Unravelling the clinical heterogeneity of undefined recurrent fever over time in the European registries on Autoinflammation.

BACKGROUND: Systemic autoinflammatory disorders (SAIDs) represent a growing spectrum of diseases characterized by dysregulation of the innate immune system. The most common pediatric autoinflammatory fever syndrome, Periodic Fever, Aphthous Stomatitis, Pharyngitis, Adenitis (PFAPA), has well defined clinical diagnostic criteria, but there is a subset of patients who do not meet these criteria and are classified as undefined autoinflammatory diseases (uAID). This project, endorsed by PRES, supported by the EMERGE fellowship program, aimed to analyze the evolution of symptoms in recurrent fevers without molecular diagnosis in the context of undifferentiated AIDs, focusing on PFAPA and syndrome of undifferentiated recurrent fever (SURF), using data from European AID registries. METHODS: Data of patients with PFAPA, SURF and uSAID were collected from 3 registries including detailed epidemiological, demographic and clinical data, results of the genetic testing and additional laboratory investigations with retrospective application of the modified Marshall and PRINTO/Eurofever classification criteria on the cohort of PFAPA patients and preliminary SURF criteria on uSAID/SURF patients. RESULTS: Clinical presentation of PFAPA is variable and some patients did not fit the conventional PFAPA criteria and exhibit different symptoms. Some patients did not meet the criteria for either PFAPA or SURF, highlighting the heterogeneity within these groups. The study also explored potential overlaps between PFAPA and SURF/uAID, revealing that some patients exhibited symptoms characteristic of both conditions, emphasizing the need for more precise classification criteria. CONCLUSIONS: Patients with recurrent fevers without molecular diagnoses represent a clinically heterogeneous group. Improved classification criteria are needed for both PFAPA and SURF/uAID to accurately identify and manage these patients, ultimately improving clinical outcomes.

Phagocytic cell death leads to enhanced release of pro-inflammatory S100A12 in familial Mediterranean fever.

BACKGROUND: Familial Mediterranean fever (FMF) is a prototypical autoinflammatory syndrome associated with phagocytic cell activation. Pyrin mutations are the genetic basis of this disease, and its expression has been shown in monocytes, granulocytes, dendritic cells, and synovial fibroblasts. Pyrin functions as a cytosolic pattern recognition receptor and forms a distinct pyrin inflammasome. The phagocyte-specific protein S100A12 is predominantly expressed in granulocytes and belongs to the group of damage associated molecular patterns (DAMP). S100A12 can be detected at massively elevated levels in the serum of FMF patients, even in clinically inactive disease. Whether this is crucial for FMF pathogenesis is as yet unknown, and we therefore investigated the mechanisms of S100A12 release from granulocytes of FMF patients presenting clinically inactive. RESULTS: We demonstrate that FMF neutrophils from patients in clinical inactive disease possess an intrinsic activity leading to cell death even in exogenously unstimulated neutrophils. Cell death resembles NETosis and is dependent on ROS and pore forming protein gasdermin D (GSDMD), as inhibitors for both are capable of completely block cell death and S100A12 release. When pyrin-activator TcdA (Clostridium difficile toxin A) is used to stimulate, neutrophilic cell death and S100A12 release are significantly enhanced in neutrophils from FMF patients compared to neutrophils from HC. CONCLUSIONS: We are able to demonstrate that activation threshold of neutrophils from inactive FMF patients is decreased, most likely by pre-activated pyrin. FMF neutrophils present with intrinsically higher ROS production, when cultured ex vivo. This higher baseline ROS activity leads to increased GSDMD cleavage and subsequent release of, e.g., S100A12, and to increased cell death with features of NETosis and pyroptosis. We show for the first time that cell death pathways in neutrophils of inactive FMF patients are easily triggered and lead to ROS- and GSDMD-dependent activation mechanisms and possibly pathology. This could be therapeutically addressed by blocking ROS or GSDMD cleavage to decrease inflammatory outbreaks when becoming highly active.

Breaking down the fences among registries on autoinflammatory diseases: the E-Merge project.

BACKGROUND: Among the various numbers of different autoinflammatory diseases (AIDs), the absolute majority of them remains rare, with a single representative in large populations. This project, endorsed by PRES, supported by the EMERGE fellowship program, and performed in line with the Metadata registry for the ERN RITA (MeRITA), has the objective of performing a data synchronization attempt of the most relevant research questions regarding clinical features, diagnostic strategies, and optimal management of autoinflammatory diseases. RESULTS: An analysis of three large European registries: Eurofever, JIR-cohort and AID-Net, with a total coverage of 7825 patients from 278 participating centers from different countries, was performed in the context of epidemiological and clinical data merging. The data collected and evaluated in the registries does not cover only pediatric patients, but also adults with newly diagnosed AIDs. General aspects of the existing epidemiological data have been discussed in the context of patient global distribution, potential diagnostic delays, access to genetic testing, and the availability of the treatment. CONCLUSIONS: In general, the results indicate a great potential for upcoming collaborative work using existing data in cohorts that enhance the quality of medical care performed for patients with autoinflammatory diseases.

[Cushing's syndrome with subsequent tertiary adrenocortical insufficiency after simultaneous multiple intra-articular local glucocorticoid treatment : Keep an eye on hormone deficiency conditions requiring treatment after multiple administrations of local steroids]. / Cushing-Syndrom mit konsekutiver tertiärer Nebennierenrindeninsuffizienz nach simultaner multipler intraartikulärer Lokaltherapie mit Glukokortikoiden : Bei Mehrfachgabe von lokalen Steroiden behandlungsbedürftige Hormonmangelzustände im Blick behalten.

After simultaneous multiple local treatment with glucocorticoids at 46 sites a 4­year-old female patient with newly diagnosed polyarticular juvenile idiopathic arthritis (JIA) initially developed Cushing's syndrome followed by a gradual worsening of her condition and finally an acute high fever urinary tract infection. Iatrogenic adrenocortical insufficiency after multiple intra-articular glucocorticoid administration was diagnosed. The possibility of severe systemic glucocorticoid side effects after extensive local treatment should be included in the regular management of JIA patients.

A child with soft-tissue infection and lymphadenitis.

We report a case of a soft-tissue infection with Francisella philomiragia, a rare opportunistic pathogen in individuals with chronic granulomatous disease.

[Classification of autoinflammatory diseases based on pathophysiological mechanisms]. / Klassifikation autoinflammatorischer Erkrankungen anhand pathophysiologischer Mechanismen.

Monogenic autoinflammatory diseases present with systemic inflammation with the involvement of multiple organs. With the help of modern molecular genetic techniques a large number of diseases with previously unknown pathomechanisms have been described in recent years. This knowledge can be utilized to group autoinflammatory diseases according to the signalling pathways involved and thus provide a better understanding of these entities.

[Still's disease as biphasic disorder : Current knowledge on pathogenesis and novel treatment approaches]. / Das Still-Syndrom als biphasische Erkrankung : Aktuelle Erkenntnisse zur Pathogenese und neue therapeutische Ansätze.

Still's disease covers a range of disorders from systemic juvenile idiopathic arthritis (SJIA) up to adult onset Still's disease (AOSD). The overlapping clinical features suggest that SJIA and AOSD are different manifestations of a phenotypic continuum in different age stages. Still's disease is clinically characterized by fever, rash, joint involvement, lymphadenopathy and serositis. In this review the more recent pathogenetic model of a biphasic disease course is presented. The initial autoinflammation with predominant dysregulation of innate immunity is the basis of the "window of opportunity" hypothesis for the early use of a cytokine blockade. If the disease is not stopped in this phase, a phenotype change to a disease with destructive arthritis regularly occurs, in which dysregulation of the mechanisms of adaptive immunity plays a special role. The understanding of Still's disease as a biphasic disease enables the monitoring of molecular signatures. At the same time, this opens up perspectives for phase-specific targeted treatment using modern treat-to-target strategies.

Refining the dermatological spectrum in primary immunodeficiency: mucosa-associated lymphoid tissue lymphoma translocation protein 1 deficiency mimicking Netherton/Omenn syndromes.

The proteinase mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1), which forms part of the caspase recruitment domain-containing protein 11-B-cell lymphoma 10-MALT1 signalosome complex, plays a direct role in nuclear factor kappa B activation. Here, we describe the case of a female infant with severe immune dysregulation leading to recurrent systemic infections, failure to thrive and severe crises of ichthyosiform erythroderma with high levels of serum IgE. Hence, initial symptoms indicated Netherton syndrome or Omenn syndrome. Surprisingly, sequence analyses of SPINK5 and RAG1/RAG2, respectively, excluded these diseases. During the hospital stay the patient's health deteriorated, despite intensive care therapy, and she died. In order to delineate the diagnosis, whole-exome sequencing was performed. Two compound heterozygous mutations in MALT1 were found and verified by Sanger sequencing (exon 2 c.245T>C, exon 2 c.310dup), which led to a MALT1 deficiency at the protein level. Based on these results, an immunological analysis was performed, as was immunofluorescence staining of key skin proteins, to confirm a diagnosis of MALT1 deficiency. This case report provides a closer description of the clinical and histological skin phenotype of MALT1 deficiency, and we conclude that MALT1 deficiency must be considered a possible differential diagnosis of Netherton and Omenn syndromes. What's already known about this topic? Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) deficiency is a combined immunodeficiency. MALT1 is part of the caspase recruitment domain-containing protein 11-B-cell lymphoma 10-MALT1 signalosome complex, which is essential for nuclear factor kappa B activation. Current publications describe a phenotype of recurrent systemic infections; only in a few cases has an inflammatory involvement of the integument been described. What does this study add? A closer description of the cutaneous phenotype of MALT1 deficiency in a patient with two novel MALT1 mutations. Immune mapping of follicular epidermis shows lympho-epithelial Kazal-type-related inhibitor is reduced in MALT1 deficiency and absent on interfollicular staining. Clinically, MALT1 deficiency mimics Netherton syndrome and Omenn syndrome, and should be considered a differential diagnosis.

[Primary Immunodeficiency: Primary Antibody Disorders in Respiratory Medicine]. / Primäre Immundefekte: Antikörpermangelerkrankungen in der Pneumologie.

Clinical manifestations of primary immunodeficiency are heterogeneous, and early diagnosis is challenging. Leading symptoms are recurrent upper and lower respiratory tract infections. Response to antibiotic therapy is often reduced. Beside infectious complications autoimmunity, autoinflammation and malignant diseases occur frequently. About 50 % of all PID patients are diagnosed after childhood, and the main group are patients with primary antibody deficiencies. Treatment of choice is the immunoglobulin substitution and the prophylactic or therapeutic use of antibiotics. In patients presenting with immunodysregulation, immunosuppression is additionally indicated. Especially due to recurrent lower airway infection and/or interstitial lung diseases PID patients have a decreased live expectancy. Hence, both early diagnosis and sufficient therapy are mandatory.

[Evidence-based treatment recommendations for familial Mediterranean fever : A joint statement by the Society for Pediatric and Adolescent Rheumatology and the German Society for Rheumatology]. / Evidenzbasierte Therapieempfehlungen für das familiäre Mittelmeerfieber : Eine gemeinsame Stellungnahme der Gesellschaft für Kinder- und Jugendrheumatologie und der Deutschen Gesellschaft für Rheumatologie.

BACKGROUND: Familial Mediterranean fever (FMF) in Germany is a rare, genetically linked disease of childhood and adolescence, which is characterized by recurrent febrile episodes and clinical signs of peritonitis, pleuritis and arthritis. Treatment with colchicine is effective and well-tolerated in the majority of patients; however, some patients do not sufficiently respond to this treatment or are intolerant to colchicine. For these patients first-line treatment with biologics which block interleukin-1 can be used. OBJECTIVE: The aim was to formulate evidence-based treatment recommendations for patients with an insufficient response and intolerance to colchicine treatment. METHODS: Based on a literature search and the European League Against Rheumatism (EULAR) recommendations on FMF from 2016 the appointed members of the Society for Pediatric and Adolescent Rheumatology (GKJR) and the German Society for Rheumatology (DGRh) convened to work out and form a consensus in a joint statement on evidence-based treatment recommendations on FMF. RESULTS: After intensive discussions all decisions were in concordance. A total of 5 superordinate principles and 10 recommendations were agreed upon. DISCUSSION: The joint activities of the GKJR and the DGRh were successfully concluded in a timely manner. The recommendations form a good basis for optimal treatment of all age groups of patients with FMF.

IL-6 blockade in systemic juvenile idiopathic arthritis - achievement of inactive disease and remission (data from the German AID-registry).

BACKGROUND: Systemic juvenile idiopathic arthritis (sJIA) is a complex disease with an autoinflammatory component of unknown etiology related to the innate immune system. A major role in the pathogenesis has been ascribed to proinflammatory cytokines like interleukin-6 (IL-6), and effective drugs inhibiting their signaling are being developed. This study evaluates sJIA patients treated with the IL-6 inhibitor tocilizumab (TCZ) concerning clinical response rate, disease course and adverse effects in a real-life clinical setting. METHODS: In 2009 a clinical and research consortium was established, including an online registry for autoinflammatory diseases (AID) ( https://aid-register.de ). Data for this retrospective TCZ study were documented by 13 centers. RESULTS: From 7/2009 to 4/2014, 200 patients with sJIA were recorded in the AID-registry. Out of these, 46 (19 m, 27 f, age 1-18 years) received therapy with TCZ. Long term treatment (median 23 months) has been documented in 24/46 patients who were evaluated according to Wallace criteria (active disease 6/24, inactive disease 5/24, remission 13/24 cases). Under observation co-medication were used in 40/46 cases. Adverse events were reported in 11/46 patients. The clinical response rate (no clinical manifestation, no increased inflammation parameters) within the first 12 weeks of treatment was calculated to be 35%. CONCLUSION: Out of 200 sJIA children reported in the German AID-registry, 46 were treated with TCZ, showing a clinical response rate of 35% during the first 12 weeks, and inactive disease and/or remission under medication in 75% after one year. Adverse events were seen in 24% and severe adverse events in 4%. TRIAL REGISTRATION: The AID-Registry is funded by the BMBF (01GM08104, 01GM1112D, 01GM1512D).

[Role of genetics in familial Mediterranean fever]. / Rolle der Genetik beim familiären Mittelmeerfieber.

Familial Mediterranean fever (FMF) is caused by mutations within the Mediterranean fever (MEFV) gene. These gain of function mutations lead to an increased activation of the inflammasome pyrin with a subsequent disproportional proinflammatory reaction. Classically, in FMF patients two pathogenic mutations affecting both alleles are found in the molecular genetic analysis; however, it is well known that the phenotype can also be caused either by mutations with lower penetrance or unknown significance. Furthermore, in a significant number of patients only one or even no MEFV mutations can be detected. Heterozygous mutation carriers who do not suffer from classical FMF, can also present with other signs of inflammation, e. g. subclinical increased inflammation markers, associated inflammatory diseases or unclassified symptoms. Thus, FMF does not follow a classical autosomal recessive inheritance and a variable gene dose effect has to be considered, which is furthermore modulated by other mostly unknown genetic variants and environmental factors. This article summarizes the broad spectrum of clinical presentations associated with MEFV mutations and analyzes the effect of the gene dose on the phenotypical expression. Furthermore, the impact of the molecular genetic analysis on the diagnostics of a patient and on the individualized management of the disease is discussed.

Activated STING in a vascular and pulmonary syndrome.

BACKGROUND: The study of autoinflammatory diseases has uncovered mechanisms underlying cytokine dysregulation and inflammation. METHODS: We analyzed the DNA of an index patient with early-onset systemic inflammation, cutaneous vasculopathy, and pulmonary inflammation. We sequenced a candidate gene, TMEM173, encoding the stimulator of interferon genes (STING), in this patient and in five unrelated children with similar clinical phenotypes. Four children were evaluated clinically and immunologically. With the STING ligand cyclic guanosine monophosphate-adenosine monophosphate (cGAMP), we stimulated peripheral-blood mononuclear cells and fibroblasts from patients and controls, as well as commercially obtained endothelial cells, and then assayed transcription of IFNB1, the gene encoding interferon-ß, in the stimulated cells. We analyzed IFNB1 reporter levels in HEK293T cells cotransfected with mutant or nonmutant STING constructs. Mutant STING leads to increased phosphorylation of signal transducer and activator of transcription 1 (STAT1), so we tested the effect of Janus kinase (JAK) inhibitors on STAT1 phosphorylation in lymphocytes from the affected children and controls. RESULTS: We identified three mutations in exon 5 of TMEM173 in the six patients. Elevated transcription of IFNB1 and other gene targets of STING in peripheral-blood mononuclear cells from the patients indicated constitutive activation of the pathway that cannot be further up-regulated with stimulation. On stimulation with cGAMP, fibroblasts from the patients showed increased transcription of IFNB1 but not of the genes encoding interleukin-1 (IL1), interleukin-6 (IL6), or tumor necrosis factor (TNF). HEK293T cells transfected with mutant constructs show elevated IFNB1 reporter levels. STING is expressed in endothelial cells, and exposure of these cells to cGAMP resulted in endothelial activation and apoptosis. Constitutive up-regulation of phosphorylated STAT1 in patients' lymphocytes was reduced by JAK inhibitors. CONCLUSIONS: STING-associated vasculopathy with onset in infancy (SAVI) is an autoinflammatory disease caused by gain-of-function mutations in TMEM173. (Funded by the Intramural Research Program of the National Institute of Arthritis and Musculoskeletal and Skin Diseases; ClinicalTrials.gov number, NCT00059748.).

Proteomic analysis of plasma identifies the Toll-like receptor agonists S100A8/A9 as a novel possible marker for systemic sclerosis phenotype.

BACKGROUND: Systemic sclerosis (SSc) is an autoimmune disease characterised by fibrosis of the skin and the internal organs. Except for anticentromere, antitopoisomerase I and antipolymerase III antibodies, there are no reliable circulating markers predicting susceptibility and internal organ complications. This study has exploited a proteome-wide profiling method with the aim to identify new markers to identify SSc phenotype. METHOD: 40 SSc patients were included for proteomic identification. Patients were stratified as having diffuse cutaneous SSc (dcSSc) (n=19) or limited cutaneous SSc (lcSSc) (n=21) according to the extent of skin involvement. As controls 19 healthy donors were included. Blood was drawn and plasma was stored before analysing with the SELDI-TOF-MS. For replication in serum, the cohort was extended with 60 SSc patients. RESULTS: Proteomic analysis revealed a list of 25 masspeaks that were differentially expressed between SSc patients and healthy controls. One of the peaks was suggestive for S100A8, a masspeak we previously found in supernatant of plasmacytoid dendritic cells from SSc patients. Increased expression of S100A8/A9 in SSc patients was confirmed in replication cohort compared with controls. Intriguingly, S100A8/A9 was highest in patients with limited cutaneous SSc having lung fibrosis. CONCLUSIONS: S100A8/A9 was robustly found to be elevated in the circulation of SSc patients, suggesting its use as a biomarker for SSc lung disease and the need to further explore the role of TLR in SSc.

[Self-medication to treat pain in attacks of familial Mediterranean fever: aiming to find a new approach to pain management]. / Schmerztherapeutische Bedarfsmedikation bei Attacken von familiärem Mittelmeerfieber : Auf der Suche nach einem schmerztherapeutischen Ansatz.

BACKGROUND: Familial Mediterranean fever (FMF) is an autoinflammatory disease characterized by bouts of fever and serositis. Morbidity caused by bouts as well as self-medication were assessed among patients of Turkish ancestry living in Germany (D) or Turkey (T) in order to evaluate current analgetic concepts from a patient's perspective. MATERIAL AND METHODS: D and T were asked about the 3 months preceding the interview. RESULTS: A total of 40 D and 40 T were included; 35/40 D and 40/40 T were on colchicine. In the last 3 months, 61.3 % had ≥ 1 bout and suffered from peritonitis (87.8 %), fever (61.2 %), myalgia (45 %), pleuritis (42.8 %), arthralgia (36.7 %), and cephalgia (32.6 %). Of the patients, 65.3 % were bedridden during bouts, 61.2 % sought the attention of a physician, 53.1 % were unable to work or attend school, and 38.8 % were hospitalized. The following drugs were taken: NSAIDs (45.6 %), NSAIDs and paracetamol (42.6 %), and combinations of NSAIDs with other analgesics. NSAIDs (58.6 %) and paracetamol (20.7 %) were considered the most potent substances. CONCLUSION: FMF inflicts substantial morbidity. Patients most commonly rely on NSAIDs and paracetamol to relieve symptoms of FMF bouts.

Efficacy and safety of the interleukin-1 antagonist rilonacept in Schnitzler syndrome: an open-label study.

BACKGROUND: Schnitzler syndrome (SchS) is a rare disease with suspected autoinflammatory background that shares several clinical symptoms, including urticarial rash, fever episodes, arthralgia, and bone and muscle pain with cryopyrin-associated periodic syndromes (CAPS). Cryopyrin-associated periodic syndromes respond to treatment with interleukin-1 antagonists, and single case reports of Schnitzler syndrome have shown improvement following treatment with the interleukin-1 blocker anakinra. This study evaluated the effects of the interleukin-1 antagonist rilonacept on the clinical signs and symptoms of SchS. METHODS: Eight patients with SchS were included in this prospective, single-center, open-label study. After a 3-week baseline, patients received a subcutaneous loading dose of rilonacept 320 mg followed by weekly subcutaneous doses of 160 mg for up to 1 year. Efficacy was determined by patient-based daily health assessment forms, physician's global assessment (PGA), and measurement of inflammatory markers including C-reactive protein (CRP), serum amyloid A (SAA), and S100 calcium-binding protein A12 (S100A12). RESULTS: Treatment with rilonacept resulted in a rapid clinical response as demonstrated by significant reductions in daily health assessment scores and PGA scores compared with baseline levels (P < 0.05). These effects, which were accompanied by reductions in CRP and SAA, continued over the treatment duration. Rilonacept treatment was well tolerated. There were no treatment-related severe adverse events and no clinically significant changes in laboratory safety parameters. CONCLUSION: Rilonacept was effective and well tolerated in patients with SchS and may represent a promising potential therapeutic option.

Monitoring disease activity by stool analyses: from occult blood to molecular markers of intestinal inflammation and damage.

It is a common experience that gastrointestinal symptoms urge us to differentiate inflammatory bowel disease (IBD) from functional disorders. Furthermore, in patients with proven IBD the disease activity has to be accurately monitored. Faecal markers of neutrophil influx into the mucosa are promising indicators of intestinal inflammation. Some neutrophil-derived proteins may be linked to the pathogenesis of IBD due to their functions as damage-associated molecular pattern molecules (DAMPs). Phagocyte-specific DAMPs of the S100 family are released from neutrophils or monocytes, followed by pro-inflammatory activation of pattern recognition receptors. The complex of S100A8/S100A9 was termed "calprotectin" and has been in use as a faecal marker for 10 years. More recently, faecal S100A12 has been reported to be an even more accurate faecal marker of inflammation. We review the biology of this novel group of molecules which can be used as surrogate markers directly linked to the molecular mechanisms of gut inflammation.

Phagocyte-specific S100 proteins are released from affected mucosa and promote immune responses during inflammatory bowel disease.

Phagocyte-derived S100 proteins are endogenous activators of innate immune responses. S100A12 binds to the receptor for advanced glycation end-products, while complexes of S100A8/S100A9 (myeloid-related proteins, MRP8/14; calprotectin) are ligands of toll-like receptor 4. These S100 proteins can be detected in stool. In the present study we analyse the release of S100A12 and MRP8/14 from intestinal tissue. Specimens from patients with Crohn's disease (CD; n = 30), ulcerative colitis (UC; n = 30), irritable bowel syndrome (IBS; n = 30) or without inflammation (n = 30) were obtained during endoscopy. After 24 h culture, S100A12 and MRP8/14 were analysed in supernatants. Endoscopic, histological, laboratory and clinical disease activity measures were documented. We found an increased spontaneous release of S100A12 from tissue in inflammatory bowel disease (IBD). The release of S100A12 into the supernatants was 28-fold enhanced in inflamed tissue when compared to non-inflamed tissue (mean 46.9 vs. 1.7 ng/ml, p < 0.0001). In active CD, release of S100A12 and MRP8/14 was strongly dependent on localization, with little release from sites of active ileal inflammation compared to colonic inflammation. This difference was more pronounced for S100A12 than for MRP8/14. S100A12 and MRP8/14 provoked up-regulation of adhesion molecules and chemokines on human intestinal microvascular endothelial cells (HIMECs) isolated from normal colonic tissue. The direct release of phagocyte-derived S100 proteins from inflamed tissues may reflect secretion from infiltrating neutrophils (S100A12) and also monocytes or epithelial cells (MRP8/14). Via activation of pattern recognition receptors, these proteins promote inflammation in intestinal tissue. The enhanced mucosal release can explain the correlation of fecal markers with disease activity in IBD.

Faecal S100A12 as a non-invasive marker distinguishing inflammatory bowel disease from irritable bowel syndrome.

OBJECTIVE: S100A12 is a pro-inflammatory protein that is secreted by granulocytes. S100A12 serum levels increase during inflammatory bowel disease (IBD). We performed the first study analysing faecal S100A12 in adults with signs of intestinal inflammation. METHODS: Faecal S100A12 was determined by ELISA in faecal specimens of 171 consecutive patients and 24 healthy controls. Patients either suffered from infectious gastroenteritis confirmed by stool analysis (65 bacterial, 23 viral) or underwent endoscopic and histological investigation (32 with Crohn's disease, 27 with ulcerative colitis, and 24 with irritable bowel syndrome; IBS). Intestinal S100A12 expression was analysed in biopsies obtained from all patients. Faecal calprotectin was used as an additional non-invasive surrogate marker. RESULTS: Faecal S100A12 was significantly higher in patients with active IBD (2.45 +/- 1.15 mg/kg) compared with healthy controls (0.006 +/- 0.03 mg/kg; p<0.001) or patients with IBS (0.05 +/- 0.11 mg/kg; p<0.001). Faecal S100A12 distinguished active IBD from healthy controls with a sensitivity of 86% and a specificity of 100%. We also found excellent sensitivity of 86% and specificity of 96% for distinguishing IBD from IBS. Faecal S100A12 was also elevated in bacterial enteritis but not in viral gastroenteritis. Faecal S100A12 correlated better with intestinal inflammation than faecal calprotectin or other biomarkers. CONCLUSIONS: Faecal S100A12 is a novel non-invasive marker distinguishing IBD from IBS or healthy individuals with a high sensitivity and specificity. Furthermore, S100A12 reflects inflammatory activity of chronic IBD. As a marker for neutrophil activation, faecal S100A12 may significantly improve our arsenal of non-invasive biomarkers of intestinal inflammation.