Pyrin Inflammasome Activation Defines Colchicine-Responsive SURF Patients from FMF and Other Recurrent Fevers.

Syndrome of undifferentiated recurrent fever (SURF) is characterized by recurrent fevers, a lack of confirmed molecular diagnosis, and a complete or partial response to colchicine. Despite the clinical similarities to familial Mediterranean fever (FMF), the underlying inflammatory mechanisms of SURF are not yet understood. We here analyzed the in vitro activation of the pyrin inflammasome in a cohort of SURF patients compared to FMF and PFAPA patients. Peripheral blood mononuclear cells (PBMC) were collected from SURF (both colchicine-treated and untreated), FMF, PFAPA patients, and healthy donors. PBMC were stimulated ex vivo with Clostridium difficile toxin A (TcdA) and a PKC inhibitor (UCN-01), in the presence or absence of colchicine. The assembly of the pyrin inflammasome was evaluated by measuring the presence of apoptosis-associated Speck-like protein containing caspase recruitment domain (ASC) specks in monocytes using flow cytometry. IL-1ß secretion was quantified using an ELISA assay. No differences in TcdA-induced activation of pyrin inflammasome were observed among FMF, PFAPA, and healthy donors. Untreated SURF patients showed a reduced response to TcdA, which was normalized after colchicine treatment. In contrast to FMF, SURF patients, similar to PFAPA patients and healthy donors, did not exhibit pyrin inflammasome activation in response to UCN-01-mediated pyrin dephosphorylation. These data demonstrate that in vitro functional analysis of pyrin inflammasome activation can differentiate SURF from FMF and PFAPA patients, suggesting the involvement of the pyrin inflammasome in the pathophysiology of SURF.

Long-term efficacy of MAS825, a bispecific anti-IL1ß and IL-18 monoclonal antibody, in two patients with sJIA and recurrent episodes of MAS.

INTRODUCTION: Systemic juvenile idiopathic arthritis (sJIA), a multifaceted autoinflammatory disorder, can be complicated by life-threatening conditions such as macrophage activation syndrome (MAS) and interstitial lung disease (ILD). The management of these conditions presents a therapeutic challenge, underscoring the need for innovative treatment approaches. OBJECTIVES: to report the possible role of MAS825, a bispecific anti-IL1ß and IL-18 monoclonal antibody, in the treatment of multi-drug-resistant sJIA. METHODS: We report two patients affected by sJIA with severe and refractory MAS and high serum IL-18 levels, responding to dual blockade of IL-1ß and IL-18. RESULTS: The first patient is a 20-year-old man, presenting a severe MAS complicated by thrombotic microangiopathy, following SARS-CoV-2 infection. He was treated with MAS825, with quick improvement. Eighteen months later, the patient is still undergoing biweekly treatment with MAS825, associated with MTX, ciclosporin and low-dose glucocorticoids, maintaining good control over the systemic features of the disease.The second patient, a 10-year-old girl, presented a severe MAS case, complicated by posterior reversible encephalopathy syndrome (PRES), following an otomastoiditis. The MAS was not fully controlled despite treatment with IV high-dose glucocorticoids, anakinra and ciclosporin. She began biweekly MAS825, which led to a prompt amelioration of MAS parameters. After 10 months, the patient continues to receive MAS825 and is in complete remission. CONCLUSION: In light of the pivotal role of IL-1ß and IL-18 in sJIA, MAS and ILD, MAS825 might represent a possible valid and safe option in the treatment of drug-resistant sJIA, especially in the presence of high serum IL-18 levels.

Complex regulation of alarmins S100A8/A9 and secretion via gasdermin D pores exacerbates autoinflammation in familial Mediterranean fever.

BACKGROUND: Familial Mediterranean fever (FMF), caused by mutations in the pyrin-encoding MEFV gene, is characterized by uncontrolled caspase-1 activation and IL-1ß secretion. A similar mechanism drives inflammation in cryopyrin-associated periodic fever syndrome (CAPS) caused by mutations in NLRP3. CAPS and FMF, however, result in largely different clinical manifestations, pointing to additional, autoinflammatory pathways involved in FMF. Another hallmark of FMF is extraordinarily high expression of S100A8 and S100A9. These alarmins are ligands of Toll-like receptor 4 and amplifiers of inflammation. However, the relevance of this inflammatory pathway for the pathogenesis of FMF is unknown. OBJECTIVE: This study investigated whether mutations in pyrin result in specific secretion of S100A8/A9 alarmins through gasdermin D pores' amplifying FMF pathology. METHODS: S100A8/A9 levels in FMF patients were quantified by enzyme-linked immunosorbent assay. In vitro models with knockout cell lines and specific protein inhibitors were used to unravel the S100A8/A9 secretion mechanism. The impact of S100A8/A9 to the pathophysiology of FMF was analyzed with FMF (MEFVV726A/V726A) and S100A9-/- mouse models. Pyrin-S100A8/A9 interaction was investigated by coimmunoprecipitation, immunofluorescence, and enzyme-linked immunosorbent assay studies. RESULTS: The S100A8/A9 complexes directly interacted with pyrin. Knocking out pyrin, caspase-1, or gasdermin D inhibited the secretion of these S100 alarmins. Inflammatory S100A8/A9 dimers were inactivated by tetramer formation. Blocking this inactivation by targeted S100A9 deletion in a murine FMF model demonstrated the relevance of this novel autoinflammatory pathway in FMF. CONCLUSION: This is the first proof that members of the S100 alarmin family are released in a pyrin/caspase-1/gasdermin D-dependent pathway and directly drive autoinflammation in vivo.

Spontaneous NLRP3 inflammasome-driven IL-1-ß secretion is induced in severe COVID-19 patients and responds to anakinra treatment.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may result in a severe pneumonia associated with elevation of blood inflammatory parameters, reminiscent of cytokine storm syndrome. Steroidal anti-inflammatory therapies have shown efficacy in reducing mortality in critically ill patients; however, the mechanisms by which SARS-CoV-2 triggers such an extensive inflammation remain unexplained. OBJECTIVES: To dissect the mechanisms underlying SARS-CoV-2-associated inflammation in patients with severe coronavirus disease 2019 (COVID-19), we studied the role of IL-1ß, a pivotal cytokine driving inflammatory phenotypes, whose maturation and secretion are regulated by inflammasomes. METHODS: We analyzed nod-like receptor protein 3 pathway activation by means of confocal microscopy, plasma cytokine measurement, cytokine secretion following in vitro stimulation of blood circulating monocytes, and whole-blood RNA sequencing. The role of open reading frame 3a SARS-CoV-2 protein was assessed by confocal microscopy analysis following nucleofection of a monocytic cell line. RESULTS: We found that circulating monocytes from patients with COVID-19 display ASC (adaptor molecule apoptotic speck like protein-containing a CARD) specks that colocalize with nod-like receptor protein 3 inflammasome and spontaneously secrete IL-1ß in vitro. This spontaneous activation reverts following patient's treatment with the IL-1 receptor antagonist anakinra. Transfection of a monocytic cell line with cDNA coding for the ORF3a SARS-CoV-2 protein resulted in ASC speck formation. CONCLUSIONS: These results provide further evidence that IL-1ß targeting could represent an effective strategy in this disease and suggest a mechanistic explanation for the strong inflammatory manifestations associated with COVID-19.

An Update on Familial Mediterranean Fever.

(1) Background: Familial Mediterranean Fever (FMF) is the prototypal autoinflammatory disease, characterized by recurrent bursts of neutrophilic inflammation. (2) Methods: In this study we look at the most recent literature on this condition and integrate it with novel information on treatment resistance and compliance. (3) Results: The canonical clinical presentation of FMF is in children with self-limited episodes of fever and polyserositis, associated with severe long-term complications, such as renal amyloidosis. It has been described anecdotally since ancient times, however only recently it has been characterized more accurately. We propose an updated overview on the main aspects of pathophysiology, genetics, diagnosis and treatment of this intriguing disease. (4) Conclusions: Overall, this review presents the all the main aspects, including real life outcome of the latest recommendation on treatment resistance of FMF, a disease, that not only helped understanding the pathophysiology of the auto inflammatory process but also the functioning of the innate immune system itself.

Dysregulation in B-cell responses and T follicular helper cell function in ADA2 deficiency patients.

Adenosine deaminase 2 deficiency (DADA2) is an autoinflammatory disease characterized by inflammatory vasculopathy, early strokes associated often with hypogammaglobulinemia. Pure red cell aplasia, thrombocytopenia, and neutropenia have been reported. The defect is due to biallelic loss of function of ADA2 gene, coding for a protein known to regulate the catabolism of extracellular adenosine. We therefore investigated immune phenotype and B- and T-cell responses in 14 DADA2 patients to address if ADA2 mutation affects B- and T-cell function. Here, we show a significant decrease in memory B cells, in particular class switch memory, and an expansion of CD21low B cells in DADA2 patients. In vitro stimulated B lymphocytes were able to secrete nonfunctional ADA2 protein, suggesting a cell intrinsic defect resulting in an impairment of B-cell proliferation and differentiation. Moreover, CD4+ and CD8+ T cells were diminished; however, the frequency of circulating T follicular helper cells was significantly increased but they had an impairment in IL-21 production possibly contributing to an impaired B cell help. Our findings suggest that ADA2 mutation could lead to a B-cell intrinsic defect but also to a defective Tfh cell function, which could contribute to the immunodeficient phenotype reported in DADA2 patients.

A novel knock-in mouse model of cryopyrin-associated periodic syndromes with development of amyloidosis: Therapeutic efficacy of proton pump inhibitors.

BACKGROUND: Cryopyrin-associated periodic syndromes (CAPS) are a group of autoinflammatory diseases linked to gain-of-function mutations in the NOD-like receptor family, pyrin domain containing 3 (NLRP3) gene, which cause uncontrolled IL-1ß secretion. Proton pump inhibitors (PPIs), which are commonly used as inhibitors of gastric acid production, also have anti-inflammatory properties, protect mice from sepsis, and prevent IL-1ß secretion by monocytes from patients with CAPS. OBJECTIVE: We sought to develop a novel Nlrp3 knock-in (KI) mouse model of CAPS to study amyloidosis, a severe CAPS complication, and test novel therapeutic approaches. METHODS: We generated KI mice by engineering the N475K mutation, which is associated with the CAPS phenotype, into the mouse Nlrp3 gene. KI and wild-type mice received PPIs or PBS intraperitoneally and were analyzed for survival, inflammation, cytokine secretion, and amyloidosis development. RESULTS: Mutant Nlrp3 KI mice displayed features that recapitulate the immunologic and clinical phenotype of CAPS. They showed systemic inflammation with high levels of serum proinflammatory cytokines, inflammatory infiltrates in various organs, and amyloid deposits in the spleen, liver, and kidneys. Toll-like receptor stimulated macrophages from KI mice secreted high levels of IL-1ß, IL-18, and IL-1α but low amounts of IL-1 receptor antagonist. Treatment of KI mice with PPIs had a clear clinical effect, showing a reduction in inflammatory manifestations, regression of amyloid deposits, and normalization of proinflammatory and anti-inflammatory cytokine production by macrophages. CONCLUSION: Nlrp3 KI mice displayed a CAPS phenotype with many characteristics of autoinflammation, including amyloidosis. The therapeutic effectiveness of PPIs associated with a lack of toxicity indicates that these drugs could represent relevant adjuvants to the anti-IL-1 drugs in patients with CAPS and other IL-1-driven diseases.

A Novel LC-MS/MS-Based Method for the Diagnosis of ADA2 Deficiency from Dried Plasma Spot.

Adenosine Deaminase 2 Deficiency (DADA2) (OMIM: 607575) is a monogenic, autoinflammatory disease caused by the loss of functional homozygous or heterozygous mutations in the ADA 2 gene (previously CECR1, Cat Eye Syndrome Chromosome Region 1). A timely diagnosis is crucial to start Anti-TNF therapies that are efficacious in controlling the disease. The confirmation of DADA2 is based on DNA sequencing and enzymatic assay. It is, thus, very important to have robust and reliable assays that can be rapidly utilized in specialized laboratories that can centralize samples from other centers. In this paper, we show a novel enzymatic assay based on liquid chromatography-tandem mass spectrometry that allows the accurate determination of the ADA2 enzyme activity starting from very small amounts of plasma spotted on filter paper (dried plasma spot). The method allows significantly distinguishing healthy controls from affected patients and carriers and could be of help in implementing the diagnostic workflow of DADA2.

Cell stress increases ATP release in NLRP3 inflammasome-mediated autoinflammatory diseases, resulting in cytokine imbalance.

Cell stress is implicated in triggering bouts of systemic inflammation in patients with autoinflammatory disorders. Blood monocytes from patients affected by NLRP3-mediated cryopyrin-associated periodic syndromes (CAPS) release greater amounts of IL-1ß than monocytes from unaffected subjects. Here we show that stress lowers the threshold of activation; blood monocytes from CAPS patients maintain the high levels of secreted IL-1ß (fivefold) and IL-18 (10-fold) when stimulated with 1,000-fold less LPS than that required for full IL-1ß secretion in control subjects. Unexpectedly, IL-1α secretion is increased 10-fold, indicating that inflammatory episodes in CAPS may not be entirely a result of IL-1ß but may also involve IL-1α. In CAPS monocytes, LPS induces the externalization of copious amounts of ATP (10-fold), which drive IL-1ß, IL-18, and IL-1α release via activation of the P2X purinoceptor 7. This enhanced ATP release appears to be the link between cell stress and increased cytokine secretion in CAPS. In the later phase after LPS stimulation, CAPS monocytes undergo oxidative stress, which impairs production of the anti-inflammatory IL-1 receptor antagonist (IL-1Ra). Remarkably, IL-1Ra secretion is fully restored by treatment with antioxidants. In two patients with the same NLRP3 mutation, but different disease severity, monocytes from the mildly affected patient exhibited more efficient redox response, lower ATP secretion, and more balanced cytokine production. Thus, the robustness of the individual antioxidant response increases the tolerance to stress and reduces the negative effect of the disease. Pharmacologic block of P2X purinoceptor 7 and improved stress tolerance may represent novel treatment strategies in stress-associated inflammatory diseases.

ADA2 deficiency (DADA2) as an unrecognised cause of early onset polyarteritis nodosa and stroke: a multicentre national study.

OBJECTIVES: To analyse the prevalence of CECR1 mutations in patients diagnosed with early onset livedo reticularis and/or haemorrhagic/ischaemic strokes in the context of inflammation or polyarteritis nodosa (PAN). Forty-eight patients from 43 families were included in the study. METHODS: Direct sequencing of CECR1 was performed by Sanger analysis. Adenosine deaminase 2 (ADA2) enzymatic activity was analysed in monocyte isolated from patients and healthy controls incubated with adenosine and with or without an ADA1 inhibitor. RESULTS: Biallelic homozygous or compound heterozygous CECR1 mutations were detected in 15/48 patients. A heterozygous disease-associated mutation (p.G47V) was observed in two affected brothers. The mean age of onset of the genetically positive patients was 24 months (6 months to 7 years). Ten patients displayed one or more cerebral strokes during their disease course. Low immunoglobulin levels were detected in six patients. Thalidomide and anti-TNF (tumour necrosis factor) blockers were the most effective drugs. Patients without CECR1 mutations had a later age at disease onset, a lower prevalence of neurological and skin manifestations; one of these patients displayed all the clinical features of adenosine deaminase 2deficiency (DADA2) and a defective enzymatic activity suggesting the presence of a missed mutation or a synthesis defect. CONCLUSIONS: DADA2 accounts for paediatric patients diagnosed with PAN-like disease and strokes and might explain an unrecognised condition in patients followed by adult rheumatologist. Timely diagnosis and treatment with anti-TNF agents are crucial for the prevention of severe complications of the disease. Functional assay to measure ADA2 activity should complement genetic testing in patients with non-confirming genotypes.

Disease activity accounts for long-term efficacy of IL-1 blockers in pyogenic sterile arthritis pyoderma gangrenosum and severe acne syndrome.

OBJECTIVE: To provide a rationale for anti-IL-1 treatment in pyogenic sterile arthritis, pyoderma gangrenosum and acne (PAPA) by defining whether IL-1ß secretion is enhanced; requires NLRP3; and correlates with proline-serine-threonine phosphatase-interacting protein 1 mutations, disease activity and/or the clinical picture in PAPA. METHODS: Monocytes were isolated from 13 patients and 35 healthy donors and studied at baseline and following activation. Secretion pattern of IL-1ß, IL-1α, IL-1Ra, IL-6, IL-18 and TNF-α was assessed in supernatants by ELISA. The NLRP3 requirement for IL-1ß secretion was investigated by silencing technique in PAPA and healthy donor monocytes. Long-term follow-up (mean 26 months, range 4-38) was performed in five patients enrolled in an anti-IL-1 regimen. RESULTS: IL-1ß secretion in PAPA is increased, requires NLRP3 and correlates with disease activity. Patients with a history of osteoarticular flares release more IL-1ß, IL-6 and TNF-α compared with those with predominant cutaneous recurrences. Monocytes from patients in anti-IL-1 treatment dramatically reduced IL-1ß secretion after ex vivo activation, and long-term follow-up demonstrated decreased frequency of flares and normalization of acute phase reactants in all the patients. A straightforward correlation between genotype and IL-1ß signalling was not observed suggesting that factors other than mutation itself may play a role in regulating IL-1ß secretion and response to treatment in PAPA. CONCLUSION: PAPA patients with active lesions display increased NLRP3-mediated IL-1ß secretion, and long-term efficacy of IL-1 blockade was demonstrated. Even if other mechanisms related to the complex proline-serine-threonine phosphatase-interacting protein 1 protein networking might play additional roles, this study further supports the potential of IL-1 blockade as an effective therapeutic strategy in PAPA syndrome.

Dysregulation of miRNA-30e-3p targeting IL-1ß in an international cohort of systemic autoinflammatory disease patients.

Autoinflammation is the standard mechanism seen in systemic autoinflammatory disease (SAID) patients. This study aimed to investigate the effect of a candidate miRNA, miR-30e-3p, which was identified in our previous study, on the autoinflammation phenotype seen in SAID patients and to analyze its expression in a larger group of European SAID patients. We examined the potential anti-inflammatory effect of miR-30e-3p, which we had defined as one of the differentially expressed miRNAs in microarray analysis involved in inflammation-related pathways. This study validated our previous microarray results of miR-30e-3p in a cohort involving European SAID patients. We performed cell culture transfection assays for miR-30e-3p. Then, in transfected cells, we analyzed expression levels of pro-inflammatory genes; IL-1ß, TNF-α, TGF-ß, and MEFV. We also performed functional experiments, caspase-1 activation by fluorometric assay kit, apoptosis assay by flow cytometry, and cell migration assays by wound healing and filter system to understand the possible effect of miR-30e-3p on inflammation. Following these functional assays, 3'UTR luciferase activity assay and western blotting were carried out to identify the target gene of the aforementioned miRNA. MiR-30e-3p was decreased in severe European SAID patients like the Turkish patients. The functional assays associated with inflammation suggested that miR-30e-3p has an anti-inflammatory effect. 3'UTR luciferase activity assay demonstrated that miR-30e-3p directly binds to interleukin-1-beta (IL-1ß), one of the critical molecules of inflammatory pathways, and reduces both RNA and protein levels of IL-1ß. miR-30e-3p, which has been associated with IL-1ß, a principal component of inflammation, might be of potential diagnostic and therapeutic value for SAIDs. KEY MESSAGES: miR-30e-3p, which targets IL-1ß, could have a role in the pathogenesis of SAID patients. miR-30e-3p has a role in regulating inflammatory pathways like migration, caspase-1 activation. miR-30e-3p has the potential to be used for future diagnostic and therapeutic approaches.

Adenosine Deaminase 2 Deficiency (DADA2): A Crosstalk Between Innate and Adaptive Immunity.

Deficiency of Adenosine deaminase 2 (DADA2) is a monogenic autoinflammatory disorder presenting with a broad spectrum of clinical manifestations, including immunodeficiency, vasculopathy and hematologic disease. Biallelic mutations in ADA2 gene have been associated with a decreased ADA2 activity, leading to reduction in deamination of adenosine and deoxyadenosine into inosine and deoxyinosine and subsequent accumulation of extracellular adenosine. In the early reports, the pivotal role of innate immunity in DADA2 pathogenic mechanism has been underlined, showing a skewed polarization from the M2 macrophage subtype to the proinflammatory M1 subtype, with an increased production of inflammatory cytokines such as TNF-α. Subsequently, a dysregulation of NETosis, triggered by the excess of extracellular Adenosine, has been implicated in the pathogenesis of DADA2. In the last few years, evidence is piling up that adaptive immunity is profoundly altered in DADA2 patients, encompassing both T and B branches, with a disrupted homeostasis in T-cell subsets and a B-cell skewing defect. Type I/type II IFN pathway upregulation has been proposed as a possible core signature in DADA2 T cells and monocytes but also an increased IFN-ß secretion directly from endothelial cells has been described. So far, a unifying clear pathophysiological explanation for the coexistence of systemic inflammation, immunedysregulation and hematological defects is lacking. In this review, we will explore thoroughly the latest understanding regarding DADA2 pathophysiological process, with a particular focus on dysregulation of both innate and adaptive immunity and their interacting role in the development of the disease.

Proteomic Signatures of Monocytes in Hereditary Recurrent Fevers.

Hereditary periodic recurrent fevers (HRF) are monogenic autoinflammatory associated to mutations of some genes, such as diseases caused by mutations of including MEFV, TNFRSF1A and MVK genes. Despite the identification of the causative genes, the intracellular implications related to each gene variant are still largely unknown. A large -scale proteomic analysis on monocytes of these patients is aimed to identify with an unbiased approach the mean proteins and molecular interaction networks involved in the pathogenesis of these conditions. Monocytes from HRF 15 patients (5 with MFV, 5 TNFRSF1A and 5with MVK gene mutation) and 15 healthy donors (HDs) were analyzed by liquid chromatography and tandem mass spectrometry before and after lipopolysaccharide (LPS) stimulation. Significant proteins were analyzed through a Cytoscape analysis using the ClueGo app to identify molecular interaction networks. Protein networks for each HRF were performed through a STRING database analysis integrated with a DISEAE database query. About 5000 proteins for each HRF were identified. LPS treatment maximizes differences between up-regulated proteins in monocytes of HRF patients and HDs, independently from the disease's activity and ongoing treatments. Proteins significantly modulated in monocytes of the different HRF allowed creating a disease-specific proteomic signatures and interactive protein network. Proteomic analysis is able to dissect the different intracellular pathways involved in the inflammatory response of circulating monocytes in HRF patients. The present data may help to identify a "monocyte proteomic signature" for each condition and unravel new possible unexplored intracellular pathways possibly involved in their pathogenesis. These data will be also useful to identify possible differences and similarities between the different HRFs and some multifactorial recurrent fevers.

Case Report: Susceptibility to viral infections and secondary hemophagocytic lymphohistiocytosis responsive to intravenous immunoglobulin as primary manifestations of adenosine deaminase 2 deficiency.

Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive disease associated with a highly variable clinical presentation, including systemic vasculitis, immunodeficiency, and cytopenia. We report a case of a 16-year-old girl affected by recurrent viral infections [including cytomegalovirus (CMV)-related hepatitis and measles vaccine virus-associated manifestations] and persistent inflammation, which occurred after Parvovirus infection and complicated by secondary hemophagocytic lymphohistiocytosis (HLH). HLH's first episode presented at 6 years of age and was preceded by persistent fever and arthralgia with evidence of Parvovirus B19 infection. The episode responded to intravenous steroids but relapsed during steroids tapering. High-dose intravenous immunoglobulin (IVIG) helped manage her clinical symptoms and systemic inflammation. The frequency of IVIG administration and the dosage were progressively reduced. At the age of 9, she experienced varicella zoster virus (VZV) reactivation followed by the recurrence of the inflammatory phenotype complicated by HLH with neurological involvement. Again, high-dose steroids and monthly IVIG resulted in a quick response. Targeted next-generation sequencing (NGS) for autoinflammatory diseases and immunodeficiencies revealed the homozygous Leu183Pro ADA2 mutation, which was confirmed by Sanger analysis. ADA2 enzymatic test showed a complete loss of ADA2 activity. For about 3 years, IVIG alone was completely effective in preventing flares of inflammation and neurological manifestations. Anti-TNF treatment was started at the age of 13 for the appearance of recurrent genital ulcers, with a complete response. This case further expands the clinical spectrum of DADA2 and emphasizes the importance of extensive genetic testing in clinical phenotypes characterized by persistent unspecific inflammatory syndromes. The use of high doses of IVIG might represent a possible effective immune modulator, especially in combination with anti-TNF treatment.

Clinical characterization, long-term follow-up, and response to treatment of patients with syndrome of undifferentiated recurrent fever (SURF).

OBJECTIVES: To describe a homogeneous group of patients with undifferentiated recurrent fevers followed-up in a tertiary referral center for systemic autoinflammatory diseases (SAIDs). METHODS: Patients with undifferentiated recurrent fevers seen at our Center from 2008 to 2021 and followed-up for at least one year were included in a retrospective study. Monogenic recurrent fevers, patients carrying variants of unknown origin and PFAPA (Periodic Fever, Aphthous Stomatitis, Pharyngitis, Adenitis) syndrome were excluded. RESULTS: Fifty patients (34 male, 16 female) were included in the study. The median age at onset was 3 years, and the median follow-up was 3.3 years. At baseline, arthralgia (70%) and abdominal pain (65%) were the most frequent manifestations. NSAIDs or steroids on demand had a variable and transient effect. Tonsillectomy was ineffective in the 10 patients (20%) that underwent surgery. Forty-eight patients (96%) were treated with colchicine. A complete response (absence of fever) was achieved in 31 patients (64.6%). Nine patients (18%) showed a partial response, with a median reduction of fever episodes per year of 72%. Nine patients (16.7%) were considered resistant to colchicine. The presence of generalized lymphadenopathy and, to a lesser extent, exudative tonsillitis was associated with a lack of response to colchicine. CONCLUSIONS: We describe the largest series of patients with syndrome of undifferentiated recurrent fever (SURF) reported in the literature so far. SURF should be considered as a distinct clinical entity in the context of multifactorial autoinflammatory diseases.

Case Report: Consistent disease manifestations with a staggered time course in two identical twins affected by adenosine deaminase 2 deficiency.

Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive disease associated with a highly variable clinical presentation, including vasculitis, immunodeficiency, and hematologic manifestations, potentially progressing over time. The present study describes the long-term evolution of the immuno-hematological features and therapeutic challenge of two identical adult twin sisters affected by DADA2. The absence of plasmatic adenosine deaminase 2 (ADA2) activity in both twins suggested the diagnosis of DADA2, then confirmed by genetic analysis. Exon sequencing revealed a missense (p.Leu188Pro) mutation on the paternal ADA2 allele. While, whole genome sequencing identified an unreported deletion (IVS6_IVS7del*) on the maternal allele predicted to produce a transcript missing exon 7. The patients experienced the disease onset during childhood with early strokes (Patient 1 at two years, Patient 2 at eight years of age), subsequently followed by other shared DADA2-associated features, including neutropenia, hypogammaglobulinemia, reduced switched memory B cells, inverted CD4:CD8 ratio, increased naïve T cells, reduced follicular regulatory T cells, the almost complete absence of NK cells, T-large granular cell leukemia, and osteoporosis. Disease evolution differed: clinical manifestations presented several years earlier and were more pronounced in Patient 1 than in Patient 2. Due to G-CSF refractory life-threatening neutropenia, Patient 1 successfully underwent an urgent hematopoietic stem cell transplantation (HSCT) from a 9/10 matched unrelated donor. Patient 2 experienced a similar, although delayed, disease evolution and is currently on anti-TNF therapy and anti-infectious prophylaxis. The unique cases confirmed that heterozygous patients with null ADA2 activity deserve deep investigation for possible structural variants on a single allele. Moreover, this report emphasizes the importance of timely recognizing DADA2 at the onset to allow adequate follow-up and detection of disease progression. Finally, the therapeutic management in these identical twins raises significant concerns as they share a similar phenotype, with a delayed but almost predictable disease evolution in one of them, who could benefit from a prompt definitive treatment like elective allogeneic HSCT. Additional data are required to assess whether the absence of enzymatic activity at diagnosis is associated with hematological involvement and is also predictive of bone marrow dysfunction, encouraging early HSCT to improve functional outcomes.

HLA-G and HLA-E in patients with juvenile idiopathic arthritis.

OBJECTIVE: To investigate the expression and release of HLA-G and HLA-E in JIA. METHODS: Soluble (s)HLA-G and HLA-E were measured in sera from 58 JIA patients and 54 healthy donors. Surface expression of HLA-G, HLA-E and immunoglobulin-like transcript (ILT)2 and ILT4, two receptors for HLA-G, was assessed on T, B cells and monocytes from peripheral blood (PB) and SF of 12 JIA patients and from PB of 12 controls. RESULTS: Serum sHLA-G concentration was significantly lower in patients than in controls. Both sHLA-G and sHLA-E were detected in SF and sHLA-E concentration in SF was higher in extended oligoarticular/polyarticular than in limited oligoarticular JIA. Patients compared with controls showed: (i) down-regulation of HLA-E and ILT2 expression on T cells; (ii) up-regulation of HLA-E expression on B cells and monocytes; and (iii) down-regulation of ILT4 expression on monocytes. Comparing JIA patients' SF and PB we found: (i) up-regulation of HLA-E and ILT2 expression in T and B cells and monocytes; and (ii) down-regulation of ILT4 expression in monocytes. ILT4 was up-regulated in monocytes from oligoarticular extended/polyarticular compared with oligoarticular limited JIA. CONCLUSIONS: A lower concentration of sHLA-G in sera may predispose to JIA, as observed for other autoimmune diseases. sHLA-E concentration in SF correlate with the number of affected joints. Higher ILT2 expression on SF cell populations compared with PB may be related to high sHLA-G concentration in SF. Higher HLA-E expression in SF than in PB cell populations may protect them from NK cytolysis.

Syndrome of Undifferentiated Recurrent Fever (SURF): An Emerging Group of Autoinflammatory Recurrent Fevers.

Syndrome of undifferentiated recurrent fever (SURF) is a heterogeneous group of autoinflammatory diseases (AID) characterized by self-limiting episodes of systemic inflammation without a confirmed molecular diagnosis, not fulfilling the criteria for periodic fever, aphthous stomatitis, pharyngitis and adenopathy (PFAPA) syndrome. In this review, we focused on the studies enrolling patients suspected of AID and genotyped them with next generation sequencing technologies in order to describe the clinical manifestations and treatment response of published cohorts of patients with SURF. We also propose a preliminary set of indications for the clinical suspicion of SURF that could help in everyday clinical practice.