Tocilizumab use in giant cell arteritis: comparing Pharmaceutical Benefits Scheme eligible and ineligible cases in South Australia.

Tocilizumab (TCZ) is increasingly used as a steroid-sparing agent in giant cell arteritis (GCA), but there are strict Pharmaceutical Benefits Scheme (PBS) restrictions for its use in Australia. Patients who do not meet the PBS criteria can obtain TCZ through public hospital individual patient use (IPU) schemes which may not be universally accessible. We compared patients receiving IPU-approved TCZ with patients receiving PBS-subsidised TCZ and found IPU approvals were granted mainly for visual loss, a serious complication of GCA, in patients who otherwise failed to meet PBS criteria. Further studies demonstrating that TCZ is comparatively more effective than prednisolone monotherapy, as well as cost-effective, are needed to substantiate the rationale for expanding PBS approval criteria.

Outcome predictors of immune-mediated necrotizing myopathy-a retrospective, multicentre study.

OBJECTIVES: Evidence-based treatment protocols are currently lacking for immune-mediated necrotizing myopathy (IMNM). In this multicentre retrospective study, we examined baseline clinical characteristics and treatment variables that may predict short-term outcomes of patients with IMNM. METHODS: Muscle biopsies from the John Hunter Hospital and the Royal Adelaide Hospital obtained between 2012 and 2019 were reviewed at a single laboratory at South Australia Pathology. All biopsies with histological features of IMNM were identified. Demographics of study subjects, clinical information and myositis-specific antibody status were recorded along with muscle strength, serum creatine kinase (CK) and treatment regimens at baseline and 3 and 6 months. Primary outcome measures were muscle strength and serum CK at 3 and 6 months. Mixed-effects regression models in a Bayesian framework were performed using the R statistical package. RESULTS: Female sex, older age, initial prednisone dose and i.v. methylprednisolone were associated with greater improvement in serum CK. In patients with moderate-severe disease at baseline, early IVIG was associated with greater improvement in hip flexor strength at 6 months. CONCLUSION: Early IVIG was associated with clinical improvement in the short-term follow-up in IMNM. Female sex, older age, initial oral prednisone dose and initial use of i.v. methylprednisolone were associated with better biochemical improvement.

Autoantibodies against four-and-a-half-LIM domain 1 (FHL1) in inflammatory myopathies: results from an Australian single-centre cohort.

OBJECTIVES: To determine the prevalence and associations of autoantibodies targeting a muscle-specific autoantigen, four-and-a-half-LIM-domain 1 (FHL1), in South Australian patients with histologically-confirmed idiopathic inflammatory myopathies (IIM) and in patients with SSc. MATERIAL AND METHODS: Sera from patients with IIM (n = 267) from the South Australian Myositis Database (SAMD), SSc (n = 174) from the Australian Scleroderma Cohort Study (ASCS) and healthy controls (HC, n = 100) were analysed for anti-FHL1 autoantibodies by Enzyme-Linked ImmunoSorbent Assay (ELISA). RESULTS: Autoantibodies to FHL1 were more frequent in patients with IIM (37/267, 13.8%) compared with SSc (12/174, 7%) (P < 0.02) and HC (2/100, 2%) (P < 0.001). The most common IIM subtypes among FHL1+ IIM patients were (32%) and IBM (2/37, 32%). No statistically significant differences in muscular or extra-muscular manifestations of IIM were found when comparing patients who were anti-FHL1+ with their anti-FHL1- counterparts. In 29/37 (78%) anti-FHL1+ patients, no myositis-specific autoantibodies (MSA) were present. In FHL1+ muscle biopsies, there was less frequent infiltration by CD45+ cells (P = 0.04). There was a trend for HLA alleles DRB1*07 and DRB1*15 to be more frequent in anti-FHL1+ compared with anti-FHL1- patients (9/25 vs 19/113, P = 0.09 and 8/25 vs 15/114, P = 0.09, respectively). CONCLUSIONS: We report a substantial prevalence (13.8%) of anti-FHL1 autoantibodies in a large cohort of patients with histologically confirmed IIM; 75% of these cases did not have a detectable myositis-specific autoantibody. Anti-FHL1 autoantibodies were also detected in a subgroup of patients with SSc (7%), indicating that anti-FHL1 autoantibodies may not be myositis-specific. The trend towards an HLA-DR association might indicate a specific immune response to the FHL1 protein.

Clinical Characteristics of Myositis Associated with Graft-Versus-Host Disease.

PURPOSE OF REVIEW: Recipients of allogeneic hematopoietic stem cell transplantation (HSCT) are at increased risk for inflammatory myositis; histological subsets reported include dermatomyositis, necrotising myopathy and chronic graft-versus-host disease (cGVHD)-related myositis. Though corticosteroids and various immunosuppressive therapies have been used, there is a lack of consensus guidelines dictating therapy. RECENT FINDINGS: Recent evidence suggests the fascia as a preferential target in cGVHD myositis, with conditioning regimens promoting fascial microtrauma. Positron emission tomography (PET) can be a useful diagnostic tool, and case reports suggest that the Bruton's tyrosine kinase inhibitor ibrutinib may have therapeutic potential. Emerging therapies include targeted B cell depletion with rituximab, and extracorporeal photophoresis. Clinicians need to be vigilant for the development of inflammatory myositis post-allogeneic HSCT as most patients respond to treatment. Advances in immunohistochemistry to determine the dominant cell type and cytokine profile may enable targeted and individualised therapies.

Inclusion-body myositis and primary Sjögren syndrome: mechanisms for shared etiologies.

Herein we report a case of sporadic inclusion-body myositis (sIBM) occurring at an unusually young age in a patient with primary Sjögren syndrome, and use the case to explore possible shared mechanisms for disease susceptibility. Possible factors may include the association of both conditions with the 8.1 ancestral haplotype; the presence of anti-cN1A antibodies, which, although considered specific for sIBM, are also seen in pSS; and the shared association with T-cell large granular lymphocyte leukemia (T-LGLL). Further evaluation of this patient did in fact reveal underlying T-LGLL and mechanisms by which T cells in sIBM may escape immune regulation and contribute to disease phenotype are explored. Despite myofiber infiltration with CD8-positive T cells in sIBM, and, although sIBM is traditionally considered treatment-refractory, we report a significant response to the anti-CD20 monoclonal antibody, rituximab, and discuss possible mechanisms by which this response may be mediated.

Biologic therapy in the idiopathic inflammatory myopathies.

The idiopathic inflammatory myopathies (IIM) are a group of autoimmune diseases resulting from inflammation of muscle and manifesting as weakness, though a range of extra-muscular manifestations are observed. These are often correlated closely with disease subtype and the presence of myositis-specific/myositis-associated antibodies. IIM are notoriously difficult to treat and often refractory to glucocorticoid therapy and synthetic immunosuppressants. Both the innate and adaptive immune systems are implicated in the pathogenesis of IIM. A growing understanding of the key cytokines as well as the cell-mediated and antibody effectors of disease has identified multiple potential targets for biologic therapy. The most widely used of these is B-cell depletion via rituximab though the tumour necrosis factor inhibitors and other biologic therapies used in diseases such as rheumatoid arthritis, systemic lupus erythematosus and multiple sclerosis have also been trialled. This review summarises the literature thus far on biologic therapy in IIM, highlighting both the significant trials that influence current treatment regimens and also the continuing need for further research to inform more effective therapies.

Radiographic patterns of muscle involvement in the idiopathic inflammatory myopathies.

INTRODUCTION: This study assesses the burden, distribution, and evolution of muscle inflammation and damage on MRI among subtypes of idiopathic inflammatory myopathy (IIM). METHODS: Musculoskeletal MRIs performed in 66 patients with IIM and 10 patients with non-IIM between 2009 and 2016 were retrospectively graded for muscle edema, fatty replacement (FR), and atrophy. RESULTS: Immune-mediated necrotizing myopathy (IMNM) patients had severe and extensive lower limb muscle edema, FR, and atrophy. The pelvic muscles and adductors were significantly more affected than in patients with dermatomyositis and polymyositis. Inclusion body myositis (IBM) was characterized by marked anterior thigh involvement, which stabilized or progressed at follow-up imaging. Atrophy and FR grades improved over time in some non-IBM IIM patients. DISCUSSION: Patients with IMNM and IBM have characteristic patterns of muscle MRI abnormalities that may allow them to be differentiated radiologically from other IIM subtypes. Muscle damage in non-IBM IIM may be reversible.

Prevalence of other connective tissue diseases in idiopathic inflammatory myopathies.

We sought to determine the prevalence of additional connective tissue diseases (CTDs) in patients with idiopathic inflammatory myopathies (IIM), and to study the muscle biopsy patterns in various clinico-serologic subsets of myositis. We undertook a retrospective cohort study of 648 patients with a histological diagnosis of IIM. The following was determined from the South Australian Myositis Database: presence of associated CTDs, histological details and presence of myositis-specific (MSA) or myositis-associated (MAA) antibodies. Among patients with IIM, a significantly greater proportion had systemic sclerosis 32/648 (4.9%) than mixed connective tissue disease (12/648, p = 0.003), primary Sjogren's syndrome (12/648, p = 0.003), systemic lupus erythematosus (10/648, p < 0.001) or rheumatoid arthritis (6/648, p = 0.0001). Polymyositis was the most common IIM diagnosis regardless of the presence or absence of CTD. MSA/MAA was more commonly detected in those with systemic sclerosis than those with IIM alone (OR 5.35, p < 0.005). The higher prevalence of SSc (compared with other CTDs) in IIM, together with the more frequent detection of autoantibodies in this group, suggests that these conditions may be linked.

Proton pump inhibitors are not associated with inflammatory myopathies: A case control study.

INTRODUCTION: A rare association of proton pump inhibitor (PPI) use with the development of inflammatory myopathies (IM) has been reported, but, unlike with statin medications, there is limited data supporting or refuting this observation. METHODS: A case-control study was conducted on patients with IM. Clinical information, medications, and demographics were recorded. Controls were matched 3:1 for age and gender. RESULTS: Two hundred twenty-one cases of IM were identified. No association of PPI use with IM was observed when compared with controls (odds ratio 1.04 [95% confidence interval 0.68-1.58]) and similar results were observed after adjusting for diabetes, cardiovascular disease, and statin exposure (adjusted odds ratio 1.084 [95% confidence interval 0.69-1.70]). There was no association of any histologic subtype of IM with PPI exposure. DISCUSSION: Our findings do not support an association of PPI exposure with IM. Co-prescription of PPI with other medications was not considered and could be further investigated with larger cohorts. Muscle Nerve 58:855-857, 2018.

Inflammatory myopathies after allogeneic stem cell transplantation.

Introduction,: Graft-versus-host disease (GVHD) is a recognized complication of allogeneic stem cell transplantation (allo-SCT) and may affect muscle. We investigated the incidence and subtypes of inflammatory myopathy (IM) in South Australian recipients of allo-SCT. METHODS: Recipients of allo-SCT from 2004 to 2014 at the Royal Adelaide Hospital were identified. Records were reviewed to identify patients with weakness, creatine kinase (CK) elevation, and muscle biopsy confirming IM. RESULTS: Weakness was present in 32 of 224 patients who received allo-SCT patients reviewed, and CK was raised in 7 of 20 patients with weakness. Six patients developed biopsy-confirmed IM; 3 patients had chronic GVHD-related myopathy, 2 had necrotizing myopathy, and 1 had dermatomyositis (DM) associated with anti-melanoma differentiation associated protein 5 (MDA5) antibodies. The incidence of IM was calculated to be 2 cases per thousand annually. DISCUSSION: Among recipients of allo-SCT, weakness is common, and the incidence of IM is increased. Histopathological diagnoses are varied, and we report findings of necrotizing myopathy and anti-MDA5-associated DM. Muscle Nerve 58:790-795, 2018.

Infections and vaccinations as possible triggers of inflammatory myopathies.

INTRODUCTION: The role of vaccinations and infections in triggering idiopathic inflammatory myopathies (IIM) has not been confirmed. METHODS: Among patients with histologically confirmed myositis, infections or vaccinations administered prior to myositis onset were determined. The characteristics of this group were compared with controls (myositis patients without prior infection or vaccination). RESULTS: The frequency of IIM with a prior vaccination was 20 of 206 (9.7%), infection was 29 of 206 (14%), and either vaccination or infection was 49 of 206 (23.8%). Dermatomyositis (DM) was more frequent among patients with preceding vaccination (P = 0.03) or prior infections (P = 0.02) than among controls. Antibodies to Ro52 were more frequent among patients with preceding vaccination than among controls (P = 0.002). DISCUSSION: Although causality is not shown, the occurrence of prior infection or vaccination in 24% of patients with IIM prompts further inquiry. The overrepresentation of DM in those with preceding vaccination and the possible role of antibodies to Ro52 in susceptibility to vaccine-induced myositis require confirmation. Muscle Nerve 56: 987-989, 2017.

The PTPN22 gene is associated with idiopathic inflammatory myopathy.

INTRODUCTION: The aim of this study was to determine whether a single-nucleotide polymorphism (SNP; 1858CT, R620W) in the protein tyrosine phosphatase N22 (PTPN22) gene confers susceptibility to idiopathic inflammatory myopathy (IIM) in South Australian patients with IIM. METHODS: Genotyping was performed on stored DNA from 199 patients with histologically confirmed polymyositis (PM), dermatomyositis (DM), and inclusion body myositis (IBM), and then compared with 455 matched controls. Associations with the 8.1 ancestral haplotype (AH), and myositis-specific (MSA) and myositis-associated (MAA) autoantibodies were investigated. RESULTS: The PTPN22 R620W minor allele frequency was increased in IIM patients (50 of 398, 12.6%) compared with controls (75 of 910, 8.2%) (odds ratio 1.6, 95% confidence interval 1.1-2.3, P = 0.016). In IIM patients, there was no association between the R620W minor allele and detection of any MSA/MAA (P = 0.70), nor any evidence of epistasis with the 8.1 AH (P = 0.69). CONCLUSIONS: The PTPN22 R620W minor allele is associated with susceptibility to IIM in SA patients, independent of the 8.1 AH. Muscle Nerve, 2016 Muscle Nerve 55: 270-273, 2017.

Use of intravenous immunoglobulin therapy for myositis: an audit in South Australian patients.

In South Australia, between 2000 and 2014, 57 patients with idiopathic inflammatory myositis (IIM) were treated with intravenous immunoglobulin (IVIg). We reviewed disease characteristics to determine predictors of response to therapy and IVIg dosing and duration to identify opportunities to rationalise IVIg use. Patients with dermatomyositis/polymyositis had a response rate of 77% and were more likely than inclusion body myositis to respond to therapy. Consideration should be given to the use of the lowest possible dose of IVIg and to the undertaking of trials of cessation of IVIg in patients with stable IIM.

Dense genotyping of immune-related loci in idiopathic inflammatory myopathies confirms HLA alleles as the strongest genetic risk factor and suggests different genetic background for major clinical subgroups.

OBJECTIVES: The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of rare autoimmune diseases characterised by muscle weakness and extramuscular manifestations such as skin rashes and interstitial lung disease. We genotyped 2566 IIM cases of Caucasian descent using the Immunochip; a custom array covering 186 established autoimmune susceptibility loci. The cohort was predominantly comprised of patients with dermatomyositis (DM, n=879), juvenile DM (JDM, n=481), polymyositis (PM, n=931) and inclusion body myositis (n=252) collected from 14 countries through the Myositis Genetics Consortium. RESULTS: The human leucocyte antigen (HLA) and PTPN22 regions reached genome-wide significance (p<5×10(-8)). Nine regions were associated at a significance level of p<2.25×10(-5), including UBE2L3, CD28 and TRAF6, with evidence of independent effects within STAT4. Analysis of clinical subgroups revealed distinct differences between PM, and DM and JDM. PTPN22 was associated at genome-wide significance with PM, but not DM and JDM, suggesting this effect is driven by PM. Additional suggestive associations including IL18R1 and RGS1 in PM and GSDMB in DM were identified. HLA imputation confirmed that alleles HLA-DRB1*03:01 and HLA-B*08:01 of the 8.1 ancestral haplotype (8.1AH) are most strongly associated with IIM, and provides evidence that amino acids within the HLA, such as HLA-DQB1 position 57 in DM, may explain part of the risk in this locus. Associations with alleles outside the 8.1AH reveal differences between PM, DM and JDM. CONCLUSIONS: This work represents the largest IIM genetic study to date, reveals new insights into the genetic architecture of these rare diseases and suggests different predominating pathophysiology in different clinical subgroups.

Effects of rituximab in connective tissue disorders related interstitial lung disease.

OBJECTIVES: Interstitial lung disease (ILD) is a key prognostic factor in connective tissue disorders (CTDs). The aim of our study was to assess the changes in pulmonary functional tests (PFTs) in various CTDs, including anti-synthetase syndrome (SYN), systemic sclerosis (SSc) and mixed connective tissue disorder (MCTD), following the use of rituximab therapy. METHODS: A multicentre retrospective analysis of patients with ILD secondary to SYN (n=15), MCTD (n=6) and SSc (n=23). PFTs were performed at baseline and at 1 and 2 years of follow-up. The primary outcome was the change in forced vital capacity (FVC) at 1 year. RESULTS: In the SYN population, median FVC changed from 53.0% (42.0-90.0) at baseline to 51.4% (45.6-85.0) at 1 year and 63.0 (50-88) (p=0.6) at 2 years (p=0.14). In SSc, FVC changed from 81.0% (66.0-104.0) at baseline to 89.0% (65.0-113.0) at 1 year (p=0.1) and 74.5 (50-91) at 2 years (p=0.07). In the MCTD population, FVC changed from 64.5% (63.0-68.0) at baseline to 63.0% (59.0-71.0) at 1 year (p=0.6) and 61 (59-71) after 2 years (p=0.8). DLCO showed a trend for improvement in the SYN population (p=0.06 at 1 year and 0.2 at years) while changes remain non-significant in the SSc and MCTD patients. In SYN patients, the percentage of responders at 1 year for FVC (33.3%) was greater than in SSc (9.5%) (p=0.07) and MCTD (17%) (p=0.45). RTX showed a satisfactory safety profile. CONCLUSIONS: A trend of improvement of PFTs was observed in SYN patients although not reaching significance, while SSc and MCTD patients were stabilised.

Clinical and genetic associations of autoantibodies to 3-hydroxy-3-methyl-glutaryl-coenzyme a reductase in patients with immune-mediated myositis and necrotizing myopathy.

INTRODUCTION: Inhibition of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) with statins may trigger idiopathic inflammatory myositis (IIM) or immune-mediated necrotizing myopathy (IMNM). Anti-HMGCR antibodies have been detected in patients with IIM/IMNM. We aimed to determine the associations of anti-HMGCR in IIM/IMNM. METHODS: Anti-HMGCR antibodies were detected by ELISA in sera from patients with IIM/IMNM. RESULTS: Anti-HMGCR antibodies were detected in 19 of 207 patients with IIM/IMNM, and there was a trend toward an association with male gender (P = 0.079). Anti-HMGCR antibodies were associated strongly with statin exposure (OR = 39, P = 0.0001) and HLA-DRB1*11 (OR = 50, P < 0.0001). The highest risk for development of anti-HMGCR antibodies was among HLA-DR11 carriers exposed to statins. Univariate analysis showed a strong association of anti-HMGCR antibodies with diabetes mellitus (P = 0.008), which was not confirmed by multiple regression. Among anti-HMGCR(+) patients there was a trend toward increased malignancy (P = 0.15). CONCLUSIONS: Anti-HMGCR antibodies are seen in all subtypes of IIM and IMNM and are associated strongly with statin use and HLA-DR11. Muscle Nerve 52: 196-203, 2015.