Aspirin hypersensitivity: a practical guide for cardiologists.

Aspirin has been known for a long time and currently stays as a cornerstone of antithrombotic therapy in cardiovascular disease. In patients with either acute or chronic coronary syndromes undergoing percutaneous coronary intervention aspirin is mandatory in a dual antiplatelet therapy regimen for prevention of stent thrombosis and/or new ischaemic events. Aspirin is also currently a first-option antithrombotic therapy after an aortic prosthetic valve replacement and is occasionally required in addition to oral anticoagulants after implantation of a mechanical valve. Presumed or demonstrated aspirin hypersensitivity is a main clinical problem, limiting the use of a life-saving medication. In the general population, aspirin hypersensitivity has a prevalence of 0.6%-2.5% and has a plethora of clinical presentations, ranging from aspirin-exacerbated respiratory disease to anaphylaxis. Although infrequent, when encountered in clinical practice aspirin hypersensitivity poses for cardiologists a clinical dilemma, which should never be trivialized, avoiding-as much as possible-omission of the drug. We here review the epidemiology of aspirin hypersensitivity, provide an outline of pathophysiological mechanisms and clinical presentations, and review management options, starting from a characterization of true aspirin allergy-in contrast to intolerance-to suggestion of desensitization protocols.

Interleukin-1 family cytokines and soluble receptors in hidradenitis suppurativa.

Hidradenitis suppurativa (HS) is a chronic skin disease, characterized by clinical inflammation of the hair follicle with the recurrence of abscesses, nodules, and tunnels. Recently, several studies suggested a role of IL-1 family (IL-1F) cytokines in eliciting and sustaining the disease. The aim of this work is to perform a comprehensive analysis of IL-1F cytokines, soluble inhibitors and receptors in a cohort of HS patients not treated with biological agents. Sixteen patients affected by HS and 16 healthy controls were recruited; clinical data were collected and disease severity evaluated by means of the International HS Severity Score System (IHS4). Serum levels of IL-1F cytokines, inhibitors and receptors were measured using a Multiplex Assays. IL-18 and free IL-18 levels were significantly higher in patients vs controls. Among soluble inhibitors, IL-1Ra, IL-1R2 and ST2/IL-1R4 were significantly increased. IL-18, free IL-18 and IL-33 levels are strongly correlated with IHS4. Also the inhibitors IL-1Ra and IL-18BP show a correlation with IHS4. The data obtained in this study confirm the involvement of IL-1F cytokines in mediating the disease and determining its severity and suggest a possible role for IL-18 as novel serum biomarker of active disease.

The multifaceted role of mast cells in the pathogenesis of rheumatoid arthritis.

Mast cells (MC) are tissue duelling cells playing an active role in both innate and adaptive immune system. They act as first players in different microbial infections and exert a crucial role in allergy, chronic inflammation, fibrosis, and rheumatic diseases (RD), including rheumatoid arthritis (RA). MC are normally present in human synovia and they increase in the joints of RA patients, contributing to inflammatory and remodelling processes. Due to their great plasticity and multifunctionality, MC exert a wide range of roles in different stages of the disease. To date, the results obtained by in-vitro and in-vivo studies have contributed to better clarify the dynamic role of MC in local arthritis of RA and have improved our knowledge on different aspect of the disease. Although different mice models have been extensively used to investigate the contribution of MC in different stages of RA, those models often fail to reproduce the complexity and the heterogeneity of the human disease. Here, we provide an overview on different roles of MC in RA pathogenesis and how these cells might influence some clinical features of the disease.

Allergy Workup in the Diagnosis of COVID-19 Vaccines-Induced Hypersensitivity Reactions and Its Impact on Vaccination.

INTRODUCTION: Immediate and delayed hypersensitivity reactions (HSR) to COVID-19 vaccines are rare adverse events that need to be prevented, diagnosed, and managed in order to guarantee adherence to the vaccination campaign. The aims of our study were to stratify the risk of HSR to COVID-19 vaccines and propose alternative strategies to complete the vaccination. METHODS: 1,640 subjects were screened for vaccinal eligibility, according to national and international recommendations. Among them, we enrolled for allergy workup 152 subjects, 43 with HSR to COVID-19 vaccines and 109 at high risk of HSR to the first dose. In vivo skin tests with drugs and/or vaccines containing PEG/polysorbates were performed in all of them, using skin prick test and, when negative, intradermal tests. In a subgroup of patients resulted negative to the in vivo skin tests, the programmed dose of COVID-19 vaccine (Pfizer/BioNTech) was administered in graded doses regimen, and detection of neutralizing anti-spike antibodies was performed in these patients after 4 weeks from the vaccination, using the SPIA method. RESULTS: Skin tests for PEG/polysorbates resulted positive in only 3% (5/152) of patients, including 2 with previous HSR to COVID-19 vaccines and 3 at high risk of HSR to the first dose. Among the 147 patients with negative skin tests, 97% (143/147) were eligible for vaccination and 87% (124/143) of them received safely the programmed COVID-19 vaccine dose. Administration of graded doses of Pfizer/BioNTech vaccine were well tolerated in 17 out of 18 patients evaluated; only 1 developed an HSR during the vaccination, less severe than the previous one, and all developed neutralizing anti-spike antibodies after 4 weeks with values comparable to those subjects who received the vaccine in unfractionated dose. CONCLUSION: On the whole, the usefulness of the skin tests for PEG/polysorbates seems limited in the diagnosis of HSR to COVID-19 vaccines. Graded doses regimen (Pfizer/BioNTech) is a safe and effective alternative strategy to complete the vaccinal course.

Repeated SARS-CoV-2 vaccination in cancer patients treated with immune checkpoint inhibitors: induction of high-avidity anti-RBD neutralizing antibodies.

BACKGROUND: Cancer patients are more vulnerable to COVID-19 and are thus given high priority in vaccination campaigns. In solid cancer patients treated with checkpoint inhibitors, we evaluated the amount of anti-RBD and neutralizing antibodies and antibody avidity after two or three doses of the vaccine. METHODS: Thirty-eight solid cancer patients, 15 untreated hematological patients and 21 healthy subjects were enrolled in the study. Blood was collected before the first dose (T0), 21 days after the second (T2) and in 18 solid cancer patients also 15 days after the third dose of vaccine (T3). IgG, IgM and IgA anti-RBD antibodies were detected by ELISA. Neutralizing antibodies were measured testing the inhibition of RBD binding to ACE2. Antibody avidity was evaluated in 18 patients by a urea avidity ELISA. RESULTS: IgG anti-RBD antibodies were produced in 65.8% of the cancer patients at T2, and in 60% of hematological patients at levels lower than healthy controls. IgM and IgA anti-RBD antibodies were also produced in 5.3% and 21% cancer patients, respectively. At T3, a significant increase in anti-RBD IgG levels was observed. Neutralizing antibodies were produced in 68.4% of cancer patients as compared with 93% of untreated hematological patients and 100% of controls, at titers lower than in healthy subjects. At T3, neutralizing antibodies and avidity of IgG anti-RBD increased; 6/18 patients negative at T2 developed neutralizing antibodies at T3. CONCLUSION: The data indicate that in cancer patients mRNA vaccine induces high avidity anti-RBD antibodies and neutralizing antibodies that increase after the third dose. The process of induction and selection of high-affinity antibodies is apparently unaffected by the treatment with anti-PD-1 or anti-PD-L1 antibodies.

Anti-glutathione S-transferase omega 1-1 (GSTO1-1) antibodies are increased during acute and chronic inflammation in humans.

Glutathione S-transferase omega-1 (GSTO1-1) is a cytosolic enzyme involved in the modulation of critical inflammatory pathways as well as in cancer progression. Auto-antibodies against GSTO1-1 were detected in the serum of patients with esophageal squamous cell carcinoma and were proposed as potential biomarkers in the early detection of the disease. Our findings show that anti-GSTO1-1 antibodies can be found in a variety of inflammatory diseases, including autoimmune rheumatoid arthritis, infectious SARS-CoV-2, and trichinellosis. Our findings strongly suggest that anti-GSTO1-1 antibodies may be a marker of tissue damage/inflammation rather than a specific tumor-associated biomarker.

Evidence for charge-based mimicry in anti dsDNA antibody generation.

Mechanisms for the generation of anti-dsDNA autoantibodies are still not completely elucidated. One theory states that dsDNA interacts for mimicry with antibodies raised versus other antigens but molecular features for mimicry are unknown. Here we show that, at physiological acid-base balance, anti-Annexin A1 binds IgG2 dsDNA in a competitive and dose-dependent way with Annexin A1 and that the competition between the two molecules is null at pH 9. On the other hand, these findings also show that dsDNA and Annexin A1 interact with their respective antibodies on a strictly pH-dependent basis: in both cases, the binding was minimal at pH 4 and maximal at pH9-10. The anionic charge of dsDNA is mainly conferred by the numerous phosphatidic residues. The epitope binding site of Annexin A1 for anti-Annexin A1 IgG2 was here characterized as a string of 34 amino acids at the NH2 terminus, 10 of which are anionic. Circulating levels of anti-dsDNA and anti-Annexin A1 IgG2 antibodies were strongly correlated in patients with systemic lupus erythematosus (n 496) and lupus nephritis (n 425) stratified for age, sex, etc. These results show that dsDNA competes with Annexin A1 for the binding with anti-Annexin A1 IgG2 on a dose and charged mediated base, being able to display an inhibition up to 75%. This study provides the first demonstration that dsDNA may interact with antibodies raised versus other anionic molecules (anti-Annexin A1 IgG2) because of charge mimicry and this interaction may contribute to anti-dsDNA antibodies generation.

Component-Resolved Diagnosis for Endotyping Patients with Chronic Rhinosinusitis with Nasal Polyps.

BACKGROUND: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a predominantly type 2 inflammation-mediated disease of the nasal mucosa and paranasal sinuses that often coexists with asthma. The role of atopy in the development and severity of CRSwNP is still a controversial issue. OBJECTIVE: The aim of our study was to propose a systematic allergy workup to identify atopic patients in the context of CRSwNP and to characterize their allergen sensitization profile (sources/molecules). METHODS: Patients with a diagnosis of CRSwNP (n = 97) were studied in the otorhinolaryngologist and allergy settings. Demographic and clinical data were collected for each patient. Different allergen sensitization profiles (sources/molecules) were evaluated in atopic CRSwNP patients by using component-resolved diagnosis (CRD). RESULTS: In our cohort of patients, the CRSwNP was frequently diagnosed during adulthood with significant impact on health-related quality of life. Asthma and atopy were the most common comorbidities with a prevalence of asthma in the atopic group. In CRSwNP patients sensitized to grass pollens and/or to house dust mites, the CRD analysis revealed a prevalence of sensitization to species-specific allergens of Phleum pratense (Phl p1, Phl p2, and Phl p5) or Dermatophagoides pteronyssinus (Der p1 and Der p2) rather than to cross-reactive ones. CONCLUSION: To define the allergen sensitization profile in atopic CRSwNP patients by CRD, it may be useful to better characterize type 2 inflammation, thus providing a personalized endotype-driven treatment.

Second Wave Antibodies in Autoimmune Renal Diseases: The Case of Lupus Nephritis.

Clinical Trial registry name and registration number: Zeus study, NCT02403115.

Serum IgG2 antibody multicomposition in systemic lupus erythematosus and lupus nephritis (Part 1): cross-sectional analysis.

OBJECTIVES: Serum anti-dsDNA and anti-nucleosome IgGs have been proposed as signatures for SLE and LN in limited numbers of patients. We sought to show higher sensitivity and specificity of the same antibodies with the IgG2 isotype and included IgG2 antibodies vs specific intracellular antigens in the analysis. METHODS: A total of 1052 SLE patients with (n = 479) and without (n = 573) LN, recruited at different times from the beginning of symptoms, were included in the study. Patients with primary APS (PAPS, n = 24), RA (RA, n = 24) and UCTD (UCTD, n = 96) were analysed for comparison. Anti-nucleosome (dsDNA, Histone2A, Histone3), anti-intracellular antigens (ENO1), anti-annexin A1 and anti-C1q IgG2 were determined by non-commercial techniques. RESULTS: The presence in the serum of the IgG2 panel was highly discriminatory for SLE/LN vs healthy subjects. Serum levels of anti-dsDNA and anti-C1q IgG2 were more sensitive than those of IgGs (Farr radioimmunoassay/commercial assays) in identifying SLE patients at low-medium increments. Of more importance, serum positivity for anti-ENO1 and anti-H2A IgG2 discriminated between LN and SLE (ROC T0-12 months), and high levels at T0-1 month were detected in 63% and 67%, respectively, of LN, vs 3% and 3%, respectively, of SLE patients; serum positivity for each of these was correlated with high SLEDAI values. Minor differences existed between LN/SLE and the other rheumatologic conditions. CONCLUSION: Nephritogenic IgG2 antibodies represent a specific signature of SLE/LN, with a few overlaps with other rheumatologic conditions. High levels of anti-ENO1 and anti-H2A IgG2 correlated with SLE activity indexes and were discriminatory between SLE patients limited to the renal complication and other SLE patients. TRIAL REGISTRATION: The Zeus study was registered at https://clinicaltrials.gov, NCT02403115.

Serum IgG2 antibody multi-composition in systemic lupus erythematosus and in lupus nephritis (Part 2): prospective study.

OBJECTIVES: Circulating anti-ENO1 and anti-H2A IgG2 have been identified as specific signatures of LN in a cross-over approach. We sought to show whether the same antibodies identify selected population of patients with LN with potentially different clinical outcomes. METHODS: Here we report the prospective analysis over 36 months of circulating IgG2 levels in patients with newly diagnosed LN (n=91) and SLE (n=31) and in other patients with SLE recruited within 2 years from diagnosis (n=99). Anti-podocyte (ENO1), anti-nucleosome (DNA, histone 2 A, histone 3) and anti-circulating proteins (C1q, AnnexinA1-ANXA1) IgG2 antibodies were determined by home-made techniques. RESULTS: LN patients were the main focus of the study. Anti-ENO1, anti-H2A and anti-ANXA1 IgG2 decreased in parallel to proteinuria and normalized within 12 months in the majority of patients while anti-dsDNA IgG2 remained high over the 36 months. Anti-ENO1 and anti-H2A had the highest association with proteinuria (Heat Map) and identified the highest number of patients with high proteinuria (68% and 71% respectively) and/or with reduced estimated glomerula filtration rate (eGFR) (58% for both antibodies) compared with 23% and 17% of anti-dsDNA (agreement analysis). Anti-ENO1 positive LN patients had higher proteinuria than negative patients at T0 and presented the maximal decrement within 12 months. CONCLUSIONS: Anti-ENO1, anti-H2A and anti-ANXA1 antibodies were associated with high proteinuria in LN patients and Anti-ENO1 also presented the maximal reduction within 12 months that paralleled the decrease of proteinuria. Anti-dsDNA were not associated with renal outcome parameters. New IgG2 antibody signatures should be utilized as tracers of personalized therapies in LN. TRIAL REGISTRATION: The Zeus study was registered at https://clinicaltrials.gov (study number: NCT02403115).

Evaluation of neutrophil extracellular trap deregulated formation in pyoderma gangrenosum.

Pyoderma gangrenosum (PG) is a neutrophilic dermatose (ND) characterized by a dense neutrophilic infiltrate in the affected tissue. Neutrophil extracellular traps (NETs) are web-like structures released by neutrophils and composed of cytosolic and granule proteins assembled on a scaffold of decondensed chromatin. Very little is known about the role of NETosis in PG. Here, we assessed the possible implication of NETosis in the pathogenesis of PG by investigating the NETosis in the ulcers of 26 PG patients. We demonstrated that neutrophils in the PG skin lesions undergo an aberrant level of NETosis in 100% of the analysed cases (N = 26). All control and abscess biopsies were instead negative for the NETosis. In addition, neutrophils from peripheral blood of PG patients showed a significantly higher rate of spontaneous, but not induced, NETosis. Overall, this study suggests that the NETosis may contribute to systemic inflammation and tissue destruction in PG, thus representing a possible novel therapeutic target.

COVID-19: the new challenge for rheumatologists. One year later.

At the beginning of COVID-19, we underlined that this pandemic was a new challenge for rheumatologists. On the one hand, it was necessary to clarify the impact of this new viral disease on the natural history of many rheumatic diseases and, on the other hand, to define the beneficial or harmful effects of the synthetic or targeted therapies used for their treatment. In addition, we have postulated that in view of the common pathogenetic mechanisms involved, the therapeutic armamentarium currently employed in the management of viral or idiopathic systemic autoimmune rheumatic diseases could be useful to control the "cytokine storm" induced by SARS-COV-2. One year later, in the present review we have analysed the progress of the knowledge on both these aspects and updated the algorithms initially proposed for a rational use of the synthetic and targeted anti-inflammatory and immunomodulatory agents in the management of COVID-19.

18-FDG PET for large vessel vasculitis diagnosis and follow-up.

OBJECTIVES: Large vessel vasculitis (LVV) are chronic inflammatory diseases that affect arteries. While a mere clinical-serological approach does not seem sensitive either in the initial evaluation nor in long-term monitoring, 18-FDG positron emission tomography (18-FDG PET) is currently considered a useful assessment tool in LVV. We aimed at exploring the utility of 18-FDG, compared with traditional assessments, in the short- and long-term follow-up of patients with LVV. In addition, we compared patterns of vascular involvement in patients with Takayasu's arteritis (TAK) and giant cell arteritis (GCA). METHODS: We retrospectively analysed 47 patients affected by LVV, evaluating clinics, blood chemistry and 18-FDG PET results, at two time points, short-term (average 8 months after diagnosis) and long-term (average 29 months). RESULTS: 18-FDG PET uptake, expressed as mean value of SUV max, decreased significantly during follow-up in all the patients. A low concordance between 18-FDG PET and acute phase reactants levels was observed, but also a good sensitivity in detecting the response to treatment. CONCLUSIONS: The results confirm the role of 18-FDG PET as a powerful tool in the evaluation of LVV, both at the time of diagnosis and during monitoring. Furthermore, the data confirm that GCA and TAK are part of the same disease spectrum.

New biomarkers in SLE: from bench to bedside.

Biomarkers may have a diagnostic or monitoring value, or may predict response to therapy or disease course. The aim of this review is to discuss new serum and urinary biomarkers recently proposed for the diagnosis and management of SLE patients. Novel sensitive and specific assays have been proposed to evaluate complement proteins, 'old' biomarkers that are still a cornerstone in the management of this disease. Chemokines and lectins have been evaluated as surrogate biomarkers of IFN signature. Other cytokines like the B cell activating factor (BAFF) family cytokines are directly related to perturbations of the B cell compartment as key pathogenetic mechanism of the disease. A large number of urine biomarkers have been proposed, either related to the migration and homing of leukocytes to the kidney or to the local regulation of inflammatory circuits and the survival of renal intrinsic cells. The combination of traditional disease-specific biomarkers and novel serum or urine biomarkers may represent the best choice to correctly classify, stage and treat patients with SLE.

Fingerprinting of anti-alpha enolase antibodies in systemic sclerosis.

OBJECTIVES: Anti-alpha enolase antibodies have been detected in systemic sclerosis (SSc), but little is known on their fine specificity and their predictive value on single disease manifestations. The aim of this work is to perform an epitope mapping of alpha enolase by means of truncated recombinant proteins and to analyse the clinico-serological correlations of anti-alpha enolase antibodies in SSc patients. METHODS: Thirty-eight SSc patients were recruited and fully clinically and serologically characterised. Plasmids encoding full length and truncated polypeptides of alpha enolase were generated; the polypeptides were purified under native conditions and used in dot blot to test sera from SSc patients and controls. The densitometric values obtained on all the polypeptides with anti-IgG subclass specific antibodies were analysed by cluster analysis and partial least square regression. RESULTS: Anti-alpha enolase antibodies (mostly IgG1 and IgG2) are detected in 47% of SSc patients. IgG1 target the amino terminal region of alpha enolase, while IgG2 are more restricted to the central portion of the molecule. Anti-alpha enolase antibodies are not associated with disease-specific antibodies or with interstitial lung disease and do not identify patients affected by the limited vs. diffuse form. CONCLUSIONS: Anti-alpha enolase antibodies are very frequent in SSc but are not associated with clinical or serological features of the disease. Further studies on larger cohorts of patients are necessary to define their possible contribution in defining specific subsets of the disease.

Circulating levels of IL-1 family cytokines and receptors in Alzheimer's disease: new markers of disease progression?

BACKGROUND: Although the mechanisms underlying AD neurodegeneration are not fully understood, it is now recognised that inflammation could play a crucial role in the initiation and progression of AD neurodegeneration. A neuro-inflammatory network, based on the anomalous activation of microglial cells, includes the production of a number of inflammatory cytokines both locally and systemically. These may serve as diagnostic markers or therapeutic targets for AD neurodegeneration. METHODS: We have measured the levels of the inflammation-related cytokines and receptors of the IL-1 family in serum of subjects with AD, compared to mild cognitive impairment (MCI), subjective memory complaints (SMC), and normal healthy subjects (NHS). Using a custom-made multiplex ELISA array, we examined ten factors of the IL-1 family, the inflammation-related cytokines IL-1α, IL-1ß, IL-18, and IL-33, the natural inhibitors IL-1Ra and IL-18BP, and the soluble receptors sIL-1R1, sIL-1R2, sIL-1R3, and sIL-1R4. RESULTS: The inflammatory cytokines IL-1α and IL-1ß, their antagonist IL-1Ra, and their soluble receptor sIL-1R1 were increased in AD. The decoy IL-1 receptor sIL-1R2 was only increased in MCI. IL-33 and its soluble receptor sIL-1R4 were also significantly higher in AD. The soluble form of the accessory receptor for both IL-1 and IL-33 receptor complexes, sIL-1R3, was increased in SMC and even more in AD. Total IL-18 levels were unchanged, whereas the inhibitor IL-18BP was significantly reduced in MCI and SMC, and highly increased in AD. The levels of free IL-18 were significantly higher in MCI. CONCLUSIONS: AD is characterised by a significant alteration in the circulating levels of the cytokines and receptors of the IL-1 family. The elevation of sIL-1R4 in AD is in agreement with findings in other diseases and can be considered a marker of ongoing inflammation. Increased levels of IL-1Ra, sIL-1R1, sIL-1R4, and IL-18BP distinguished AD from MCI and SMC, and from other inflammatory diseases. Importantly, sIL-1R1, sIL-1R3, sIL-1R4, and IL-18BP negatively correlated with cognitive impairment. A significant elevation of circulating sIL-1R2 and free IL-18, not present in SMC, is characteristic of MCI and disappears in AD, making them additional interesting markers for evaluating progression from MCI to AD.

Anti-citrullinated alpha enolase antibodies, interstitial lung disease and bone erosion in rheumatoid arthritis.

Objectives: RA is an articular chronic inflammatory disease that in a subgroup of patients can also present with extra-articular manifestations (EAMs). Despite intense investigation on this topic, reliable biomarkers for EAMs are lacking. In recent years several ACPAs, including those targeting anti-citrullinated alpha enolase peptide-1 (anti-CEP-1), have been identified in patients with RA. Data about the ability of anti-CEP-1 to predict the development of erosive disease are confliciting and no evidence concerning their possible association with EAMs in RA is currently available. The aim of this study was to investigate the prevalence and significance of anti-CEP-1 with regard to the association with erosive disease and EAMs in a large cohort of patients with RA. Methods: Anti-CCP and anti-CEP-1 antibodies have been assessed on serum samples of RA patients, healthy donors and patients with SpA using commercially available ELISA kits. Results: Anti-CEP-1 antibodies are detectable in over 40% of RA patients and are associated with erosive RA and with RA-associated interstitial lung disease (ILD). Conclusion: Anti-CEP-1 antibodies may represent a useful biomarker for RA-associated ILD and erosive disease to be employed in clinical practice.

IL-1 family cytokines and receptors in IgG4-related disease.

BACKGROUND/AIM: The IgG4-related disease (IgG4-RD) is a fibroinflammatory condition that can affect almost any organ, often associated with eosinophilia and increased levels of IgE and IgG4. Overexpression in tissues of Th2-related cytokines but also of IFN-γ has been reported. Given the major role of Il-1 family cytokines in inducing and regulating inflammation, and the paucity of data so far available in IgG-RD, we performed a comprehensive analysis of IL-18, related IL-1 family cytokines and soluble receptors in these patients. PATIENTS AND METHODS: Fifteen patients fulfilling the criteria for the diagnosis of IgG4-RD and 80 blood donors as control were recruited. Cytokines of the IL-1 family (IL-1α, IL-1ß, IL-33, IL-18), soluble receptors (sIL-1R1, sIL-1R2, sIL-1R3, ST2/sIL-1R4) and antagonists (IL-1Ra, IL-18 binding protein -IL-18BP-) were measured in sera by multiarray ELISA assay. Free IL-18 was calculated as the amount of IL-18 not inhibited by IL-18BP. RESULTS: Half of the patients had a multiorgan disease, mainly affecting retroperitoneum, lymph nodes and pancreas. sIL-1R1 (p=0.0001), sIL-1R2 (p=0.0024), ST2/sIL-1R4 (p=0.002) were significantly increased in IgG4-RD sera compared with healthy controls; sIL-R3 was significantly lower in patients vs controls (p=0,0006). CONCLUSIONS: The increased levels of the soluble forms of the two IL-1 receptors IL-1R1 and IL-1R2 suggest the need to dampen IL-1-mediated inflammation at the tissue level. Elevated circulating ST2/sIL-1R4 levels may represent the marker of an ongoing protective mechanism, but their contribution to organ damage cannot be excluded. On the whole, the data suggest a tight control of IL-1 family cytokines signalling in IgG4-RD.