Characterisation of IL-1 family members in Sweet syndrome highlights the overexpression of IL-1β 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-1β, IL-36γ, IL-33 and IL-1R3 (IL-1RaP) in SS. The expression profile of IL-1β, 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-1β 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-1β. This study shows that IL-1β 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-1β 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.

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.).

Certain Autoimmune Manifestations Are Associated With Distinctive Karyotypes and Outcomes in Patients With Myelodysplastic Syndrome: A Retrospective Cohort Study

Autoimmune manifestations (AIMs) are common in patients with myelodysplastic syndrome (MDS). This study aimed to investigate whether AIMs are associated with a specific cytogenetic abnormalities and worse survival in patients with MDS. A total of 67 MDS patients with AIMs and 134 age- and sex-matched MDS patients without AIMs, all of whom received medical care at Seoul National University Hospital from January 2000 through July 2014, were enrolled. The clinical features, chromosomal abnormalities, and outcomes were examined. The effect of AIMs on mortality was estimated after adjusting for age, sex, and the International Prognostic Scoring System. The mean age (±SD) at the time of MDS diagnosis was 54.5 ± 17.1 years, and 44.8% of patients were male. Neutrophilic dermatosis (ND; Sweet syndrome and pyoderma gangrenosum) was the most prevalent AIM (n = 24 36%]), followed by Behcet disease (10 [15%]), rheumatoid arthritis (9 [13%]), vasculitis (8 [12%]), myositis (3 [4%]), spondyloarthropathy (3 [4%]), and systemic lupus erythematous (2 [3%]). ND and vasculitis occurred at the time of MDS diagnosis, whereas other AIMs occurred years after MDS diagnosis. Deletion of 5q was associated with ND (P = 0.001), whereas trisomy 8 was associated with Behcet disease (P = 0.015). Strikingly, ND was associated with a 1.8-fold increase in mortality (95% CI 1.033-3.093; P = 0.038). Certain AIMs in MDS patients are associated with distinctive karyotypes and worse survival. A larger study is needed to confirm whether the presence of AIMs influences disease outcome in MDS.

Initially lymphocytic Sweet's syndrome in male patients with myelodysplasia: a distinguished clinicopathological entity? Case report and systematic review of the literature

BACKGROUND

Sweet's syndrome (SS) is an acute febrile neutrophilic dermatosis. It can occur as an idiopathic, drug-induced or malignancy-associated entity. SS is also seen in patients with myelodysplastic syndrome (MDS) where it may present atypically, both clinically and histologically. In a few rare cases of MDS, lymphocytic infiltrates are the presenting feature of SS.

METHODS

MEDLINE and Scopus were the data sources for our review.

RESULTS

A clinicopathological subsetemerged of 12 male SS patients with MDS and a mean age of 67.3 years in which the initial SS lesions were lymphocytic infiltrates. However, from 0.5 to 8 years later, sequential biopsies revealed neutrophilic dermal infiltration typical of SS.

CONCLUSION

Initially lymphocytic infiltrates in this subset could be attributed either to an early timing of the biopsy concerning the age of the lesion or to the dysgranulopoiesis syndrome. A possible relationship between the dysfunction of the receptor of the granulocyte-macrophage colony stimulating factor, the gene of which is located on the pseudoautosomal X-Y region, may exist in MDS patients with initially lymphocytic SS. This could explain the male gender of this subset and might establish initially lymphocytic SS as a distinguished clinicopathological entity for predicting the occurrence and even the prognosis of MDS.

Familial Mediterranean fever gene as a possible modifier of Sweet syndrome with chronic myelogenous leukemia

Sweet syndrome is a multisystem inflammatory disorder characterized by acute fever, as well as painful erythematous plaques infiltrated with mature neutrophils in the absence of vasculitis. The pathogenesis of the disease has not yet been clarified, although several proinflammatory cytokines have been reported to be involved in the disease process. We describe here a patient clinically diagnosed with Sweet syndrome with chronic myelogenous leukemia. The mutational analysis of the patient revealed a compound heterozygous E148Q/R202Q mutation in exon 2 of MEFV gene, which is a causative gene for familial Mediterranean fever. This is the first report to describe MEFV gene mutations in Sweet syndrome. Our results suggest that Sweet syndrome may be mediated though similar inflammatory mechanisms to those of familial Mediterranean fever.

Clonality in the setting of Sweet's syndrome and pyoderma gangrenosum is not limited to underlying myeloproliferative disease

BACKGROUND

The neutrophilic dermatoses encompass, among others, Sweet's syndrome (SS) and pyoderma gangrenosum (PG), which are associated with underlying systemic diseases including myeloid dyscrasias.

METHODS

On skin biopsies from 16 patients with biopsy-proven SS and/or PG, we performed an X-inactivation assay to detect clonal restriction of neutrophils. There were two patient categories based on known diseases at the time of diagnosis: patients with myeloproliferative disease and patients without myeloproliferative disease.

RESULTS

Among seven patients with acute myelogenous leukemia and two with myelodysplastic syndrome, clonal restriction was found in five; three were homozygous, precluding analysis. Among the seven control patients, infiltrates were clonally restricted in five; one was polyclonal and the other was homozygous for the allele, precluding analysis. Of the five patients with clonally restricted infiltrates, one was subsequently diagnosed with myelodysplasia, one had unexplained neutropenia and an additional patient developed breast cancer. Overall, the incidence of clonality in both groups was the same, averaging 81%.

CONCLUSION

These findings suggest that clonality in neutrophilic dermatoses, while characteristic of underlying myeloid dyscrasia, is not observed exclusively in the setting of myeloproliferative diseases. The significance of clonal neutrophilic infiltrates unassociated with myeloproliferative disease is unclear, but it may have some implications regarding the pathogenesis of sterile neutrophilic infiltrates. Clonality is well described in the setting of lymphomatoid hypersensitivity, reflecting an overzealous response to antigenic stimuli. One could speculate a similar mechanism operational in cases of apparently reactive SS/PG associated with monoclonality; a localized form of cutaneous neutrophilic dyscrasia is also possible.

Homozygous mutations in LPIN2 are responsible for the syndrome of chronic recurrent multifocal osteomyelitis and congenital dyserythropoietic anaemia (Majeed syndrome)

BACKGROUND

Majeed syndrome is an autosomal recessive, autoinflammatory disorder characterised by chronic recurrent multifocal osteomyelitis and congenital dyserythropoietic anaemia. The objectives of this study were to map, identify, and characterise the Majeed syndrome causal gene and to speculate on its function and role in skin and bone inflammation.

METHODS

Six individuals with Majeed syndrome from two unrelated families were identified for this study. Homozygosity mapping and parametric linkage analysis were employed for the localisation of the gene responsible for Majeed syndrome. Direct sequencing was utilised for the identification of mutations within the genes contained in the region of linkage. Expression studies and in silico characterisation of the identified causal gene and its protein were carried out.

RESULTS

The phenotype of Majeed syndrome includes inflammation of the bone and skin, recurrent fevers, and dyserythropoietic anaemia. The clinical picture of the six affected individuals is briefly reviewed. The gene was mapped to a 5.5 cM interval (1.8 Mb) on chromosome 18p. Examination of genes in this interval led to the identification of homozygous mutations in LPIN2 in affected individuals from the two families. LPIN2 was found to be expressed in almost all tissues. The function of LPIN2 and its role in inflammation remains unknown.

CONCLUSIONS

We conclude that homozygous mutations in LPIN2 result in Majeed syndrome. Understanding the aberrant immune response in this condition will shed light on the aetiology of other inflammatory disorders of multifactorial aetiology including isolated chronic recurrent multifocal osteomyelitis, Sweet syndrome, and psoriasis.

Expansion of trisomy 8 and Sweet syndrome in a prolonged course of aplastic anemia

We describe a 17-year-old boy with aplastic anemia who had Sweet syndrome develop with increasing expansion of trisomy 8. The diagnosis of aplastic anemia was made at 6 years of age. Cytopenias partially responded to danazol therapy. Cytogenetic studies of bone marrow (BM) cells were normal until the detection of trisomy 8 at 14 years of age. This clone increased with the progression of cytopenias. Cell sorting and fluorescence in situ hybridization analysis revealed that trisomy 8 was present only in nonlymphoid elements. When the patient was 17 years of age, Sweet syndrome developed. BM study showed myelodysplastic features, in which trisomy 8 occupied 74% of BM cells with additional chromosomal changes. Trisomy 8 may contribute to the late transformation of myeloid lineages in BM failure.

Sweet's syndrome in the setting of CD34-positive acute myelogenous leukemia treated with granulocyte colony stimulating factor: evidence for a clonal neutrophilic dermatosis

BACKGROUND

Sweet's syndrome in the setting of hematologic dyscrasias can be categorized into paraneoplastic-associated SS, drug-induced SS, and SS with leukemia cutis. Apart from those cases demonstrating concomitant leukemic infiltrates, it has been surmised that SS is a reactive phenomenon induced by a specific cytokine milieu.

METHODS

The authors present a patient with CD34+ acute myelogenous leukemia (AAML) who developed SS in the setting granulocyte colony stimulating factor (GCSF) therapy. Routine light microscopy and molecular studies were carried on the patient's skin biopsy specimen and post-treatment marrow. An X inactivation assay for clonality was employed.

RESULTS

Routine light microscopic examination revealed differentiated myeloid precursors including myelocytes and metamyelocytes within the subcutis; myeloblasts were not identified. In addition, in the overlying skin, features typical of SS were observed. The neutrophils demonstrated dysplastic features including hypolobation compatible with a Pseudo Pelger-Huet anomaly. X inactivation studies showed clonality both within her post-treatment marrow and skin biopsy specimen.

CONCLUSIONS

Sweet's syndrome developing in CD34+ AML patients following GCSF therapy likely reflects therapy induced differentiation of sequestered leukemic cells, hence indicative of a clonal neutrophilic dermatosis.

[Overlap of Sjögren-lupus erythematosus syndrome]

Patients with anti-SSA(Ro)-positive Sjögren's syndrome (SS)/lupus erythematosus (LE) overlap are a immunogenetically, serologically and clinically homogeneous group; what they have in common is an increased frequency of the HLA-DR3 phenotype, demonstrating SSA(Ro) antibody activity and the typical annular, polycyclic, erythematous lesions of subacute cutaneous LE. The sicca symptoms of SS may develop long after the cutaneous lesions of LE have been present, or vice versa, as well as vasculitic, purpuric, and Sweet's syndrome-like lesions. The elderly, predominantly female patients are at enhanced risk for pulmonary and neurological disease, but glomerulonephritis occurs infrequently. We present an 81-year-old, SSA(Ro) antibody-positive and HLA-DR3-positive woman with SS/LE overlap syndrome, who had cutaneous LE for 30 years, developing sicca symptoms, vasculitic and Sweet's syndrome-like skin lesions only years after the LE symptoms. Although there is still some discussion as to whether phenotypical SS/LE overlap represents a distinct disease or is secondary SS in SLE or systemic SS with cutaneous involvement, the SS/LE overlap syndrome seems well enough delineated to be considered as a disease entity with separate implications for therapy and prognosis. Its position in the spectrum of anti-SSA(Ro) antibody- and HLA-DR3-positive diseases and its relationship to SS and to anti-SSA(Ro) antibody-positive LE are discussed.

Sweet's syndrome in myeloid malignancy: a report of two cases

Two patients with a myeloid malignancy in whom Sweet's syndrome (acute febrile neutrophilic dermatosis) was diagnosed, are described. They suffered from fever and showed cutaneous lesions, with infiltration of the skin by mature neutrophils without signs of vasculitis. In one of them the clonal origin of the infiltrating neutrophils could be demonstrated by in situ hybridization. In this patient an association with the use of recombinant human granulocyte-colony stimulating factor was suspected. In the other patient, Sweet's syndrome was the initial symptom of haematological disease. Inadequate wound healing after surgical procedures led to the diagnosis.