A comparison of patients' and physicians' assessments of disease activity using the Swedish version of the Systemic Lupus Activity Questionnaire.

OBJECTIVES: We compared patients' assessments of systemic lupus erythematosus (SLE) disease activity by a Swedish version of the Systemic Lupus Activity Questionnaire (SLAQ) with physicians' assessments by the Systemic Lupus Activity Measure (SLAM) and Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K). We also explored the performance of the SLAQ in patients with short (< 1 year) versus long (≥ 1 year) disease duration. METHOD: Patients filled out the SLAQ before physicians' assessments. Correlations between SLAQ total, subscales (Symptom score, Flares, Patients global) and SLAM and SLEDAI-2K, as well as between the corresponding items in SLAQ and SLAM, were evaluated using Spearman's ρ. Comparisons between patients with different disease durations were performed with Mann-Whitney U or chi-squared tests. RESULTS: We included 203 patients (79% women), with a median age of 45 years [interquartile range (IQR) 33-57 years] and disease duration of 5 years (IQR 0-14 years). Correlations between physicians' SLAM without laboratory items (SLAM-nolab) and patients' assessments were: SLAQ total, ρ = 0.685, Symptom score, ρ = 0.651, Flares, ρ = 0.547, and Patients global, ρ = 0.600. Of the symptom items, fatigue (ρ = 0.640), seizures (ρ = 0.635), and headache (ρ = 0.604) correlated most closely. Neurology/stroke syndrome, skin, and lymphadenopathy correlated less well (ρ < 0.24). Patients' and physicians' assessments were notably more discordant for patients with short disease durations. CONCLUSION: We confirm that the SLAQ can be used to monitor disease activity. However, the discrepancy between patients' and physicians' assessments was greater for patients with short versus long disease duration. We encourage further use of the SLAQ, but would like to develop a shorter version which would be valuable in modern, partly web-based, clinical care.

Anti-Ro/SSA autoantibody-positive women's experience of information given on the risk of congenital heart block.

OBJECTIVE: Congenital heart block (CHB) may develop in fetuses of women with anti-Ro/SSA autoantibodies, and carries substantial morbidity and mortality. The aim was to evaluate how information on CHB is imparted and identify areas of improvement. METHODS: A questionnaire was distributed to anti-Ro/SSA antibody-positive women who had either participated in a surveillance programme but whose expected child did not develop CHB (n = 100, denoted Doppler-Assessed Pregnancies (DAP) group) or given birth to a child with CHB (n = 88, denoted CHB-Affected Pregnancies (CAP) group). RESULTS: The response rate was 83% (157/188). Most women received the information on CHB when they were already pregnant (DAP group 60%, CAP group 83%). However, a majority of them would have wanted the information before pregnancy (DAP group 52%, CAP group 56%), and most stated that it would not have influenced their decision to have a child (DAP group 77%, CAP group 58%). The ability to both understand the information and to perceive the information as sufficient were significantly higher when someone trained in paediatric cardiology gave the information. CONCLUSIONS: Our findings indicate that information on CHB should be given to women before pregnancy. The data further highlight the importance of having specific knowledge for giving relevant and understandable, yet sufficient information.

Ro/SSA autoantibody-positive pregnancy: reactions to serial fetal Doppler echocardiographic surveillance.

OBJECTIVE: The risk for congenital heart block (CHB) associated with maternal Ro/SSA autoantibodies is low, but the possibility of treating early stages of disease has seen the introduction of Doppler echocardiographic surveillance programs with serial examinations during the CHB susceptibility weeks of pregnancy. The aim of the present study was to understand how Ro/SSA autoantibody-positive women having undergone Doppler echocardiographic surveillance programs and giving birth to children without CHB experienced their pregnancy and frequent ultrasound examinations. METHODS: A validated questionnaire based on data from an interview-study was distributed to Ro/SSA-positive women supervised with Doppler examinations during their pregnancy (n = 100). RESULTS: The response rate was 79%. The majority of the women (61%) reported that the increased number of ultrasound examinations influenced their pregnancy, but in a positive way, with qualified information and additional support from health care personnel in conjunction with the examinations. Further, the visits to the clinic provided opportunities to see the ultrasound picture of the expected infant. However, one-third of the women also reported stress in relation to the examinations. CONCLUSIONS: Fetal echocardiographic surveillance holds many and predominantly positive effects for Ro/SSA-positive women during pregnancy in addition to the medical advantages.

Determination of the minimal clinically important difference for seven measures of fatigue in Swedish patients with systemic lupus erythematosus.

OBJECTIVE: To estimate the minimal clinically important difference (MCID) in seven self-administered measures assessing fatigue in Swedish patients with systemic lupus erythematosus (SLE). METHOD: The participants (n = 51, women 98%, age 52.8 ± 12.1 years, disease duration 18.7 ± 13.6 years) met in groups of six to nine persons. After completing seven fatigue questionnaires [the Fatigue Severity Scale (FSS); the Multidimensional Assessment of Fatigue (MAF) scale; the 20-item Multidimensional Fatigue Inventory (MFI); the Chalder Fatigue Scale (CFS); the Short Form-36 Vitality subscale (VT); the Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-F) scale; and the Numeric Rating Scale (NRS)], each respondent had a minimum of five face-to-face discussions, followed by an individual comparative assessment of their own level of fatigue (seven-grade scale). This method resulted in 260 contrasting assessments; MCIDs were first calculated using the paired differences and then established by a regression approach. Patients were asked to comment on their experience with the questionnaires and whether they captured their fatigue adequately. RESULTS: The paired approach (using 'little more fatigue' as an anchor for MCID during the face-to-face comparative assessments) provided estimates of 4.6-17.0; the regression approach provided estimates of 4.3-10.8. Estimates using the regression approach were consistently lower than those using the paired model. The MCID estimates were least favourable and fewer respondents supported the use of the NRS compared to the other self-reported questionnaires. CONCLUSIONS: All seven instruments detect MCIDs for fatigue in Swedish patients with SLE. However, the single-question measure was not supported by the MCID estimates or by comments from the respondents.

Lifestyle habits and fatigue among people with systemic lupus erythematosus and matched population controls.

OBJECTIVE: The objective of this paper is to identify clusters of fatigue in patients with systemic lupus erythematosus (SLE) and matched controls, and to analyze these clusters with respect to lifestyle habits, health-related quality of life (HRQoL), anxiety and depression. METHODS: Patients with SLE (n = 305) and age- and gender-matched population controls (n = 311) were included. Three measurements of fatigue (Fatigue Severity Scale (FSS), Vitality (VT, from SF-36) and Multidimensional Assessment of Fatigue scale (MAF) and hierarchic cluster analysis were used to define clusters with different degrees of fatigue. Lifestyle habits were investigated through questionnaires. HRQoL was assessed with the SF-36 and anxiety/depression with the Hospital Anxiety and Depression Scale. RESULTS: Three clusters, denominated "High," "Intermediate" and "Low" fatigue clusters, were identified. The "High" contained 80% patients, and 20% controls (median; VT 25, FSS 5.8, MAF 37.4). These had the most symptoms of depression (51%) and anxiety (34%), lowest HRQoL (p < 0.001) and they exercised least frequently. The "Intermediate" (48% patients and 52% controls) (median; VT 55, FSS 4.1, MAF 23.5) had similarities with the "Low" regarding sleep/rest whereas social status and smoking were closer to the "High." The"Low" contained 22% patients and 78% controls (median; VT 80, FSS 2.3, MAF 10.9). They had the highest perceived HRQoL (p < 0.001), least symptoms of anxiety (10%), no depression, smoked least (13%) and reported the highest percentage (24%) of exercising ≥ 3 times/week. CONCLUSION: Fatigue is common, but not a general feature of SLE. It is associated with depression, anxiety, low HRQoL and less physical exercise. Patients with SLE and population controls with a healthy lifestyle reported lower levels of fatigue. Whether lifestyle changes can reduce fatigue, which is a major problem for a majority of SLE patients, needs to be further explored.

Fear-avoidance beliefs about physical activity in adults with rheumatoid arthritis.

OBJECTIVES: The aim of this study was to describe fear-avoidance beliefs about physical activity and explore how these beliefs correlate with sociodemographic, disease-specific, and psychosocial factors in adults with rheumatoid arthritis (RA). METHOD: This cross-sectional study is part of the Physical Activity in Rheumatoid Arthritis (PARA) 2010 study. The study participants (n = 2351) were identified through the Swedish Rheumatology Quality (SRQ) registries from six rheumatology clinics in Sweden. Univariate and backwards stepwise logistic regressions were performed. RESULTS: Stepwise logistic regressions showed that male gender [odds ratio (OR) 1.55, 95% confidence interval (CI) 1.26-1.91] and having a below average income (OR 1.35, 95% CI 1.12-1.63) were associated with an increased risk of high scores on the modified Fear Avoidance-Belief Questionnaire (mFABQ). The two disease-specific factors most indicative of high mFABQ scores were high level of pain (OR 1.99, 95% CI 1.40-2.84) and poor health (OR 1.59, 95% CI 1.10-2.29). With regard to psychosocial factors, low health-related quality of life (HRQoL; OR 0.44, 95% CI 0.35-0.55) and a low score on the Exercise Self-Efficacy Scale (ESES; OR 0.66, 95% CI 0.52-0.82) were significantly associated with a high mFABQ score. The model fit was 0.27 (Nagelkerke's R(2)). CONCLUSIONS: High fear-avoidance beliefs about physical activity in patients with RA were found to be associated with being male and having a below average income, a high level of pain, poor health, a low HRQoL, and low ESES score. Additional research is warranted for adults with RA to capture the multiple potential correlates to fear-avoidance beliefs about physical activity.

Health-related quality of life, fatigue and mood in patients with SLE and high levels of pain compared to controls and patients with low levels of pain.

Objective The objective of this paper is to investigate health-related quality of life (HRQoL), fatigue, anxiety and depression in patients with systemic lupus erythematosus (SLE) and higher levels of pain and to compare them to patients with lower levels of pain and controls. Method Patients were dichotomized into two groups based on SLE-related pain score on the visual analog scale (VAS): low-pain group (76%, n=64, VAS 0-39 mm) and high-pain group (24%, n=20, VAS 40-100 mm). Sex- and age-matched controls were randomly selected from the general population. Participants were asked to complete questionnaires regarding self-reported pain, HRQoL, fatigue, anxiety and depression. Medical assessments also were recorded. Result Fatigue score in the high-pain group (median, 36.5; interquartile range (IQR), 32.5-39.7) was significantly higher (p<0.001) compared to the low-pain group (median, 23; IQR, 14.6-34.1), as well as scores for anxiety (median, 9; IQR, 6.5-11.5) and depression (median, 7.5; IQR, 5.5-9) (p<0.001). The high-pain group had significantly lower scores compared to the low-pain group in all dimensions in the SF-36 (p ≤ 0.001-0.007). No statistical differences were detected between the low-pain group and controls in any measurement except for the dimensions physical function, general health, vitality and social function in SF-36. Conclusion Patients with SLE scoring higher degrees of pain were burdened with more fatigue, anxiety and depression and lower levels of HRQoL compared to patients with lower levels of pain who did not differ significantly from the general population in most dimensions. These results elucidate the importance of identifying patients with higher degrees of pain who are probably in need of more extensive multidimensional interventions to decrease symptom burden.

Extent and characteristics of self-reported pain in patients with systemic lupus erythematosus.

OBJECTIVE: Patients' own experiences of subjective symptoms are scarcely covered, and the objective of this study was to investigate the extent and characteristics of self-reported pain in patients with systemic lupus erythematosus (SLE). METHODS: This study comprised a cross-sectional design where 84 patients with SLE were asked to complete self-assessments: visual analogue scale of pain and the Short-Form McGill Pain Questionnaire. Medical assessments, including ESR, SLAM, SLEDAI, and SLICC, were also performed. RESULTS: Of the study population, 24% reported higher levels of SLE-related pain (≥40 mm on VAS). This group had a significantly shorter disease duration, higher ESR, and higher disease activity, according to the SLAM and SLEDAI, compared to the rest of the study population. This group mainly used the words "tender," "aching," and "burning" to describe moderate and severe pain, and they used a greater number of words to describe their pain. Of the patients with higher levels of pain, 70% reported their present pain as "distressing." The most common pain location for the whole patient population was the joints. Patients rated their disease activity significantly higher than physicians did. CONCLUSION: These findings expand the current knowledge of the extent of SLE-related pain and how patients perceive this pain. The results can contribute to affirmative, supportive and caring communication and especially highlight SLE-related pain in patients with a short disease duration and high disease activity.

An exploration of patient-reported symptoms in systemic lupus erythematosus and the relationship to health-related quality of life.

OBJECTIVE: The aim of this study was to explore the most distressing symptoms of systemic lupus erythematosus (SLE) and determine how these relate to health-related quality of life (HRQoL), anxiety/depression, patient demographics, and disease characteristics (duration, activity, organ damage). METHODS: In a cross-sectional study, patients with SLE (n = 324, age 18-84 years) gave written responses regarding which SLE-related symptoms they experienced as most difficult. Their responses were categorized. Within each category, patients reporting a specific symptom were compared with non-reporters and analysed for patient demographics, disease duration, and results from the following questionnaires: the Medical Outcomes Study 36-item Short Form Health Survey (SF-36), the Hospital Anxiety and Depression Scale (HADS), the Systemic Lupus Activity Measure (SLAM), the SLE Disease Activity Index (SLEDAI), and the Systemic Lupus International Collaboration Clinics/American College of Rheumatology (SLICC/ACR) damage index. RESULTS: Twenty-three symptom categories were identified. Fatigue (51%), pain (50%), and musculoskeletal distress (46%) were most frequently reported. Compared with non-reporters, only patients reporting fatigue showed a statistically significant impact on both mental and physical components of HRQoL. Patients with no present symptoms (10%) had higher HRQoL (p < 0.001) and lower levels of depression (p < 0.001), anxiety (p < 0.01), and disease activity (SLAM) (p < 0.001). CONCLUSION: Fatigue, pain, or musculoskeletal distress dominated the reported symptoms in approximately half of the patients. Only patients reporting fatigue scored lower on both mental and physical aspects of HRQoL. Our results emphasize the need for further support and interventions to ease the symptom load and improve HRQoL in patients with SLE. Our findings further indicate that this need is particularly urgent for patients with symptoms of pain or fatigue.

Corticosteroid treatment selectively decreases mast cells in the smooth muscle and epithelium of asthmatic bronchi.

BACKGROUND: Mast cells are important in the pathophysiology of airway inflammation and evidence suggests their sub-localisation within the airway is altered in asthma. Little is known about the effect of corticosteroids on mast cell localisation within the bronchi. METHODS: We therefore performed an immunohistochemical analysis of mast cell numbers within the smooth muscle, epithelium and submucosa of healthy subjects (n = 10) and well-characterised asthmatic patients, using either ß(2)-agonists alone (n = 10) or ß(2)-agonists and inhaled corticosteroids (n = 10). RESULTS: Patients using inhaled corticosteroids displayed significantly lower numbers of mast cells within their epithelium and smooth muscle compared to those not treated with inhaled corticosteroids. Submucosal mast cells were not affected by corticosteroid treatment. Numbers of smooth muscle mast cells correlated with bronchial responsiveness and epithelial mast cells with exhaled NO. CONCLUSION: We demonstrate that glucocorticosteroids differentially affect mast cell numbers within specific airway sub-locations highlighting the importance of mast cell and smooth muscle/epithelial interactions in asthma pathogenesis.

Diagnostic performance of routine ultrasound screening for fetal abnormalities in an unselected Swedish population in 2000-2005.

OBJECTIVES: To determine the detection rate of fetal malformations and chromosomal abnormalities and the rate of false-positive ultrasound diagnoses at routine ultrasound examinations carried out by specially trained midwives in an unselected pregnant population from 2000 to 2005, and to describe the consequences of true-positive and false-positive ultrasound diagnoses of fetal malformations. METHODS: A retrospective analysis was undertaken of all babies born in Malmö, Sweden, between January 2000 and December 2005 by mothers residing in Malmö and of all fetuses with an ultrasound diagnosis of malformation made in the same time interval at the two units performing all routine pregnancy scans in Malmö. All women underwent two routine scans, at 18 and 32 weeks, including scrutiny of the fetal anatomy. Detection rates and false-positive rates were calculated per fetus. RESULTS: The prevalence of chromosomally abnormal fetuses was 0.31% (52/16 775); that of chromosomally normal fetuses with major and minor malformations was 1.80% (302/16 775) and 1.32% (222/16 775), respectively. The detection rate of fetuses with major malformations but normal chromosomes was 68% (205/302), with a detection rate at < 22 weeks of 37% (112/302). In addition, 46% (24/52) of all chromosomally abnormal fetuses were diagnosed before birth because a malformation was detected at ultrasound imaging, 33% (17/52) being detected at < 22 gestational weeks. In all, 68 pregnancies were terminated because of an ultrasound diagnosis of fetal malformation (0.4% of all pregnancies and 47% of the pregnancies in which a fetal malformation was detected by ultrasound examination before 22 weeks). A false-positive ultrasound diagnosis of malformation was made in 0.19% (31/16 180) of the normally formed fetuses and in 20 (0.12%) fetuses the abnormal finding persisted during pregnancy. No fetus assigned a false-positive diagnosis was lost by termination of pregnancy, but most were subjected to one or more unnecessary interventions before birth (e.g. amniocentesis), at birth (e.g. Cesarean section) or after birth (e.g. electrocardiogram, X-ray, ultrasound examination or treatment with antibiotics). CONCLUSIONS: In a screening program consisting of one fetal anomaly scan at 18 weeks and another at 32 weeks the detection rate of major malformations in chromosomally normal fetuses was 68% with a detection rate of 37% at < 22 weeks. The corresponding detection rates of chromosomally abnormal fetuses were 46% and 33%. Fewer than one in 500 screened fetuses had an ultrasound diagnosis of an anomaly that was not confirmed after birth.

Effect of formoterol with or without budesonide in repeated low-dose allergen challenge.

The use of combination therapy in mild asthma is debated. The current authors evaluated the effects of formoterol alone and a formoterol/budesonide combination inhaler on asthma deterioration induced by repeated low-dose allergen exposure. In total, 15 subjects with intermittent allergic asthma inhaled low doses of allergen on seven consecutive weekdays in a three-period, crossover, double-blind, double-dummy comparison between formoterol 4.5 microg Turbuhaler, budesonide 160 microg/formoterol 4.5 microg Turbuhaler and placebo, each taken as two puffs 30 min after allergen dosing. The outcome variables were: provocative dose of methacholine causing a 20% fall in forced expiratory volume in one second (PD(20)), exhaled nitric oxide fraction (F(eNO)), sputum eosinophils and prostaglandin D(2), and diary card recordings of symptoms (on a scale of 0-10), short-acting beta(2)-agonist use and evening forced expiratory volume in one second (FEV(1)). With placebo treatment, allergen exposure caused significant increases in airway hyperresponsiveness (geometric mean (coefficient of variation) PD(20): 397 (98) microg before versus 168 (82) microg after), F(eNO) (mean+/-sd 46+/-31 ppb before versus 73+/-46 ppb after) and asthma symptom score (mean+/-sd 0.39+/-0.55 before versus 0.68+/-0.67 after). Budesonide/formoterol abolished these changes and significantly improved baseline FEV(1). Formoterol alone, while providing symptom relief, was no better than placebo in protecting against the allergen-induced increase in airway inflammation. Signs of deteriorating asthma, provoked by low-dose allergen, are prevented by short-term use of budesonide/formoterol but not by temporary use of formoterol alone.

Treatment of refractory SLE with rituximab plus cyclophosphamide: clinical effects, serological changes, and predictors of response.

OBJECTIVE: To evaluate efficacy, serological responses, and predictors of response in patients with severe and refractory systemic lupus erythematosus (SLE) treated with rituximab plus cyclophosphamide. METHODS: 16 patients entered a treatment protocol using rituximab plus cyclophosphamide. Disease activity was assessed by the SLE disease activity index (SLEDAI) and by the British Isles Lupus Assessment Group (BILAG) index. RESULTS: At six months follow up, mean SLEDAI values decreased significantly from (mean (SD)) 12.1 (2.2) to 4.7 (1.1). Clinical improvement (50% reduction in SLEDAI) occurred in all but three patients. All but one patient responded according to BILAG. Remission defined as SLEDAI <3 was achieved in nine of 16 patients. Isotype analysis of anti-dsDNA antibodies revealed preferential decreases of IgG and IgA, but not IgM. Higher absolute numbers of CD19+ cells at baseline were correlated with shorter depletion time (r = -0.6). CONCLUSIONS: The majority of patients improved following rituximab plus cyclophosphamide. The differential downregulation of anti-DNA of the IgG and IgA but not the IgM isotypes supports the hypothesis that cells producing pathogenic autoantibodies are preferentially targeted by the treatment. The fact that greater absolute numbers of CD19+ cells at baseline predict a less impressive clinical and serological response suggests that more flexible dosing could be advantageous.

Biopsy-verified response of severe lupus nephritis to treatment with rituximab (anti-CD20 monoclonal antibody) plus cyclophosphamide after biopsy-documented failure to respond to cyclophosphamide alone.

BACKGROUND: The monoclonal anti-B cell antibody rituximab (Rituxin, Mabthera) may be of benefit in antibody-driven diseases, including systemic lupus erythematosus (SLE) nephritis. PATIENTS AND TREATMENT: Two female patients with biopsy-confirmed severe and active SLE nephritis despite treatment with cyclophosphamide (CyX) were given four rituximab infusions plus two additional CyX infusions. RESULTS: Both patients tolerated the treatment well and SLE activity improved. On repeat kidney biopsy after the combined treatment, Patient 1 showed a profound reduction of nephritis activity, and she was maintained on low-dose prednisolone only. A repeat biopsy after 1 year confirmed the sustained reduction of lupus nephritis activity. In Patient 2, rebiopsy after combined treatment also showed a significant reduction in disease activity. CONCLUSION: These cases provide histopathological documentation of a significant treatment benefit from rituximab plus CyX in two patients refractory to CyX alone. This combination is being explored further as salvage therapy for such CyX-resistant patients.

Preventability of vehicle-related fatalities.

Several different methods have been used to evaluate the survivability of traffic injuries. Previously published methods were reviewed to develop a specific method for vehicle-related fatalities. All fatally injured victims (n = 474) of vehicle-related crashes in the four northern-most counties of Sweden during a 5-year period were studied. Almost half (48%) of the victims had non-survivable injuries. The remaining cases were classified into different injury groups according to the Injury Severity Score (ISS) including 56 (12%) with an ISS < 25, 150 (32%) with ISS 25-49 and 42 (9%) with ISS 50-74. The median distance from the scene to the nearest hospital was 49 km. In the cases with ISS < 50 the medical care was further analyzed. In close to half of these cases, the victim did not receive optimal care in time with transportation time being of major importance. The absence of first aid was judged to have contributed to the death in 4% of the cases.

Deficient brain snRNP70K in patients with Down syndrome.

The small nuclear ribonucleoprotein 70K (snRNP 70K; U1-70 kDa) is an integral part of the spliceosome, a large RNA-protein complex catalyzing the removal of introns from nuclear pre-mRNA. snRNP is one of the best-studied essential subunits of snRNPs, is highly conserved and its inactivation was shown to result in complete inhibition of splicing. Applying subtractive hybridization, we found a sequence with 100% identity to snRNP absent in fetal Down syndrome (DS) brain. This observation made us determine snRNP-mRNA steady-state levels and protein levels in brains of adult patients with DS. snRNP-mRNA and protein levels of five individual brain regions of DS and controls each, were determined by blotting techniques. snRNP-mRNA steady state levels were significantly decreased in DS brain. Performing Western blots with monoclonal and human antibodies, snRNP protein levels were decreased in several regions of DS brain, although one monoclonal antibody did not reveal different snRNP-immunoreactivity. Although decreased snRNP-protein could be explained by decreased mRNA-steady state levels, another underlying mechanism might be suggested: snRNP is one of the death substrates rapidly cleaved during apoptosis by interleukin-1-beta-converting enzyme-like (ICE) proteases, which was well-documented by several groups. As apoptosis is unrequivocally taking place in DS brain leading to permanent cell loses, decreased snRNP-protein levels may therefore reflect decreased synthesis and increased apoptosis-related proteolytic cleavage.

Characterization of recombinant human autoantibody fragments directed toward the autoantigenic U1-70K protein.

The U1-70K protein is specifically bound to stemloop I of the U1 small nuclear RNA contained in the U1 small nuclear ribonucleoprotein complex (U1 snRNP), which is involved in the splicing of pre-mRNA. All components of the U1 snRNP complex, including the U1-70K protein, are important autoantigens in patients with systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). Here we describe for the first time the selection and characterization of recombinant human anti-U1-70K single chain autoantibody fragments (anti-hU1-70K scFv) from autoimmune patient-derived phage display antibody libraries. All scFv specifically recognize parts of the hU1-70K protein and its apoptotic 40-kDa cleavage product. In Western blotting assays a number of scFv preferentially recognize the 40-kDa apoptotic cleavage fragment of the U1-70K protein, suggesting a possible involvement of this apoptotic cleavage product in the autoimmune response of patients. The germline gene usage of these recombinant autoantibodies was also determined. Using several U1-70K deletion and point mutants of both human (h) and Drosophila melanogaster (Dm) origin, it was established that the U1-70K epitope that is recognized by the anti-hU1-70K scFv is located within the RNA binding domain.

Key residues revealed in a major conformational epitope of the U1-70K protein.

Epitopes depending on three-dimensional folding of proteins have during recent years been acknowledged to be main targets for many autoantibodies. However, a detailed resolution of conformation-dependent epitopes has to date not been achieved in spite of its importance for understanding the complex interaction between an autoantigen and the immune system. In analysis of immunodominant epitopes of the U1-70K protein, the major autoantigen recognized by human ribonucleoprotein (RNP)-positive sera, we have used diversely mutated recombinant Drosophila melanogaster 70K proteins as antigens in assays for human anti-RNP antibodies. Thus, the contribution of individual amino acids to antigenicity could be assayed with the overall structure of the major antigenic domain preserved, and analysis of how antigenicity can be reconstituted rather than obliterated was enabled. Our results reveal that amino acid residue 125 is situated at a crucial position for recognition by human anti-RNP autoantibodies and that flanking residues at positions 119-126 also appear to be of utmost importance for recognition. These results are discussed in relation to structural models of RNA-binding domains, and tertiary structure modeling indicates that the residues 119-126 are situated at easily accessible positions in the end of an alpha-helix in the RNA binding region. This study identifies a major conformation-dependent epitope of the U1-70K protein and demonstrates the significance of individual amino acids in conformational epitopes. Using this model, we believe it will be possible to analyze other immunodominant regions in which protein conformation has a strong impact.

Autoantibody profiles in canine ANA-positive sera investigated by immunoblot and ELISA.

Canine systemic lupus erythematosus (SLE) has a similar disease expression as human SLE, but the serological characterisation of the canine disease is as yet incomplete. In the present study, we examined the specificity of antinuclear antibodies (ANA) in indirect immunofluorescence (IIF) positive canine sera. Sixty-four canine IIF ANA positive sera were characterised using HeLa cell nuclear extract immunoblots and recombinant U1-70K ELISA. We compared these results with a previously shown concordance between indirect immunofluorescence and immunodiffusion in canine SLE serological diagnosis. One canine serum reacting with Sm proteins was observed, and five canine sera presented anti-RNP autoantibodies against the antigens 70K, A, C, and/or B/B'. The autoantigen most frequently recognised was a 43 kDa nuclear protein, previously described as hnRNP G. This prominent canine autoantigen was missing in the commercially available extract designed for immunodiffusion testing of human sera. Other prominent canine autoantigens were found not to be identical with the principal human ones, thus making present human test systems deficient for the use in canine systemic connective disease diagnosis. The development of antigenic extract designed for canine autoimmune autoantigens is necessary in order to make immunodiffusion a useful method in canine diagnosis. The anti-RNP positive canine sera were examined in more detail and we found that the human major antigenic region of the most prominent RNP antigen, the U1-70K protein, also is targeted by canine autoantibodies. Thus, the response against the RNP antigen seems to be conserved between man and dog.

Autoepitope-mapping of the U1-70K protein with human-Drosophila chimeric proteins.

The 70K protein is the major autoantigen for anti-RNP autoantibodies directed against the U1 small nuclear ribonucleoprotein complex particle. The U1-70K protein has been epitope-mapped by various groups, and a major antigenic region of about 70 amino acids has been found which overlaps with the RNA binding motif. Attempts to map the major antigenic region further with smaller cloned fragments or with peptides have been hampered by total loss of, or strongly reduced, antigenicity. Thus the major antigenic region is composed of conformational epitopes and a detailed analysis of particular epitopes has not been possible. In the present work, we examine the antigenicity of chimeric proteins assembled from the highly conserved Drosophila melanogaster 70K proteins grafted with human 70K segments. With this approach, the effects on antigenicity of exchanging particular segments can be assayed with the overall structure of the major antigenic domain kept relatively constant. Our results, supported by depletion experiments, show that residues 99-128 from the human protein are essential for recognition by both human and canine anti-RNP autoantibodies. These residues have to be presented in a manner that allows correct conformational interaction between the different protein domains.