Domain reactivity of autoantibodies to calpastatin in patients with systemic rheumatic diseases.

Abstract Autoantibodies to calpastatin (endogenous inhibitor of calpain, a calcium-dependent neutral proteinase) have been detected in sera of patients with rheumatoid arthritis (RA) and other diseases. We investigated the epitope reactivity of anticalpastatin autoantibodies in patients with rheumatic diseases. cDNAs encoding each calpastatin domain (L, I, II, III, and IV) were amplified by PCR and ligated into an expression vector. The fusion proteins were expressed in E. coli. The presence of autoantibodies specific for each calpastatin domain was assayed in sera of patients with various rheumatic diseases by immunoblotting the fusion proteins with these sera. Of the RA patient sera, 81% reacted with at least one calpastatin domain. This reaction was significantly greater than with sera from patients with systemic lupus erythematosus (46%), scleroderma (32%), polymyositis/dermatomyositis (43%), and normal controls (13%). Domains I and II were recognized by RA patient sera significantly more than by other patient sera, whereas domains III and IV reacted almost equally among all patient sera. Although, collectively, sera from RA and lupus patients reacted equally with all domains, scleroderma sera tended to react with only domains I and IV and myositis sera tended to recognize only domains III and IV. Patients with RA positive for anticalpastatin antibodies exhibited more active disease (i.e., a higher erythrocyte sedimentation rate and C-reative protein level) than antibody-negative patients. Our results suggest that anticalpastatin antibodies were detected in RA with the highest frequency and that different domain reactivity was shown among different diseases. The presence of these antibodies in sera may be related to the type of disease and, in RA, with disease activity, suggesting their importance in rheumatic disorders.

Association of human leukocyte antigen class II genes with autoantibody profiles, but not with disease susceptibility in Japanese patients with systemic sclerosis.

OBJECT: To examine the role of human leukocyte antigen (HLA) class II genes in the development of systemic sclerosis (SSc) as well as in the clinical and serologic expression of SSc in patients. METHODS: HLA-DRB1, DRB3, DRB4, DQB1, and DPB1 alleles were determined by genotyping; and serum antinuclear antibodies were identified using indirect immunofluorescence, double immunodiffusion and immunoprecipitation. PATIENTS: One hundred and five Japanese patients with SSc and 104 race-matched healthy controls. RESULTS: Frequencies of DRB1 and DQB1 alleles were not different between SSc patients and healthy controls, while DPB1*0901 was marginally increased in SSc patients. In contrast, SSc-related autoantibodies were closely associated with the clinical features. HLA class II genes were detected as follows: anti-DNA topoisomerase I antibody with diffuse cutaneous involvement, pulmonary fibrosis, and DRB1*1502-DQB1*0601-DPB1*0901; anti-U1RNP antibody with overlapping features of lupus and/or myositis and DRB1*0401/*0802-DQB1*0302; and anticentromere antibody with limited cutaneous involvement and DRB1*0101-DQB1*0501-DPB1*0402. In the analysis of the association of HLA class II and the clinical features in SSc patients significant differences were obtained only for the increased frequencies of arthritis and rheumatoid factor in patients with DRB1*0405 compared to those without. CONCLUSION: HLA class II genes strongly influence the production of SSc-related autoantibodies rather than the development of SSc. In addition, SSc is a composite disease of distinctive subsets defined by serum autoantibodies, which have specific clinical and HLA class II associations.

[Detection of isotype-specific autoantibodies to calpastatin in sera from patients with rheumatic diseases using heat-treated HeLa cell extract as an antigen source for immunoblotting].

To detect immunoglobulin isotype-specific autoantibodies to native human calpastatin in patients with rheumatic diseases, we performed immunoblot analysis using the heated HeLa cell extracts to enrich heat-resistant calpastatin. The calpastatin molecule that was apparently migrated to 110 kD by SDS-PAGE was confirmed to react with monoclonal anti-human calpastatin antibody in immunoblotting. IgG antibodies to calpastatin were detected in 22 of 48 sera (46%) from patients with RA, whereas only 20% (5/25), 11% (2/19) and 13% (2/15) of sera from SLE, SSc and PM/DM had IgG anti-calpastatin antibodies, respectively. IgM antibodies were also found in 40% (19/48) of RA and 12% (3/25) of SLE patients but not detected in sera from patients with other rheumatic diseases. IgA antibodies were found in only one RA and one SLE serum. In RA, 7 of 48 sera (15%) had IgM antibodies alone, but all SLE sera with IgM antibodies had IgG antibodies. Thus, anti-calpastatin autoantibodies were detected by using the native human calpastatin. Although these autoantibodies were found in patients with various rheumatic diseases, they were present in RA patients at the highest frequency. In particular, the presence of IgM antibodies appeared to be more specific in RA patients.

Spectrum and clinical significance of autoantibodies against transfer RNA.

OBJECTIVE: To characterize the clinical features of patients who have autoantibodies against transfer RNA (tRNA) or tRNA-associated proteins. METHODS: Sera from 1,472 patients with suspected systemic rheumatic disease were screened by RNA immunoprecipitation of HeLa cell extracts. The specificities of the antibodies that precipitated tRNAs were further analyzed by immunoprecipitation using deproteinized RNAs and 35S-methionine-labeled HeLa cell extracts, followed by immunoblotting. RESULTS: Forty-one serum samples (2.8%) were found to immunoprecipitate tRNAs. Thirteen patients were identified as having previously defined anti-aminoacyl-tRNA synthetase antibodies (anti-histidyl-tRNA synthetase in 4 patients, anti-threonyl-tRNA synthetase in 1, anti-alanyl-tRNA synthetase in 3, anti-glycyl-tRNA synthetase in 4, and anti-isoleucyl-tRNA synthetase in 1). All 13 patients had myositis and/or interstitial pneumonitis. Sera from the remaining 28 patients immunoprecipitated previously unidentified tRNAs, including 13 serum samples that bound deproteinized cognate tRNA; 24 of the 28 patients met criteria for either systemic lupus erythematosus (SLE) or Sjögren's syndrome (SS). In addition, nonerosive polyarthritis, leukocytopenia, rheumatoid factor, and characteristic annular or papulosquamous recurrent erythema were noted in these patients; however, renal involvement was rare. Sera from 16 of these 28 patients also contained anti-Ro/SSA and/or anti-La/SSB antibodies. While 189 patient sera precipitated Ro/SSA and/or La/SSB-associated RNAs but not tRNA, only 12 of the patients (6.3%) developed skin lesions (P=0.0009, odds ratio 8.85). CONCLUSION: Novel autoantibodies against tRNAs or tRNA-associated proteins were identified in 28 sera. These autoantibodies appear to be distinct from anti-aminoacyl-tRNA synthetase antibodies and are associated with SLE and SS. The presence of anti-Ro/SSA and/or anti-La/SSB along with anti-tRNA antibodies is more strongly associated with recurrent erythema than is the presence of anti-Ro/SSA or anti-La/SSB alone.

[Two cases of polymyositis associated with interstitial pneumonia with anti-OJ (isoleucyl tRNA synthetase) antibodies].

We present two cases of polymyositis (PM) associated with interstitial pneumonia (IP) whose sera contain autoantibodies to OJ (isoleucyl tRNA synthetase). The first patient is a 51 year-old female who was diagnosed as rheumatoid arthritis (RA) and treated with gold and corticosteroid at another hospital. She was admitted to Keio University Hospital due to worsening of dyspnea on exertion and polyarthritis. Laboratory findings revealed elevation of serum CK and LDH. A diagnosis of PM was made based on the myogenic pattern of EMG and pathological feature by muscle biopsy. Chest radiography and CT showed interstitial fibrosis. Because of clinical deterioration, the dose of corticosteroid was increased (prednisolone 50 mg/day) and her symptom was stabilized. The second patient, a 62 year-old male, was admitted to Kawasaki Municipal Hospital because of dyspnea on exertion, polyarthritis, and fever. He was diagnosed as PM associated with IP on the basis of his clinical and laboratory findings, and chest radiography. He was treated with methylprednisolone pulse therapy (800 mg/day for three days) and his symptoms were improved. Both patients were found to have autoantibodies to OJ. Autoantibodies to aminoacyl tRNA synthetase have been described to be associated with myositis and/or IP. In North American, it was reported that all patients with anti-OJ had either myositis or IP or both. This suggests that anti-OJ was commonly associated with the anti-synthetase syndrome observed with other anti-synthetases. This is the first report of Japanese patients with anti-OJ antibody. The clinical features of these patients were likely to be similar to those observed in North American patients. However, further studies are necessary to clarify the precise clinical significance of this antibody.

Anti-transfer RNA antibodies in two patients with pulmonary fibrosis, Raynaud's phenomenon and polyarthritis.

Patient W.S. (a 61-year-old woman) and patient T.M. (a 41-year-old man) developed recurrent fevers, polyarthritis, Raynaud's phenomenon and interstitial pulmonary fibrosis without apparent polymyositis. From HeLa cell extracts, sera from both patients immunoprecipitated all species of intact and deproteinised tRNAs. To identify the antibody binding site more precisely, tRNAs transcribed in vitro from cloned Escherichia coli tRNA genes and various mutants were prepared and used as antigens for immunoprecipitation. When the TpsiC loop, or the D loop were deleted, such mutants were not bound by both sera, suggesting that the D and TpsiC loops were required for antibody binding. Abrogation of tRNA binding occurred when 18G of tRNATrp was replaced with 18A to break the tertiary L-shape structure of tRNA. These results strongly suggest that sera from W.S. and T.M. recognise the tertiary conformation of L-shaped tRNA which is constructed with both D and TpsiC loops. These autoantibodies may also serve as a marker for a new subset of patients with connective tissue diseases that is distinct from anti-aminoacyl-tRNA synthetase syndrome.

[The efficacy of combination therapy with prednisolone (PSL) and methotrexate (MTX) on radiographic progression in patients with rheumatoid arthritis (RA)].

A case-controlled study was performed, based on early active RA patients treated with MTX; Prednisolone (PSL) was also given in sixteen patients (PSL + MTX group) and each of them was matched for age and sex with a control who have never received PSL (MTX group). No significant differences in radiographic progression were found between the 2 groups. Analysis of radiographic parameters showed that CRP, erythrocyte sedimentation rate, and titers of serum rheumatoid factors after 6 months treatment and their integral amounts during cource were significantly high in the patients with marked radiographic progression. There was no relationship between radiographic progression and treatment with PSL. These results suggested that the indication of PSL therapy for RA is limited for patients with the poor decrease in the level of CRP, erythrocyte sedimentation rate, and rheumatoid factor by MTX treatment.

[Analysis of autoantigens and clinical significance of antinuclear antibodies].

A highly sensitive RNA-immunoprecipitation assay (Lerner-Steitz assay) is a unique and useful method of identifying autoantibodies to RNA-associated antigens. In this study, we identified novel autoantibodies to tRNAs using RNA-immunoprecipitation assay. In screening of 1472 sera by RNA-immunoprecipitation using HeLa cell extracts as an antigen source, 41 sera were found to immunoprecipitate tRNAs. Fifteen of these 41 sera also immunoprecipitated deproteinized tRNAs, indicating that these 15 sera contained anti-tRNA antibodies. Three sera immunoprecipitated naked tRNA from E. coli. When in vitro transcripts from cDNAs encoding E. coli tRNAs and their synthesized mutants were used as antigens, it was demonstrated that the representative serum recognized the conformational epitope of the "L"-shape structure which was conserved in all tRNAs of all species. This finding suggests the role of bacterial infection in the development of autoantibodies and autoimmune diseases. Two of 15 sera containing anti-tRNA antibodies were identified as anti-PL-12 (alanyl-tRNA synthetase) antibodies. Eleven of the remaining 13 patients were diagnosed as either SLE, Sjögren's syndrome or their overlap. In addition, fever, Raynaud's phenomenon, polyarthritis, leukocytopenia and characteristic annular erythema were frequently found in these patients. Novel autoantibodies to tRNAs appeared to be associated with common clinical features but were distinct from previously described anti-aminoacyl-tRNA synthetases.

[Novel autoantibodies that recognize native transfer RNAs in patients with systemic rheumatic diseases].

Autoantibodies directed against aminoacyl-tRNA synthetases are well described in adult polymyositis/dermatomyositis. However, the characteristics of antibodies against other tRNA and tRNA-associated proteins have not been well defined. In this study, we identified novel autoantibodies to total tRNAs in patients with systemic rheumatic diseases and characterized the structure that was recognized by anti-tRNA antibodies. We identified fifteen patients sera that immunoprecipitated the deproteinized cognate tRNA. Two of them were identified as having previously well-defined anti-PL-12 antibodies. Three of the remaining 13 patient sera immunoprecipitated naked tRNA of E. coli. To investigate the antibody binding site on tRNAs, we have used in vitro transcripts from cDNAs encoding wild type tRNAs of E. coli and their synthesized mutants. These sera revealed different reactivity to mutated tRNAs. Eleven of these 13 patients met disease specific criteria for: SLE (3 patients), Sjögren's syndrome (6), or SLE/Sjögren's syndrome overlap (2). In addition, fever, Raynaud's phenomenon, and non-erosive polyarthritis, were frequently found in these patients. In summary, we have identified novel antibodies to tRNAs which appear to be quite common, and distinct from previously described anti-aminoacyl-tRNA synthetase antibodies.

[Successful treatment of toe gangrene with moderate-dose steroid therapy in a patient with systemic sclerosis (CREST syndrome)].

A 68-year-old woman first noticed Raynaud's phenomenon at the age of 35, and she was diagnosed as having systemic sclerosis (SSc) because of cutaneous calcinosis, sclerodactyly, telangiectasia, sausage-like finger, digital pitting scar in 1971. In October, 1994, she was suffered from cold sensation in her right foot, and on November 2 she noticed the painful ulcers on the right toe, which progressed to be gangrenous. Every antiplatelet or thrombolytic agents including PGE1, argatroban, sarpogrelate hydrochloride and urokinase were unsuccessful. Angiograms revealed marked narrowing of bilateral anterior and posterior tibial and peroneal arteries. Prednisolone 30 mg/day was started, which resulted in successful response within 10 days. Large vessel involvement in SSc patients has been reported to be rare, and its treatment remains to be established. We believe our case help understanding the pathophysiology of such rare manifestation in SSc.

Fever of unknown origin responding to steroid therapy.

It is not uncommon to find cases of fever of unknown origin (FUO) in which no final diagnosis is made ever after various examinations. We investigated such cases of undiagnosed FUO, with fever persisting for a long periods and responding to steroid therapy. Among 4,596 patients who were hospitalized over 3-year period from September 1991, 25 met Petersdorf's definition of FUO. Among these 25 patient, six cases were steroid-responsive undiagnosed FUO (SR-FUO). Patients with SR-FUO had the following characteristics: marked inflammatory findings and severe illness; without a definite underlying disease being found despite various examinations; no findings which indicated any known diseases such as adult-onset Still's disease, polymyalgia rheumatica, or other collagen diseases; elderly onset, at 58 to 77 years of age (mean age: 67 years); no improvement with antibiotics, antituberculous agents, or antimycotic drugs; significant improvement of symptoms and signs with steroid therapy; and a relatively good prognosis. SR-FUO, which is not caused by any known disease and is highly responsive to steroids, is included among the FUO cases which we have difficulty in diagnosing and treating.

[Toxicity of low-dose methotrexate in rheumatoid arthritis--clinical characteristics in patients with MTX-induced pancytopenia and interstitial pneumonitis].

Pancytopenia and interstitial pneumonitis are one of the most serious and unpredictable adverse effects of low dose, pulse methotrexate (MTX) in treating rheumatoid arthritis (RA). It is important to investigate the historical, clinical or immunologic features associated with the development of such toxicity, in order to use MTX more appropriately. Two hundred eighty four patients (female 230 male 54) with rheumatoid arthritis had been treated with pulse weekly oral MTX with a mean follow-up of 33.2 months. Adverse effects which required the discontinuation of MTX occurred in 47 patients (16.5%). Gastrointestinal toxicity occurred most frequently (14 patients) and liver dysfunction occurred in 9 patients. Four patients (1.4%) developed pancytopenia, and six patients (2.1%) developed interstitial pneumonitis. All patients who developed pancytopenia were old female with long history of active, deforming rheumatoid arthritis, The cumulative dose of MTX ranged from 15 mg to 760 mg at the time pancytopenia developed. Impaired renal function, hypoalbuminemia, and multiple medication were observed, and antinuclear antibodies were positive in most patients. It should be noted that severe stomatitis preceded or accompanied with pancytopenia in all patients. Blood counts returned to the normal level in 7 to 14 days. All patients who developed interstitial pneumonitis were old female. The cumulative dose ranged from 65 mg to 580 mg. Pre-existance of lung diseases, history of adverse effects of other DMARDs, the presence of Raynaud's phenomenon, and antinuclear antibodies appeared to be risk factors for interstitial pneumonitis. All patients recovered with high dose of corticosteroid and mechanical ventilation. Such clinical characteristics that are associated with MTX-induced pancytopenia or interstitial pneumonitis should be reminded in the treatment of rheumatoid arthritis with MTX.

Mixed-cryoglobulinemia associated with cutaneous vasculitis and pulmonary symptoms.

A 45-year-old Japanese man with Sjögren's syndrome developed recurrent skin ulcers, palpable purpura, and dyspnea. Serum mixed-type cryoglobulin level was elevated. A biopsy of his skin lesion showed the characteristic leukocytoclastic vasculitis of mixed-type cryoglobulinemia. Dyspnea, skin ulcers, and purpura resolved along with a reduction in the serum cryoglobulin level after prednisolone administration. This patient demonstrated cryoglobulinemia-associated vasculitis, as well as possible cryoglobulinemia-associated pulmonary symptoms.

Clinical characteristics of patients with rheumatoid arthritis and methotrexate induced pneumonitis.

OBJECTIVE: To determine the clinical features of methotrexate (MTX) pneumonitis in patients treated for rheumatoid arthritis (RA). METHODS: The medical records of 284 patients with RA who had been treated with oral MTX (mean followup 33.2 mo) were reviewed retrospectively. RESULTS: MTX induced interstitial pneumonitis developed in 6 patients (2.1%). The affected patients were significantly older than those without MTX pneumonitis (67.3 +/- 9.8 vs 52.4 +/- 12.6 yrs, respectively; p < 0.005). The cumulative MTX dose ranged from 65 to 580 mg at the time pneumonitis developed. Five of the patients (83%) had preexisting interstitial abnormalities, while only 29 of the 278 patients without MTX pneumonitis (10%) had such abnormalities (p < 0.001). The frequency of adverse effects due to previous treatment with disease modifying antirheumatic drugs (DMARD) was 66.7% in MTX pneumonitis patients and 14.3% in the other 278 patients (p < 0.01). CONCLUSION: Advanced age, preexisting interstitial abnormalities, and previous adverse reactions to DMARD may be associated with MTX pneumonitis. Patients with these characteristics require careful monitoring during MTX therapy.

[Case of MPO-ANCA positive interstitial pneumonitis and necrotizing, crescentic glomerulonephritis].

A 52-year-old man was admitted to our hospital in July 1995, because of intermittent claudication, paresthesia on foot and gross hematuria. Chest radiograph in 1988 revealed bilateral interstitial shadows and proteinuria had been pointed out since 1992. On admission, chest X-ray and computed tomography showed diffuse interstitial shadow, however it had not been changed for several years. Laboratory tests revealed elevated level of erythrocyte sedimentation rate, C-reactive protein, immunoglobulin, rheumatoid factor, IgG-rheumatoid factor, and immune complex. Serum MPO-ANCA were positive. Although serum creatinine level and renal function test were normal, renal biopsy demonstrated crescentic formation and necrotizing vasculitis. Immunofluorescence and electron microscopy demonstrated no remarkable deposit in glomerulus. A diagnosis of microscopic polyarteritis necrotizing and crescentic glomerulonephritis (NCGN) was made. Treatment was initiated with 30 mg of prednisolone, followed by marked improvement of intermittent claudication, and decreased titer of serum MPO-ANCA. Previous reports have demonstrated the association of MPO-ANCA with rapidly progressive NCGN, microscopic polyarteritis, and occasionally pulmonary hemorrhage recognized as pulmonary-renal syndrome. However, the present case suggests the possibility that another disease subset may also be associated with MPO-ANCA, which is characterized by interstitial pneumonitis and slowly progressive glomerulonephritis.

Novel autoantibodies directed against the common tertiary configuration of transfer RNA in a patient with interstitial lung disease.

OBJECTIVE: To identify and characterize a novel autoantibody, anti-WS, that binds total transfer RNA (tRNA). METHODS: Serum from patient WS, who had polyarthritis, Sjögren's syndrome, Raynaud's phenomenon, and interstitial pulmonary fibrosis, was used in this study. Characteristics of anti-WS and antibody-reactive determinants of tRNA were investigated by 32P immunoprecipitation using HeLa cell RNA and deletion mutants of tRNA transcribed in vitro. RESULTS: WS serum produced nucleolar and cytoplasmic staining on indirect immunofluorescence. 32P immunoprecipitation assays demonstrated that this serum immunoprecipitated total tRNAs and 5.8S and 5S ribosomal RNAs from 32P-labeled HeLa cell extract. When deproteinized RNA was used as antigen source, total tRNAs were still precipitated by WS serum. An immunoprecipitation study, using various deletion mutants of Escherichia coli tRNA, demonstrated that both D and T psi C loops were needed for antibody binding. Substitution of nucleotide 18G with 18A of E coli tRNA(Trp), which is essential in the formation of the tertiary "L" shape of tRNA, inhibited binding by anti-WS antibodies. CONCLUSION: Anti-WS antibodies are novel autoantibodies directed against tRNAs. The antibody binding site is the common L-shaped tertiary structure conformed by the D loop and T psi C loop of tRNA, suggesting that the antibodies are induced by a conserved sequence among all species. Furthermore, these antibodies could be a marker for a newly recognized subset of connective tissue disease.

[Liver disease in systemic lupus erythematosus].

Liver disease in 193 patients (17 male and 176 female) with systemic lupus erythematosus (SLE) at Kawasaki Municipal Hospital were analyzed. Abnormal transaminase levels were found in 78 case (40.4%). Among them, there were 35 patients whose liver disease were identified. There were 12 patients whom no cause could be found other than SLE. Other liver disease were as follows: fatty liver in 9 cases, virus infection in 5 cases, gall stone and/or cholecystitis in 3 cases, drug allergy in 2 cases, autoimmune hepatitis 2 cases, primary biliary cirrhoses in 1 case. Liver disease with systemic lupus erythematosus was frequent, but there was no severe case.

[Causes of death in 140 patients with rheumatoid arthritis].

The causes of death in 140 patients (30 male and 110 female) with rheumatoid arthritis (RA) at Kawasaki Municipal Hospital are analyzed. Autopsies were performed in 58%. The causes of death were infection (25.7%), heart disease (20.0%), renal failure (10.7%), cerebrovascular disease (10.0%), and respiratory failure (8.5%). The causes of death in RA patients were compared with those of 243 non-rheumatoid patients. Infection, congestive heart failure, renal failure and respiratory failure were more common causes of death in RA than in the control group. It should be noted that neoplasms are infrequent causes of death in patients with RA. The survival time (onset to death) of RA patients appears to be increasing year by year.

Cause of death in 81 autopsied patients with rheumatoid arthritis.

OBJECTIVE: To evaluate the cause of death and complications in a series of autopsied patients with rheumatoid arthritis (RA). METHODS: A clinicopathological study of 81 autopsied patients with RA was performed. RESULTS: In order of frequency, the causes of death were infection (23.5%), heart disease (17.3%), respiratory failure (9.9%), renal failure (9.9%), and gastrointestinal disease (9.9%). Observed complications of RA were systemic angiitis in 25 cases (30.8%), systemic amyloidosis in 17 cases (21.0%), and pulmonary fibrosis in 28 cases (34.6%). No patient had both angiitis and amyloidosis simultaneously. The prevalence of systemic angiitis tended to decrease during the study period (1960-1990), while systemic amyloidosis tended to increase. CONCLUSION: The cause of death in RA is difficult to analyze accurately because RA itself is a chronic systemic inflammation disease.