RAS-mutant leukaemia stem cells drive clinical resistance to venetoclax.

Cancer driver mutations often show distinct temporal acquisition patterns, but the biological basis for this, if any, remains unknown. RAS mutations occur invariably late in the course of acute myeloid leukaemia, upon progression or relapsed/refractory disease1-6. Here, by using human leukaemogenesis models, we first show that RAS mutations are obligatory late events that need to succeed earlier cooperating mutations. We provide the mechanistic explanation for this in a requirement for mutant RAS to specifically transform committed progenitors of the myelomonocytic lineage (granulocyte-monocyte progenitors) harbouring previously acquired driver mutations, showing that advanced leukaemic clones can originate from a different cell type in the haematopoietic hierarchy than ancestral clones. Furthermore, we demonstrate that RAS-mutant leukaemia stem cells (LSCs) give rise to monocytic disease, as observed frequently in patients with poor responses to treatment with the BCL2 inhibitor venetoclax. We show that this is because RAS-mutant LSCs, in contrast to RAS-wild-type LSCs, have altered BCL2 family gene expression and are resistant to venetoclax, driving clinical resistance and relapse with monocytic features. Our findings demonstrate that a specific genetic driver shapes the non-genetic cellular hierarchy of acute myeloid leukaemia by imposing a specific LSC target cell restriction and critically affects therapeutic outcomes in patients.

Clonal landscape and clinical outcomes of telomere biology disorders: somatic rescuing and cancer mutations.

Telomere biology disorders (TBD), caused by pathogenic germline variants in telomere-related genes, present with multi-organ disease and a predisposition to cancer. Clonal hematopoiesis (CH) as a marker of cancer development and survival in TBD is poorly understood. Here, we characterized the clonal landscape of a large cohort of 207 TBD patients with a broad range of age and phenotype. CH occurred predominantly in symptomatic patients and in signature genes typically associated with cancers: PPM1D, POT1, TERT promoter (TERTp), U2AF1S34, and/or TP53. Chromosome 1q gain (Chr1q+) was the commonest karyotypic abnormality. Clinically, multiorgan involvement and CH in TERTp, TP53, and splicing factor genes associated with poorer overall survival. Chr1q+, and splicing factor or TP53 mutations significantly increased the risk of hematologic malignancies, regardless of the clonal burden. Chr1q+ and U2AF1S34 mutated clones were pre-malignant events associated with the secondary acquisition of mutations in genes related to hematologic malignancies. Like known effects of Chr1q+ and TP53-CH, functional studies demonstrated that U2AF1S34 mutations primarily compensated for aberrant upregulation of TP53 and interferon pathways in telomere-dysfunctional hematopoietic stem cells, highlighting the TP53 pathway as a canonical route of malignancy in TBD. In contrast, somatic POT1/PPM1D/TERTp-CH had distinct trajectories unrelated to cancer development. With implications beyond TBD, our data show that telomere dysfunction is a strong selective pressure for CH. In TBD, CH is a poor prognostic marker associated with worse overall survival. The identification of key regulatory pathways that drive clonal transformation in TBD allows the identification of patients at a higher risk of cancer development.

Hematopoietic and eosinophil-specific LNK(SH2B3) deficiency promote eosinophilia and arterial thrombosis.

Increased eosinophil counts are associated with cardiovascular disease and may be an independent predictor of major cardiovascular events. However, the causality and underlying mechanisms are poorly understood. GWAS have shown an association of a common LNK variant (R262W, T allele) with eosinophilia and atherothrombotic disorders. LNK(TT) reduces LNK function and Lnk-deficient mice display accelerated atherosclerosis and thrombosis. This study was undertaken to assess the role of eosinophils in arterial thrombosis in mice with hematopoietic Lnk deficiency. Hematopoietic Lnk deficiency increased circulating and activated eosinophils, JAK/STAT signaling in eosinophils and carotid arterial thrombosis with increased eosinophil abundance and extracellular trap formation (EETosis) in thrombi. Depletion of eosinophils by anti-Siglec-F antibody or by the ∆dbIGata1 mutation eliminated eosinophils in thrombi and markedly reduced thrombosis in mice with hematopoietic Lnk deficiency but not in control mice. Eosinophil depletion reduced neutrophil abundance and NETosis in thrombi without altering circulating neutrophil counts. To assess the role of Lnk specifically in eosinophils, we crossed Lnkf/f mice with eoCre mice. Lnk∆eos mice displayed isolated eosinophilia, increased eosinophil activation and accelerated arterial thrombosis associated with increased EETosis and NETosis in thrombi. DNase I infusion abolished EETs and NETs in thrombi and reversed the accelerated thrombosis. Human iPSC-derived LNK(TT) eosinophils showed increased activation and EETosis relative to isogenic LNK(CC) eosinophils, demonstrating human relevance. These studies show a direct link between eosinophilia, EETosis and atherothrombosis in hematopoietic Lnk deficiency and an essential role of eosinophil LNK in suppression of arterial thrombosis.

BRCC3-Mediated NLRP3 Deubiquitylation Promotes Inflammasome Activation and Atherosclerosis in Tet2 Clonal Hematopoiesis.

BACKGROUND: Clonal hematopoiesis (CH) has emerged as an independent risk factor for atherosclerotic cardiovascular disease, with activation of macrophage inflammasomes as a potential underlying mechanism. The NLRP3 (NLR family pyrin domain containing 3) inflammasome has a key role in promoting atherosclerosis in mouse models of Tet2 CH, whereas inhibition of the inflammasome product interleukin-1ß appeared to particularly benefit patients with TET2 CH in CANTOS (Cardiovascular Risk Reduction Study [Reduction in Recurrent Major CV Disease Events]). TET2 is an epigenetic modifier that decreases promoter methylation. However, the mechanisms underlying macrophage NLRP3 inflammasome activation in TET2 (Tet methylcytosine dioxygenase 2) deficiency and potential links with epigenetic modifications are poorly understood. METHODS: We used cholesterol-loaded TET2-deficient murine and embryonic stem cell-derived isogenic human macrophages to evaluate mechanisms of NLRP3 inflammasome activation in vitro and hypercholesterolemic Ldlr-/- mice modeling TET2 CH to assess the role of NLRP3 inflammasome activation in atherosclerosis. RESULTS: Tet2 deficiency in murine macrophages acted synergistically with cholesterol loading in cell culture and with hypercholesterolemia in vivo to increase JNK1 (c-Jun N-terminal kinase 1) phosphorylation and NLRP3 inflammasome activation. The mechanism of JNK (c-Jun N-terminal kinase) activation in TET2 deficiency was increased promoter methylation and decreased expression of the JNK-inactivating dual-specificity phosphatase Dusp10. Active Tet1-deadCas9-targeted editing of Dusp10 promoter methylation abolished cholesterol-induced inflammasome activation in Tet2-deficient macrophages. Increased JNK1 signaling led to NLRP3 deubiquitylation and activation by the deubiquitinase BRCC3 (BRCA1/BRCA2-containing complex subunit 3). Accelerated atherosclerosis and neutrophil extracellular trap formation (NETosis) in Tet2 CH mice were reversed by holomycin, a BRCC3 deubiquitinase inhibitor, and also by hematopoietic deficiency of Abro1, an essential scaffolding protein in the BRCC3-containing cytosolic complex. Human TET2-/- macrophages displayed increased JNK1 and NLRP3 inflammasome activation, especially after cholesterol loading, with reversal by holomycin treatment, indicating human relevance. CONCLUSIONS: Hypercholesterolemia and TET2 deficiency converge on a common pathway of NLRP3 inflammasome activation mediated by JNK1 activation and BRCC3-mediated NLRP3 deubiquitylation, with potential therapeutic implications for the prevention of cardiovascular disease in TET2 CH.

Consensus statement on the diagnosis and treatment of sclerosing diseases of the skin, Part 2: Scleromyxoedema and scleroedema.

The term 'sclerosing diseases of the skin' comprises specific dermatological entities, which have fibrotic changes of the skin in common. These diseases mostly manifest in different clinical subtypes according to cutaneous and extracutaneous involvement and can sometimes be difficult to distinguish from each other. The present consensus provides an update to the 2017 European Dermatology Forum Guidelines, focusing on characteristic clinical and histopathological features, diagnostic scores and the serum autoantibodies most useful for differential diagnosis. In addition, updated strategies for the first- and advanced-line therapy of sclerosing skin diseases are addressed in detail. Part 2 of this consensus provides clinicians with an overview of the diagnosis and treatment of scleromyxoedema and scleroedema (of Buschke).

Differential diagnosis of red scalp. The importance of trichoscopy.

Red scalp is a common complaint which may constitute a diagnostic and therapeutic challenge in daily clinical practice. Among the numerous diseases which cause diffuse scalp erythema are psoriasis, seborrheic dermatitis, contact dermatitis, diffuse lichen planopilaris, dermatomyositis and scalp rosacea. Accurate diagnosis is crucial for optimal treatment outcomes. Histology most frequently discriminates the underlying condition, but it requires scalp biopsy. In many cases the combination of clinical examination and trichoscopy is sufficient for establishing the correct diagnosis. The main trichoscopic features of psoriasis are silver-white scaling, regular distributed dotted (glomerular) vessels or twisted red loops and punctate hemorrhages. Yellowish-white scaling and thin arborizing vessels are typical features of seborrheic dermatitis. Contact dermatitis is characterized by the presence of yellow exudate and polymorphic vessels, while perifollicular scaling and erythema with the lack of follicular openings are typical findings in lichen planopilaris. In scalp dermatomyositis, tortuous and arborizing vessels with interfollicular and perifollicular pigmentation may be detected. The most characteristic features of scalp rosacea are perifollicular scaling and arborizing vessels. This review also summarizes histologic features and therapeutic options for these conditions.

The role of trichoscopy beyond hair and scalp diseases. A review.

Trichoscopy is a diagnostic tool for hair and scalp diseases. It was recently shown that it also allows the identification of features associated with disorders that typically do not affect the scalp. The aim of this article was to analyse and outline the usefulness of trichoscopy in suspecting such diseases. Connective tissue diseases were the most investigated systemic disorders in regard to trichoscopy. The most common features of systemic lupus erythematosus, systemic sclerosis and dermatomyositis are thick arborizing and tortuous vessels. Avascular areas are present in systemic sclerosis. Spermatozoa-like vessels may be observed in cutaneous T-cell lymphomas, while salmon-coloured areas with arborizing and linear vessels may be seen in patients with cutaneous B-cell lymphomas. In patients with advanced multiple myeloma, follicular spicules may be observed. Trichoscopic features of angiosarcomas include pink areas, red, polymorphic areas and dark red to purple areas. Polymorphous vessels and whitish areas on a pink background are the predominating trichoscopic features of metastases of malignant tumours to the scalp. Cutaneous sarcoidosis is characterized by orange-coloured areas and telangiectasias. Systemic amyloidosis may manifest with salmon-coloured perifollicular halos, while the most common trichoscopic features of syphilitic alopecia are as follows: decreased number of hairs per follicular unit, vellus hairs, background erythema, focal atrichia and yellow dots. In conclusion, dermatologists may suspect some systemic diseases on the basis of trichoscopic findings.

Immunopathogenesis of Atopic Dermatitis: Focus on Interleukins as Disease Drivers and Therapeutic Targets for Novel Treatments.

Atopic dermatitis is a chronic, recurrent inflammatory skin disorder manifesting by eczematous lesions and intense pruritus. Atopic dermatitis develops primarily as a result of an epidermal barrier defect and immunological imbalance. Advances in understanding these pathogenetic hallmarks, and particularly the complex role of interleukins as atopic dermatitis drivers, resulted in achieving significant therapeutic breakthroughs. Novel medications involve monoclonal antibodies specifically blocking the function of selected interleukins and small molecules such as Janus kinase inhibitors limiting downstream signaling to reduce the expression of a wider array of proinflammatory factors. Nevertheless, a subset of patients remains refractory to those treatments, highlighting the complexity of atopic dermatitis immunopathogenesis in different populations. In this review, we address the immunological heterogeneity of atopic dermatitis endotypes and phenotypes and present novel interleukin-oriented therapies for this disease.

Oxidized Phospholipids Promote NETosis and Arterial Thrombosis in LNK(SH2B3) Deficiency.

BACKGROUND: LNK/SH2B3 inhibits Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling by hematopoietic cytokine receptors. Genome-wide association studies have shown association of a common single nucleotide polymorphism in LNK (R262W, T allele) with neutrophilia, thrombocytosis, and coronary artery disease. We have shown that LNK(TT) reduces LNK function and that LNK-deficient mice display prominent platelet-neutrophil aggregates, accelerated atherosclerosis, and thrombosis. Platelet-neutrophil interactions can promote neutrophil extracellular trap (NET) formation. The goals of this study were to assess the role of NETs in atherosclerosis and thrombosis in mice with hematopoietic Lnk deficiency. METHODS: We bred mice with combined deficiency of Lnk and the NETosis-essential enzyme PAD4 (peptidyl arginine deiminase 4) and transplanted their bone marrow into Ldlr-/- mice. We evaluated the role of LNK in atherothrombosis in humans and mice bearing a gain of function variant in JAK2 (JAK2V617F). RESULTS: Lnk-deficient mice displayed accelerated carotid artery thrombosis with prominent NETosis that was completely reversed by PAD4 deficiency. Thrombin-activated Lnk-/- platelets promoted increased NETosis when incubated with Lnk-/- neutrophils compared with wild-type platelets or wild-type neutrophils. This involved increased surface exposure and release of oxidized phospholipids (OxPL) from Lnk-/- platelets, as well as increased priming and response of Lnk-/- neutrophils to OxPL. To counteract the effects of OxPL, we introduced a transgene expressing the single-chain variable fragment of E06 (E06-scFv). E06-scFv reversed accelerated NETosis, atherosclerosis, and thrombosis in Lnk-/- mice. We also showed increased NETosis when human induced pluripotent stem cell-derived LNK(TT) neutrophils were incubated with LNK(TT) platelet/megakaryocytes, but not in isogenic LNK(CC) controls, confirming human relevance. Using data from the UK Biobank, we found that individuals with the JAK2VF mutation only showed increased risk of coronary artery disease when also carrying the LNK R262W allele. Mice with hematopoietic Lnk+/- and Jak2VF clonal hematopoiesis showed accelerated arterial thrombosis but not atherosclerosis compared with Jak2VFLnk+/+ controls. CONCLUSIONS: Hematopoietic Lnk deficiency promotes NETosis and arterial thrombosis in an OxPL-dependent fashion. LNK(R262W) reduces LNK function in human platelets and neutrophils, promoting NETosis, and increases coronary artery disease risk in humans carrying Jak2VF mutations. Therapies targeting OxPL may be beneficial for coronary artery disease in genetically defined human populations.

Patients with alopecia areata are at risk of endothelial dysfunction: results of a case-control study.

BACKGROUND: Alopecia areata (AA) is an autoimmune form of hair loss, which may affect any hair-bearing area. It has been suggested that AA is associated with an increased risk of metabolic and cardiovascular comorbidities. AIM: To evaluate the early predictors of cardiovascular disease [endothelial function (EF) and arterial stiffness (AS)] in patients with AA without prior cardiovascular disease, and compare with healthy controls (HCs). METHODS: In total, 52 patients with AA (38 women and 14 men; mean age 41 years, range 30-52 years) and 34 HCs, matched for age, sex and body mass index, were enrolled in the study. EF, expressed as reactive hyperaemia index (RHI), and AS, identified by augmentation index at 75 beats/min (AI@75) were assessed with the use of the Endo-PAT 2000 device. Endothelial dysfunction (ED) was defined as RHI value ≤1.67. RESULTS: ED was observed in 22 of 52 patients with AA (42%) and in 4 of 34 HCs (12%) (P < 0.01). Moreover, mean RHI was lower in patients with AA compared with HCs (1.90 ± 0.31 vs. 2.11 ± 0.45; P = 0.03). There was no significant difference in AI@75 between patients with AA and HCs. CONCLUSIONS: Patients with AA show abnormalities in early predictors of cardiovascular diseases. Regular cardiovascular screening might be appropriate for patients with AA.

Diagnostic Accuracy of Trichoscopy in Trichotillomania: A Systematic Review.

Trichotillomania is formally classified as a mental health disorder, but it is commonly diagnosed by dermatologists. The aim of this systematic review is to assess the diagnostic value of trichoscopy in diagnosing trichotillomania. The analysis identified the 7 most specific trichoscopic features in trichotillomania. These features had the following prevalence and specificity: trichoptilosis (57.5%; 73/127 and 97.5%, respectively), v-sign (50.4%; 63/125 and 99%), hook hairs (43.1%; 28/65 and 100%), flame hairs (37.1%; 52/140 and 96.5%), coiled hairs (36.8%; 46/125 and 99.6%), tulip hairs (36.4%; 28/77 and 89.6%), and hair powder (35.6%; 42/118 and 97.9%). The 2 most common, but least specific, features were broken hairs and black dots. In conclusion, trichoscopy is a reliable new diagnostic method for hair loss caused by hair pulling. Trichoscopy should be included as a standard procedure in the differential diagnosis of trichotillomania in clinical practice.

Features of classic lichen planopilaris and frontal fibrosing alopecia in reflectance confocal microscopy: A preliminary study.

BACKGROUND: Classic lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) are primary lymphocytic cicatricial alopecia. In patients with ambiguous clinical presentation, reflectance confocal microscopy (RCM) a new noninvasive skin imaging technique, could be a helpful diagnostic tool. The aim of our study was to describe the characteristic features of classic LPP and FFA using RCM. MATERIALS AND METHODS: Ten patients with classic lichen planopilaris and two with frontal fibrosing alopecia were examined with RCM. RESULTS: Lichenoid inflammatory infiltrate around the hair follicle was observed in three cases of classic LPP and FFA (3/12; 25.0%). Extensive perifollicular fibrosis was seen in nine patients (9/12; 75.0%) with classic LPP and FFA. An increased number of white, ill-defined, coarse dermal fibers at the level of the superficial dermis were visible in seven cases (7/12; 58.3%). Moreover, dilated blood vessels were present in seven patients with classic LPP and FFA (7/12; 58.3%). CONCLUSION: Summing up, reflectance confocal microscopy allows to visualize major key diagnostic features of classic lichen planopilaris and frontal fibrosing alopecia in the real time. The value of RCM examination in scarring alopecia needs to be further evaluated, but it appears to be a useful adjuvant tool for the initial diagnosis of classic LPP and FFA.

The Influence of Microbiome Dysbiosis and Bacterial Biofilms on Epidermal Barrier Function in Atopic Dermatitis-An Update.

Atopic dermatitis (AD) is a common inflammatory dermatosis affecting up to 30% of children and 10% of adults worldwide. AD is primarily driven by an epidermal barrier defect which triggers immune dysregulation within the skin. According to recent research such phenomena are closely related to the microbial dysbiosis of the skin. There is growing evidence that cutaneous microbiota and bacterial biofilms negatively affect skin barrier function, contributing to the onset and exacerbation of AD. This review summarizes the latest data on the mechanisms leading to microbiome dysbiosis and biofilm formation in AD, and the influence of these phenomena on skin barrier function.

Biological drugs in the treatment of atopic dermatitis - current recommendations of the Polish Dermatological Society, the Polish Society of Allergology, the Polish Pediatric Society and the Polish Society of Family Medicine.

Atopic dermatitis (AD) is secondary to genetic, immunological and microbiological disorders as well as epidermal barrier defects, which are the main targets of therapy. The disease proceeds with periodic exacerbations. Its development and course are influenced by numerous environmental and individual factors. In recent decades, in industrialized countries, there has been a threefold increase in the incidence of AD. There is also an increasing number of cases resistant to topical treatment. Effective treatment of AD should provide control of clinical symptoms, prevent exacerbations and improve the quality of life of patients. The multifactorial etiopathogenesis and various endotypes and phenotypes of AD justify the tendency to optimize and personalize the therapy. Currently, we recommend the use of dupilumab for the treatment of patients from 12 years of age with moderate and severe atopic dermatitis, who do not respond to topical treatment.

Angioedema. Interdisciplinary diagnostic and therapeutic recommendations of the Polish Dermatological Society (PTD) and Polish Society of Allergology (PTA).

Angioedema is a non-inflammatory oedema of the subcutaneous tissue and/or mucosal membranes. It most commonly coexists with urticaria wheals and is considered to be a deep form of urticaria. Less commonly, it occurs in isolation and can take two basic forms: acquired angioedema and hereditary angioedema. Currently, there are 4 defined types of acquired angioedema and 7 types of hereditary angioedema. Treatment of angioedema depends on its form and etiological factors. Especially the genetic form, i.e. hereditary angioedema, is a considerable challenge for medical specialists, particularly dermatologists and allergists.

Chronic ulcerative stomatitis: A comprehensive review and proposal for diagnostic criteria.

Chronic ulcerative stomatitis (CUS) is an immune-mediated disorder characterized by oral erosions and ulcers usually refractory to conventional treatments. The disease often involves middle-aged and older women with painful lesions sometimes resembling those of erosive oral lichen planus (OLP). The most affected sites are the buccal mucosa, the gingiva and the tongue, but the skin is involved in 22.5% of cases. Histopathologic features in CUS are non-specific and indistinguishable from those of OLP, with the exception of the presence of a mixed infiltrate composed of lymphocytes and plasma cells. Direct immunofluorescence (DIF) analysis reveals the presence of stratified epithelium-specific antinuclear antibodies (SES-ANA) in the lower third of the epithelium. The IgG antibodies detected on DIF are directed against the ∆Np63α isoform of p63 expressed in the nuclei of the epithelial basal cells. A distinguishing feature of CUS is the low response to conventional corticosteroid therapy and the good outcome with hydroxychloroquine at the dosage of 200 mg/day or higher dosages. This paper presents a comprehensive review of CUS and is accompanied by a new case report (the 73rd case) and a proposal for updated diagnostic criteria.

Trichoscopy of alopecia areata in children. A retrospective comparative analysis of 50 children and 50 adults.

BACKGROUND/OBJECTIVES: Trichoscopic findings characteristic of alopecia areata have been established in adults. The objective of the study was to assess trichoscopic findings in children with alopecia areata. METHODS: Retrospective analysis of trichoscopic findings in 50 children (3-11 years old) and 50 adults (19-31 years old) with alopecia areata was performed. RESULTS: Yellow dots were less commonly detected in children compared with adults (26/50, 52% vs 48/50, 96%). Pigtail hairs and empty follicular openings were more commonly observed in children compared with adults (14/50, 28% vs 2/50, 4% and 40/50, 80% vs 16/50, 32%, respectively). No significant difference in the frequency of other trichoscopic features between children and adults was found. Black dots, broken hairs, exclamation mark hairs, and tapered hairs were detected in 20/50 (40%), 27/50 (54%), 22/50 (44%), and 6/50 (12%) children, respectively, and in 26/50 (52%), 27/50 (54%), 20/50 (40%), and 11/50 (22%) adults, respectively. Triangular hairs (short hidden hairs), short vellus hairs, and upright regrowing hairs were observed in 22/50 (44%), 35/50 (70%), and 23/50 (46%) children, respectively, and in 24/50 (48%), 37/50 (74%), and 28/50 (56%) adults, respectively. Pohl-Pinkus constrictions were present in 2/50 (4%) children and 4/50 (8%) adults. CONCLUSIONS: The most common trichoscopic findings of alopecia areata in children are empty follicular openings and short vellus hairs. Pigtail hairs and empty follicular openings are more commonly presented in children compared with adults. In contrast, yellow dots are less commonly observed in children compared with adults. Triangular hairs (short hidden hairs) are new trichoscopic findings of alopecia areata.