaria. As photodermatosis could imply severe diseases sometimes requiring hospitalization, it is critical to maintain this expertise.

Evaluation of the benefit of thermal spa therapy in plaque psoriasis: the PSOTHERMES randomized clinical trial.

Spa therapy is considered an add-on treatment for psoriasis, but without any objective evaluation in the absence of randomized trials. This multicenter, open-label, randomized trial compared immediate spa therapy versus a control group having usual treatments until study assessments at 4.5 months. Spa therapy was proposed in five French spa resorts with standardized programs. Inclusion criteria were adults with plaque psoriasis, Dermatology Life Quality Index (DLQI) > 10, and stable medical treatment in the last 6 months. The main objective was DLQI ≤ 10 at 4.5 months after inclusion. VQ-Dermato and EQ5D-3L also assessed quality of life (QoL), Perceived Stress Scale (PSS) stress, and visual analogue scales (VAS) pain and pruritus. Between January 2015 and November 2018, 128 patients were randomized to either immediate spa therapy (64) (within 34 days, median) or usual treatments (61) until assessment at 4.5 months. Most were first-time spa users (71.2%). Mean DLQI and Psoriasis Area and Severity Index at inclusion were 16.7 and 10.5, respectively. Immediate spa therapy patients achieved the primary objective for 66.1% [95% CI 52.6% > 77.9%] vs 41.4% [95% CI 28.6% > 55.1%] control group patients (p = 0.007). VQ-Dermato scores and pruritus VAS significantly improved. Outcomes at 12-month follow-up of the immediate spa therapy group showed persistent improvement of DLQI, VQ-Dermato, and pruritus. This randomized controlled trial demonstrated that a cure of spa therapy improves QoL and alleviates certain symptoms of psoriasis, in short and long terms. This justifies its integration in the therapeutic strategies for psoriasis. Trial registration number: ClinicalTrials.gov Identifier: NCT02098213.

Nivolumab in previously untreated melanoma without BRAF mutation.

BACKGROUND: Nivolumab was associated with higher rates of objective response than chemotherapy in a phase 3 study involving patients with ipilimumab-refractory metastatic melanoma. The use of nivolumab in previously untreated patients with advanced melanoma has not been tested in a phase 3 controlled study. METHODS: We randomly assigned 418 previously untreated patients who had metastatic melanoma without a BRAF mutation to receive nivolumab (at a dose of 3 mg per kilogram of body weight every 2 weeks and dacarbazine-matched placebo every 3 weeks) or dacarbazine (at a dose of 1000 mg per square meter of body-surface area every 3 weeks and nivolumab-matched placebo every 2 weeks). The primary end point was overall survival. RESULTS: At 1 year, the overall rate of survival was 72.9% (95% confidence interval [CI], 65.5 to 78.9) in the nivolumab group, as compared with 42.1% (95% CI, 33.0 to 50.9) in the dacarbazine group (hazard ratio for death, 0.42; 99.79% CI, 0.25 to 0.73; P<0.001). The median progression-free survival was 5.1 months in the nivolumab group versus 2.2 months in the dacarbazine group (hazard ratio for death or progression of disease, 0.43; 95% CI, 0.34 to 0.56; P<0.001). The objective response rate was 40.0% (95% CI, 33.3 to 47.0) in the nivolumab group versus 13.9% (95% CI, 9.5 to 19.4) in the dacarbazine group (odds ratio, 4.06; P<0.001). The survival benefit with nivolumab versus dacarbazine was observed across prespecified subgroups, including subgroups defined by status regarding the programmed death ligand 1 (PD-L1). Common adverse events associated with nivolumab included fatigue, pruritus, and nausea. Drug-related adverse events of grade 3 or 4 occurred in 11.7% of the patients treated with nivolumab and 17.6% of those treated with dacarbazine. CONCLUSIONS: Nivolumab was associated with significant improvements in overall survival and progression-free survival, as compared with dacarbazine, among previously untreated patients who had metastatic melanoma without a BRAF mutation. (Funded by Bristol-Myers Squibb; CheckMate 066 ClinicalTrials.gov number, NCT01721772.).

Characterization of foreign materials in paraffin-embedded pathological specimens using in situ multi-elemental imaging with laser spectroscopy.

Pathologists typically encounter many disparate exogenous materials in clinical specimens during their routine histopathological examinations, especially within the skin, lymph nodes, and lungs. These foreign substances may be free extracellular deposits or induce several clinical abnormalities or histopathological patterns. However, pathologists almost never investigate or report the chemical nature of exogenous metals in clinical specimens due to a lack of convenient and available technologies. In this paper, a novel strategy based on laser-induced breakdown spectroscopy (LIBS) technology is evaluated for in situ multi-elemental tissue imaging. The improved procedures allow visualization of the presence of chemical elements contained within paraffin-embedded specimens of medical interest with elemental images that are stackable with conventional histology images. We selected relevant medical situations for which the associated pathology reports were limited to the presence of lymphohistiocytic and inflammatory cells containing granules (a granuloma and a pseudolymphoma) or to lymph nodes or skin tissues containing pigments or foreign substances. Exogenous elements such as aluminum, titanium, copper, and tungsten were identified and localized within the tissues. The all-optical LIBS elemental imaging instrument that we developed is fully compatible with conventional optical microscopy used for pathology analysis. When combined with routine histopathological analysis, LIBS is a versatile technology that might help pathologists establish or confirm diagnoses for a wide range of medical applications, particularly when the nature of external agents present in tissues needs to be investigated.

Haploinsufficiency for NR3C1, the gene encoding the glucocorticoid receptor, in blastic plasmacytoid dendritic cell neoplasms.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and highly aggressive leukemia for which knowledge on disease mechanisms and effective therapies are currently lacking. Only a handful of recurring genetic mutations have been identified and none is specific to BPDCN. In this study, through molecular cloning in an index case that presented a balanced t(3;5)(q21;q31) and molecular cytogenetic analyses in a further 46 cases, we identify monoallelic deletion of NR3C1 (5q31), encoding the glucocorticoid receptor (GCR), in 13 of 47 (28%) BPDCN patients. Targeted deep sequencing in 36 BPDCN cases, including 10 with NR3C1 deletion, did not reveal NR3C1 point mutations or indels. Haploinsufficiency for NR3C1 defined a subset of BPDCN with lowered GCR expression and extremely poor overall survival (P = .0006). Consistent with a role for GCR in tumor suppression, functional analyses coupled with gene expression profiling identified corticoresistance and loss-of-EZH2 function as major downstream consequences of NR3C1 deletion in BPDCN. Subsequently, more detailed analyses of the t(3;5)(q21;q31) revealed fusion of NR3C1 to a long noncoding RNA (lncRNA) gene (lincRNA-3q) that encodes a novel, nuclear, noncoding RNA involved in the regulation of leukemia stem cell programs and G1/S transition, via E2F. Overexpression of lincRNA-3q was a consistent feature of malignant cells and could be abrogated by bromodomain and extraterminal domain (BET) protein inhibition. Taken together, this work points to NR3C1 as a haploinsufficient tumor suppressor in a subset of BPDCN and identifies BET inhibition, acting at least partially via lncRNA blockade, as a novel treatment option in BPDCN.

Exogenous human herpesvirus 6 reinfection after tumor-infiltrating T-lymphocyte therapy.

Exogenous human herpes virus 6 (HHV-6) reinfection has never been reported in patients receiving tumor-infiltrating T lymphocytes therapy. We report an unusual case of HHV-6 infection following infusion of HHV-6 infected autologous T lymphocytes. HHV-6 infection could interfere with the tumor antigen immune recognition and the efficacy of immunotherapy.

The melanoma tumor glyco-code impacts human dendritic cells' functionality and dictates clinical outcomes.

Subversion of immunity is a hallmark of cancer development. Dendritic cells (DCs) are strategic immune cells triggering anti-tumor immune responses, but tumor cells exploit their versatility to subvert their functions. Tumor cells harbor unusual glycosylation patterns, which can be sensed through glycan-binding receptors (lectins) expressed by immune cells that are crucial for DCs to shape and orientate antitumor immunity. Yet, the global tumor glyco-code and its impact on immunity has not been explored in melanoma. To decrypt the potential link between aberrant glycosylation patterns and immune evasion in melanoma, we investigated the melanoma tumor glyco-code through the GLYcoPROFILE™ methodology (lectin arrays), and depicted its impact on patients' clinical outcome and DC subsets' functionality. Specific glycan patterns correlated with clinical outcome of melanoma patients, GlcNAc, NeuAc, TF-Ag and Fuc motifs being associated with poor outcome, whereas Man and Glc residues elicited better survival. Strikingly, tumor cells differentially impacting cytokine production by DCs harbored distinct glyco-profiles. GlcNAc exhibited a negative influence on cDC2s, whereas Fuc and Gal displayed inhibitory impacts on cDC1s and pDCs. We further identified potential booster glycans for cDC1s and pDCs. Targeting specific glycans on melanoma tumor cells restored DCs' functionality. The tumor glyco-code was also linked to the nature of the immune infiltrate. This study unveils the impact of melanoma glycan patterns on immunity, and paves the way for innovative therapeutic options. Glycans/lectins interactions arise as promising immune checkpoints to rescue DCs from tumor' hijacking to reshape antitumor immunity and inhibit immunosuppressive circuits triggered by aberrant tumor glycosylation.

Skin cancers under Janus kinase inhibitors: A World Health Organization drug safety database analysis.

BACKGROUND: Janus kinase (JAK) inhibitors are targeted therapies with a potential imunomodulatory and anti-inflammatory effect, indicated in various dysimmune pathologies. Skin cancers have been reported to occur in patients treated with JAK inhibitors. However, drug safety in clinical trials did not confirm that risk, but these studies are performed on controlled population and in a limited time of follow up. OBJECTIVES: The aim of this study is to evaluate in real life condition if a disproportionality signal exists between JAK inhibitors treatment and skin cancers. METHODS: We performed cases/non cases analysis in VigiBase® (the World Health Organization international database of suspected adverse drug reaction) using information component to search for a disproportionality signal of skin cancers from JAK inhibitor. We extracted all reports of skin cancers from the French Pharmacovigilance database occurring since 1978 up to 31st December 2019 for the three existing JAK inhibitors on market: ruxolitinib, tofacitinib and baricitinib. Only melanoma, squamous cell carcinoma and Merkel cell carcinoma were analyzed, according to the pathophysiology of these cancers and their link with immunosuppression. RESULTS: A disproportionality signal was found positive for squamous cell carcinoma with ruxolitinib (IC025=3.92) and tofacitinib (IC025=0.82), for melanoma with ruxolitinib (IC025=0.81) and tofacitinib (IC025=0.74), and Merkel cell carcinoma with ruxolitinib (IC025=4) and tofactinib (IC025=1.01) and only for Merkel cell carcinoma with baricitinib (IC025=0.53). Moreover, Merkel cell carcinoma, a very rare skin cancer more prevalent in immunodepressed patients was particularly represented in our sample and was associated with a significant disproportionality signal with all the studied JAK inhibitors. CONCLUSION: Our study shows that JAK inhibitors could be associated with an extra risk to develop skin cancers. Could an anti-viral or immunovigilance disruption mechanism brought by JAK inhibitors explain an over-risk with Merkel cell carcinoma, which were notably represented in our sample? Considering pharmacovigilance method limitations, further pharmacoepidemiological studies are required to assess a causal link between JAK inhibitors treatment and skin cancers development.

Diversification of circulating and tumor-infiltrating plasmacytoid DCs towards the P3 (CD80+ PDL1-)-pDC subset negatively correlated with clinical outcomes in melanoma patients.

Objectives: Plasmacytoid DCs (pDCs) play a critical yet enigmatic role in antitumor immunity through their pleiotropic immunomodulatory functions. Despite proof of pDC diversity in several physiological or pathological contexts, pDCs have been studied as a whole population so far in cancer. The assessment of individual pDC subsets is needed to fully grasp their involvement in cancer immunity, especially in melanoma where pDC subsets are largely unknown and remain to be uncovered. Methods: We explored for the first time the features of diverse circulating and tumor-infiltrating pDC subsets in melanoma patients using multi-parametric flow cytometry, and assessed their clinical relevance. Based on CD80, PDL1, CD2, LAG3 and Axl markers, we provided an integrated overview of the frequency, basal activation status and functional features of pDC subsets in melanoma patients together with their relationship to clinical outcome. Results: Strikingly, we demonstrated that P3-pDCs (CD80+PDL1-) accumulated within the tumor of melanoma patients and negatively correlated with clinical outcomes. The basal activation status, diversification towards P1-/P2-/P3-pDCs and functionality of several pDC subsets upon TLR7/TLR9 triggering were perturbed in melanoma patients, and were differentially linked to clinical outcome. Conclusion: Our study shed light for the first time on the phenotypic and functional heterogeneity of pDCs in the blood and tumor of melanoma patients and their potential involvement in shaping clinical outcomes. Such novelty brightens our understanding of pDC complexity, and prompts the further deciphering of pDCs' features to better apprehend and exploit these potent immune players. It highlights the importance of considering pDC diversity when developing pDC-based therapeutic strategies to ensure optimal clinical success.

In Vivo Reflectance Microscopy of Meissner Corpuscles and Bedside Measures of Large Fiber Sensory Function: A Normative Data Cohort.

BACKGROUND AND OBJECTIVES: The goal of this work was to establish age-, sex-, and body dimension-adjusted normal cutoff values for Meissner corpuscle (MC) densities via in vivo reflectance confocal microscopy (RCM), timed vibration sensory thresholds with a 128-Hz tuning fork, and touch-pressure sensory thresholds with standardized monofilaments for clinical and research application. METHODS: Seventy-seven prospectively recruited individuals without signs or symptoms of peripheral neuropathy or a condition or neurotoxin exposure that can alter sensory function underwent cross-sectional evaluation of MC densities via in vivo RCM, monofilament touch-pressure sensory thresholds, and timed vibration sensory thresholds in nondominant upper and lower extremities. Age-, sex-, and body dimension (e.g., height)-adjusted normal values were developed. The fifth percentile for MC densities and timed vibration thresholds and 95th percentile for MF touch-pressure thresholds were selected as normal cutoff points. RESULTS: Participants were 9 to 89 years of age. Age and sex were uniformly distributed. Timed vibration and touch-pressure thresholds were less sensitive with increasing age and were more sensitive in the hand than in the leg or foot within individuals. Timed vibration thresholds did not differ by sex or body dimensions. Touch-pressure thresholds were lower (more sensitive) at the thenar eminence and digit V in the hand in women compared to men but otherwise did not differ by sex at other measurement locations. Body dimensions did not affect touch-pressure thresholds. There were no apparent age-related floor effects for the 5th and 95th percentile normal cutoff values for timed vibration or touch-pressure thresholds, respectively. MC densities also declined with age and were highest at digit V and lowest at the arch within individuals. MC densities were affected by sex or body dimensions at all imaging sites, with lower densities seen in male participants or larger individuals. MC densities were quantifiable in the hand of all participants and were associated with touch-pressure thresholds at all locations. DISCUSSION: This study establishes age-, sex-, and body dimension-adjusted normal cutoff values for 2 easily applied measures of large fiber sensory function and RCM assessment of MC densities for multiple limb locations. These results will aid in the detection and monitoring of peripheral sensory nerve disorders.

Unique CLR expression patterns on circulating and tumor-infiltrating DC subsets correlated with clinical outcome in melanoma patients.

Subversion of immunity by tumors is a crucial step for their development. Dendritic cells (DCs) are strategic immune cells that orchestrate anti-tumor immune responses but display altered functions in cancer. The bases for such DCs' hijacking are not fully understood. Tumor cells harbor unusual glycosylation patterns of surface glycoproteins and glycolipids. DCs express glycan-binding receptors, named C-type lectin receptors (CLR), allowing them to sense changes in glycan signature of their environment, and subsequently trigger a response. Recognition of tumor glycans by CLRs is crucial for DCs to shape antitumor immunity, and decisive in the orientation of the response. Yet the status of the CLR machinery on DCs in cancer, especially melanoma, remained largely unknown. We explored CLR expression patterns on circulating and tumor-infiltrating cDC1s, cDC2s, and pDCs of melanoma patients, assessed their clinical relevance, and further depicted the correlations between CLR expression profiles and DCs' features. For the first time, we highlighted that the CLR repertoire of circulating and tumor-infiltrating cDC1s, cDC2s, and pDCs was strongly perturbed in melanoma patients, with modulation of DCIR, CLEC-12α and NKp44 on circulating DCs, and perturbation of Dectin-1, CD206, DEC205, DC-SIGN and CLEC-9α on tumor-infiltrating DCs. Furthermore, melanoma tumor cells directly altered CLR expression profiles of healthy DC subsets, and this was associated with specific glycan patterns (Man, Fuc, GlcNAc) that may interact with DCs through CLR molecules. Notably, specific CLR expression profiles on DC subsets correlated with unique DCs' activation status and functionality and were associated with clinical outcome of melanoma patients. Higher proportions of DCIR-, DEC205-, CLEC-12α-expressing cDCs were linked with a better survival, whereas elevated proportions of CD206-, Dectin1-expressing cDCs and NKp44-expressing pDCs were associated with a poor outcome. Thus, melanoma tumor may shape DCs' features by exploiting the plasticity of the CLR machinery. Our study revealed that melanoma manipulates CLR pathways to hijack DC subsets and escape from immune control. It further paved the way to exploit glycan-lectin interactions for the design of innovative therapeutic strategies, which exploit DCs' potentialities while avoiding hijacking by tumor, to properly reshape anti-tumor immunity by manipulating the CLR machinery.

Dysfunctional BTN3A together with deregulated immune checkpoints and type I/II IFN dictate defective interplay between pDCs and γδ T cells in melanoma patients, which impacts clinical outcomes.

OBJECTIVES: pDCs and γδ T cells emerge as potent immune players participating in the pathophysiology of cancers, yet still remaining enigmatic while harbouring a promising potential for clinical translations. Despite strategic and closed missions, crosstalk between pDCs and γδ T cells has not been deciphered yet in cancers, especially in melanoma where the long-term control of the tumor still remains a challenge. METHODS: This prompted us to explore the interplay between pDCs and γδ T cells in the context of melanoma, investigating the reciprocal features of pDCs or γδ T cells, the underlying molecular mechanisms and its impact on clinical outcomes. RESULTS: TLRL-activated pDCs from the blood and tumor infiltrate of melanoma patients displayed an impaired ability to activate, to modulate immune checkpoints and trigger the functionality of γδ T cells. Conversely, γδ T cells from the blood or tumor infiltrate of melanoma patients activated by PAg were defective in triggering pDCs' activation and modulation of immune checkpoints, and failed to elicit the functionality of pDCs. Reversion of the dysfunctional cross-talks could be achieved by specific cytokine administration and immune checkpoint targeting. Strikingly, we revealed an increased expression of BTN3A on circulating and tumor-infiltrating pDCs and γδ T cells from melanoma patients, but stressed out the potential impairment of this molecule. CONCLUSION: Our study uncovered that melanoma hijacked the bidirectional interplay between pDCs and γδ T cells to escape from immune control, and revealed BTN3A dysfunction. Such understanding will help harness and synergise the power of these potent immune cells to design new therapeutic approaches exploiting their antitumor potential while counteracting their skewing by tumors to improve patient outcomes.

Theranostic AGuIX nanoparticles as radiosensitizer: A phase I, dose-escalation study in patients with multiple brain metastases (NANO-RAD trial).

BACKGROUND AND PURPOSE: Brain metastasis impacts greatly on patients' quality of life and survival. The phase I NANO-RAD trial assessed the safety and maximum tolerated dose of systemic administration of a novel gadolinium-based nanoparticle, AGuIX, in combination with whole brain radiotherapy in patients with multiple brain metastases not suitable for stereotactic radiotherapy. MATERIALS AND METHODS: Patients with measurable brain metastases received escalating doses of AGuIX nanoparticles (15, 30, 50, 75, or 100 mg/kg intravenously) on the day of initiation of WBRT (30 Gy in 10 fractions) in 5 cohorts of 3 patients each. Toxicity was assessed using NCI Common Terminology Criteria for Adverse Events v4.03. RESULTS: Fifteen patients with 354 metastases were included. No dose-limiting toxic effects were observed up to AGuIX 100 mg/kg. Plasma elimination half-life of AGuIX was similar for all groups (mean 1.3 h; range 0.8-3 h). Efficient targeting of metastases (T1 MRI enhancement, tumor selectivity) and persistence of AGuIX contrast enhancement were observed in metastases from patients with primary melanoma, lung, breast, and colon cancers. The concentration of AGuIX in metastases after administration was proportional to the injected dose. Thirteen of 14 evaluable patients had a clinical benefit, with either stabilization or reduction of tumor volume. MRI analysis showed significant correlation between contrast enhancement and tumor response, thus supporting a radiosensitizing effect. CONCLUSION: Combining AGuIX with radiotherapy for patients with brain metastases is safe and feasible. AGuIX specifically targets brain metastases and is retained within tumors for up to 1 week; ongoing phase II studies will more definitively assess efficacy.

Plasmacytoid dendritic cells and dermatological disorders: focus on their role in autoimmunity and cancer.

Dendritic cells (DC), considered as immunological sentinels of the organism since they are antigen presenting cells, create the link between innate and adaptive immunity. DC include myeloid dendritic cells (MDC) and plasmacytoid dendritic cells (PDC). The presence of PDC, cells capable of producing large quantities of interferon alpha (IFN-alpha) in response to pathogenic agents or danger signals, seems to be closely related to pathological conditions. PDC have been observed in inflammatory immunoallergic dermatological disorders, in malignant cutaneous tumours and in cutaneous lesions of infectious origin. They seem to play a crucial role in the initiation of the pathological processes of autoimmune diseases such as lupus or psoriasis. Their function within a tumour context is not as well known and is controversial. They could have a tolerogenic role towards tumour cells in the absence of an activator but they also have the capacity to become activated in response to Toll-like receptor (TLR) ligands and could therefore be useful for therapeutic purposes.

Potent Bidirectional Cross-Talk Between Plasmacytoid Dendritic Cells and γδT Cells Through BTN3A, Type I/II IFNs and Immune Checkpoints.

Plasmacytoid DCs (pDCs) and γδT cells are both critical players in immunosurveillance against pathogens and cancer due to their ability to sense microbes and cell stress through recognition of pathogen-associated molecular patterns or altered metabolism [phosphoantigens (PAgs)]. Their unique features, high functional plasticity and ability to interact with many immune cell types allow them to bridge innate and adaptive immunity, initiating and orientating widely immune responses, hence contributing to protective and pathogenic immune responses. Yet, despite strategic and closed missions, potential interactions between pDCs and γδT cells are still unknown. Here we investigated whether there is interplay between pDCs and γδT cells and the underlying molecular mechanisms. Purified human pDCs and γδT cells were cocultured in presence of TLR-L, PAg, and zoledronate (Zol) to mimic both infectious and tumor settings. We demonstrated that TLR7/9L- or Zol-stimulated pDCs drive potent γδT-cell activation, Th1 cytokine secretion and cytotoxic activity. Conversely PAg-activated γδT cells trigger pDC phenotypic changes and functional activities. We provided evidence that pDCs and γδT cells cross-regulate each other through soluble factors and cell-cell contacts, especially type I/II IFNs and BTN3A. Such interplay could be modulated by blocking selective immune checkpoints. Our study highlighted crucial bidirectional interactions between these key potent immune players. The exploitation of pDC-γδT cells interplay represents a promising opportunity to design novel immunotherapeutic strategies and restore appropriate immune responses in cancers, infections and autoimmune diseases.