Clinical and immunogenetic features of patients with autoantibodies to asparaginyl-transfer RNA synthetase

OBJECTIVE: We have previously described anti-KS autoantibodies and provided evidence that they are directed against asparaginyl-transfer RNA (tRNA) synthetase (AsnRS). The aim of the present study was to identify patients with anti-AsnRS autoantibodies and elucidate the clinical significance of this sixth antisynthetase antibody. In particular, we studied whether it was associated with the syndrome of myositis (polymyositis or dermatomyositis [DM]), interstitial lung disease (ILD), arthritis, and other features that had been previously associated with the 5 other anti-aminoacyl-tRNA synthetase autoantibodies. METHODS: More than 2,500 sera from patients with connective tissue disease (including myositis and ILD) and controls were examined for anti-AsnRS autoantibodies by immunoprecipitation (IP). Positive and control sera were tested for the ability to inhibit AsnRS by preincubation of the enzyme source with the serum. The HLA class II (DRB1, DQA1, DQB1, DPB1) alleles were identified from restriction fragment length polymorphism of polymerase chain reaction-amplified genomic DNA. RESULTS: Anti-AsnRS antibodies were identified in the sera of 8 patients (5 Japanese, 1 American, 1 German, and 1 Korean) by IP of the same distinctive set of tRNA and protein that differed from those precipitated by the other 5 antisynthetases, and these antibodies showed specific inhibition of AsnRS activity. Two of these patients had DM, but 7 of 8 (88%) had ILD. Four patients (50%) had arthritis, and 1 had Raynaud's phenomenon. This antisynthetase was very rare among myositis patients (present in 0% of Japanese myositis patients), but it was found in 3% of Japanese ILD patients. Thus, most patients with anti-AsnRS had chronic ILD with or without features of connective tissue disease. Interestingly, all 4 Japanese patients tested had DR2 (DRB1*1501/1502), compared with 33% of healthy controls. CONCLUSION: These results indicate that anti-AsnRS autoantibodies, like anti-alanyl-tRNA synthetase autoantibodies, have a stronger association with ILD than with myositis and may be associated with the DR2 phenotype.     

Clinical heterogeneity and prognostic features of South Australian patients with anti‐synthetase autoantibodies

Aim: To determine the clinical, serological and prognostic features of patients with autoantibodies against three aminoacyl‐transfer RNA synthetases (ARS), namely Jo‐1 (histidyl‐tRNA synthetase), PL‐7 (threonyl‐tRNA synthetase) and PL‐12 (alanyl‐tRNA synthetase) in South Australia. Methods: Patients with autoantibodies against ARS detected by line immunoassay (anti‐Jo1, anti‐PL7, anti‐PL12) or enzyme‐linked immunosorbent assay (anti‐Jo1) were identified from existing laboratory databases for the period 1994–2009. Demographic, clinical and serological data were obtained by retrospective review of patients' medical records and laboratory databases. Results: Forty‐two patients with autoantibodies were identified (anti‐Jo1 = 37, anti‐PL7 = 4, anti‐PL12 = 1). Females were more commonly affected than males (M : F = 12:30). Twenty‐one patients had polymyositis (anti‐Jo1 = 17, anti‐PL7 = 4), seven dermatomyositis (anti‐Jo1 = 6, anti‐PL12 = 1), 10 overlap syndrome (anti‐Jo1 = 10; lupus = 4, scleroderma = 3, Sjögren's syndrome = 2 and rheumatoid arthritis = 2) and four had interstitial lung disease (ILD) only (anti‐Jo1 = 4). ILD was present in 69%, polyarthritis in 59% and positive anti‐nuclear antibody (ANA) in 43% of patients. Concurrence of autoantibodies against Ro‐52 with Jo‐1 was seen in 12 patients. The mean follow‐up period was 8.3 years (95% CI 5.8–10.8) with 12 deaths. Poor prognostic indicators were age of onset >60 years (P= 0.001), cancer (P= 0.002), negative ANA (P= 0.006) and negative autoantibodies to extractable nuclear antigens (P= 0.02). Conclusion: Patients with autoantibodies against ARS present with varied clinical features and occasionally with isolated lung involvement (amyopathic ILD). Older age of onset, malignancy and negative immunologic tests are predictors of poor prognosis. Concurrence of autoantibodies against Jo‐1 and Ro‐52 may reflect a coupling effect during generation of autoimmunity.     

The clinical and immunogenetic features of patients with autoantibodies to the nucleolar antigen PM-Scl.

The clinical and laboratory features of 32 patients with anti-PM-Scl were studied. Patients with this rare autoantibody suffered from a homogenous overlap connective tissue disease defined by Raynaud phenomenon (32/32), features of scleroderma (31/32), arthritis (31/32, erosive in 9/32), myositis (28/32), lung restriction (25/32), calcinosis (15/32), and sicca (11/32). Significant renal and neurologic involvement was uncommon. All patients examined (22/22) had HLA-DR3, and 50% of these patients were homozygous. Our patients responded favorably to moderate immunosuppression and, with therapy, the disease generally has a good prognosis; over 50% of our series (17/32) remained well on minimal or no immunosuppression after a median follow-up of 8 years.     

Autoantibodies to glycyl–transfer RNA synthetase in myositis. Association with dermatomyositis and immunologic heterogeneity

Objective. To elucidate the clinical significance and immunologic heterogeneity of anti–glycyl–transfer RNA (tRNA) synthetase antibodies in polymyositis/dermatomyositis (PM/DM). Methods. Sera from 345 patients with rheumatic diseases, including 91 with myositis, were examined using immunoprecipitation assays. Autoantibodies to aminoacyl-tRNA synthetases were further analyzed with 2-dimensional RNA fractionation and via inhibition of in vitro aminoacylation. Results. Serum from 1 patient with DM and interstitial lung disease immunoprecipitated glycyl-tRNA synthetase along with only 1 of 4 associated tRNAs, in comparison with control anti–glycyl-tRNA synthetase antibodies, which bound the enzyme along with all 4 associated tRNAs. Immunoblotting findings and a lack of in vitro inhibition aminoacylation of tRNA^gly by serum from this patient also suggested differences between the epitope specificity of this serum and that of other sera with anti–glycyl-tRNA synthetase antibodies. Conclusion. This identification of antibodies to glycyl-tRNA synthetase from a patient with DM underscores the association of this specificity with the disease. The finding that these antibodies bound an epitope outside the active site of the synthetase enzyme, in contrast to most anti–aminoacyl-tRNA synthetases, emphasizes the immunologic heterogeneity of these autoantibodies.     

Novel conformation of histidyl–transfer RNA synthetase in the lung

Objective

We previously proposed that novel expression and/or conformation of autoantigens in the target tissue may play a role in generating phenotype‐specific immune responses. The strong association of autoantibodies to histidyl–transfer RNA synthetase (HisRS, Jo‐1) with interstitial lung disease in patients with myositis led us to study HisRS expression and conformation in the lung.

Methods

Normal human tissue specimens were probed with a novel anti‐HisRS antibody recognizing its granzyme B–cleavable conformation by immunoblotting and immunohistochemistry. The HisRS granzyme B site was mapped using site‐directed mutagenesis, and its relationship to the antibody recognition domain was evaluated in tandem immunoprecipitation/granzyme B cleavage studies.

Results

The HisRS α‐helical coiled‐coil N‐terminal domain recognized by autoantibodies is bounded by a granzyme B cleavage site. In immunoprecipitation studies with patient sera, HisRS was found to exist in 2 conformations, defined by sensitivity to cleavage by granzyme B and modification by autoantibody binding. Despite similar global expression of HisRS in different tissue, expression of its granzyme B–cleavable form was enriched in the lung and localized to the alveolar epithelium.

Conclusion

A proteolytically sensitive conformation of HisRS exists in the lung, the target tissue associated with this autoantibody response. We thus propose that autoimmunity to HisRS is initiated and propagated in the lung.

     

Clinical and serological features of 35 patients with anti-Ki autoantibodies

The objective of this study was to analyse clinical and serological associations of anti-Ki antibodies. Thirty-five patients with anti-Ki antibodies, detected by CIE, selected from laboratory routine, were studied. All patients were affected by autoimmune diseases: SLE and pSS were the most frequent diagnoses. The cohort was constituted by 27 female and eight males. Main clinical features were skin involvement (60%), xerophtalmia (48.6%), Raynaud's phenomenon (43%), photosensitivity (34%), xerostomia (31.4%). CNS involvement was present in four (11.4%) and renal disease in seven cases (20%). ANA, anti-dsDNA and RF were detected in 100%, 60% and 34.5%. In SLE, anti-Ki was detected in 6% of cases, more frequently in males compared to other SLE patients without anti-Ki (P < 0.004). Nineteen anti-Ki positive patients affected by SLE showed more frequently malar rash and multiple autoantibody specificities compared to 16 anti-Ki positive patients with other diseases (P = 0.044 and P = 0.0003, respectively). Our study confirms a preferential occurrence of anti-Ki antibodies in patients with sicca and skin involvement. Malar rash and multiple ANA specificities were significantly associated with SLE compared to other diseases in our study. Anti-Ki were detected in 6% of patients with SLE with a significant prevalence in males.     

Antibodies to glycyl–transfer rna synthetase in patients with myositis and interstitial lung disease

Objective. We have previously described anti-EJ antibodies, and provided evidence that these antibodies react with glycyl–transfer RNA (gly-tRNA) synthetase. The aim of the present study was to identify patients with anti-EJ antibodies and describe the clinical associations of the antibody, in particular, whether it is associated with the syndrome of myositis and interstitial lung disease (ILD) that has been previously associated with autoantibodies to the aminoacyl-tRNA synthetases for histidine, threonine, and alanine. Methods. Sera from patients with suspected or proven polymyositis or dermatomyositis (DM), sera with anticytoplasmic patterns, and control sera were tested for anti-EJ antibodies by immunoprecipitation (IPP). Positive sera and controls were tested for the ability to inhibit gly-tRNA synthetase by preincubation of the enzyme source with the serum. Results. Anti-EJ antibodies were demonstrated in the sera of 5 patients, by IPP of characteristic tRNAs and protein. Original serum EJ and each of the new sera significantly inhibited the enzymatic activity of gly-tRNA synthetase but not histidyl-tRNA synthetase. All 5 of the new patients had inflammatory myopathy, a typical DM rash, and ILD. One, who had an overlap syndrome with systemic lupus erythematosus, had anti-EJ at least 4 months before the development of clinical myositis. Arthritis and Raynaud's phenomenon, other features associated with antisynthetases, were also seen. Conclusion. Anti-EJ is associated with the syndrome of myositis and lung disease that is seen in association with other antisynthetases. The finding of specific inhibition of gly-tRNA synthetase by all anti-EJ–positive sera strongly supports the identification of EJ antigen as gly-tRNA synthetase.     

Clinical characteristics of Japanese patients with anti-OJ (anti-isoleucyl-tRNA synthetase) autoantibodies

OBJECTIVES: The clinical and laboratory characteristics of seven patients with anti-aminoacyl-tRNA synthetase (ARS) autoantibodies, specifically anti-OJ (anti-isoleucyl-tRNA synthetase), were examined and compared with previously published findings. METHODS: Serum samples from 1135 Japanese patients with various autoimmune diseases and 48 normal individuals were screened for anti-OJ antibodies using RNA and protein immunoprecipitation assays. The patients whose sera contained anti-OJ antibodies were assessed regarding clinical symptoms, clinical course, laboratory findings, chest radiography and chest computed tomography. RESULTS: Sera from seven patients were found to contain anti-OJ antibodies. These autoantibodies were associated with interstitial lung disease (ILD) and myositis. The diagnoses of the seven patients were idiopathic interstitial pneumonias (IIPs) in three, polymyositis (PM) in three and PM-rheumatoid arthritis (RA) overlap in the remaining one. All patients had ILD, but muscle weakness and polyarthritis were seen only in four. Raynaud's phenomenon and sclerodactyly were absent in all patients. CONCLUSIONS: These results indicate that the presence of anti-OJ autoantibodies may distinguish a subtype of anti-ARS syndrome that is more closely associated with ILD than myositis or Raynaud's phenomenon.     

Clinical,serologic, and immunogenetic features in polish patients with idiopathic inflammatory myopathies

Objective. To determine the clinical, serologic, and immunogenetic correlations in patients with idiopathic inflammatory myopathies (IIM), and to evaluate the useful grouping of some diseases for practical clinical purposes. Methods. Patients with IIM were categorized according to clinical presentation as compared with auto-antibody specificity. Serum samples from 84 patients were screened for myositis-specific autoantibodies (MSAs) by indirect immunofluorescence and double immunodiffusion. All sera were also studied by protein A-assisted immunoprecipitation. Genomic DNA was isolated from peripheral blood mononuclear cells, and HLA-DQA1 and DRB1 alleles were determined. The patients were seen and followed up for many years in the same center. Results. MSAs were present in 19% of patients. The most common MSAs were antisynthetases in 13% of patients (Jo-1 10.7%, PL-12 1.2%, and EJ 1.2%), associated with the antisynthetase syndrome. Anti-SRP was found in 1.2% of patients, associated with polymyositis, and anti-Mi-2 in 4.9%, found exclusively in patients with dermatomyositis. The most frequent MSA was PM-Scl in 23.8% of patients, associated with scleromyositis, and Ku was present in 9.6% of patients with overlap syndromes. The alleles that were found at a significantly increased frequency were HLA-DRB1*0301 (59.4%) and DQA1*0501 (71.6%), which are in linkage disequilibrium. DQA1*0501 was present in 85.7% of patients with antisynthetases, and in 100% of patients with PM-Scl and Ku. Conclusion. The HLA-DRB1*0301; DQA1*0501 haplotype was found to be significantly increased in this population overall and in those myositis patients with antisynthetase, anti-PM-ScI, and anti-Ku antibodies. The results of this study confirm that IIM are heterogeneous syndromes, but can be divided into more useful groups on the basis of clinical, serologic, and immunogenetic features.     

Clinical characteristics of Japanese patients with anti-PL-7 (anti-threonyl-tRNA synthetase) autoantibodies

OBJECTIVE: The clinical and laboratory features of seven Japanese patients with anti-aminoacyl-tRNA synthetase (ARS) autoantibodies against PL-7 (anti-threonyl-tRNA synthetase) were analyzed and compared with previously published findings. METHODS: Serum samples from 1,135 Japanese patients with various autoimmune diseases were screened for anti-PL-7 antibodies using RNA and protein immunoprecipitation assays. The patients whose sera contained anti-PL-7 antibodies were assessed regarding clinical symptoms and clinical course. RESULTS: Sera from seven patients were found to have anti-PL-7 antibodies. These autoantibodies were associated with polymyositis/dermatomyositis (PM/DM) and/or interstitial lung disease (ILD). The clinical diagnoses of these seven patients were PM - systemic sclerosis (SSc) overlap (5 patients), DM (1 patient) and idiopathic pulmonary fibrosis (IPF) (1 patient). All patients had ILD with a chronic course and six also had arthritis (85%) and five sclerodactyly (71%). CONCLUSIONS: These results indicate that anti-PL-7 autoantibodies are closely associated with PM-SSc overlap as well as ILD, arthritis and sclerodactyly in our series of Japanese patients.     

Clinical and histopathological features of myopathies in Japanese patients with anti-SRP autoantibodies

To elucidate the clinical and histopathological features associated with autoantibodies to the signal recognition particle (SRP), we have studied 23 Japanese patients with this specificity among 3,500 patients with polymyositis/dermatomyositis and other connective tissue diseases. Anti-SRP antibodies were determined based on analysis of RNA and protein components by immunoprecipitation assays. The pathological analysis was performed by using special stainings including alkaline phosphatase, myosin ATPase, and modified Gomori trichrome stainings. Twenty-one (92%) of these 23 patients had myositis, 8 of whom (38%) required cytotoxic agents or intravenous immunoglobulin therapy in addition to corticosteroid therapy. Four patients (16%) had rheumatoid arthritis, two of whom had no features of myositis. Muscle biopsy specimens of 11 patients were examined histologically in detail. All 11 had muscle fiber necrosis and/or regeneration, but only one had infiltration of inflammatory cells. Six of the 11 (55%) patients showed type I fiber predominance by ATPase staining, while eight control myositis patients without anti-SRP antibodies did not. There was no correlation of other neurogenic features in histology with the presence of anti-SRP antibodies. These studies suggest that anti-SRP autoantibodies are most likely to be related to myopathies that are resistant to corticosteroid therapy and without inflammation histopathologically. An erratum to this article can be found at     

Clinical and immunogenetic characterization of Mexican patients with 'rhupus'

The coexistence of systemic lupus erythematosus and rheumatoid arthritis (rhupus), is a rare clinical condition. To date, 50 cases of rhupus have been described worldwide; however, the lack of clinical criteria for this rheumatic condition has created confusion in the characterization of this disorder. Nevertheless, in this paper we describe a comprehensive clinical and serological characterization of a cohort of 22 Mexican patients with rhupus, supported by generic HLA-DR phenotyping. We found that rhupus patients have a special clinical behavior. In this setting, the signs and symptoms of rheumatoid arthritis prevail, little organic damage associated with systemic lupus erythematosus (SLE) exists and none of the cases present thrombosis or morbidity during pregnancy in spite of presenting a high frequency of anticardiolipin antibodies. We also found an increased frequency of HLA-DR1 and HLA-DR2 alleles compared to healthy ethnically matched controls, systemic lupus erythematosus and rheumatoid arthritis patients.     

Clinical features and outcomes of the patients with anti-glycyl tRNA synthetase syndrome

Clinical Rheumatology - To analyze the clinical features and outcomes of the patients with anti-glycyl tRNA synthetase (anti-EJ) syndrome in a large Chinese cohort. The medical records, imaging,...     

Antibody to threonyl–transfer rna synthetase in myositis sera

The prevalence and clinical correlations of antithreonyl–transfer RNA synthetase (anti–PL-7), as well as the relationship of anti–PL-7 to anti–histidyl–transfer RNA synthetase (anti–Jo-1) were studied in 109 sera from patients with myositis. Inhibition of threonine aminoacylation was used to screen for anti–PL-7. Sera from 3 patients, 2 with polymyositis and 1 with polymyositis–overlap syndrome, and a fourth serum from a patient with dermatomyositis, which was previously found to contain anti–PL-7, inhibited >90% of activity (3.7% of 109 sera). All 4 sera reacted strongly in an enzyme-linked immunosorbent assay with enzyme that was either affinity purified with anti–PL-7 or was biochemically purified. There was no indication of cross-reactivity by aminoacylation inhibition or, for most sera, by enzyme-linked immunosorbent assay. Anti–PL-7 is an uncommon myositis-associated antibody that is independent of anti–Jo-1, but is directed at a functionally related enzyme.     

Clinical features of patients with anti-neutrophil cytoplasmic autoantibodies targeting native myeloperoxidase antigen

Objectives

Anti-neutrophil cytoplasmic autoantibodies (ANCA) are useful diagnostic markers in systemic vasculitic disorders with small-vessel involvement, but depending on the particular test used, the myeloperoxidase (MPO)-ANCA results are variable. In the present study, we performed a comparative analysis between our originally developed nMPO-ANCA assay that targets the native MPO antigen and other commercially available assays using sera of patients with clinical features of ANCA-associated vasculitis (AAV).

Methods

Sera of 24 patients strongly suspected of having AAV were examined for the presence of MPO-ANCAs by our nMPO-ANCA assay and by other commercial-based MPO-ANCA assays. These results were correlated to indirect immunofluorescence microscopy staining patterns and patient clinical parameters.

Results

Eighteen out of 24 patients (75 %) were positive for nMPO-ANCA, compared with 13 out of 24 patients (54 %) by one of the most frequently used commercial-based MPO-ANCA enzyme-linked immunosorbent assays (ELISAs) in Japan. Interestingly, the patients who tested positive with our nMPO-ANCA assay alone showed clinical features of AAV marked by continuous fever, polyarthritis, and mild nephritis. The titers of nMPO-ANCA decreased in association with clinical improvement after treatment.

Conclusions

Our data suggest that a positive nMPO-ANCA result, which identifies antibodies to human native MPO antigen, correlates with AAV disease activity. Moreover, the nMPO-ANCA test has clinical utility in detecting AAV-affected patients who have tested negative using commercially available assays.     

Clinical subsets associated with different anti-aminoacyl transfer RNA synthetase antibodies and their association with coexisting anti-Ro52

Objective: To characterize clinical features of polymyositis/dermatomyositis (PM/DM) patients with different anti-aminoacyl transfer RNA synthetase (ARS) antibodies and their association with anti-Ro52.

Methods: Autoantibodies in sera from 97 Japanese patients (36 PM, 56 DM, and 5 clinically amyopathic DM), who satisfied Bohan and Peter or modified Sontheimer's criteria, were characterized by immunoprecipitation and enzyme-linked immunosorbent assay. Clinical information was from medical records. Features associated with different anti-ARS and anti-Ro52 antibodies were analyzed.

Results: The prevalence of anti-ARS was similar to other studies (Jo-1, 22%; EJ, 4%; OJ, 1%; PL-12, 1%), except for a high prevalence of anti-PL-7 (12%), which allowed us to characterize patients carrying this specificity. Serum creatine kinase?>3000 IU/l was less common in anti-PL-7-positive patients (57%) than anti-Jo-1-positive patients (18%) (p?=?0.0328) and was not found in anti-EJ-positive individuals. Interstitial lung disease was common in anti-ARS-positive patients (97%) (p?<?0.0001 vs. 48% in anti-ARS-negative). Anti-Ro52 antibodies were frequently detected with anti-ARS (59%) (57% in anti-Jo-1, 67% in anti-PL-7) (vs. 21% in anti-ARS-negative, p?<?0.0002). Anti-Ro52 was associated with overlap syndrome (26%) (vs. 7% in anti-Ro52-negative, p?=?0.0119).

Conclusions: Patients with different anti-ARS in combination with anti-Ro52 appear to be associated with distinctive clinical subsets.     

Clinical,immunogenetic and outcome features of Hispanic systemic lupus erythematosus patients of different ethnic ancestry

The aim of this study was to compare and contrast the clinical, immunogenetic and outcome features of two subgroups of Hispanic patients with systemic lupus erythematosus (SLE), one from Northern Spain (Spaniards) and one of from the USA (Hispano-Americans: Hispanics primarily of Mexican ancestry (Amerindian and Spaniard backgrounds). Patients with SLE as per the American College of Rheumatology classification criteria, from two University-affiliated Hospitals (Universidad de Cantabria) and disease of five or less years in duration (n = 28) and with four years of follow up constituted the Spaniard subgroup. Fifty-two patients of Hispano-American ancestry from the LUMINA (Lupus in Minority populations: Nature versus Nurture) cohort constituted the Hispano-American subgroup. Patients were studied using a similar protocol. In short, sociodemographic, clinical, immunological, immunogenetic and psychosocial and behavioral features were obtained at enrollment into the study (baseline visit) and yearly thereafter. The relationship between these variables and disease activity at baseline and over time, as measured by the systemic lupus activity measure (SLAM) and disease damage, as measured by the SLICC (Systemic Lupus International Collaborating Clinics) Damage Index (SDI) were determined. Variables found to be significant at P = 0.10 were then entered into multivariable linear regression models with disease activity at baseline and over time, and damage as the outcome measures. Patients of Hispano-American and Spaniard ethnicity had comparable sociodemographic features except for home density, which was higher among the Hispano-Americans. HLA-DRB1*08 was associated with SLE among the Hispano-Americans but not among the Spaniards. Hispano-American patients had more severe disease as manifested by more frequent clinical manifestations (renal and neurological), higher SLAM scores at baseline and over time and higher SDI scores at the year 4 visit (that despite the fact that Hispano-American patients had overall shorter disease duration than the Spaniard patients). Hispano-American ethnicity, younger age at disease onset and the number of ACR criteria at baseline and over time were consistently associated with disease activity, whereas increased home density and the absence of HLA-DRB1*0301 were significant predictors only over time. Disease damage was associated with disease activity over time, the number of ACR criteria at baseline, increased home density and the presence of HLA-DRB1*08. This is the first longitudinal study of SLE in two different Hispanic subgroups. Hispanics with a strong Amerindian background have a more serious disease than that observed in Spaniards. Genetic and socio-economic differences between these two Hispanic subgroups probably account for these findings.