Prognostic value of 18 FDG-PET at diagnosis and follow-up in giant cell arteritis: An observational restrospective study.

OBJECTIVES: To evaluate the ability of 18FDG PET/CT, at diagnosis of giant cell arteritis (GCA) and during follow-up, to predict occurrence of relapse in large-vessel GCA (LV-GCA). METHODS: We conducted a retrospective study using the French Study Group for Large-Vessel Vasculitis (GEFA) network. Data from patients with LV-GCA diagnosed by PET/CT and who had PET/CT in the following year were collected. For each PET/CT, PET vascular activity score (PETVAS) and total vascular score (TVS) were assessed, and their ability to predict the occurrence of subsequent relapse was assessed. RESULTS: A total of 65 LV-GCA patients were included, of whom 55 had undergone a follow-up PET/CT 3 to 12 months after the diagnosis of GCA. Patients for whom the second PET/CT (PET2) was performed during active GCA were excluded. PETVAS and TVS decreased between PET1 and PET2 in all patients (p < 0.001). There was no correlation between vascular activity scores in PET2 and time to prednisone taper. For relapse prediction, at PET1, the AUC of the TVS and PETVAS were respectively 51.9 and 41.9 at 6 months, 55.3 and 49.7 at 1 year, 55 and 55.7 at 2 years. For PET2, the AUC were respectively 46.1 and 46.7 at 6 months, 52.1 and 48.9 at 1 year, 58.4 and 52.3 at 2 years. CONCLUSION: PET vascular activity scores at diagnosis and at follow-up PET/CT performed outside a period of GCA activity do not display high performance to predict the occurrence of subsequent relapse in LV-GCA patients.

Difficult-to-treat primary immune thrombocytopenia in adults: Prevalence and burden. Results from the CARMEN-France registry.

The aim of this study was to assess the prevalence and the burden of difficult-to-treat primary ITP (pITP), defined by the need for another ITP treatment after romiplostim and eltrombopag. Adult patients were selected in the prospective, real-world CARMEN-France registry up to December 2021. Out of 821 adult patients with pITP, 29 had difficult-to-treat ITP (3.5%; 95% confidence interval [CI]: 2.3%-4.8% in total; 7.6%; 95% CI: 4.9%-10.2% of patients needing ≥2nd line treatment). The 3-year cumulative incidence of bleeding, infection and thrombosis was 100%, 24.1% and 13.8% respectively. The median cumulative duration of hospital stays was 31 days (median follow-up: 30.3 months).

Rituximab as maintenance therapy for ANCA-associated vasculitides: pooled analysis and long-term outcome of 277 patients included in the MAINRITSAN trials.

OBJECTIVE: To compare the long-term efficacy and safety of azathioprine (AZA), 18-month fixed-schedule rituximab (RTX), 18-month tailored RTX and 36-month RTX in preventing relapses in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis who achieved a complete remission after induction therapy. Patients treated with 36-month RTX received either a fixed or a tailored regimen for the first 18 months and a fixed regimen for the last 18 months (36-month fixed/fixed RTX and 36-month tailored/fixed RTX, respectively). METHODS: The Maintenance of Remission using Rituximab in Systemic ANCA-associated Vasculitis (MAINRITSAN) trials sequentially compared: 18-month fixed-schedule RTX versus AZA (MAINRITSAN); 18-month fixed-schedule RTX versus 18-month tailored-RTX (MAINRITSAN2); and extended therapy to 36 months with four additional RTX infusions after MAINRITSAN2 versus placebo (MAINRITSAN3). Patients were then followed prospectively through month 84 and their data were pooled to analyse relapses and adverse events. The primary endpoint was relapse-free survival at month 84. RESULTS: 277 patients were enrolled and divided in 5 groups: AZA (n=58), 18-month fixed-schedule RTX (n=97), 18-month tailored-RTX (n=40), 36-month tailored/fixed RTX (n=42), 36-month fixed/fixed RTX (n=41). After adjustment for prognostic factors, 18-month fixed-schedule RTX was superior to AZA in preventing major relapses at month 84 (HR 0.38, 95% CI 0.20 to 0.71). The 18-month tailored-RTX regimen was associated with an increased risk of major relapse compared with fixed-schedule regimen (HR 2.92, 95% CI 1.43 to 5.96). The risk of major relapse was similar between 36-month fixed/fixed and 18-month fixed-RTX (HR 0.69, 95% CI 0.38 to 1.25). CONCLUSIONS: According to these results, it appears that the 84-month remission rate is higher with an 18-month fixed RTX regimen compared with AZA and 18-month tailored RTX. Also, extending RTX to 36 months does not appear to reduce the long-term relapse rate compared with the 18-month fixed RTX regimen. However, as this study was underpowered to make this comparison, further prospective studies are needed to determine the potential long-term benefits of extending treatment in these patients.

Regulatory T-cell dysfunctions are associated with increase in tumor necrosis factor α in autoimmune hemolytic anemia and participate in Th17 polarization.

Warm autoimmune hemolytic anemia (wAIHA) is a rare acquired autoimmune disease mediated by antibodies targeting red blood cells. The involvement of CD4 T-helper cells has been scarcely explored, with most findings extrapolated from animal models. Here, we performed quantification of both effector T lymphocytes (Teff) and regulatory T cells (Treg), associated with functional and transcriptomic analyses of Treg in human wAIHA. We observed a shift of Teff toward a Th17 polarization concordant with an increase in serum interleukin-17 concentration that correlates with red blood cell destruction parameters, namely lactate dehydrogenase and bilirubin levels. A decrease in circulating Treg, notably effector Treg, associated with a functional deficiency, as represented by their decrease capability to inhibit Teff proliferation, were also observed. Treg deficiency was associated with a reduced expression of Foxp3, the master transcription factor known to maintain the Treg phenotype stability and suppressive functions. Transcriptomic profiling of Treg revealed activation of the tumor necrosis facto (TNF)-α pathway, which was linked to increased serum TNF-α concentrations that were twice as high as in controls. Treg transcriptomic profiling also suggested that post-translational mechanisms possibly accounted for Foxp3 downregulation and Treg dysfunctions. Since TNF-α participates in the rupture of immune tolerance during wAIHA, its inhibition could be of interest. To this end, the effects of fostamatinib, a SYK inhibitor, were investigated in vitro, and we showed that besides the inhibition of erythrocyte phagocytosis by monocytes, fostamatinib is also able to dampen TNF-α production, thus appearing as a promising multitargeting therapy in wAIHA (clinicaltrials gov. Identifier: NCT02158195).

Giant cell arteritis associated with scalp, tongue or lip necrosis: A French multicenter case control study.

BACKGROUND: Scalp, tongue and/or lip necrosis are rare complications of GCA. OBJECTIVES: To describe characteristics and outcome of patients with giant cell arteritis (GCA) -related scalp, tongue and/or lip necrosis. METHODS: A retrospective nationwide multicenter study included 20 GCA patients with scalp, tongue, and/or lip necrosis diagnosed between 1998 and 2021 and 80 GCA control patients matched for age, sex and management period. Logistic regression analyses were conducted to identify baseline characteristics associated with scalp, tongue and/or lip necrosis. RESULTS: Compared to controls, patients with scalp, tongue and/or lip necrosis showed significantly more cranial manifestations (headache, p=0.045; scalp tenderness, p=0.006; jaw claudication, p=0.02). No differences were observed between both groups regarding the occurrence of visual symptoms or large vessel involvement. At diagnosis, GCA patients with necrosis more likely received IV methylprednisolone infusions and higher doses of oral prednisone. There were no differences regarding vascular complications during follow up. Compared to controls, survival was decreased in GCA patients with necrosis (p=0.003). In a multivariable logistic regression model, scalp tenderness [odds ratio (OR) 4.81(95 % CI: 1.57, 14.79), p = 0.006] and cognitive disorder [OR 6.42 (95 % CI: 1.01, 40.60), p=0.048] were identified as factors associated to scalp, tongue, and/or lip necrosis. CONCLUSION: Our results suggest that scalp, tongue, and/or lip necrosis is associated to higher mortality in GCA patients. Scalp tenderness and cognitive disorder were significant factors associated to this very rare complication of GCA.

Neointimal myofibroblasts contribute to maintaining Th1/Tc1 and Th17/Tc17 inflammation in giant cell arteritis.

Vascular smooth muscle cells (VSMCs) have been shown to play a role in the pathogenesis of giant cell arteritis (GCA) through their capacity to produce chemokines recruiting T cells and monocytes in the arterial wall and their ability to migrate and proliferate in the neointima where they acquire a myofibroblast (MF) phenotype, leading to vascular stenosis. This study aimed to investigate if MFs could also impact T-cell polarization. Confocal microscopy was used to analyze fresh fragments of temporal artery biopsies (TABs). Healthy TAB sections were cultured to obtain MFs, which were then treated or not with interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) and analyzed by immunofluorescence and RT-PCR. After peripheral blood mononuclear cells and MFs were co-cultured for seven days, T-cell polarization was analyzed by flow cytometry. In the neointima of GCA arteries, we observed a phenotypic heterogeneity among VSMCs that was consistent with a MF phenotype (α-SMA+CD90+desmin+MYH11+) with a high level of STAT1 phosphorylation. Co-culture experiments showed that MFs sustain Th1/Tc1 and Th17/Tc17 polarizations. The increased Th1 and Tc1 polarization was further enhanced following the stimulation of MFs with IFN-γ and TNF-α, which induced STAT1 phosphorylation in MFs. These findings correlated with increases in the production of IL-1ß, IL-6, IL-12 and IL-23 by MFs. Our study showed that MFs play an additional role in the pathogenesis of GCA through their ability to maintain Th17/Tc17 and Th1/Tc1 polarizations, the latter being further enhanced in case of stimulation of MF with IFN-γ and TNF-α.

Correction: Full-field optical coherence tomography for the diagnosis of giant cell arteritis.

[This corrects the article DOI: 10.1371/journal.pone.0234165.].

Pro-angiogenic changes of T-helper lymphocytes in hereditary hemorrhagic telangiectasia.

Hereditary hemorrhagic telangiectasia (HHT) is a rare inherited disease due to heterozygous loss-of-function mutations on the BMP9/10 pathway (ENG, ACVRL1 or MADH4 mainly). HHT endothelial cells are prone to lose their quiescence, leading to progressive appearance of numerous telangiectases on skin and mucosa (complicated by epistaxis and anemia), and to larger arteriovenous malformations in lungs, liver and brain. HHT is also associated with T lymphocyte abnormalities, which are currently poorly understood. We quantified by flow-cytometry the main T lymphocyte circulating subsets in 40 HHT patients and 20 matched healthy controls. Immunostaining was done on 2 HHT skin telangiectases. Disruptions in T lymphocyte homeostasis was observed, characterized by increases in subsets known to promote angiogenesis: Th2 (1.38% vs 1.15%, p=0.021), Th17 (0.32% vs 0.22%, p=0.019 2) and Treg (4.94% vs 3.51%, p= 0.027). T angiogenic lymphocytes (Tang), defined as CD3+CD31+CXCR4+ T cells, were at similar levels in both groups, but the proportion of VEGF-A+ Tang after stimulation was higher in the HHT group compared to controls (68.2% vs 44.9%, p=0.012). The global HHT T lymphopenia predominantly affected the effector memory T-helper cells (200 vs 270 cells/mm3, p=0.017), and the lymphocytic infiltrate around HHT telangiectases consisted of memory T-helper cells. The Th17 circulating subset was positively correlated with the monthly epistaxis duration (r coefficient: +0,431, p=0.042), prospectively assessed. HHT T-helper lymphocytes are affected by several pro-angiogenic changes, potentially resulting from their recruitment by abnormal endothelial cells. They could constitute a biologically relevant source of VEGF-A and a valuable therapeutic target in HHT.

Dysregulation of neutrophil oxidant production and interleukin-1-related cytokines in granulomatosis with polyangiitis.

OBJECTIVES: Neutrophils play a key role in ANCA-associated vasculitis, both as targets of autoimmunity and facilitators of vascular damage. In granulomatosis with polyangiitis (GPA), data regarding the production of reactive oxygen species (ROS) in neutrophils are unclear. Further, recent data suggests that ROS production could have an anti-inflammatory effect through the regulation of the inflammasome and IL-1-related cytokines. We aimed to analyse the ROS production in neutrophils from patients with GPA and investigate its association with IL-1-related cytokines and the autoantigen proteinase 3 (PR3). METHODS: Seventy-two GPA patients with disease flare were included in the NEUTROVASC prospective cohort study. ROS production was evaluated in whole blood of patients with active GPA and compared with the same patients in remission or healthy controls. Associations between ROS production, PR3 membrane expression on neutrophils, serum levels of IL-1-related cytokines as well as inflammasome-related proteins were analyzed. RESULTS: We observed a robust defect in ROS production by neutrophils from patients with active GPA compared with healthy controls, independent of glucocorticoid treatment. Serum levels of IL-1-related cytokines were significantly increased in GPA patients, particularly in patients with kidney involvement, and levels of these cytokines returned to normal after patients achieved remission. Further, inflammasome-related proteins were significantly dysregulated in the cytosol of neutrophils as well as the serum from GPA patients. CONCLUSION: Our data suggests that ROS production and regulation of the inflammasome in neutrophils from patients with GPA are disturbed and may be a potential therapeutic target. CLINICAL TRIAL REGISTRATION NUMBER: NCT01862068, clinicaltrials.gov, https://www.clinicaltrials.gov.

Heart and systemic sclerosis-findings from a national cohort study.

OBJECTIVES: Heart involvement is one of the leading causes of death in systemic sclerosis (SSc). The prevalence of SSc-related cardiac involvement is poorly known. Our objective was to investigate the prevalence and prognosis burden of different heart diseases in a nationwide cohort of patients with SSc. METHODS: We used data from a multicentric prospective study using the French SSc national database. Focusing on SSc-related cardiac involvement, we aimed to determine its incidence and risk factors. RESULTS: Over the 3528 patients with SSc 312 (10.9%) had SSc-related cardiac involvement at baseline. They tended to have a diffuse SSc subtype more frequently, more severe clinical features, and presented more cardiovascular risk factors. From the 1646 patients available for follow-up analysis, SSc-related cardiac involvement was associated with an increased risk of death. There was no significant difference in overall survival between SSc-related cardiac involvement, ischaemic heart disease or pulmonary arterial hypertension. Regarding survival analysis, 98 patients developed SSc-related cardiac involvement at five years (5-year event rate: 11.15%). Regarding reduced LVEF < 50% and left ventricular diastolic dysfunction, the 5-year event rate was 2.49% and 5.84% respectively. Pericarditis cumulative incidence at five years was 3%. Diffuse SSc subtype was a risk factor for SSc-related cardiac involvement and pericarditis. Female sex was associated with less left ventricular diastolic dysfunction incidence. CONCLUSIONS: Our results describe the incidence and prognostic burden of SSc-related cardiac involvement at a large scale, with gender and diffuse SSc subtype as risk factors. Further analyses should assess the potential impact of treatment on these various cardiac outcomes.

Clinical presentation, course, and prognosis of patients with mixed connective tissue disease: A multicenter retrospective cohort.

OBJECTIVES: The objective of this study is to better characterize the features and outcomes of a large population of patients with mixed connective tissue disease (MCTD). METHODS: We performed an observational retrospective multicenter cohort study in France. Patients who fulfilled at least one diagnostic criterion set for MCTD and none of the criteria for other differentiated CTD (dCTD) were included. RESULTS: Three hundred and thirty patients (88% females, median [interquartile range] age of 35 years [26-45]) were included. The diagnostic criteria of Sharp or Kasukawa were met by 97.3% and 93.3% of patients, respectively. None met other classification criteria without fulfilling Sharp or Kasukawa criteria. After a median follow-up of 8 (3-14) years, 149 (45.2%) patients achieved remission, 92 (27.9%) had interstitial lung disease, 25 (7.6%) had pulmonary hypertension, and 18 (5.6%) died. Eighty-five (25.8%) patients progressed to a dCTD, mainly systemic lupus erythematosus (15.8%) or systemic sclerosis (10.6%). Median duration between diagnosis and progression to a dCTD was 5 (2-11) years. The presence at MCTD diagnosis of an abnormal pattern on nailfold capillaroscopy (odds ratio [OR] = 2.44, 95% confidence interval [95%CI] [1.11-5.58]) and parotid swelling (OR = 3.86, 95%CI [1.31-11.4]) were statistically associated with progression to a dCTD. Patients who did not progress to a dCTD were more likely to achieve remission at the last follow-up (51.8% vs. 25.9%). CONCLUSIONS: This study shows that MCTD is a distinct entity that can be classified using either Kasukawa or Sharp criteria, and that only 25.8% of patients progress to a dCTD during follow-up.

Impact of BRAFV600E mutation on aggressiveness and outcomes in adult clonal histiocytosis.

Histiocytoses encompass a wide spectrum of diseases, all characterized by tissue infiltration by CD68+ histiocytes. Most adult histiocytoses are considered clonal diseases because they highlight recurrent somatic mutations in the MAP-kinase pathway gene, primarily BRAF. The presence of BRAF mutation is associated with widespread disease in children with Langerhans cell histiocytosis (LCH) or cardiovascular/neurological involvement in Erdheim-Chester disease (ECD). Nevertheless, few data are available on adult clonal histiocytosis. This is why we have conducted a retrospective study of all patients with clonal histiocytosis in our institution and present the data according to the presence of BRAF mutation. Among 27 adult patients (10 ECD, 10 LCH, 5 Rosai-Dorfman disease (RDD), and 3 mixed ECD/LCH), 11 (39%) have BRAF mutation with gain of function (n = 9) and deletion (n = 2). Those patients had frequent multicentric disease with risk organ involvement, especially the brain and cardiovascular system. They had frequent associated myeloid neoplasms (mostly chronic myelomonocytic leukemia) and received more frequently targeted therapy as the front-line therapy. Nevertheless, its presence did not affect the overall survival or relapse-free survival probably due to the emergence of efficient therapies. To conclude, rapid and accurate molecular establishment in adult clonal histiocytoses is crucial because BRAFV600E mutation correlates with multicentric disease with organ involvement and incomplete metabolic response.

[Epidemiology and pathophysiology of giant cell arteritis]. / Épidémiologie et physiopathologie de l'artérite à cellules géantes.

EPIDEMIOLOGY AND PATHOPHYSIOLOGY OF GIANT CELL ARTERITIS. Giant cell arteritis (GCA) is a granulomatous vasculitis. It affects patients over 50 years of age, predominantly women. The pathophysiology of GCA involves genetic and environmental factors leading to the development of inflammation and subsequent large artery wall remodelling, the mechanisms of which are increasingly understood. The process is thought to begin with the activation of dendritic cells in the vessel wall. These then recruit and activate CD4 T cells, inducing their proliferation and polarisation into Th1 and Th17 cells, which produce interferon-gamma (IFN-γ) and interleukin-17 (IL-17) respectively. IFN-γ activates vascular smooth muscle cells, which produce chemokines that induce the recruitment of other mononuclear cells (CD4 and CD8 T cells and monocytes). This inflammatory infiltrate, the differentiation of monocytes into macrophages induce the production of other mediators that cause remodeling of the vascular wall based on destruction of the arterial wall, neoangiogenesis and intimal hyperplasia. This remodelling leads to the ischaemic manifestations of GCA by causing stenosis or even occlusion of the affected vessels. More recently, mechanisms have been identified that allow the perpetuation of inflammation and vascular remodelling, explaining the chronic evolution of GCA.

ÉPIDÉMIOLOGIE ET PHYSIOPATHOLOGIE DE L'ARTÉRITE À CELLULES GÉANTES. L'artérite à cellules géantes (ACG) est une vascularite granulomateuse affectant les patients de plus de 50 ans, préférentiellement les femmes. La physiopathologie de l'ACG fait intervenir des facteurs génétiques et environnementaux qui conduisent à l'apparition d'une inflammation, puis d'un remodelage de la paroi des artères de gros calibre dont les mécanismes sont de mieux en mieux compris. On pense que le processus débute par l'activation des cellules dendritiques de la paroi vasculaire qui recrutent ensuite les lymphocytes T CD4, les activent et induisent leur prolifération et leur polarisation en lymphocytes Th1 et Th17, qui produisent respectivement de l'interféron gamma (IFN-γ) et de l'interleukine 17 (IL-17). L'IFN-γ active les cellules musculaires lisses vasculaires qui produisent des chimiokines induisant le recrutement d'autres cellules mononucléées (lymphocytes T CD4 et CD8 ; monocytes). Cet infiltrat inflammatoire, la différenciation des monocytes en macrophages induisent la production d'autres médiateurs qui provoquent un remodelage de la paroi vasculaire reposant sur une destruction de la paroi artérielle, une néoangiogenèse et une hyperplasie intimale. Ce remodelage conduit à la sténose, voire à l'occlusion, des vaisseaux atteints et ainsi aux manifestations ischémiques de l'ACG. Plus récemment, des mécanismes permettant d'entretenir l'inflammation et le remodelage vasculaire ont été mis en évidence et permettent d'expliquer l'évolution chronique de l'ACG.

[Diagnosis of giant cell arteritis]. / Diagnostic de l'artérite à cellules géantes.

DIAGNOSIS OF GIANT CELL ARTERITIS. The diagnosis of giant cell arteritis (GCA) must be made promptly in order to initiate appropriate treatment aimed at relieving symptoms and avoiding ischemic complications, particularly visual ones. The diagnosis of GCA is based on the occurrence, in a patient over 50, of clinical signs of GCA, primarily recent headaches, or polymyalgia rheumatica, as «evidence¼ of large-vessel vasculitis, which is provided by histological analysis of an arterial fragment, usually the temporal artery, or by imaging of the cephalic arteries, the aorta and/ or its main branches by Doppler US scan, angio-CT, 18fluorodeoxyglucose PET scan or more rarely by MRI angiography. In addition, in more than 95% of cases, patients have an elevation in markers of inflammatory syndrome. This is less marked in the case of visual or neurological ischemic complications. Two main GCA phenotypes can be distinguished: on the one hand, cephalic GCA, in which cephalic vessel involvement predominates and which identifies patients at the greatest risk of ischemic complications; on the other hand, extracephalic GCA concerns younger patients with a lower ischemic risk but with more aortic complications and more frequent relapses. The establishment «fast track¼ type structures in specialized centers allows for rapid management in order to identify patients to be treated in order to avoid ischemic complications and to quickly perform the necessary examinations to confirm the diagnosis and ensure that the patient receives appropriate management.

DIAGNOSTIC DE L'ARTÉRITE À CELLULES GÉANTES. Le diagnostic d'artérite à cellules géantes (ACG) doit être porté rapidement pour initier un traitement adapté visant à soulager les symptômes et éviter les complications ischémiques, en particulier visuelles, de la maladie. Le diagnostic repose sur la survenue, chez un patient de plus de 50 ans, de signes cliniques d'ACG, au premier rang desquels les céphalées récentes, ou de pseudopolyarthrite rhizomélique et d'une « preuve ¼ de vascularite des artères de gros calibre qui est apportée par l'analyse histologique d'un fragment artériel, généralement l'artère temporale, ou par l'imagerie des artères céphaliques, de l'aorte et/ou de ses principales branches par l'échographie-Doppler, l'angioscanner, le TEP-scan au 18fluorodéoxyglucose et plus rarement l'angio-IRM. De plus, les patients présentent, dans plus de 95 % des cas, un syndrome inflammatoire biologique. Celui-ci est moins marqué en cas de complication ischémique visuelle ou neurologique. On distingue deux grands phénotypes d'ACG non exclusifs : d'une part, l'ACG céphalique où prédomine l'atteinte des vaisseaux céphaliques avec un risque plus élevé de complication ischémique ; d'autre part, l'ACG extracéphalique, qui concerne des patients moins âgés chez qui le risque ischémique est plus faible mais qui ont davantage de complications aortiques et rechutent plus souvent. La mise en place de structures de type fast track dans des centres spécialisés permet une prise en charge rapide afin d'identifier les patients à traiter en urgence, d'éviter les complications ischémiques et de réaliser rapidement les examens nécessaires à la confirmation du diagnostic et à une prise en charge adaptée.

[Treatment of giant cell arteritis]. / Traitement de l'artérite à cellules géantes.

TREATMENT OF GIANT CELL ARTERITIS. The treatment of giant cell arteritis (GCA) is based on glucocorticoids. This treatment significantly reduces the risk of ischemic complications, especially those of a visual nature, rapidly relieves the symptoms of the disease, and eliminates the inflammatory syndrome. The diagnosis of GCA must be able to question if corticosteroid therapy is ineffective. Once the symptoms have resolved and the inflammatory syndrome has normalized, glucocorticosteroids are tapered very gradually. The goal is to discontinue glucocorticosteroids in 12 to 18 months. Nearly half of patients experience flares during the glucocorticoid taper. These are usually benign, not visually life-threatening, and easily controlled by increasing glucocorticoids. However, these relapses contribute to prolonging the treatment duration and thus the cumulative dose of glucocorticoids received by patients, which leads to the occurrence of adverse effects of glucocorticoids in almost all patients. For this reason, it is sometimes necessary to prescribe glucocorticoid-sparing treatments, particularly methotrexate and tocilizumab. The efficacy of these treatments and others in development is essential and to be discussed. In addition, the management of patients with GCA should include preventive measures to reduce cardiovascular, infectious and osteoporosis risks.

TRAITEMENT DE L'ARTÉRITE À CELLULES GÉANTES. Le traitement de l'artérite à cellules géantes (ACG) repose sur la corticothérapie par voie générale. Ce traitement permet de diminuer significativement le risque de survenue de complication ischémique, en particulier visuelle, soulage rapidement les symptômes de la maladie et fait disparaître le syndrome inflammatoire. Face à une absence d'efficacité de la corticothérapie ou à un échappement rapide après que le traitement a été débuté, le diagnostic d'ACG doit être remis en cause. Une fois les symptômes disparus et le syndrome inflammatoire normalisé, les doses de corticoïdes sont diminuées très progressivement avec pour objectif le sevrage en douze à dix-huit mois. Lors de la décroissance des doses de corticoïdes, près de la moitié des patients présentent une ou plusieurs rechutes de la maladie. Celles-ci sont généralement bénignes, ne mettent pas en jeu le pronostic visuel et sont facilement contrôlées par une augmentation des doses de corticoïdes. Cependant, ces rechutes contribuent à prolonger la durée du traitement et donc la dose cumulée de corticoïdes reçue par les patients, ce qui conduit, chez presque tous les patients, à la survenue d'effets indésirables de la corticothérapie. C'est la raison pour laquelle la prescription de traitements d'épargne en corticoïdes, en particulier le méthotrexate et le tocilizumab, est parfois nécessaire. La place de ces traitements, et d'autres en cours de développement, est essentielle et sujet à débattre. Enfin, la prise en charge des patients atteints d'ACG doit inclure des mesures préventives pour diminuer le risque cardiovasculaire, le risque infectieux et le risque d'ostéoporose.