Extraction and differentiation of the Su autoantigen from calf thymus nuclei.

Antibodies to Su antigen have been reported previously as a distinct antigen-antibody system associated with connective tissue diseases; most specifically systemic lupus erythematosus and undifferentiated connective tissue disease. The Su antigen was first identified by double immunodiffusion using calf thymus nuclear extract (CTNE) as a source for Su antigen. In this report, enhanced extraction of Su antigen was achieved using deoxyribonuclease I (DNase) for preparation of CTNE. Only the Sm antigen was found in comparable quantities in the DNase CTNE. Western immunoblotting and immunoprecipitation employing DNase CTNE and extracts of [35S]methionine-labeled HeLa cells respectively were used for further characterization and differentiation of the Su antigen. Sera from patients positive for Su antibodies by double immunodiffusion were found to react most specifically with antigen components in a molecular weight range of approximately 50-55 kDa. These methods should assist in further understanding the biochemical properties of the Su antigen.

Pristane induces high titers of anti-Su and anti-nRNP/Sm autoantibodies in BALB/c mice. Quantitation by antigen capture ELISAs based on monospecific human autoimmune sera.

Autoantibodies to Su and anti-nRNP/Sm are common in human and murine systemic lupus erythematosus (SLE), and are also produced by BALB/c mice with SLE-like autoimmunity induced by pristane. Antigen capture ELISAs employing monospecific human autoimmune IgG were developed to quantitate the production of anti-Su and anti-nRNP/Sm autoantibodies in 77 sera from BALB/c mice with pristane-induced autoimmunity. The sensitivity and specificity of the anti-Su antigen capture ELISA were 100% compared with immunoprecipitation of 35S-labeled cellular proteins. All 16 immunoprecipitation positive sera were positive in the anti-nRNP/Sm antigen capture ELISA (100% sensitivity), whereas 55/61 immunoprecipitation negative sera were negative by ELISA (90% specificity). The 6/61 immunoprecipitation negative sera that were ELISA positive were probably true positives because subsequent sera obtained from the same mice were positive by both techniques. Thus, the antigen capture ELISA may be somewhat more sensitive than immunoprecipitation. The titers of anti-Su and anti-nRNP/Sm positive antibodies in the sera were as high as 1:25,000-1:250,000 by ELISA, suggesting that autoantibodies may be produced in pristane-primed BALB/c mice at levels comparable to those seen in spontaneous autoimmune disease. We conclude that antigen capture ELISAs based on human autoimmune sera were highly sensitive and specific for detecting murine anti-Su and anti-nRNP/Sm antibodies. This technique will be useful for quantitating antibodies in murine autoimmune disease models, since antigen capture ELISA avoids the use of denatured or recombinant antigens, permitting antibodies recognizing tertiary and quaternary structures to be detected.

Synovial cysts and ganglia: the value of magnetic resonance imaging.

Synovial and ganglion cysts commonly present in close proximity to joints and skeletal structures in rheumatic disorders. Familiarity with the presentation of these soft tissue masses can facilitate timely diagnosis and effective management, thus avoiding costly and potentially high-risk procedures to patients. Management usually consists of local, nonsurgical approaches. A patient with chronic joint deformities and clinical features primarily consistent with mixed connective tissue disease is described. Multiple localized masses developed at her right elbow and were identified on T2-weighted magnetic resonance imaging as multiloculated cysts that dissected from the elbow joint. The cysts were treated successfully by needle aspiration and intraarticular corticosteroid injection. The clinical associations, diagnosis, treatment, and management of synovial cysts and ganglions are reviewed.

Diagnosis of inflammatory myopathy by percutaneous needle biopsy with demonstration of the focal nature of myositis.

Inflammatory myopathies are a group of acquired disorders with histologic features of inflammation and nonspecific myopathic changes in the muscle fibers. Up to 25% of patients with clinical features of polymyositis reportedly have no inflammatory changes in their muscle biopsy specimens, but the absence of inflammatory infiltrates does not exclude an inflammatory myopathy. However, whether the lack of inflammation is caused by sampling variation or by a total lack of demonstrable inflammation in a particular patient has been unclear in the literature. The authors diagnosed polymyositis in six patients who underwent percutaneous muscle biopsy using a Bergstrom needle. Through one skin incision, the needle was inserted into different areas within the muscle compartment, obtaining three or four concurrent specimens from each patient. In all cases of needle biopsy, adequate tissue was obtained for histochemical and electron microscopic examination. All patients tolerated the procedure well and resumed normal daily activities the morning after biopsy. Although we saw inflammatory changes in at least one biopsy specimen from each patient, one or more of the remaining specimens contained no evidence of inflammation. This illustrates that inflammatory infiltrates can be focal in polymyositis. Because a specific diagnosis of inflammatory myopathy cannot be made in the absence of demonstrable inflammation, the diagnostic yield of multiple percutaneous needle biopsy specimen is potentially higher than that of the traditional single biopsy specimen obtained with the open surgical method.

Cardiac tamponade and pericardial disorders in connective tissue diseases: case report and literature review.

Pericardial disorders occurring in connective tissue diseases are not uncommon and may present as acute or chronic pericarditis with or without an effusion. In many instances, a diagnosis of pericardial involvement is not found until autopsy. Echocardiography and other currently employed radiographic techniques have enhanced the ability to make a diagnosis. Approximate frequencies of common connective tissue disorders with pericardial involvement include scleroderma (59%), systemic lupus erythematosus (44%), mixed connective tissue disease (30%), rheumatoid arthritis (24%), and polymyositis/dermatomyositis (11%). Cardiac tamponade or constriction is rare. This article describes a patient with clinical features consistent with mixed connective tissue disease that presented with a pericardial effusion and cardiac tamponade. In addition, a review of pericardial involvement in connective tissue diseases and the occurrence of cardiac tamponade or constriction is included.

Thoracolumbar compression fractures presenting with an acute ileus.

Corticosteroids are commonly used in the treatment of connective tissue diseases such as systemic lupus erythematosus. Although they are usually efficacious, osteoporosis leading to spine compression fractures is not uncommon. In this case report, we describe an elderly patient with systemic lupus erythematosus on long-term corticosteroid therapy who presented with symptoms of acute abdomen with minimal low back symptoms. No intraabdominal process was found by abdominal studies and exploratory laparotomy. Increased lower back symptoms led to further skeletal spine studies, which initially demonstrated a compression fracture at the twelfth thoracic (T12) vertebra. Later, a T8 and a fourth lumbar (L4) compression fracture were also found. Her abdominal and lower back symptoms resolved on conservative therapy. Although the rate of these occurrences are unknown, compression spine fractures should be considered in elderly patients presenting with acute abdomen after being on long-term corticosteroid therapy.

Childhood agricultural and adult occupational exposures to organic dusts in a population-based case-control study of systemic lupus erythematosus.

Organic dust exposure can influence the development and symptoms of immune-related diseases such as atopy and asthma, but has rarely been examined in relation to systemic autoimmunity. The present analyses explore the association of lifetime farm and occupational organic dust exposures with systemic lupus erythematosus (SLE) in recently diagnosed patients (n = 265) compared with controls (n = 355) frequency matched by age, sex and state. Questionnaire data included childhood farm residence, childhood and adult experience with specific crops, and adult work in textiles, hog or poultry processing and paper or furniture manufacture. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated by logistic regression models including age, sex, state, race, education and silica exposure. Overall childhood or adult farm contact and childhood farm residence were not associated with SLE. Farm contact with livestock was inversely associated with SLE (OR = 0.55, 95% CI 0.35, 0.88). This effect was most pronounced among those with childhood farm residence and both childhood and adult livestock exposure (OR = 0.19; 95% CI 0.06, 0.63), but was difficult to separate from adult exposure to grains or corn. Other adult occupational exposures were not associated with SLE risk overall, regardless of childhood farm residence or livestock exposure, although an inverse association was seen among non-smokers (OR = 0.59; 95% CI 0.33, 1.1), particularly for textile work (OR = 0.34; 95% CI 0.19, 0.64). These exploratory findings support the development of studies to specifically investigate the effects of organic dust exposure on SLE risk, with particular attention to exposure assessment and characterization of demographics, smoking and other occupational exposures.

Method for analysis of antigen-antibody precipitins in double immunodiffusion.

Ribonucleoprotein (RNP) antigen-antibody precipitin bands obtained by two-dimensional double immunodiffusion were systematically analyzed and compared using a microcomputer and a SPSS-PC statistical analysis package. Precipitins rated in respective agarose concentrations ranging from 0.3% to 1.5% were obtained from twofold dilutions of a calf thymus nuclear extract (CTNE) containing RNP antigen. These dilutions were reacted against the same dilutions of plasma containing anti-RNP antibody. A Mean Quality Index Score was calculated at each agarose concentration from the sum of ratings assigned for the intensity (thickness) of precipitin bands times the sum of ratings assigned for the clarity (clearness and sharpness) of the precipitin bands. This product was divided by the total number of possible precipitin reactions. The Mean Quality Index Score for the 0.4% agarose was significantly higher than the other concentrations (p less than or equal to 0.05). This method or similar approaches may allow a more systematic way of comparing precipitins developed in gel immunodiffusion.

Coombs'-negative spherocytic hemolytic anemia and severe necrotizing renal vasculitis.

Vasculitis may be complicated by either hypoproliferative or hemolytic anemias. We have described a patient with a Coombs'-negative spherocytic hemolytic anemia and severe necrotizing renal vasculitis, two disorders not having been previously linked. The disorders were temporally related and both responded to immunosuppressive therapy. The precise cause of the hemolytic anemia remains unknown.

Characterization of a new antigen-antibody system (Su) in patients with systemic lupus erythematosus.

A new antigen (Su) from calf thymus nuclear extract that reacts with sera from patients with systemic lupus erythematosus (SLE) is described. Antibodies to Su, demonstrated by immunodiffusion, were most frequently found in patients with a diagnosis of probable or definite SLE. Thirty-seven percent of patients with Su antibodies and a diagnosis of SLE were positive for antinuclear antibodies by indirect immunofluorescence, but lacked specific antibodies previously associated with SLE. Patients with Su antibodies exhibited a higher frequency of Raynaud's phenomenon, but exhibited a lower frequency of malar rash, alopecia, and arthritis when compared with SLE patients in previously published reports. The Su antigen is weakly acidic, heat-stable at 37 degrees C, heat-sensitive at 56 degrees C, resistant to DNase and RNase, but sensitive to trypsin. Its molecular weight approximated 154,000 daltons by Sepharose chromatography. The Su antibody may be associated with a subset of SLE patients with distinct clinical features, and may serve as a serologic marker for patients who are positive for fluorescent antinuclear antibodies but have no other detectable SLE-associated antibodies.

Syndrome of the rectus abdominis muscle mimicking the acute abdomen.

The syndrome of the rectus abdominis muscle is a disorder of unknown etiology that produces rupture or tear of the epigastric artery, and stretches the rectus cutaneous medialis nerve, producing excruciating pain. The disorder is misdiagnosed in 60% to 93% of cases. We report two cases that presented as acute abdomen. One helpful diagnostic test was the lidocaine test, accomplished by subcutaneous injection of lidocaine into the sheath of the rectus abdominis muscle near the rectus cutaneous medialis nerve; the procedure provided immediate pain relief and the patients remained asymptomatic. In addition to helping establish a diagnosis quickly the lidocaine test may spare the patient the unnecessary morbidity or mortality of more invasive procedures.

Salicortin: a repeat-attack new-mechanism-based Agrobacterium faecalis beta-glucosidase inhibitor.

Salicortin, a natural product abundant in most members of the Salicaceae family, is a mechanism-based inactivator of Agrobacterium faecalis beta-glucosidase. Inactivation is delayed in the presence of competitive inhibitors, thereby demonstrating the requirement for an enzyme-bound salicortin before inactivation. Product studies suggest that inactivation proceeds via a quinone methide intermediate formed by the fragmentation of the aglycone of salicortin while it is bound to the enzyme. Tryptic digest and HPLC/MS studies confirm the role of quinone methide attack and also show that the enzyme undergoes multiple modifications. In addition, when the inactivation was run in the presence of a mutant inactive form of the enzyme, HPLC/MS analyses clearly showed no modification of the mutant enzyme, demonstrating that the quinone methide does not exist in free solution and suggesting that inactivation is active-site directed.

Clinical relevance of PM-1 antibody and physiochemical characterization of PM-1 antigen.

Using an improved immunodiffusion test with partially purified antigen, PM-1 antibody was identified in the serum of 18 patients. In 67% this system was associated with a polymyositis-scleroderma overlap, it occurred less frequently in polymyositis, dermatomyositis and scleroderma, and was not detected in other rheumatic diseases. The predominant clinical features of PM-1 positive patients were muscle weakness, sclerodactyly, Raynaud's phenomenon and pulmonary disease; widespread sclerodermatous features with infrequent. Characterization of the PM-1 antigen showed it to be a heat sensitive, trypsin sensitive acidic protein associated with the cell nucleus and possibly with nucleoli.

MRL mice produce anti-Su autoantibody, a specificity associated with systemic lupus erythematosus.

Certain autoimmune mouse strains exhibit features similar to human SLE. To discover genetic and immunologic events governing expression of a new SLE-associated antibody, the presence of anti-Su and its relationship to other SLE-related antibodies (anti-Sm, -ribonucleoprotein, -Ro (SS-A), -La (SS-B)) were determined in MRL and other autoimmune and nonautoimmune mice. By double immunodiffusion, sera from 34/183 (19%) 4- to 10-mo-old MRL/Mp-lpr/lpr (MRL/lpr) and 28/108 (26%) 8- to 20-mo-old MRL/Mp(-)+/+ (MRL/+) mice were positive for anti-Su antibodies. Anti-Sm antibodies were found in 60/183 (33%) and 39/108 (36%) of these animals, respectively. The two specificities were found together in individual mice more frequently than would be predicted by chance. In contrast, C57BL/6-lpr/lpr (B6/lpr) mice rarely showed either specificity. Analysis of F1 hybrids between B6/lpr and MRL/lpr and of F1 x MRL/lpr backcross mice suggested that a small number of autosomal recessive genes controlled the anti-Su and anti-Sm responses. With the exception of a single NZB serum sample, NZB, BXSB, and nonautoimmune mice were negative for all antibodies tested, and no mice were positive for anti-RNP, anti-Ro, or anti-La. MRL/lpr and MRL/+ autoimmune mice thus provide unique models for human SLE, because they express several of the SLE-specific marker autoantibodies. These models should be useful in disclosing molecular and immunologic events governing autoantibody expression in this condition.

Antibodies to a nuclear/nucleolar antigen in patients with polymyositis overlap syndromes.

A precipitating antigen-antibody system has been characterized that occurs in patients with polymyositis. At least half of the patients not only have polymyositis but also have scleroderma. The proposed name for this antigen found in calf thymus extract (CTE) is PM-Scl, to indicate the almost universal presence of polymyositis and the frequent occurrence of scleroderma in the patients who make antibodies to this antigen. The antigen is probably nucleolar since all sera which precipitate with the PM-Scl antigen stain the nucleoli of Hep2 cells by indirect immunofluorescence. The PM-Scl immune system is a distinctive one different from the other known precipitins that occur in patients with polymyositis and dermatomyositis including Jo1, nRNP, and Mi. This PM-Scl antigen and its antibody represent one system which constitutes part of the reactions previously designated as PM1. Interlaboratory exchange of sera and extracts have established the unique nature of this reaction which occurs in patients with inflammatory myopathy.

Smoking and use of hair treatments in relation to risk of developing systemic lupus erythematosus.

OBJECTIVE: To examine the association between smoking and hair treatments (dyes, permanents) and risk of developing systemic lupus erythematosus (SLE). METHODS: Patients (n = 265) diagnosed between January 1, 1995, and July 31, 1999, were recruited through 4 university based and 30 community based rheumatology practices in eastern North Carolina and South Carolina. Controls (n = 355) were identified through driver's license records and were frequency matched to patients by age, sex, and state. Data collection included a 60 min in-person interview. Analyses were limited to experiences that occurred before age at diagnosis (patients) or reference age (controls). Because the prevalence of use of hair treatments among men was very low, the analyses of those exposures were limited to women. RESULTS: There was no association with smoking history and risk of developing SLE when analyzed as status (current, former, or never-smoker) or measures of dose (duration or pack-years). Use of permanent hair dyes in women was associated with a small increased risk of developing SLE (OR 1.5, 95% CI 1.0, 2.2). This association increased with longer duration of use (compared with nonusers, OR 1.7, 95% CI 1.0, 2.7 for 6 or more years). There was little evidence of an association between SLE and use of temporary dyes or of permanents and straighteners. CONCLUSION: These results suggest at most a weak association between SLE risk and permanent hair dyes or smoking. Genetic variability in the metabolism of these products may be important to assess in future studies.

Eosinophilic fasciitis with porphyria cutanea tarda and progressive destructive arthritis.

The course of arthritis with eosinophilic fasciitis is poorly documented. We report a patient in whom polyarthritis preceded the clinical appearance of eosinophilic fasciitis and progressed over a 14-year period to a destructive process with inflammatory and degenerative characteristics. Porphyria cutanea tarda and transient extramedullary pancytopenia complicated this patient's disease.

Systemic lupus erythematosus and genetic variation in the interleukin 1 gene cluster: a population based study in the southeastern United States.

BACKGROUND: Interleukin (IL)1alpha and IL1beta, and their endogenous receptor antagonist (IL1Ra), have been related to the pathology of systemic lupus erythematosus (SLE), but the role of IL1 polymorphisms in the aetiology of SLE is unknown. OBJECTIVE: To examine polymorphisms at IL1alpha -889(C-->T), IL1alpha +4845(C-->T), IL1beta -511(C-->T), IL1beta +3953(G-->T), and IL1Ra (86 bp VNTR) in a population based study of SLE in North Carolina and South Carolina. METHODS: Genotypes from 230 cases who met ACR classification criteria, and from 275 controls matched for age, sex, and state, were analysed separately for African Americans and whites. Odds ratios (ORs) were estimated by logistic regression models for each locus alone and also after adjusting for polymorphisms at adjacent loci. RESULTS: An increased risk of SLE for the IL1alpha -889C/C genotype compared with carriage of the -889T allele was found in both African Americans (OR = 3.1, p = 0.001) and whites (OR = 2.9, p = 0.005). In African Americans, carriage of the IL1beta -511T allele was associated with a higher risk of SLE than carriage of the -511C/C genotype (OR = 2.4, p = 0.017), independent of variation at IL1alpha -889. CONCLUSIONS: The observed associations support the hypothesis that genetic variation in IL1 is involved in the aetiology of SLE and merit further investigation.