Anti-SAE autoantibody in dermatomyositis: original comparative study and review of the literature.

OBJECTIVE: Among specific autoantibodies in DM, the anti-small ubiquitin-like modifier activating enzyme (SAE) antibody is rare. We aim to describe the clinical characteristics, cancer prevalence, and muscle pathology of anti-SAE-positive DM. METHODS: Patients with a diagnosis of DM and sera positive for the anti-SAE antibody were recruited from 19 centres in this retrospective observational study. The available muscular biopsies were reviewed. We conducted a comparison with anti-SAE-negative DM and a review of the literature. RESULTS: Of the patients in the study (n = 49), 84% were women. Skin involvement was typical in 96% of patients, with 10% having calcinosis, 18% ulceration and 12% necrosis; 35% presented with a widespread skin rash. Muscular disease affected 84% of patients, with mild weakness [Medical Research Council (MRC) scale 4 (3, 5)], although 39% of patients had dysphagia. Muscular biopsies showed typical DM lesions. Interstitial lung disease was found in 21% of patients, mainly with organizing pneumonia pattern, and 26% of patients showed dyspnoea. Cancer-associated myositis was diagnosed in 16% of patients and was responsible for the majority of deaths, its prevalence being five times that of the general population. IVIG therapy was administered to 51% of the patients during the course of the disease. Comparison with anti-SAE-negative DM (n = 85) showed less and milder muscle weakness (P = 0.02 and P = 0.006, respectively), lower creatinine kinase levels (P < 0.0001) and less dyspnoea (P = 0.003). CONCLUSION: Anti-SAE positive DM is a rare subgroup associated with typical skin features but a potentially diffuse rash, a mild myopathy. Interstitial lung disease defines an organizing pneumonia pattern. Cancer associated DM prevalence is five times that of the general population. TRIAL REGISTRATION: ClinicalTrials.gov, http://clinicaltrials.gov, NCT04637672.

Abatacept/Ruxolitinib and Screening for Concomitant Respiratory Muscle Failure to Mitigate Fatality of Immune-Checkpoint Inhibitor Myocarditis.

Immune-checkpoint-inhibitor (ICI)-associated myotoxicity involves the heart (myocarditis) and skeletal muscles (myositis), which frequently occur concurrently and are highly fatal. We report the results of a strategy that included identification of individuals with severe ICI myocarditis by also screening for and managing concomitant respiratory muscle involvement with mechanical ventilation, as well as treatment with the CTLA4 fusion protein abatacept and the JAK inhibitor ruxolitinib. Forty cases with definite ICI myocarditis were included with pathologic confirmation of concomitant myositis in the majority of patients. In the first 10 patients, using recommended guidelines, myotoxicity-related fatality occurred in 60%, consistent with historical controls. In the subsequent 30 cases, we instituted systematic screening for respiratory muscle involvement coupled with active ventilation and treatment using ruxolitinib and abatacept. The abatacept dose was adjusted using CD86 receptor occupancy on circulating monocytes. The myotoxicity-related fatality rate was 3.4% (1/30) in these 30 patients versus 60% in the first quartile (P < 0.0001). These clinical results are hypothesis-generating and need further evaluation. SIGNIFICANCE: Early management of respiratory muscle failure using mechanical ventilation and high-dose abatacept with CD86 receptor occupancy monitoring combined with ruxolitinib may be promising to mitigate high fatality rates in severe ICI myocarditis. See related commentary by Dougan, p. 1040. This article is highlighted in the In This Issue feature, p. 1027.

Necrosis in anti-SRP+ and anti-HMGCR+myopathies: Role of autoantibodies and complement.

OBJECTIVE: To characterize muscle fiber necrosis in immune-mediated necrotizing myopathies (IMNM) with anti-signal recognition particle (SRP) or anti-3-hydroxy-3-methylglutarylcoenzyme A reductase (HMGCR) antibodies and to explore its underlying molecular immune mechanisms. METHODS: Muscle biopsies from patients with IMNM were analyzed and compared to biopsies from control patients with myositis. In addition to immunostaining and reverse transcription PCR on muscle samples, in vitro immunostaining on primary muscle cells was performed. RESULTS: Creatine kinase levels and muscle regeneration correlated with the proportion of necrotic fibers (r = 0.6, p < 0.001). CD68+iNOS+ macrophages and a Th-1 immune environment were chiefly involved in ongoing myophagocytosis of necrotic fibers. T-cell densities correlated with necrosis but no signs of cytotoxicity were detected. Activation of the classical pathway of the complement cascade, accompanied by deposition of sarcolemmal immunoglobulins, featured involvement of humoral immunity. Presence of SRP and HMGCR proteins on altered myofibers was reproduced on myotubes exposed to purified patient-derived autoantibodies. Finally, a correlation between sarcolemmal complement deposits and fiber necrosis was observed (r = 0.4 and p = 0.004). Based on these observations, we propose to update the pathologic criteria of IMNM. CONCLUSION: These data further corroborate the pathogenic role of anti-SRP and anti-HMGCR autoantibodies in IMNM, highlighting humoral mechanisms as key players in immunity and myofiber necrosis.

High risk of cancer in autoimmune necrotizing myopathies: usefulness of myositis specific antibody.

Cancer can occur in patients with inflammatory myopathies. This association is mainly observed in dermatomyositis, and myositis-specific antibodies have allowed us to delineate patients at an increased risk. Malignancy is also reported in patients with necrotizing autoimmune myopathies, but the risk remains elusive. Anti-signal recognition particle or anti-HMGCR antibodies have been specifically associated with necrotizing autoimmune myopathies. We aimed at screening the incidence of cancer in necrotizing autoimmune myopathies. A group of patients (n = 115) with necrotizing autoimmune myopathies with or without myositis-specific antibodies was analysed. Malignancy occurred more frequently in seronegative necrotizing autoimmune myopathies patients and in HMGCR-positive patients compared to anti-signal recognition particle positive patients. Synchronous malignancy was diagnosed in 21.4% and 11.5% of cases, respectively, and incidence of cancer was higher compared to the general population in both groups. No specific type of cancer was predominant. Patients suffering from a synchronous cancer had a decreased median survival time. Cancer screening is necessary in seronegative necrotizing autoimmune myopathies and in HMGCR-positive patients but not in anti-signal recognition particle-positive patients.

Infliximab Versus Adalimumab in the Treatment of Refractory Inflammatory Uveitis: A Multicenter Study From the French Uveitis Network.

OBJECTIVE: To analyze the factors associated with response to anti-tumor necrosis factor (anti-TNF) treatment and compare the efficacy and safety of infliximab (IFX) and adalimumab (ADA) in patients with refractory noninfectious uveitis. METHODS: This was a multicenter observational study of 160 patients (39% men and 61% women; median age 31 years [interquartile range 21-42]) with uveitis that had been refractory to other therapies, who were treated with anti-TNF (IFX 5 mg/kg at weeks 0, 2, 6, and then every 5-6 weeks [n = 98] or ADA 40 mg every 2 weeks [n = 62]). Factors associated with complete response were assessed by multivariate analysis. Efficacy and safety of IFX versus ADA were compared using a propensity score approach with baseline characteristics taken into account. Subdistribution hazard ratios (SHRs) and 95% confidence intervals (95% CIs) were calculated. RESULTS: The main etiologies of uveitis included Behçet's disease (BD) (36%), juvenile idiopathic arthritis (22%), spondyloarthropathy (10%), and sarcoidosis (6%). The overall response rate at 6 and 12 months was 87% (26% with complete response) and 93% (28% with complete response), respectively. The median time to complete response was 2 months. In multivariate analysis, BD and occurrence of >5 uveitis flares before anti-TNF initiation were associated with complete response to anti-TNF (SHR 2.52 [95% CI 1.35-4.71], P = 0.004 and SHR 1.97 [95% CI 1.02-3.84], P = 0.045, respectively). Side effects were reported in 28% of patients, including serious adverse events in 13%. IFX and ADA did not differ significantly in terms of occurrence of complete response (SHR 0.65 [95% CI 0.25-1.71], P = 0.39), serious side effects (SHR 0.22 [95% CI 0.04-1.25], P = 0.089), or event-free survival (SHR 0.55 [95% CI 0.28-1.08], P = 0.083). CONCLUSION: Anti-TNF treatment is highly effective in refractory inflammatory uveitis. BD is associated with increased odds of response. IFX and ADA appear to be equivalent in terms of efficacy.

Life-Threatening Hypercalcemia Revealing Diffuse and Isolated Acute Sarcoid-Like Myositis: A New Entity? (A Case-Series).

Up to 50% patients with sarcoidosis display extra-pulmonary disease. However, initial and isolated (ie, without lung disease) acute muscular involvement associated with pseudo-malignant hypercalcemia is very uncommon. We report on 3 cases of life-threatening hypercalcemia revealing florid and isolated acute sarcoid-like myositis.All patients complained of fatigue, progressive general muscle weakness, and weight loss. Laboratory tests showed a severe life-threatening hypercalcemia (>3.4 mmol/L). Hypercalcemia was associated with increased serum level of 1,25-(OH)2 vitamin D and complicated with acute renal failure. One patient displayed acute pancreatitis due to hypercalcemia.In all cases, PET-scan, performed for malignancy screening, incidentally revealed an intense, diffuse, and isolated muscular fluorodeoxyglucose (FDG) uptake consistent with diffuse non-necrotizing giant cells granulomatous myositis demonstrated by muscle biopsy. Of note, creatine phosphokinase blood level was normal in all cases. No patients displayed the usual thoracic features of sarcoidosis.All patients were treated with high dose steroids and achieved rapid, complete, and sustained remission. A review of English and French publications in Medline revealed 5 similar published cases.Steroid-sensitive acute sarcoid-like myositis causing high calcitriol levels and life-threatening hypercalcemia should be recognized as a separate entity.

Dermatomyositis With or Without Anti-Melanoma Differentiation-Associated Gene 5 Antibodies: Common Interferon Signature but Distinct NOS2 Expression.

The anti-melanoma differentiation-associated gene 5 (MDA5) autoantibody is specifically associated with dermatomyositis (DM). Nevertheless, anti-MDA5(+)-patients experience characteristic symptoms distinct from classic DM, including severe signs of extramuscular involvement; however, the clinical signs of myopathy are mild or even absent. The morphological and immunological features are not yet described in adulthood. Data concerning the pathophysiology of anti-MDA5 DM are sparse; however, the importance of the interferon (IFN) type I pathway involved in DM has been shown. Our aim was to define morphological alterations of the skeletal muscle and the intrinsic immune response of anti-MDA5-positive DM patients. Immunohistological and RT-PCR analysis of muscle biopsy specimens from anti-MDA5 and classic DM were compared. Those with anti-MDA5 DM did not present the classic features of perifascicular fiber atrophy and major histocompatibility complex class I expression. They did not show significant signs of capillary loss; tubuloreticular formations were observed less frequently. Inflammation was focal, clustering around single vessels but significantly less intense. Expression of IFN-stimulated genes was up-regulated in anti-MDA5 DM; however, the IFN score was significantly lower. Characteristic features were observed in anti-MDA5 DM and not in classic DM patients. Only anti-MDA5 DM showed numerous nitric oxide synthase 2-positive muscle fibers with sarcoplasmic colocalization of markers of regeneration and cell stress. Anti-MDA5-positive patients demonstrate a morphological pattern distinct from classic DM.

Association of both Langerhans cell histiocytosis and Erdheim-Chester disease linked to the BRAFV600E mutation.

Histiocytoses are a group of heterogeneous diseases that mostly comprise Langerhans cell histiocytosis (LCH) and non-LCH. The association of LCH with non-LCH is exceptional. We report 23 patients with biopsy-proven LCH associated with Erdheim-Chester disease (ECD) (mixed histiocytosis) and discuss the significance of this association. We compare the clinical phenotypes of these patients with those of 56 patients with isolated LCH and 53 patients with isolated ECD. The average age at diagnosis was 43 years. ECD followed (n = 12) or was diagnosed simultaneously with (n = 11) but never preceded LCH. Although heterogeneous, the phenotype of patients with mixed histiocytosis was closer to that of isolated ECD than to that of isolated LCH (principal component analysis). LCH and ECD improved in response to interferon alpha-2a treatment in only 50% of patients (8 of 16). We found the BRAF(V600E) mutation in 11 (69%) of 16 LCH lesions and in 9 (82%) of 11 ECD lesions. Eight patients had mutations in both ECD and LCH biopsies. Our findings indicate that the association of LCH and ECD is not fortuitous and suggest a link between these diseases involving the BRAF(V600E) mutation.

Inflammatory myopathies with anti-Ku antibodies: a prognosis dependent on associated lung disease.

Anti-Ku antibodies have been reported in a wide spectrum of autoimmune diseases, sometimes in association with inflammatory myopathies (IM). We studied the clinical, laboratory, and muscle histologic features of all anti-Ku-positive patients detected in our hospital during the last 10 years, as well as their treatment and outcomes. Anti-Ku antibodies were found in 34 patients (0.46% of 20,600 sera positive for antinuclear antibodies), and complete data were available for 30 patients; 86.7% were female, mean age was 49 years (range, 20-73 yr). The most frequent clinical manifestations were arthralgia (77%) and Raynaud phenomenon (53%). Eleven (37%) patients had IM, 8 of them as part of an overlap syndrome defined as IM associated with connective autoimmune disease (5 systemic sclerosis [SSc], 2 Sjögren syndrome (SS), and 1 systemic lupus erythematosus [SLE]). Of 21 patients without IM, 19 had autoimmune diseases (including 6 SLE, 2 SSc, 2 SS, and 2 rheumatoid arthritis), 1 had bronchial neoplasia, and 1 had nephroangiosclerosis. Clinical features of the 9 patients with IM were myalgia (91%), proximal muscle weakness (89%), and dysphagia (36%). All had increased creatine kinase (median, 2210 U/L; range, 194-4073 U/L). Muscle biopsy showed necrosis, inflammation, and positive HLA class I immunostaining. Interstitial lung disease (ILD) was detected on computed tomography (CT) scan in 11 patients (37%) and was significantly more frequent in patients with IM (82% vs. 10.5%, p < 0.001). Fourteen (47%) patients required no immunosuppressive treatment or only a low corticosteroid dose (<15 mg/d, n = 3). A high dose of corticosteroids was more frequently administered in patients with IM (10/11 cases, 80% with associated ILD) than in patients without IM (4/19 cases, 0 with ILD). Complete muscle remission after steroids occurred in 73% of patients with IM. Lung disease was corticoresistant in 6 of 8 (75%) treated cases.Anti-Ku antibodies remain rarely detected, but their presence can be frequently associated with corticosensitive IM and severe, corticoresistant ILD.

A phase I trial of adeno-associated virus serotype 1-γ-sarcoglycan gene therapy for limb girdle muscular dystrophy type 2C.

γ-Sarcoglycanopathy or limb girdle muscular dystrophy type 2C is an untreatable disease caused by autosomal recessively inherited mutations of the γ-sarcoglycan gene. Nine non-ambulatory patients (two males, seven females, mean age 27 years; range 16-38 years) with del525T homozygous mutation of the γ-sarcoglycan gene and no γ-sarcoglycan immunostaining on muscle biopsy were divided into three equal groups to receive three escalating doses of an adeno-associated virus serotype 1 vector expressing the human γ-sarcoglycan gene under the control of the desmin promoter, by local injection into the extensor carpi radialis muscle. The first group received a single injection of 3 × 10(9) viral genomes in 100 µl, the second group received a single injection of 1.5 × 10(10) viral genomes in 100 µl, and the third group received three simultaneous 100-µl injections at the same site, delivering a total dose of 4.5 × 10(10) viral genomes. No serious adverse effects occurred during 6 months of follow-up. All nine patients became adeno-associated virus serotype 1 seropositive and one developed a cytotoxic response to the adeno-associated virus serotype 1 capsid. Thirty days later, immunohistochemical analysis of injected-muscle biopsy specimens showed γ-sarcoglycan expression in all three patients who received the highest dose (4.7-10.5% positively stained fibres), while real-time polymerase chain reaction detected γ-sarcoglycan messenger RNA. In one patient, γ-sarcoglycan protein was detected by western blot. For two other patients who received the low and intermediate doses, discrete levels of γ-sarcoglycan expression (<1% positively stained fibres) were also detectable. Expression of γ-sarcoglycan protein can be induced in patients with limb girdle muscular dystrophy type 2C by adeno-associated virus serotype 1 gene transfer, with no serious adverse effects.

Pulmonary involvement in Erdheim-Chester disease: a single-center study of thirty-four patients and a review of the literature.

OBJECTIVE: Erdheim-Chester disease (ECD) is a rare form of non-Langerhans' cell histiocytosis that may present with pulmonary involvement. We undertook the current study to evaluate the characteristic features of pulmonary involvement in ECD, in the largest single-center series of patients reported to date. METHODS: We performed a retrospective study of the characteristics of 34 consecutive patients with biopsy-proven ECD who were referred to the internal medicine department of Pitié-Salpêtrière Hospital between 1981 and November 2008. RESULTS: Data were obtained from 23 men and 11 women. The median age at the time of diagnosis was 53.7 years (range 16-73 years), and the median followup was 3.5 years (1.4-5.3 years). Eight patients (24%) had pulmonary symptoms. High-resolution computed tomography (HRCT) scans of the chest revealed involvement of lung parenchyma in 18 patients (53%) and of the pleura in 14 patients (41%). Bronchoalveolar lavage fluid analysis revealed the presence of an opalescent aspirate in all the patients studied. Treatment with corticosteroids and/or interferon-α (IFNα) resulted in a marked improvement of the pulmonary lesions in only a single patient. Comparison of the survival between patients with and those without pulmonary involvement yielded no significant difference between the groups (P = 0.82). CONCLUSION: Pulmonary involvement in ECD has been overlooked in previous studies. HRCT reveals typical lesions in most patients. There is no clear response of these lesions to corticosteroids and IFNα. The overall prognosis of the disease is poor, but pulmonary involvement does not appear to be a major prognostic factor in ECD.