Proteasome inhibitor-associated histiocytoid Sweet's syndrome: Clinical and histological similarities to Nakajo-Nishimura syndrome suggest a potential mechanism.

Histiocytoid Sweet's syndrome (HSS) is a variant of Sweet's syndrome (SS) that clinically resembles SS but differs histologically by infiltrates, predominantly composed of immature cells of the myeloid lineage. Medications such as proteasome inhibitors have been reported to cause HSS but there has been little discussion on the underlying mechanism. Here we report two cases of HSS associated with a proteasome inhibitor. Both patients were on ixazomib for the treatment of multiple myeloma and presented with acute erythematous plaques on the upper half of the body. Pathological findings were consistent with HSS. Similarities between proteasome inhibitor-induced HSS and Nakajo-Nishimura syndrome, an inherited inflammatory disease, can be identified both clinically and histologically, suggesting a potential explanation of the mechanism behind proteasome inhibitor-associated HSS.

Targeting IL-13 with tralokinumab normalizes type 2 inflammation in atopic dermatitis both early and at 2 years.

BACKGROUND: Tralokinumab is a monoclonal antibody that specifically neutralizes interleukin (IL)-13, a key driver of skin inflammation and barrier abnormalities in atopic dermatitis (AD). This study evaluated early and 2-year impacts of IL-13 neutralization on skin and serum biomarkers following tralokinumab treatment in adults with moderate-to-severe AD. METHODS: Skin biopsies and blood samples were evaluated from a subset of patients enrolled in the Phase 3 ECZTRA 1 (NCT03131648) and the long-term extension ECZTEND (NCT03587805) trials. Gene expression was assessed by RNA sequencing; protein expression was assessed by immunohistochemistry and immunoassay. RESULTS: Tralokinumab improved the transcriptomic profile of lesional skin by Week 4. Mean improvements in the expression of genes dysregulated in AD were 39% at Week 16 and 85% at 2 years with tralokinumab, with 15% worsening at Week 16 with placebo. At Week 16, tralokinumab significantly decreased type 2 serum biomarkers (CCL17/TARC, periostin, and IgE), reduced epidermal thickness versus placebo, and increased loricrin coverage versus baseline. Two years of tralokinumab treatment significantly reduced expression of genes in the Th2 (IL4R, IL31, CCL17, and CCL26), Th1 (IFNG), and Th17/Th22 (IL22, S100A7, S100A8, and S100A9) pathways as well as increased expression of epidermal differentiation and barrier genes (CLDN1 and LOR). Tralokinumab also shifted atherosclerosis signaling pathway genes (SELE, IL-37, and S100A8) toward non-lesional expression. CONCLUSION: Tralokinumab treatment improved epidermal pathology, reduced systemic markers of type 2 inflammation, and shifted expression of key AD biomarkers in skin towards non-lesional levels, further highlighting the key role of IL-13 in the pathogenesis of AD. CLINICAL TRIAL REGISTRATION: NCT03131648, NCT03587805.

Presence of immunoglobulin E-expressing antibody-secreting cells in the dermis close to bullous pemphigoid lesions.

Antibody-secreting cells (ASCs) produce immunoglobulin (Ig) G and IgE autoantibodies in secondary lymphoid organs. Evidence also suggests their existence in the skin in various chronic inflammatory conditions, and in association with CXCL12 and CXCL13, they regulate the recruitment/survival of ASCs and germinal center formation to generate ASCs, respectively. However, the presence of IgG and IgE in bullous pemphigoid (BP) lesions needs to be addressed. Here, we aimed to analyse BP skin for the presence of IgG and IgE and the factors contributing to their generation, recruitment, and persistence. Skin samples from 30 patients with BP were stained to identify ASCs and the immunoglobulin type they expressed. The presence of tertiary lymphoid organ (TLO) elements, which generate ASCs in non-lymphoid tissues, and the chemokines CXCL12 and CXCL13, which regulate the migration/persistence of ASCs in lymphoid tissues and formation of TLOs, respectively, were evaluated in BP skin. BP skin harboured ASCs expressing the two types of antibodies IgG and IgE. ASCs were found in high-grade cellular aggregates containing TLO elements: T cells, B cells, CXCL12+ cells, CXCL13+ cells and high endothelial venules. IgG+ ASCs were detected among these aggregates, whereas IgE+ ASCs were dispersed throughout the dermis. CXCL12+ fibroblast-like cells were located close to ASCs. The inflammatory microenvironment of BP lesions may contribute to the antibody load characteristic of the skin of patients with BP by providing a site for the presence of ASCs. CXCL13 and CXCL12 expression may contribute to the generation and recruitment/survival of ASCs, respectively.

Metabolic reprogramming and macrophage polarization in granuloma formation.

This review article delves into the complexities of granuloma formation, focusing on the metabolic reprogramming within these immune structures, especially in tuberculosis and sarcoidosis. It underscores the role of the monocyte-macrophage lineage in granuloma formation and maintenance, emphasizing the adaptability of these cells to environmental cues and inflammatory stimuli. Key to the discussion is the macrophage polarization influenced by various cytokines, with a detailed exploration of the metabolic shifts towards glycolysis under hypoxic conditions and the utilization of the pentose phosphate pathway (PPP) for crucial biosynthetic processes. Significant attention is given to the metabolism of L-arginine in macrophages and its impact on immune response and granuloma function. The review also highlights the role of mechanistic target of rapamycin (mTOR) signaling in macrophage differentiation and its implications in granulomatous diseases. Discoveries such as elevated PPP activity in granuloma-associated macrophages and the protective role of NADPH against oxidative stress offer novel insights into granuloma biology. The review concludes by suggesting potential therapeutic targets within these metabolic pathways to modulate granuloma formation and function, proposing new treatment avenues for conditions characterized by chronic inflammation and granuloma formation. This work contributes significantly to the understanding of immune regulation and chronic inflammation, presenting avenues for future research and therapy in granulomatous diseases.

PNAd-expressing vessels characterize the dermis of CD3+ T-cell-mediated cutaneous diseases.

T-cell recruitment to skin tissues is essential for inflammation in different cutaneous diseases; however, the mechanisms by which these T cells access the skin remain unclear. High endothelial venules expressing peripheral node address in (PNAd), an L-selectin ligand, are located in secondary lymphoid organs and are responsible for increasing T-cell influx into the lymphoid tissues. They are also found in non-lymphoid tissues during inflammation. However, their presence in different common inflammatory cutaneous diseases and their correlation with T-cell infiltration remain unclear. Herein, we explored the mechanisms underlying the access of T cells to the skin by investigating the presence of PNAd-expressing vessels in different cutaneous diseases, and its correlation with T cells' presence. Skin sections of 43 patients with different diseases were subjected to immunohistochemical and immunofluorescence staining to examine the presence of PNAd-expressing vessels in the dermis. The correlation of the percentage of these vessels in the dermis of these patients with the severity/grade of CD3+ T-cell infiltration was assessed. PNAd-expressing vessels were commonly found in the skin of patients with different inflammatory diseases. A high percentage of these vessels in the dermis was associated with increased severity of CD3+ T-cell infiltration (P < 0.05). Additionally, CD3+ T cells were found both around the PNAd-expressing vessels and within the vessel lumen. PNAd-expressing vessels in cutaneous inflammatory diseases, characterized by CD3+ T-cell infiltration, could be a crucial entry point for T cells into the skin. Thus, selective targeting of these vessels could be beneficial in cutaneous inflammatory disease treatment.

Summary of Research: An Anti-OX40 Antibody to Treat Moderate-to-Severe Atopic Dermatitis: A Multicentre, Double-Blind, Placebo-Controlled Phase 2b Study.

This is a summary of the original article "An Anti-OX40 Antibody to Treat Moderate-to-Severe Atopic Dermatitis: a Multicentre, Double-blind, Placebo-Controlled Phase 2b Study". Atopic dermatitis (AD) is an inflammatory skin disease caused by a complex interplay of genetic factors, alterations to the skin microenvironment, and immune dysregulation, including T cells that have become uncontrolled. Rocatinlimab is an investigational agent that blocks OX40, a receptor on activated T cells that has an important role in inflammatory conditions such as AD. This summary of research provides an overview of a previously published article on the results of a phase 2b study of patients with moderate-to-severe AD who were treated with different doses of rocatinlimab or placebo and followed for up to 56 weeks. Rocatinlimab significantly improved the symptoms of AD and was well tolerated. The most common adverse events were fever, nasopharyngitis, and chills. This study supports rocatinlimab as a potentially safe and effective treatment for moderate-to-severe AD.

OX40 in the Pathogenesis of Atopic Dermatitis-A New Therapeutic Target.

Atopic dermatitis (AD) is a chronic, heterogeneous, inflammatory disease characterized by skin lesions, pruritus, and pain. Patients with moderate-to-severe AD experience chronic symptoms, intensified by unpredictable flares, and often have comorbidities and secondary complications, which can result in significant clinical burden that impacts the patient's overall quality of life. The complex interplay of immune dysregulation and skin barrier disruption drives AD pathogenesis, of which T-cell-dependent inflammation plays a critical role in patients with AD. Despite new targeted therapies, many patients with moderate-to-severe AD fail to achieve or sustain their individual treatment goals and/or may not be suitable for or tolerate these therapies. There remains a need for a novel, efficacious, well-tolerated therapeutic option that can deliver durable benefits across a heterogeneous AD patient population. Expression of OX40 [tumor necrosis factor receptor superfamily, member 4 (TNFRSF4)], a prominent T-cell co-stimulatory molecule, and its ligand [OX40L; tumor necrosis factor superfamily, member 4 (TNFSF4)] is increased in AD. As the OX40 pathway is critical for expansion, differentiation, and survival of effector and memory T cells, its targeting might be a promising therapeutic approach to provide sustained inhibition of pathogenic T cells and associated inflammation and broad disease control. Antibodies against OX40 [rocatinlimab (AMG 451/KHK4083) and telazorlimab (GBR 830)] or OX40L [amlitelimab (KY1005)] have shown promising results in early-phase clinical studies of moderate-to-severe AD, highlighting the importance of OX40 signaling as a new therapeutic target in AD.

Safety, efficacy, and pharmacokinetics of delgocitinib ointment in infants with atopic dermatitis: A phase 3, open-label, and long-term study.

BACKGROUND: Delgocitinib ointment, a topical Janus kinase inhibitor, is used as treatment of patients with atopic dermatitis (AD) aged ≥2 years in Japan. Although initiating appropriate and early treatment upon the onset of AD in childhood is important, the safety and efficacy of delgocitinib ointment in infants with AD have not been established. METHODS: This phase 3 study was conducted from October 2020 to June 2022 (number JapicCTI-205412). Eligible Japanese infants with AD aged 6 to <24 months received 0.25% or 0.5% of delgocitinib ointment twice daily for 52 weeks in an open-label uncontrolled manner. Topical corticosteroids were allowed to apply for worsening AD during the treatment period at the investigators' discretion. RESULTS: A total of 22 infants were enrolled. Adverse events (AEs) were reported in 21 (95.5%) infants and were mostly mild. No treatment-related AEs were reported. The Modified Eczema Area and Severity Index (mEASI) score continuously decreased until week 4, and the score reduction was maintained until week 52. The mean percent changes in the mEASI score from baseline were -73.5% at week 4, -81.7% at week 28, and -81.9% at week 52. Delgocitinib was not detected in the plasma of most infants (68.2%-95.2%). CONCLUSIONS: Delgocitinib ointment is well tolerated and effective for up to 52 weeks when applied to Japanese infants with AD.

Treat-to-target in dermatology: A scoping review and International Eczema Council survey on the approach in atopic dermatitis.

Treat-to-target (T2T) is a pragmatic therapeutic strategy being gradually introduced into dermatology after adoption in several other clinical areas. Atopic dermatitis (AD), one of the most common inflammatory skin diseases, may also benefit from this structured and practical therapeutic approach. We aimed to evaluate existing data regarding the T2T approach in dermatology, with a specific focus on AD, as well as the views of International Eczema Council (IEC) members on the potential application of a T2T approach to AD management. To do so, we systematically searched for peer-reviewed publications on the T2T approach for any skin disease in the PubMed and Scopus databases up to February 2022 and conducted a survey among IEC members regarding various components to potentially include in a T2T approach in AD. We identified 21 relevant T2T-related reports in dermatology, of which 14 were related to psoriasis, five to AD, one for juvenile dermatomyositis and one for urticaria. In the IEC member survey, respondents proposed treatable traits (with itch, disease severity and sleep problems getting the highest scores), relevant comorbidities (with asthma being selected most commonly, followed by anxiety and depression in adults), recommended specialists that should define the approach in AD (dermatologists, allergists and primary care physicians were most commonly selected in adults), and applicable assessment tools (both physician- and patient-reported), in both adult and paediatric patients, for potential future utilization of the T2T approach in AD. In conclusion, while the T2T approach may become a useful tool to simplify therapeutic goals and AD management, its foundation in AD is only starting to build. A multidisciplinary approach, including a wide range of stakeholders, including patients, is needed to further define the essential components needed to utilize T2T in AD.

Abrocitinib efficacy and safety in moderate-to-severe atopic dermatitis by race, ethnicity, and Fitzpatrick skin type.

BACKGROUND: Response to abrocitinib treatment for moderate-to-severe atopic dermatitis (AD) has not been evaluated across racial and ethnic subpopulations. OBJECTIVE: To assess the efficacy and safety of abrocitinib on the basis of patient race, ethnicity, and Fitzpatrick skin type (FST). METHODS: Data were pooled post hoc from patients treated with abrocitinib 200 mg, 100 mg, or placebo in 3 monotherapy trials (NCT02780167, NCT03349060, and NCT03575871). Race and ethnicity were self-reported; FST was determined by study investigators. Evaluations through Week 12 include the following: (1) Investigator's Global Assessment of clear or almost-clear skin; (2) greater than or equal to 75% improvement in Eczema Area and Severity Index or SCORing AD; (3) a greater-than-or-equal-to 4-point improvement in Peak Pruritus Numerical Rating Scale score; (4) least squares mean changes in Dermatology Life Quality Index and Patient-Oriented Eczema Measure scores; and (5) treatment-emergent adverse events. RESULTS: The sample comprised 628 White, 204 Asian, and 83 Black patients; 37 were Hispanic or Latino; 624 had FST I to III and 320 had FST IV to VI. Treatment with either abrocitinib dose was associated with greater proportions of patients achieving Investigator's Global Assessment of clear or almost-clear skin, ≥ 75% improvement in Eczema Area and Severity Index, ≥ 75% improvement in SCORing AD, and a ≥ 4-point improvement in Peak Pruritus Numerical Rating Scale, or greater score changes from baseline in Dermatology Life Quality Index and Patient-Oriented Eczema Measure vs placebo regardless of race, ethnicity, or FST. Dose-response was most prominent in White patients. In Black patients, the effects of the 2 doses were similar. Treatment-emergent adverse events were more common in White and Black than in Asian patients. CONCLUSION: Abrocitinib was more efficacious than placebo across the racial and ethnic groups and ranges of phototypes analyzed. Studies with increased representation of populations of color are warranted to elucidate potential variations in response across diverse populations. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT02780167 (phase 2b), NCT03349060 (phase 3 MONO-1), and NCT03575871 (phase 3 MONO-2).

Aberrant monocytopoiesis drives granuloma development in sarcoidosis.

In sarcoidosis, granulomas develop in multiple organs including the liver and lungs. Although mechanistic target of rapamycin complex 1 (mTORC1) activation in macrophages drives granuloma development in sarcoidosis by enhancing macrophage proliferation, little is known about the macrophage subsets that proliferate and mature into granuloma macrophages. Here, we show that aberrantly increased monocytopoiesis gives rise to granulomas in a sarcoidosis model, in which Tsc2, a negative regulator of mTORC1, is conditionally deleted in CSF1R-expressing macrophages (Tsc2csf1rΔ mice). In Tsc2csf1rΔ mice, common myeloid progenitors (CMPs), granulocyte-monocyte progenitors (GMPs), common monocyte progenitors / monocyte progenitors (cMoPs / MPs), inducible monocyte progenitors (iMoPs), and Ly6Cint CX3CR1low CD14- immature monocytes (iMOs), but not monocyte-dendritic cell progenitors (MDPs) and common dendritic cell progenitors (CDPs), accumulated and proliferated in the spleen. Consistent with this, monocytes, neutrophils, and neutrophil-like monocytes increased in the spleens of Tsc2csf1rΔ mice, whereas dendritic cells did not. The adoptive transfer of splenic iMOs into wild-type mice gave rise to granulomas in the liver and lungs. In these target organs, iMOs matured into Ly6Chi classical monocytes/macrophages (cMOs). Giant macrophages (gMAs) also accumulated in the liver and lungs, which were similar to granuloma macrophages in expression of cell surface markers such as MerTK and SLAMF7. Furthermore, the gMA-specific genes were expressed in human macrophages from sarcoidosis skin lesions. These results suggest that mTORC1 drives granuloma development by promoting the proliferation of monocyte/neutrophil progenitors and iMOs predominantly in the spleen, and that proliferating iMOs mature into cMOs and then gMAs to give rise to granuloma after migration into the liver and lungs in sarcoidosis.

Atopic dermatitis: A global health perspective.

The International Society of AD (ISAD) organized a roundtable on global aspects of AD at the WCD 2023 in Singapore. According to the Global Burden of Disease (GBD) consortium, at least 171 million individuals were affected with AD in 2019, corresponding to 2.23% of the world population, with age-standardized prevalence and incidence rates that were relatively stable from 1990 to 2019. Based on the panel experience, most AD cases are mild-to-moderate. Without parallel data on disease prevalence and severity, the GBD data are difficult to interpret in many regions. This gap is particularly important in countries with limited medical infrastructure, but indirect evidence suggests a significant burden of AD in low-and-medium resource settings, especially urban areas. The Singapore roundtable was an opportunity to compare experiences in World Bank category 1 (Madagascar and Mali), 3 (Brazil, China) and 4 (Australia, Germany, Qatar, USA, Singapore, Japan) countries. The panel concluded that current AD guidelines are not adapted for low resource settings and a more pragmatic approach, as developed by WHO for skin NTDs, would be advisable for minimal access to moisturizers and topical corticosteroids. The panel also recommended prioritizing prevention studies, regardless of the level of existing resources. For disease long-term control in World Bank category 3 and most category 4 countries, the main problem is not access to drugs for most mild-to-moderate cases, but rather poor compliance due to insufficient time at visits. Collaboration with WHO, patient advocacy groups and industry may promote global change, improve capacity training and fight current inequalities. Finally, optimizing management of AD and its comorbidities needs more action at the primary care level, because reaching specialist care is merely aspirational in most settings. Primary care empowerment with store and forward telemedicine and algorithms based on augmented intelligence is a future goal.

Activation of the pentose phosphate pathway in macrophages is crucial for granuloma formation in sarcoidosis.

Sarcoidosis is a disease of unknown etiology in which granulomas form throughout the body and is typically treated with glucocorticoids, but there are no approved steroid-sparing alternatives. Here, we investigated the mechanism of granuloma formation using single-cell RNA-Seq in sarcoidosis patients. We observed that the percentages of triggering receptor expressed on myeloid cells 2-positive (TREM2-positive) macrophages expressing angiotensin-converting enzyme (ACE) and lysozyme, diagnostic makers of sarcoidosis, were increased in cutaneous sarcoidosis granulomas. Macrophages in the sarcoidosis lesion were hypermetabolic, especially in the pentose phosphate pathway (PPP). Expression of the PPP enzymes, such as fructose-1,6-bisphosphatase 1 (FBP1), was elevated in both systemic granuloma lesions and serum of sarcoidosis patients. Granuloma formation was attenuated by the PPP inhibitors in in vitro giant cell and in vivo murine granuloma models. These results suggest that the PPP may be a promising target for developing therapeutics for sarcoidosis.