Sweet syndrome associated with moderate leukocyte adhesion deficiency type I: a case report and review of the literature.

Sweet syndrome is an acute febrile neutrophilic dermatosis characterized by the infiltration of neutrophils into the skin. It may occur idiopathically or be linked to malignancies, inflammatory or autoimmune diseases. Leukocyte adhesion deficiency type I (LAD-I) is an inborn error immunity wherein leukocytes lack adhesion molecules necessary for migration to infection sites due to mutations in the CD18 gene encoding ß2 integrins. We present a case of a 16-month-old female initially diagnosed and treated for Sweet syndrome based on histopathological findings with recurrent flare episodes. Subsequent workup revealed LAD-I, making this case the first documented association between Sweet syndrome and LAD-I. Moreover, we reviewed the pertinent literatures detailing the concurrence of neutrophilic dermatosis and immunodeficiency disorders. This case underscores the significance of comprehensive evaluation for Sweet syndrome patients who are refractory to conventional treatments.

Neutrophilic dermatosis in a patient with an IKZF1 variant and a review of monogenic autoinflammatory disorders presenting with neutrophilic dermatoses.

Monogenic diseases of immune dysregulation should be considered in the evaluation of children presenting with recurrent neutrophilic dermatoses in association with systemic signs of inflammation, autoimmune disease, hematologic abnormalities, and opportunistic or recurrent infections. We report the case of a 2-year-old boy presenting with a neutrophilic dermatosis, found to have a novel likely pathogenic germline variant of the IKAROS Family Zinc Finger 1 (IKZF1) gene; the mutation likely results in a loss of function dimerization defective protein based on reports and studies of similar variants. IKZF1 variants could potentially lead to aberrant neutrophil chemotaxis and development of neutrophilic dermatoses. Long-term surveillance is required to monitor the development of hematologic malignancy, autoimmunity, immunodeficiency, and infection in patients with pathogenic IKZF1 germline variants.

Clinical and histological features of histiocytoid Sweet syndrome associated with VEXAS syndrome.

BACKGROUND: VEXAS (Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is caused by acquired somatic mutations in UBA1. Sweet-syndrome-like skin disorders [and especially histiocytoid Sweet syndrome (HSS)] may be associated with VEXAS syndrome. OBJECTIVES: To characterize the clinical and histopathological features of HSS in patients with VEXAS syndrome. METHODS: Skin biopsies with a histological diagnosis of HSS at Rennes University Medical Center (Rennes, France) between October 2011 and January 2022 were reviewed in this study. Sanger sequencing and digital polymerase chain reaction were used to screen skin, blood and bone marrow samples for UBA1 variants, and thus classify patients as having VEXAS syndrome or not. We evaluated the clinical, histological and molecular (UBA1) characteristics of patients with or without VEXAS syndrome. RESULTS: We compared 15 skin biopsies from 7 patients found to have VEXAS syndrome and 19 skin biopsies from 15 patients without VEXAS syndrome. Persistent C-reactive protein elevation, macrocytosis, anaemia and haematological malignancies were more prevalent in patients with VEXAS syndrome [6/7 (86%), 6/7 (86%), 7/7 (100%) and 6/7 (86%), respectively] than in patients without [5/14 (36%), 6/15 (40%), 8/15 (53%) and 8/15 (53%), respectively]. These features sometimes appeared after the first skin manifestations, and a UBA1 mutation was found in the skin of five patients with VEXAS syndrome. Dermal infiltration by reniform histiocytoid cells (myeloperoxidase-positive and/or CD163-positive) and a periadnexal distribution were more frequently observed in VEXAS syndrome biopsies [15/15 (100%) and 3/15 (20%), respectively, vs. 11/19 (58%) and 0/19 (0%) in non-VEXAS syndrome biopsies, respectively]. CONCLUSIONS: Our findings might help pathologists to consider a diagnosis of VEXAS syndrome and to initiate early genetic testing.

Clinical characteristics, disease trajectories and management of vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome: a systematic review.

BACKGROUND: VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a newly discovered autoinflammatory condition characterised by somatic mutation of the UBA1 gene. The syndrome leads to multi-system inflammation affecting predominantly the skin, lungs and bone marrow. METHODS: We undertook a systematic review of the multisystem features and genotypes observed in VEXAS syndrome. Articles discussing VEXAS syndrome were included. Medline, Embase and Cochrane databases were searched. Information was extracted on: demographics, type and prevalence of clinical manifestations, genetic mutations and treatment. Meta-analysis using a random effects model was used to determine pooled estimates of serum markers. RESULTS: From 303 articles, 90 were included, comprising 394 patients with VEXAS. 99.2% were male, with a mean age of 67.1 years (SD 8.5) at disease onset. The most frequent diagnoses made prior to VEXAS were: relapsing polychondritis (n = 59); Sweet's syndrome (n = 24); polyarteritis nodosa (n = 11); and myelodysplastic syndrome (n = 10). Fever was reported in 270 cases (68.5%) and weight loss in 79 (20.1%). Most patients had haematological (n = 342; 86.8%), dermatological (n = 321; 81.5%), pulmonary (n = 297; 75.4%%) and musculoskeletal (n = 172; 43.7%) involvement, although other organ manifestations of varying prevalence were also recorded. The most commonly reported mutations were "c.122T > C pMET41Thr" (n = 124), "c.121A > G pMET41Val" (n = 62) and "c.121A > C pMet41Leu" (n = 52). Most patients received glucocorticoids (n = 240; 60.9%) followed by methotrexate (n = 82; 20.8%) and IL-6 inhibitors (n = 61, 15.4%). One patient underwent splenectomy; 24 received bone marrow transplants. CONCLUSION: VEXAS syndrome is a rare disorder affecting predominantly middle-aged men. This is the first systematic review to capture clinical manifestations, genetics and treatment of reported cases. Further studies are needed to optimise treatment and subsequently reduce morbidity and mortality.

Characterisation of IL-1 family members in Sweet syndrome highlights the overexpression of IL-1ß and IL-1R3 as possible therapeutic targets.

Sweet syndrome (SS) as a prototypic neutrophilic dermatosis (NDs) shares certain clinical and histologic features with monogenic auto-inflammatory disorders in which interleukin (IL)-1 cytokine family members play an important role. This has led to the proposal that NDs are polygenic auto-inflammatory diseases and has fuelled research to further understand the role of IL-1 family members in the pathogenesis of NDs. The aim of this study was to characterise the expression of the IL-1 family members IL-1ß, IL-36γ, IL-33 and IL-1R3 (IL-1RaP) in SS. The expression profile of IL-1ß, IL-33, IL-36γ and their common co-receptor IL-1R3 was analysed by immunohistochemistry, in situ hybridisation and double immunofluorescence (IF) in healthy control skin (HC) and lesional skin samples of SS. Marked overexpression of IL-1ß in the dermis of SS (p < 0.001), and a non-significant increase in dermal (p = 0.087) and epidermal (p = 0.345) IL-36γ expression compared to HC was observed. Significantly increased IL-1R3 expression within the dermal infiltrate of SS skin samples (p = 0.02) was also observed, whereas no difference in IL-33 expression was found between SS and HC (p = 0.7139). In situ hybridisation revealed a good correlation between gene expression levels and the above protein expression levels. Double IF identifies neutrophils and macrophages as the predominant sources of IL-1ß. This study shows that IL-1ß produced by macrophages and neutrophils and IL-1R3 are significantly overexpressed in SS, thereby indicating a potential pathogenic role for this cytokine and receptor in SS.

Identification of a neutrophil-specific PIK3R1 mutation facilitates targeted treatment in a patient with Sweet syndrome.

BackgroundAcute febrile neutrophilic dermatosis (Sweet syndrome) is a potentially fatal multiorgan inflammatory disease characterized by fever, leukocytosis, and a rash with a neutrophilic infiltrate. The disease pathophysiology remains elusive, and current dogma suggests that Sweet syndrome is a process of reactivity to an unknown antigen. Corticosteroids and steroid-sparing agents remain frontline therapies, but refractory cases pose a clinical challenge.MethodsA 51-year-old woman with multiorgan Sweet syndrome developed serious corticosteroid-related side effects and was refractory to steroid-sparing agents. Blood counts, liver enzymes, and skin histopathology supported the diagnosis. Whole-genome sequencing, transcriptomic profiling, and cellular assays of the patient's skin and neutrophils were performed.ResultsWe identified elevated IL-1 signaling in lesional Sweet syndrome skin caused by a PIK3R1 gain-of-function mutation specifically found in neutrophils. This mutation increased neutrophil migration toward IL-1ß and neutrophil respiratory burst. Targeted treatment of the patient with an IL-1 receptor 1 antagonist resulted in a dramatic therapeutic response and enabled a tapering off of corticosteroids.ConclusionDysregulated PI3K/AKT signaling is the first signaling pathway linked to Sweet syndrome and suggests that this syndrome may be caused by acquired mutations that modulate neutrophil function. Moreover, integration of molecular data across multiple levels identified a distinct subtype within a heterogeneous disease that resulted in a rational and successful clinical intervention. Future patients will benefit from efforts to identify potential mutations. The ability to directly interrogate the diseased skin allows this method to be generalizable to other inflammatory diseases and demonstrates a potential personalized medicine approach for patients with clinically challenging disease.Funding SourcesBerstein Foundation, NIH, Veterans Affairs (VA) Administration, Moseley Foundation, and H.T. Leung Foundation.

Histiocytoid Sweet Syndrome Presenting in Two Sisters With Deficiency of Deaminase Type 2.

ABSTRACT: Deficiency of adenosine deaminase type 2 (DADA2) is an autosomal recessive monogenic autoinflammatory syndrome that is classically characterised by polyarteritis nodosa, systemic vasculitis and stroke. The spectrum of disease manifestations has broadened to encompass a range of cutaneous, vascular and haematological manifestations. We report a novel association in two sisters with heterozygous p.R169G/p.M309l mutations in ADA2 with low serum ADA2 activity who both presented similarly with clinical and histological features consistent with histiocytoid Sweet syndrome.

Somatic Mutations in UBA1 and Severe Adult-Onset Autoinflammatory Disease.

BACKGROUND: Adult-onset inflammatory syndromes often manifest with overlapping clinical features. Variants in ubiquitin-related genes, previously implicated in autoinflammatory disease, may define new disorders. METHODS: We analyzed peripheral-blood exome sequence data independent of clinical phenotype and inheritance pattern to identify deleterious mutations in ubiquitin-related genes. Sanger sequencing, immunoblotting, immunohistochemical testing, flow cytometry, and transcriptome and cytokine profiling were performed. CRISPR-Cas9-edited zebrafish were used as an in vivo model to assess gene function. RESULTS: We identified 25 men with somatic mutations affecting methionine-41 (p.Met41) in UBA1, the major E1 enzyme that initiates ubiquitylation. (The gene UBA1 lies on the X chromosome.) In such patients, an often fatal, treatment-refractory inflammatory syndrome develops in late adulthood, with fevers, cytopenias, characteristic vacuoles in myeloid and erythroid precursor cells, dysplastic bone marrow, neutrophilic cutaneous and pulmonary inflammation, chondritis, and vasculitis. Most of these 25 patients met clinical criteria for an inflammatory syndrome (relapsing polychondritis, Sweet's syndrome, polyarteritis nodosa, or giant-cell arteritis) or a hematologic condition (myelodysplastic syndrome or multiple myeloma) or both. Mutations were found in more than half the hematopoietic stem cells, including peripheral-blood myeloid cells but not lymphocytes or fibroblasts. Mutations affecting p.Met41 resulted in loss of the canonical cytoplasmic isoform of UBA1 and in expression of a novel, catalytically impaired isoform initiated at p.Met67. Mutant peripheral-blood cells showed decreased ubiquitylation and activated innate immune pathways. Knockout of the cytoplasmic UBA1 isoform homologue in zebrafish caused systemic inflammation. CONCLUSIONS: Using a genotype-driven approach, we identified a disorder that connects seemingly unrelated adult-onset inflammatory syndromes. We named this disorder the VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. (Funded by the NIH Intramural Research Programs and the EU Horizon 2020 Research and Innovation Program.).

[Neutrophilic and pustular dermatoses : New autoinflammatory diseases and syndromes]. / Neutrophilenreiche und pustulöse Dermatitiden : Neue autoinflammatorische Erkrankungen und Syndrome.

This article reviews noninfectious inflammatory dermatoses with mainly neutrophilic infiltrates and the formation of pustules. The infiltrate containing neutrophils may either be mild as in urticaria or very dense, even with leukocytoclasia, as in Sweet syndrome or pyoderma gangrenosum. Neutrophilic infiltrates and pustular eruptions are caused by different noninfectious immunomechanisms. For some of them, mutations have been found (e.g. NLRC4 mutation in cryopyrin-associated periodic syndromes (CAPS) leading to activation of the inflammasome; IL36RN mutation in pustular psoriasis resulting in uncontrolled IL36 signaling). Neutrophilic dermatoses are of high interest, as they may be the cause of underlying benign or malignant conditions. In recent years, efficient targeted therapies have been developed.

MEFV gene mutations in neuro-Behçet's disease and neuro-Sweet disease.

Mediterranean fever (MEFV) gene mutations are associated with familial Mediterranean fever (FMF). Recent studies have suggested that MEFV gene mutations may act as disease modifiers in neuro-Behçet's (NBD) disease and neuro-Sweet disease (NSD). We investigated MEFV genes and clinical features in 17 patients with NBD or NSD. MEFV gene mutations were frequently observed (70.6%). Headaches and exertional leg pain were associated with MEFV gene mutations (P < 0.05). Moreover, higher frequency of white matter lesions without sites predilection (P < 0.05) and non-parenchymal lesions (P < 0.05) were also observed. MEFV gene mutations may be associated with particular findings and lesion sites.

A case of neutrophilic dermatosis with MEFV gene variant and abnormal activation of peripheral blood monocytes: a case report.

A healthy 32-year-old man had a fever and elevated levels of white blood cells (WBC) and C-reactive protein (CRP). In addition, he presented with a skin rash on his forehead, around the neck, and from the anterior chest to the abdomen. His laboratory findings showed elevated levels of hepatic enzyme, CRP, and ferritin; therefore, he was suspected to have adult-onset Still's disease (AOSD) and referred to our department. We ruled out hematological malignancy and established diagnosis of AOSD according to Yamaguchi's criteria and treated with 20 mg/day prednisolone. His clinical condition did not improve, therefore, we increased the dosage of prednisolone to 40 mg/day; however, his rash gradually expanded with papules and plaques. A cervical skin biopsy revealed neutrophil dermatosis and analysis of the MEFV gene revealed a heterozygous variant in exon 2 (E148Q). We found an elevated percentage of CD86+CD14+CD16- classical monocytes in the peripheral blood using flow cytometry. We added oral potassium iodide as a treatment for neutrophil dermatosis. Despite this treatment, his eruption and fever did not subside, therefore, we changed potassium iodide to colchicine, this improved his clinical condition. This case suggests the importance of autoinflammation-related gene abnormalities and macrophage activation in the pathogenesis of neutrophil dermatosis.

Histiocytoid Sweet syndrome harboring an isocitrate dehydrogenase 1 mutation: A case report and retrospective analysis of 29 cases of histiocytoid Sweet syndrome.

Histiocytoid Sweet syndrome (HSS) is a rare histopathologic variant of Sweet syndrome that demonstrates dermal and/or subcutaneous infiltrate with a prominent component of myeloid cells resembling histiocytes. It has been known to occur in association with hematologic neoplasms, including myelodysplastic syndrome (MDS) and acute myelogenous leukemia, but whether it confers an increased risk of such neoplasms is controversial. Here, we describe a case of a HSS that led to the diagnosis of MDS with an isocitrate dehydrogenase 1 (IDH-1) mutation and a corresponding study looking for additional cases of IDH-1 mutations in biopsies of histiocytoid and conventional Sweet syndrome.

ASK1/2 signaling promotes inflammation in a mouse model of neutrophilic dermatosis.

Mice homozygous for the Tyr208Asn amino acid substitution in the carboxy terminus of Src homology region 2 (SH2) domain-containing phosphatase 1 (SHP-1) (referred to as Ptpn6spin mice) spontaneously develop a severe inflammatory disease resembling neutrophilic dermatosis in humans. Disease in Ptpn6spin mice is characterized by persistent footpad swelling and suppurative inflammation. Recently, in addition to IL-1α and IL-1R signaling, we demonstrated a pivotal role for several kinases such as SYK, RIPK1, and TAK1 in promoting inflammatory disease in Ptpn6spin mice. In order to identify new kinases involved in SHP-1-mediated inflammation, we took a genetic approach and discovered apoptosis signal-regulating kinases 1 and 2 (ASK1 and ASK2) as novel kinases regulating Ptpn6-mediated footpad inflammation. Double deletion of ASK1 and ASK2 abrogated cutaneous inflammatory disease in Ptpn6spin mice. This double deletion further rescued the splenomegaly and lymphomegaly caused by excessive neutrophil infiltration in Ptpn6spin mice. Mechanistically, ASK regulates Ptpn6spin-mediated disease by controlling proinflammatory signaling in the neutrophils. Collectively, the present study identifies SHP-1 and ASK signaling crosstalk as a critical regulator of IL-1α-driven inflammation and opens future avenues for finding novel drug targets to treat neutrophilic dermatosis in humans.

Myelodysplastic Syndrome and Sweet's Syndrome Are Associated with a Mutation in Isocitrate Dehydrogenase 1.

BACKGROUND: Sweet's syndrome (SS) is a febrile neutrophilic dermatosis that has been clinically linked to hematological malignancies, particularly myelodysplastic syndrome (MDS), in a number of case series. Many epigenetic changes underlying MDS have been identified, such as a mutation in the isocitrate dehydrogenase 1 (IDH1) gene, which causes DNA hypermethylation and alteration of a number of genes that lead to leukemogenesis. However, the pathogenesis of malignancy-associated SS is unknown. CASE REPORT: We present two patients who were diagnosed with SS and concomitant IDH1-mutated MDS. Immunohistochemical staining of their skin lesions showed neutrophils diffusely positive for the IDH1 mutation. CONCLUSION: These cases demonstrate that IDH1 mutation may be implicated in the pathogenesis of malignancy-associated SS. Future investigation to elucidate this pathway is warranted. Establishing this molecular link can provide an earlier identification of patients with SS who are also at increased risk for developing MDS.