Marco Gattorno

Surface phenotype and antigenic specificity of human interleukin 17–producing T helper memory cells

Interleukin 17 (IL-17)–producing T helper cells (TH-17 cells) have been characterized in mice as a distinct subset of effector cells, but their identity and properties in humans remain elusive. We report here that expression of CCR6 and CCR4 together identified human memory CD4+ T cells selectively producing IL-17 and expressing mRNA encoding the human ortholog of mouse RORγt, a transcription factor, whereas CCR6 and CXCR3 identified TH1 cells producing interferon-γ and T helper cells producing both interferon-γ and IL-17. Memory T cells specific for Candida albicans were present mainly in the CCR6+CCR4+ TH-17 subset, whereas memory T cells specific for Mycobacterium tuberculosis were present in CCR6+CXCR3+ T helper type 1 subset. The elicitation of IL-17 responses correlated with the capacity of C. albicans hyphae to stimulate antigen-presenting cells for the priming of TH-17 responses in vitro and for the production of IL-23 but not IL-12. Our results demonstrate that human TH-17 cells have distinct migratory capacity and antigenic specificities and establish a link between microbial products, T helper cell differentiation and homing in response to fungal antigens.

Pathogen-induced human TH17 cells produce IFN-γ or IL-10 and are regulated by IL-1β

IL-17-producing CD4+ T helper cells (TH17) have been extensively investigated in mouse models of autoimmunity. However, the requirements for differentiation and the properties of pathogen-induced human TH17 cells remain poorly defined. Using an approach that combines the in vitro priming of naive T cells with the ex vivo analysis of memory T cells, we describe here two types of human TH17 cells with distinct effector function and differentiation requirements. Candida albicans-specific TH17 cells produced IL-17 and IFN-γ, but no IL-10, whereas Staphylococcus aureus-specific TH17 cells produced IL-17 and could produce IL-10 upon restimulation. IL-6, IL-23 and IL-1β contributed to TH17 differentiation induced by both pathogens, but IL-1β was essential in C. albicans-induced TH17 differentiation to counteract the inhibitory activity of IL-12 and to prime IL-17/IFN-γ double-producing cells. In addition, IL-1β inhibited IL-10 production in differentiating and in memory TH17 cells, whereas blockade of IL-1β in vivo led to increased IL-10 production by memory TH17 cells. We also show that, after restimulation, TH17 cells transiently downregulated IL-17 production through a mechanism that involved IL-2-induced activation of STAT5 and decreased expression of ROR-γt. Taken together these findings demonstrate that by eliciting different cytokines C. albicans and S. aureus prime TH17 cells that produce either IFN-γ or IL-10, and identify IL-1β and IL-2 as pro- and anti-inflammatory regulators of TH17 cells both at priming and in the effector phase.

Coexpression of CD25 and CD27 identifies FoxP3+ regulatory T cells in inflamed synovia

A better understanding of the role of CD4+CD25+ regulatory T cells in disease pathogenesis should follow from the discovery of reliable markers capable of discriminating regulatory from activated T cells. We report that the CD4+CD25+ population in synovial fluid of juvenile idiopathic arthritis (JIA) patients comprises both regulatory and effector T cells that can be distinguished by expression of CD27. CD4+CD25+CD27+ cells expressed high amounts of FoxP3 (43% of them being FoxP3+), did not produce interleukin (IL)-2, interferon-γ, or tumor necrosis factor, and suppressed T cell proliferation in vitro, being, on a per cell basis, fourfold more potent than the corresponding peripheral blood population. In contrast, CD4+CD25+CD27− cells expressed low amounts of FoxP3, produced effector cytokines and did not suppress T cell proliferation. After in vitro activation and expansion, regulatory but not conventional T cells maintained high expression of CD27. IL-7 and IL-15 were found to be present in synovial fluid of JIA patients and, when added in vitro, abrogated the suppressive activity of regulatory T cells. Together, these results demonstrate that, when used in conjunction with CD25, CD27 is a useful marker to distinguish regulatory from effector T cells in inflamed tissues and suggest that at these sites IL-7 and IL-15 may interfere with regulatory T cell function.

The pattern of response to anti-interleukin-1 treatment distinguishes two subsets of patients with systemic-onset juvenile idiopathic arthritis

OBJECTIVE To assess the clinical response to interleukin-1 (IL-1) blockade and in vitro IL-1beta and IL-18 secretion in patients with systemic-onset juvenile idiopathic arthritis (JIA). METHODS Twenty-two patients with systemic-onset JIA were treated with the IL-1 receptor antagonist (IL-1Ra) anakinra. Monocytes from 18 patients and 20 healthy donors were activated by different Toll-like receptor ligands. Intracellular and secreted IL-1beta and IL-18 were analyzed by Western blotting and enzyme-linked immunosorbent assay. RESULTS Ten patients with systemic-onset JIA exhibited a dramatic response to anakinra and were classified as complete responders. Eleven patients had an incomplete response or no response, and 1 patient could not be classified in terms of response. Compared with patients who had an incomplete response or no response, complete responders had a lower number of active joints (P = 0.02) and an increased absolute neutrophil count (P = 0.02). In vitro IL-1beta and IL-18 secretion in response to various stimuli was not increased and was independent of treatment efficacy. Likewise, secretion of IL-1Ra by monocytes from patients with systemic-onset JIA was not impaired. An overall low level of IL-1beta secretion upon exposure to exogenous ATP was observed, unrelated to treatment responsiveness or disease activity. CONCLUSION Two subsets of systemic-onset JIA can be identified according to patient response to IL-1 blockade. The 2 subsets appear to be characterized by some distinct clinical features. In vitro secretion of IL-1beta and IL-18 by monocytes from patients with systemic-onset JIA is not increased and is independent of both treatment outcome and disease activity.

Persistent efficacy of anakinra in patients with tumor necrosis factor receptor–associated periodic syndrome

OBJECTIVE To evaluate the efficacy and safety of treatment with the interleukin-1 receptor antagonist anakinra in patients with tumor necrosis factor receptor-associated periodic syndrome (TRAPS) requiring high cumulative doses of steroids. METHODS Four children (mean age 9.1 years [range 4-13 years]) and 1 adult (age 33 years) with TRAPS were enrolled in the study. The 3 children with cysteine mutations (C52Y, C55Y, C43R) had prolonged and frequent attacks of fever. One child with the R92Q mutation and the adult patient with the C43R mutation displayed a more chronic disease course, with fluctuating, nearly continuous symptoms and persistent elevation of acute-phase reactant levels (including serum amyloid A [SAA]). All patients were treated with anakinra (1.5 mg/kg/day). RESULTS All of the patients had a prompt response to anakinra, with disappearance of symptoms and normalization of acute-phase reactant levels, including SAA. In all pediatric patients, anakinra was withdrawn after 15 days of treatment. After a few days (mean 5.6 days [range 3-8]) a disease relapse occurred, which dramatically responded to reintroduction of anakinra. During the following period of observation (mean 11.4 months [range 4-20 months]), the patients did not experience episodes of fever or other disease-related clinical manifestations. Levels of acute-phase reactants remained in the normal range. No major adverse reactions or severe infections were observed. CONCLUSION Continuous treatment with anakinra effectively controlled both the clinical and laboratory manifestations in patients with TRAPS and prevented disease relapses.

Bone Marrow‐Derived Mesenchymal Stem Cells Induce Both Polyclonal Expansion and Differentiation of B Cells Isolated from Healthy Donors and Systemic Lupus Erythematosus Patients

Human bone marrow multipotent mesenchymal stromal cells are progenitor cells that can be expanded in vitro and differentiate into various cells of mesodermal origin. They contribute to the bone marrow reticular niche, where mature B cells and long‐lived plasma cells are maintained. Multipotent mesenchymal stromal cells were recently shown to modulate T‐ and B‐cell proliferation and differentiation, dendritic cell maturation, and natural killer activity. These immunoregulatory properties encouraged a possible use of these cells to modulate autoimmune responses in humans. We studied the influence of bone marrow mesenchymal stem cells on highly purified B‐cell subsets isolated from healthy donors and total B cells from pediatric systemic lupus erythematosus patients. Bone marrow mesenchymal stem cells promoted proliferation and differentiation into immunoglobulin‐secreting cells of transitional and naïve B cells stimulated with an agonist of Toll‐like receptor 9, in the absence of B cell receptor triggering. They strongly enhanced proliferation and differentiation into plasma cells of memory B‐cell populations. A similar effect was observed in response to polyclonal stimulation of B cells isolated from pediatric patients with systemic lupus erythematosus. This study casts important questions on bone marrow mesenchymal stem cells as a therapeutic tool in autoimmune diseases in which B‐cell activation is crucially implicated in the pathogenesis of the disease.

Treatment of autoinflammatory diseases: results from the Eurofever Registry and a literature review

Objective To evaluate the response to treatment of autoinflammatory diseases from an international registry and an up-to-date literature review. Methods The response to treatment was studied in a web-based registry in which clinical information on anonymised patients with autoinflammatory diseases was collected retrospectively as part of the Eurofever initiative. Participating hospitals included paediatric rheumatology centres of the Paediatric Rheumatology International Trial Organisation network and adult centres with a specific interest in autoinflammatory diseases. The following diseases were included: familial Mediterranean fever (FMF), cryopyrin-associated periodic syndromes (CAPS), tumour necrosis factor (TNF)-receptor associated periodic syndrome (TRAPS), mevalonate kinase deficiency (MKD), pyogenic arthritis pustulosis acne (PAPA) syndrome, deficiency of interleukin-1 receptor antagonist (DIRA), NLRP12-related periodic fever and periodic fever aphthosis pharyngitis adenitis (PFAPA) syndrome. Cases were independently validated by experts for each disease. A literature search regarding treatment of the abovementioned diseases was also performed using Medline and Embase. Results 22 months from the beginning of the enrolment, complete information on 496 validated patients was available. Data from the registry in combination with evidence from the literature confirmed that colchicine is the treatment of choice for FMF and IL-1 blockade for DIRA and CAPS. Corticosteroids on demand probably represent a valid therapeutic strategy for PFAPA, but also for MKD and TRAPS. Patients with poorly controlled MKD, TRAPS, PAPA or FMF may benefit from IL-1 blockade; anti-TNF treatment may represent a possible valuable alternative. Conclusions In the absence of high-grade evidence, these results could serve as a basis for therapeutic guidelines and to identify candidate drugs for future therapeutic trials.

A Diagnostic Score for Molecular Analysis of Hereditary Autoinflammatory Syndromes With Periodic Fever in Children

OBJECTIVE To identify a set of clinical parameters that can predict the probability of carrying mutations in one of the genes associated with hereditary autoinflammatory syndromes. METHODS A total of 228 consecutive patients with a clinical history of periodic fever were screened for mutations in the MVK, TNFRSF1A, and MEFV genes, and detailed clinical information was collected. A diagnostic score was formulated based on univariate and multivariate analyses in genetically positive and negative patients (training set). The diagnostic score was validated in an independent set of 77 patients (validation set). RESULTS Young age at onset (odds ratio [OR] 0.94, P = 0.003), positive family history of periodic fever (OR 4.1, P = 0.039), thoracic pain (OR 4.6, P = 0.05), abdominal pain (OR 33.1, P < 0.001), diarrhea (OR 3.3, P = 0.028), and oral aphthosis (OR 0.2, P = 0.007) were found to be independently correlated with a positive genetic test result. These variables were combined in a linear score whose ability to predict a positive result on genetic testing was validated in an independent data set. In this latter set, the diagnostic score revealed high sensitivity (82%) and specificity (72%) for discriminating patients who were genetically positive from those who were negative. In patients with a high probability of having a positive result on genetic testing, a regression tree analysis provided the most reasonable order in which the genes should be screened. CONCLUSION The proposed approach in patients with periodic fever will increase the probability of obtaining positive results on genetic testing, with good specificity and sensitivity. Our results further help to optimize the molecular analysis by suggesting the order in which the genes should be screened.

Pediatric Antiphospholipid Syndrome: Clinical and Immunologic Features of 121 Patients in an International Registry

OBJECTIVES. The purpose of this study was to obtain data on the association of antiphospholipid antibodies with clinical manifestations in childhood and to enable future studies to determine the impact of treatment and long-term outcome of pediatric antiphospholipid syndrome. PATIENTS AND METHODS. A European registry extended internationally of pediatric patients with antiphospholipid syndrome was established as a collaborative project of the European Antiphospholipid Antibodies Forum and Lupus Working Group of the Pediatric Rheumatology European Society. To be eligible for enrollment the patient must meet the preliminary criteria for the classification of pediatric antiphospholipid syndrome and the onset of antiphospholipid syndrome must have occurred before the patients 18th birthday. RESULTS. As of December 1, 2007, there were 121 confirmed antiphospholipid syndrome cases registered from 14 countries. Fifty-six patients were male, and 65 were female, with a mean age at the onset of antiphospholipid syndrome of 10.7 years. Sixty (49.5%) patients had underlying autoimmune disease. Venous thrombosis occurred in 72 (60%), arterial thrombosis in 39 (32%), small-vessel thrombosis in 7 (6%), and mixed arterial and venous thrombosis in 3 (2%). Associated nonthrombotic clinical manifestations included hematologic manifestations (38%), skin disorders (18%), and nonthrombotic neurologic manifestations (16%). Laboratory investigations revealed positive anticardiolipin antibodies in 81% of the patients, anti-β2-glycoprotein I antibodies in 67%, and lupus anticoagulant in 72%. Comparisons between different subgroups revealed that patients with primary antiphospholipid syndrome were younger and had a higher frequency of arterial thrombotic events, whereas patients with antiphospholipid syndrome associated with underlying autoimmune disease were older and had a higher frequency of venous thrombotic events associated with hematologic and skin manifestations. CONCLUSIONS. Clinical and laboratory characterization of patients with pediatric antiphospholipid syndrome implies some important differences between antiphospholipid syndrome in pediatric and adult populations. Comparisons between children with primary antiphospholipid syndrome and antiphospholipid syndrome associated with autoimmune disease have revealed certain differences that suggest 2 distinct subgroups.

Two-year results from an open-label, multicentre, phase III study evaluating the safety and efficacy of canakinumab in patients with cryopyrin-associated periodic syndrome across different severity phenotypes

Objective Longer-term effects of prolonged selective interleukin-1β blockade with canakinumab were evaluated in the largest cohort of cryopyrin-associated periodic syndrome (CAPS) patients studied to date. Methods Adult and paediatric CAPS patients (n=166, including canakinumab-naive and pretreated patients from previous studies) received canakinumab subcutaneously 150 mg or 2 mg/kg (≤40 kg) every 8 weeks for up to 2 years. Response and relapse was assessed using scores for disease activity, skin rash and C-reactive protein (CRP) and/or serum amyloid A (SAA) levels. Results Complete response was achieved in 85 of 109 canakinumab-naive patients (78%; 79/85 patients within 8 days, and five patients between days 10 and 21). Of 141 patients with an available relapse assessment, 90% did not relapse, their CRP/SAA levels normalised (<10 mg/l) by day 8, and remained in the normal range thereafter. Median treatment duration was 414 days (29–687 days). Upward adjustments of dose or frequency were needed in 24.1% patients; mostly children and those with severe CAPS. Predominant adverse events (AE) were infections (65.7%) of mostly mild-to-moderate severity. Serious AE reported in 18 patients (10.8%) were mainly infections and were responsive to standard treatment. The majority of patients (92%) reported having no injection-site reactions and only 8% patients reported mild-to-moderate reactions. Patients receiving vaccination (15%) showed normal immune response. Conclusions Subcutaneous canakinumab 150 mg every 8 weeks was well tolerated and provided substantial disease control in children and adults across all CAPS phenotypes. Higher canakinumab doses in younger patients and more severe CAPS disease were efficacious in achieving complete responses without evidence of increased AE. Trial registration number: NCT00685373 (clinicaltrials.gov)