Anti-hydroxy-3-methylglutaryl-coenzyme A reductase (anti-HMGCR) antibody in necrotizing myopathy: treatment outcomes, cancer risk, and role of autoantibody level.

Objective: To evaluate clinical associations of anti-hydroxy-3-methylglutaryl-coenzyme A reductase (anti-HMGCR) antibody (Ab) and statin exposure in necrotizing myopathy (NM) patients. Methods: NM without a known myositis-specific autoantibody (MSA) was ascertained from a large single-centre myositis database between 1985 and 2012. A comparison NM cohort included 32 anti-SRP+ autoantibody patients, and other control groups included 74 non-NM myositis patients and 21 non-myositis controls. Sera from all cases and controls were tested using a validated anti-HMGCR enzyme-linked immunosorbent assay. Clinical features including statin use and anti-HMGCR Ab status were compared between cases and controls. Results: Of the 256 NM muscle biopsies reviewed, only 48 subjects with available sera were identified as traditional MSA-negative NM. Anti-HMGCR positivity was significantly (p < 0.001) associated with MSA-negative NM [48% (23/48)] compared to all of the myositis and non-myositis controls [5% (6/127)]. Most anti-HMGCR Ab-positive NM patients had high titres of anti-HMGCR (83%) and a history of statin exposure (78%), along with severe muscle weakness, high creatine kinase (CK) levels (90% ≥ 5000 IU/L), a paucity of other organ manifestations, and the need for immunosuppression with prednisone and methotrexate, but generally favourable outcomes. Anti-HMGCR serum levels were associated with baseline CK levels but not muscle weakness. Conclusion: HMGCR Ab-positive NM patients are associated with statin exposure, have severe muscle weakness and high CK at presentation, lack other organ manifestations, and generally have favourable outcomes from immunosuppression. Anti-HMGCR Abs should be assessed in MSA-negative NM patients, particularly those with a history of statin exposure.

Update on the pharmacological treatment of adult myositis.

The management of patients with idiopathic inflammatory myopathy (IIM) remains a challenge given the systemic features beyond active myositis. That is, recognizing the inflammatory arthropathy, varying dermatomyositis rashes, and overt and occult features of interstitial lung disease in addition to myositis adds to the complexity of diagnosis and treatment of IIM. However, clinicians now have available many more immunosuppressive drugs as well as biologic agents for use in patients with myositis and other autoimmune diseases. Here, the use of these agents is reviewed and support based on available published literature is provided even though many studies have been small and results somewhat anecdotal. Glucocorticoids remain the initial treatment of choice in most instances and methotrexate and azathioprine are often used early in the treatment course. These agents are followed by other immunosuppressive drugs, for example mycophenolate mofetil, tacrolimus, cyclosporine and cyclophosphamide, some of which are used alone while combinations of these agents also provide an effective option. There is more rationale for the use of biologic agents such as rituximab from a mechanistic perspective and, given the incorporation of validated core set measures in assessing myositis patients, we can look forward to better designed clinical trials in the future.

Autoantibodies to a 140-kd protein in juvenile dermatomyositis are associated with calcinosis.

OBJECTIVE: The identification of novel autoantibodies in juvenile dermatomyositis (DM) may have etiologic and clinical implications. The aim of this study was to describe autoantibodies to a 140-kd protein in children recruited to the Juvenile DM National Registry and Repository for UK and Ireland. METHODS: Clinical data and sera were collected from children with juvenile myositis. Sera that recognized a 140-kd protein by immunoprecipitation were identified. The identity of the p140 autoantigen was investigated by immunoprecipitation/immunodepletion, using commercial monoclonal antibodies to NXP-2, reference anti-p140, and anti-p155/140, the other autoantibody recently described in juvenile DM. DNA samples from 100 Caucasian children with myositis were genotyped for HLA class II haplotype associations and compared with those from 864 randomly selected UK Caucasian control subjects. RESULTS: Sera from 37 (23%) of 162 patients with juvenile myositis were positive for anti-p140 autoantibodies, which were detected exclusively in patients with juvenile DM and not in patients with juvenile DM-overlap syndrome or control subjects. No anti-p140 antibody-positive patients were positive for other recognized autoantibodies. Immunodepletion suggested that the identity of p140 was consistent with NXP-2 (the previously identified MJ autoantigen). In children with anti-p140 antibodies, the association with calcinosis was significant compared with the rest of the cohort (corrected P < 0.005, odds ratio 7.0, 95% confidence interval 3.0-16.1). The clinical features of patients with anti-p140 autoantibodies were different from those of children with anti-p155/140 autoantibodies. The presence of HLA-DRB1*08 was a possible risk factor for anti-p140 autoantibody positivity. CONCLUSION: This study has established that anti-p140 autoantibodies represent a major autoantibody subset in juvenile DM. This specificity may identify a further immunogenetic and clinical phenotype within the juvenile myositis spectrum that includes an association with calcinosis.

The protein tyrosine phosphatase N22 gene is associated with juvenile and adult idiopathic inflammatory myopathy independent of the HLA 8.1 haplotype in British Caucasian patients.

OBJECTIVE: To examine single-nucleotide polymorphisms (SNPs) of the protein tyrosine phosphatase N22 gene (PTPN22) and to study the relationship between PTPN22 and the HLA region in patients with idiopathic inflammatory myopathies (IIMs). METHODS: PTPN22 SNPs were assessed in a large, cross-sectional, case-control study from the UK involving patients with adult or juvenile IIM, comprising patients with polymyositis (PM) (n=114), dermatomyositis (DM) (n=102), myositis associated with another connective tissue disease (myositis-CTD overlap syndrome) (n=64), or juvenile DM (n=101), in comparison with 748 control subjects. Seventeen PTPN22 SNPs were genotyped using the Sequenom MassArray iPLEX platform. Serotyping for myositis-specific/myositis-associated autoantibodies (MSAs/MAAs) was performed by radioimmunoprecipitation. RESULTS: A significant association was noted between the R620W variant (rs2476601) and IIM (corrected P [Pcorr]=0.0009 versus controls), and specifically with the clinical subgroup of PM (Pcorr=0.003 versus controls). A weaker association was noted with juvenile DM (Pcorr=0.009 versus controls). No significant associations were noted after stratification by serologic subgroups. The association with the R620W variant was independent of alleles forming the HLA 8.1 haplotype. No other PTPN22 SNPs were associated with IIM. The PTPN22 haplotype containing the R620W T allele was the only haplotype significantly associated with IIM. CONCLUSION: The R620W variant is a significant risk factor for IIM, independent of the HLA 8.1 haplotype. Unlike that in the HLA region, risk is not increased in individuals possessing MSAs/MAAs. These results are further evidence that the PTPN22 gene confers autoimmune susceptibility.

Tumour necrosis factor-alpha single nucleotide polymorphisms are not independent of HLA class I in UK Caucasians with adult onset idiopathic inflammatory myopathies.

OBJECTIVE: To investigate haplotype tagging single nucleotide polymorphisms (SNPs) in the tumour necrosis factor alpha (TNF-alpha) gene, in UK Caucasian idiopathic inflammatory myopathy (IIM) patients. METHODS: A cross-sectional, case-control study of four TNF-alpha SNPs was undertaken, comparing cases of polymyositis (PM) (n = 121), dermatomyositis (DM) (n = 109) and myositis overlapping with other connective tissue diseases (CTD-overlap) (n = 73) with normal subjects (n = 177). Subgroup analyses were undertaken after stratifying for myositis specific/associated antibodies. RESULTS: The TNF-308A allele demonstrated a strong association with each myositis disease subgroup vs controls [PM, odds ratio (OR) 2.8, 95% confidence interval 1.9-4.3; DM, OR 2.5, 1.6-3.8; CTD-overlap, OR 3.3, 2.1-5.1]. The TNF-308GA/AA genotype frequency was significantly increased vs controls (PM, OR 3.7, 2.1-6.3; DM, OR 3.2, 1.8-5.5; CTD-overlap, OR 5.0, 2.6-9.6) suggesting a dominant model. The association was strongest in patients possessing anti-aminoacyl transfer RNA synthetase (anti-synthetase) (OR 5.1, 3.3-8.0) or -PM-Scl (OR 5.0, 2.7-8.9) antibodies. The -1031T allele was also a significant risk factor in DM (OR 2.2, 1.4-3.6), anti-synthetase (OR 2.9, 1.6-5.3) and -PM-Scl (OR 5.6, 1.9-6.4) antibody positive patients. The TNF-308A association was lost after adjusting for HLA-B*08, but remained independent of HLA-DQB1*02 (both are alleles forming part of the common ancestral haplotype). The HLA-B*08/TNF-308A/DRB1*03/DQA1*05/DQB1*02 haplotype was a risk factor in all myositis subgroups vs controls (OR 3.0, 1.8-5.3). CONCLUSIONS: TNF-308A and -1031T alleles are significant risk factors in the IIMs. In the IIMs, the TNF-308A allele is part of the common ancestral haplotype, but is not independent of HLA-B*08.

Monocyte chemotactic protein-1 single nucleotide polymorphisms do not confer susceptibility for the development of adult onset polymyositis/dermatomyositis in UK Caucasians.

OBJECTIVES: Polymyositis (PM) and dermatomyositis (DM) form part of the idiopathic inflammatory myopathies (IIMs). The chemokine monocyte chemotactic protein-1 (MCP-1) is expressed at sites of the T cell inflammatory response in the IIMs. We thus investigate whether genetic markers in the MCP-1 gene confer disease susceptibility for the development of PM and DM. METHODS: DNA samples were analysed from a group of 195 UK Caucasian IIM patients, comprising 103 PM and 92 DM. Their results were compared with those of 162 ethnically matched controls. The polymorphic positions of three single nucleotide polymorphisms (SNPs) and one insertion-deletion sequence within regions coding for MCP-1 were tested. The SNPs examined were located in intron 1 (rs2857657, C/G), exon 2 (rs4586, A/G) and the 3 ' untranslated region (rs13900, C/T). The insertion-deletion sequence was located in intron 1 (rs3917887, AGCTCCTCCTTCTC/-). Each SNP was tested for Hardy-Weinberg equilibrium and allelic/genotypic associations. Haplotype frequencies were estimated using the Expectation/Maximization algorithm. RESULTS: There was strong linkage disequilibrium present between three out of these four markers. The majority of controls were in Hardy Weinberg equilibrium. No allelic, genotypic or haplotypic associations were detected when comparing PM or DM cases to controls, or when PM and DM were compared with each other. CONCLUSIONS: Genetic markers in the MCP-1 gene do not demonstrate significant genetic associations with the IIMs, and do not discriminate PM from DM in a UK Caucasian population.

Current approach to the treatment of polymyositis and dermatomyositis.

Although corticosteroids remain the mainstay of treatment for the inflammatory myopathies, their use is complicated by many side effects. Other immunosuppressive agents, alone or in combination, are being increasingly used for patients with other severe disease or treatment-related complications. Pulmonary disease remains a serious source of morbidity and mortality in myositis patients. Cyclophosphamide, cyclosporine, and tacrolimus are efficacious in patients with interstitial lung disease. Intravenous immunoglobulin is not only effective for the cutaneous complications of dermatomyositis but has been helpful in other extramuscular manifestations.

Myositis-specific and -associated autoantibodies: a review from the clinical perspective.

Twenty-five percent to 50% of patients with polymyositis (PM) and dermatomyositis (DM) have autoantibodies that are specific for or associated with the presence of myositis. Because of a relatively low sensitivity for the diagnosis of PM or DM, these autoantibodies are inadequate as a screening test for PM or DM in patients with suspected inflammatory myopathy. However, they may be used to support the diagnosis of myositis, and they help exclude the diagnosis of inclusion body myositis in which autoantibodies are infrequent. In addition, these antibodies are associated with homogeneous syndromes with the following reproducible clinical features and prognosis: (I) the antisynthetases generally occur with moderately severe myositis, often in association with interstitial lung disease. Raynaud's phenomenon, and arthropathy; (2) anti-SRP is a marker of severe PM with associated cardiac disease and high mortality; (3) anti-Mi-2 occurs in generally corticosteroid-responsive DM associated with a potentially severe rash; and (4) the myositis-associated autoantibodies anti-PM-ScI and anti-Ku portend a moderately favorable prognosis. Anti-PH-Scl occurs in systemic sclerosis, often in association with arthropathy and Raynaud's syndrome. Anti-Ku occurs in systemic sclerosis and other connective tissue diseases with or without myositis. Thus, both myositis-specific and -associated antibodies have clinical use in the diagnosis of PM and DM and are predictive of certain clinical syndromes and responses to treatment.

Dermatomyositis with erosive arthropathy: association with the anti-PL-7 antibody.

We describe a patient with dermatomyositis and inflammatory polyarthritis with erosive wrist arthropathy who was found to have the anti-PL-7 autoantibody directed against threonyl-tRNA synthetase.

Sensory Neuropathy With Sjögren's Syndrome, Thymoma, and Hypogammaglobulinemia.

We report a 63-year-old woman with common variable immunodeficiency (CVID) and an indolent distal sensory neuropathy. Despite having negative serologic tests for Sjögren's syndrome, evaluation of the neuropathy led to a new diagnosis of Sjögren's syndrome based on the presence of sicca symptoms, an abnormal Schirmer's test, and histologic evidence of sialadenitis. In addition, a thymoma was discovered. We conclude that the occurrence of thymoma, CVID, and Sjogren's syndrome reflect a state of systemic autoimmune dysregulation in this patient. We also reiterate the diagnostic importance of salivary gland biopsy in patients with sicca symptoms and sensory neuropathy.

Beta-adrenergic regulation of constitutive nitric oxide synthase in cardiac myocytes.

Nitric oxide (NO) has been implicated in endogenous control of myocardial contractility. However, NO release has not yet been demonstrated in cardiac myocytes. Accordingly, endogenous NO production was measured with a porphyrinic microsensor positioned on the surface of individual neonatal or adult rat ventricular myocytes (n > 6 neonatal and adult cells per experiment). In beating neonatal myocytes, there was no detectable spontaneous NO release with each contraction. However, norepinephrine (NE; 0.25-1 microM) elicited transient NO release from beating neonatal (149 +/- 11 to 767 +/- 83 nM NO) and noncontracting adult (157 +/- 13 to 791 +/- 89 nM NO) cells. NO was released by adrenergic agonists with the following rank order of potency: isoproterenol (beta1beta2) > NE (alpha/beta1) > dobutamine (beta1) approximately epinephrine (alpha/beta1beta2) > tertbutylene (beta2); NO was not released by phenylephrine (alpha). NE-evoked NO release was reversibly blocked by N(G)-monomethyl-L-arginine, trifluoperazine, guanosine 5'-O-(2-thiodiphosphate), and nifedipine but was enhanced by 3-isobutyl-1-methylxanthine (0.5 mM = 14.5 +/- 1.6%) and BAY K 8644 (10 microM = 11.9 +/- 1%). NO was also released by A-23187 (10 microM = 884 +/- 88 nM NO), guanosine 5'-O-(3-thiotriphosphate) (1 microM = 334 +/- 56 nM NO), and dibutyryl adenosine 3',5'-cyclic monophosphate (10-100 microM = 35 +/- 9 to 284 +/- 49 nM NO) but not by ATP, bradykinin, carbachol, 8-bromoguanosine 3',5'-cyclic monophosphate, or shear stress. This first functional demonstration of a constitutive NO synthase in cardiac myocytes suggests its regulation by a beta-adrenergic signaling pathway and may provide a novel mechanism for the coronary artery vasodilatation and enhanced diastolic relaxation observed with adrenergic stimulation.

Percutaneous needle muscle biopsy in the evaluation of patients with suspected inflammatory myopathy.

OBJECTIVE: To determine the usefulness of a unique method of percutaneous needle muscle biopsy (NMB) in patients with suspected idiopathic inflammatory myopathy (IIM). METHODS: The yield of percutaneous NMB was studied in 55 patients who were found to have a combination of clinical, laboratory, or electromyographic features of IIM. RESULTS: A diagnosis of IIM was confirmed histopathologically in 29 patients (53%), other specific myopathies were found in 5 (9%), nonspecific myopathic changes were present in 11 (20%), and a neurogenic process was diagnosed in 3 (5%). Nonspecific changes or no abnormalities were present in 7 patients (13%). Followup of the 18 patients with nonspecific histopathologic findings disclosed that only 3 had a subsequent disease course compatible with IIM. CONCLUSION: Percutaneous NMB is a safe, convenient, and relatively inexpensive method of muscle biopsy, with a high diagnostic yield for the pathologic confirmation of IIM. It should be considered as a primary method of acquiring muscle for histopathologic examination in the evaluation of suspected IIM.

Incidence of systemic sclerosis in Allegheny County, Pennsylvania. A twenty-year study of hospital-diagnosed cases, 1963-1982.

OBJECTIVE: To determine the incidence of hospital-diagnosed systemic sclerosis (SSc) among residents of Pittsburgh and Allegheny County, PA, from 1963 through 1982. METHODS: Medical records from all Allegheny County hospitals were searched using International Classification of Diseases codes for patients diagnosed with SSc. Each case was reviewed and verified by a physician, according to specified criteria. Age-adjusted incidence rates were computed for race and sex, and results were expressed as new cases per million population per year, with the 1970 Allegheny County population serving as the standard. RESULTS: Four hundred forty-four cases of SSc were identified during this 20-year survey, for a total annual incidence of 13.9 per million population. Overall, the incidence rate doubled during 1973-1982 compared with the first time interval of the study, with the greatest increase occurring in women. Among the younger population (ages 15-24), black women had the highest incidence of SSc (21.2 per million population). Overall, the female-to-male incidence ratio was 3:1, and was slightly higher (3.4:1) during the childbearing years (ages 15-44). Men under age 35 and children infrequently developed SSc. CONCLUSION: The incidence of SSc reported in this study increased with time. Although this trend was most likely due to improved detection and medical record techniques, the incidence rate stability in men compared with women suggests that there may have been a true increase in the incidence of SSc in this population, particularly in women.

Cytokines and nitric oxide synthase inhibitor as mediators of adrenergic refractoriness in cardiac myocytes.

We have previously proposed that pro-inflammatory cytokines and nitric oxide (NO) contributed to reversible myocardial depression in patients with sepsis and congestive heart failure. Sepsis and heart failure are also associated with refractoriness to beta-adrenoceptor agonists. Therefore, the chronotropic effects of cytokines and the NO synthase inhibitor, NG-methyl-L-arginine (NMA), on beta-adrenoceptor stimulation of neonatal cardiac myocytes were studied. Tumor necrosis factor alpha, interleukin-1 beta and interleukin-6 but not interleukin-4 or interleukin-5 significantly enhanced spontaneous beating rates compared to untreated myocytes in serum-free media for 48 h (P < 0.01; n = 12 for each). NMA also significantly enhanced spontaneous beating rates (P < 0.01; n = 12 for each). Only interleukin-1 beta treatment resulted in significant nitrite production, immunohistochemical staining for inducible nitric oxide synthase and detection of inducible NO synthase messenger RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). However, tumor necrosis factor alpha, interleukin-1 beta, interleukin-6, and NMA each completely blocked the positive chronotropic effects of the beta-adrenoceptor agonist, isoproterenol (P < 0.01; n = 12 for each). These findings are most consistent with an inducible NO synthase-independent effect of cytokines and NMA on the chronotropic responses of neonatal cardiac myocytes to beta-adrenoceptor stimulation. This effect of cytokines and NMA on adrenergic signaling may involve a myocardial constitutive NO synthase or an NO-independent mechanism.

Classification criteria for the idiopathic inflammatory myopathies.

Inasmuch as the clinical features of the idiopathic inflammatory myopathies are not easily differentiated from those of other similar rheumatic and neurologic conditions, diagnosis is often difficult. Various classification criteria for polymyositis and dermatomyositis have been suggested by a number of investigators. The most commonly accepted and used criteria include symmetric proximal muscle weakness, serum elevations of muscle enzymes, the classic electromyographic and muscle biopsy findings of inflammatory myopathy, and the typical skin rash of dermatomyositis. Although these criteria are clinically useful, they can result in misdiagnoses and inappropriate therapies. They also result in heterogeneous patient groups being selected for clinical and laboratory studies. Furthermore, they do not include recent findings related to the myositis-specific autoantibodies and magnetic resonance imaging of muscle that have been found to be important adjuncts in assessing patients with muscle weakness or elevations of muscle enzymes. A modification to the Bohan and Peter criteria is proposed to include myositis-specific autoantibodies and magnetic resonance imaging. This proposal could initiate productive discussions and investigations of the sensitivity and specificity of new classification criteria for myositis and could ultimately enhance our treatment capabilities.