[Memorandum of the German Society for Rheumatology on the quality of treatment in rheumatology - Update 2016]

On behalf of the Steering Committee of the German Society for Rheumatology, in 2016 the Interdisciplinary Commission on Healthcare Quality updated the 2008 memorandum on rheumatological healthcare in Germany. The update considers changes in therapeutic strategies, treatment targets as well as current structures in healthcare and the political framework. It concentrates on examination of the need for rheumatologists with a background in internal medicine and determines the gap between needs and supply. The internist rheumatologist is responsible for the care of patients with inflammatory rheumatic diseases and contributes to the care of patients with severe forms of other musculoskeletal diseases. At least 2 internist rheumatologists are needed for the outpatient care of 100,000 adult inhabitants, equivalent to 1350 rheumatologists in Germany. With currently 776 rheumatologists, we have little more than half of what we need. The German Society for Rheumatology calls for specific requirements planning for rheumatologists in outpatient care in order to decrease the deficit. In acute inpatient care we need specialized hospitals and wards that ensure a high quality of treatment for patients with complex diseases. We need up to 50 beds per 1 million inhabitants. At least 2 full-time internist rheumatologists and 3 further physicians are needed per 30 beds. In inpatient and outpatient rehabilitation we need 40 beds or outpatient places per 1 million inhabitants with at least 1 full-time rheumatologist and 1 further physician. In order to reduce the existing deficits and to cover the increasing future need for rheumatologists, more emphasis has to be laid on primary and secondary education. Chairs for internal rheumatology are needed at each medical university and more positions for postgraduate training in rheumatology should be provided. In all segments of healthcare the treatment aims should be jointly defined between patients and physicians. The patients should be treated in an interdisciplinary network, comprising other medical specialties, health professionals as well as patient organizations.

Current state of evidence on 'off-label' therapeutic options for systemic lupus erythematosus, including biological immunosuppressive agents, in Germany, Austria and Switzerland--a consensus report

Systemic lupus erythematosus (SLE) can be a severe and potentially life-threatening disease that often represents a therapeutic challenge because of its heterogeneous organ manifestations. Only glucocorticoids, chloroquine and hydroxychloroquine, azathioprine, cyclophosphamide and very recently belimumab have been approved for SLE therapy in Germany, Austria and Switzerland. Dependence on glucocorticoids and resistance to the approved therapeutic agents, as well as substantial toxicity, are frequent. Therefore, treatment considerations will include 'off-label' use of medication approved for other indications. In this consensus approach, an effort has been undertaken to delineate the limits of the current evidence on therapeutic options for SLE organ disease, and to agree on common practice. This has been based on the best available evidence obtained by a rigorous literature review and the authors' own experience with available drugs derived under very similar health care conditions. Preparation of this consensus document included an initial meeting to agree upon the core agenda, a systematic literature review with subsequent formulation of a consensus and determination of the evidence level followed by collecting the level of agreement from the panel members. In addition to overarching principles, the panel have focused on the treatment of major SLE organ manifestations (lupus nephritis, arthritis, lung disease, neuropsychiatric and haematological manifestations, antiphospholipid syndrome and serositis). This consensus report is intended to support clinicians involved in the care of patients with difficult courses of SLE not responding to standard therapies by providing up-to-date information on the best available evidence.

Zunehmend sachgerechte Abbildung der Rheumatologie im G-DRG-Fallpauschalensystem 2006

Starting with the second year of the so called "convergence period", specialized rheumatological treatment is now represented by a specific DRG (197Z) in the German G-DRG system. The definition of this DRG is based on the procedure codes for the complex and multimodal treatment of rheumatological inpatients (OPS 8-983 and 8-986). This will result in a more appropriate reimbursement of rheumatological treatment. The implementation of specialized rheumatological treatment can be regarded as exemplary for the incorporation of medical specializations into DRG systems. The first step is the definition of the characteristics by procedure codes, which can consequently be utilized within the grouping algorithm. After an inadequate representation of a medical specialization within the DRG system has been demonstrated, a new DRG will be established. As no cost data were available, the calculation of a cost weight for the new G-DRG 197Z is not yet possible for 2006. Hence, reimbursement has to be negotiated between the individual hospital and the budget commission of the health insurers. In this context, the use of clinical pathways is considered helpful.

High positive predictive value of specific antibodies cross-reacting with a 28-kDa Drosophila antigen for diagnosis of ankylosing spondylitis

OBJECTIVES

Diagnosis of ankylosing spondylitis (AS) can be difficult, and a specific laboratory test has not yet been introduced as a routine diagnostic tool. Our aim was to evaluate the diagnostic value of antibodies specifically binding to a recombinant 28-kDa antigen for the diagnosis of AS.

METHODS

Blinded sera were tested for antibodies binding to the procaryotically expressed 28-kDa protein using an enzyme-linked immunosorbent assay (ELISA). This purified 28-kDa protein is produced by a specific clone from an embryonic Drosophila hydei Xgtl I c-DNA library and is bound by human antibodies cross-reacting with both a 36-kDa protein of chromosomes from Drosophila melanogaster and a 69-Da HeLa S3 protein potentially involved in signal transduction pathways.

RESULTS

Serum concentrations of antibodies cross-reacting with this specific antigen were increased in 371 patients with AS compared with 37 healthy controls (39.5 vs 22.6 U/ml; P = 0.004). The positive predictive values of this ELISA test for AS were between 95.1% (95% confidence interval 90.6-97.9%) for a cut-off level of 50 U/ml and 97.4% (92.7-99.5%) for a cut-off level of 75 U/ml, and the sensitivities were between 42.1% (37.0-47.3%) for a cut-off level of 50 U/ml and 30.7% (26.1-35.7%) for a cut-off level of 75 U/ml.

CONCLUSIONS

Serum ELISA tests for antibodies cross-reacting with the 28-kDa antigen show a high positive predictive value for AS of more than 95%.

[Structural quality of acute internal medicine rheumatology clinics--Project Group of the Association of Rheumatologic Acute Clinics]

A study group representing the VRA (Association of Rheumatology Clinics in Germany) has worked out the structural quality paper presented here. Five guidelines for structural quality have been established by the VRA and are laid out in this paper. Required space and personnel for implementing these guidelines are considered. A highly competent, multi-disciplinary team must be available to ensure the long-term quality of in-patient treatment of rheumatic patients, the majority of whom are chronically ill and are suffering from chronic pain of varying intensity which restricts their daily activities. The necessity for such in-patient treatment is reflected in a 6-point-questionnaire (draft) adapted to the Appropriateness Evaluation Protocol. Considering the introduction of a flat-rate fee system (DRG-system) the structural quality paper describes the implementation of a specified electronic data processing documentation which is linked to a central hospital information system. According to the concept of benchmarking, the paper takes into account future developments of the German health system. It will be adjusted continuously to changing political guidelines for health services.

IgA and IgG autoantibodies against alpha-fodrin as markers for Sjögren's syndrome. Systemic lupus erythematosus

OBJECTIVE

To determine the prevalence of IgA and IgG autoantibodies against alpha-fodrin in patients with primary and secondary Sjögren's syndrome (SS) and controls.

METHODS

An ELISA detecting IgA and IgG antibodies against alpha-fodrin was developed. We examined the prevalence of IgA and IgG antibodies against alpha-fodrin in patients with primary and secondary SS, systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA) and blood donors.

RESULTS

IgA antibodies against alpha-fodrin were detected in 64% of patients with primary SS (n = 85), 47% of patients with secondary SS and SLE (n = 15), and 86% of patients with secondary SS and RA (n = 7). IgA autoantibodies against alpha-fodrin were detected in only one of 160 sera obtained from blood donors and in one of 50 and 2 of 12 sera obtained from SLE and RA patients without sicca syndrome, respectively. The prevalence of IgG antibodies against alpha-fodrin in SS was lower: they were detected in 55% of sera obtained from patients with primary SS, 40% of patients with secondary SS and SLE, and in 43% of patients with secondary SS and RA. Three of 160 sera from blood donors and one of 50 and 5 of 12 sera from SLE and RA patients without sicca syndrome, respectively, contained IgG antibodies against alpha-fodrin.

CONCLUSION

IgA rather than IgG antibodies against alpha-fodrin are specific for and frequently observed in primary and secondary SS and are useful markers for this autoimmune disorder.

Rheumatoid factors in systemic lupus erythematosus: association with clinical and laboratory parameters. SLE study group

The prevalence and clinical and laboratory associations of IgM, IgG and IgA rheumatoid factors (RF) were determined in 352 patients with systemic lupus erythematosus (SLE). IgM, IgG, and IgA class RF were detected in 17.9%, 20.5%, and 20.5% of the sera, respectively. RF were associated with sicca syndrome, hypergammaglobulinemia, high titer of antinuclear antibodies, anemia, SSA- and SSB-antibodies, and with the presence of HLA-DR3. RF correlated negatively with nephritis and livedo racemosa. Moreover, we observed an association of RF and parameters of inflammatory activity such as elevated erythrocyte sedimentation rate (ESR) and leukopenia. Analysis of immunoglobulin classes revealed that laboratory parameters of inflammatory activity, SSA- and SSB-antibodies and HLA-DR3 correlated with IgA RF only. IgA RF define a subgroup of SLE patients characterized by distinct autoimmune phenomena and high disease activity in the absence of nephritis.

Thrombomodulin in systemic lupus erythematosus: association with clinical and laboratory parameters

Thrombomodulin is an endothelial cell membrane glycoprotein and is detected in plasma and serum after endothelial injury. In our study comprising 311 patients with systemic lupus erythematosus (SLE) clinical and laboratory associations of elevated thrombomodulin serum concentrations were examined. Elevated thrombomodulin concentrations were detected in 7.1% of the SLE patients and were associated with nephritis including the laboratory parameters proteinuria and erythrocyte casts, vasculitis and neurological involvement of the central nervous system. These correlations remained significant after consideration of the influence of renal function. In SLE, the serum thrombomodulin concentration may become a marker to monitor damage of endothelial cells and involvement of the central nervous system.

IgM anti-dsDNA antibodies in systemic lupus erythematosus: negative association with nephritis. SLE Study Group

Antibodies against dsDNA of the IgM class were measured in sera of 352 patients with systemic lupus erythematosus, 81 blood donors and 189 patients with rheumatoid arthritis using a new ELISA based on human recombinant dsDNA as antigen. IgM anti-dsDNA antibodies were found in 52.3% of the sera from patients with systemic lupus erythematosus, but in none of the sera from 81 normal controls and 189 patients with rheumatoid arthritis. The association of these autoantibodies with 31 clinical and 37 laboratory parameters was calculated. There was a highly significant negative correlation between IgM anti-dsDNA antibodies and nephritis as well as all the laboratory parameters indicating renal disease (elevated serum creatinine concentration, proteinuria, erythrocyte casts in the urine). IgM anti-dsDNA antibodies indicate protection of lupus patients against the development of lupus nephritis. Further experiments will show whether application of IgM anti-dsDNA antibodies is effective in treating lupus nephritis.

Association of IgA anti-dsDNA antibodies with vasculitis and disease activity in systemic lupus erythematosus. SLE Study Group

Previously it has been suggested that the presence of antibodies against dsDNA of the IgA class may define a subset of systemic lupus erythematosus (SLE) patients suffering from nephritis and arthritis. Therefore, these autoantibodies were measured in sera of 352 patients with SLE, 81 blood donors, and 189 patients with rheumatoid arthritis using a new ELISA based on human recombinant dsDNA as antigen. IgA anti-dsDNA antibodies were found in 19.9% of the sera from patients with SLE, but in none of the sera from 81 normal controls and 189 patients with rheumatoid arthritis. The association of these autoantibodies with 31 clinical and 36 laboratory parameters was calculated. IgA anti-dsDNA antibodies were found to be associated with parameters of disease activity such as elevated erythrocyte sedimentation rate and consumption of complement component C3, and the clinical parameters vasculitis, with necrosis and erythema, but not with nephritis and arthritis. Therefore, IgA anti-dsDNA antibodies define a subset of SLE patients, and monitoring of IgA anti-dsDNA antibodies may be helpful as a prognostic parameter in patients with SLE.

[The rheumatoid patient as back pain patient. Diagnosis and differential diagnosis of seronegative spondylarthropathies]

Based on an epidemiology study the frequency of back pain in the population was established by forty percent. Otherwise only thirty percent of patients with backache are diagnosed definitely by practitioners. In view of these circumstances the 1991 published diagnosis criteria for spondylarthropathies are a helpful work in definition of spondylarthropathy patients. Furthermore a new described autoantibody specifically for spondylarthropathies seems to be helpful for this diagnosis of these systemic rheumatic diseases.

[RA-specific autoantibodies against a 68k antigen]

Despite commonly applied clinical criteria, the early diagnosis of rheumatoid arthritis (RA) often remains difficult, thus delaying on suitable early treatment. In search for a test furthering the early and reliable diagnosis of RA, we have screened for novel disease specific autoantibodies. To this end proteins were isolated from synovial membranes and other tissues following a special protein purification protocol, and these were separated electrophoretically. Western blots were then used to screen sera of RA patients and of individuals suffering from other rheumatic diseases for antibodies to any of these proteins. The most prominent RA specific immunoreaction was with a 68k antigen, occurring in 110 of 167 RA patients (sensitivity is 66%). The antibody could also be identified in seronegative RA patients but not in healthy individuals (55 tested), in only 1 SLE patient of a group of 98 patients with other rheumatic diseases and in 1 out of 22 HIV patients, resulting in a specificity of 99%. Moreover, the anti-68k antibody could be correlated with a more severe course of RA. 13 out of 20 anti-68k positive RA patients (58%) had subcutaneous nodules, while only 2 out of 11 anti-68k negative (20%) did. The mean sedimentation rate of these antibody positive patients was 51 mm/h and 26 mm/h for the negative respectively. The 68k antigen was shown to be present in all human tissues investigated and is probably ubiquitously expressed. It is either located in the endoplasmatic reticulum or cytoplasm or both. Its isoelectric point is 5.1. It proved to be O-glycosylated and contains only one or a few sugar residues as the untreated and the deglycosylated antigen identical electrophoretical mobilities. The patient derived anti-68k antibodies were directed against the sugar residue: deglycosylation of the antigen completely abolished its immunoreactivity. N-acetylglucosamine competes with the antibody for binding the 68k antigen. The antigen physicochemical data of the 68k antigen argue against identity with one of the autoantigens in this molecular mass range already known to be associated with RA or other autoimmune diseases. It is neither identical to the 62k human antigen (EBNA-1) nor to RA33 (A2hnRNP), the 50k Sa antigen or the Hsp70 class of heats-hock proteins. It is argued that the particular method of protein purification applied in combination with separation via SDS-PAGE in the presence of urea, made it possible to detect a hitherto unidentified antigen. Considering the striking disease specificity of the anti-68k antibody it is now worthwhile to look for corresponding autoreactive T cells in order to analyse its role in the pathogenesis of RA.

Significance of antibodies to cardiolipin in unselected patients with systemic lupus erythematosus: clinical and laboratory associations. The SLE Study Group

In a multicentre study anticardiolipin antibodies of the IgG and IgM isotypes were measured by a solid phase enzyme immunoassay in 368 patients with systemic lupus erythematosus (SLE) who were not selected on the basis of features of antiphospholipid syndrome. Clinical and laboratory associations of increased levels of anticardiolipin antibodies were evaluated. IgG and IgM antibodies to cardiolipin were documented in 224 (60.9%) and 128 (34.8%) patients, respectively. Regarding the symptoms of antiphospholipid syndrome, elevated amounts of anticardiolipin IgG were significantly associated with spontaneous abortion (P < 0.001), thrombocytopenia (P < 0.01), livedo reticularis (P < 0.01) and a positive direct Coombs test (P < 0.05), but not with thrombosis or central nervous system diseases such as epilepsy and psychosis. IgM antibodies to cardiolipin were associated with a positive direct Coombs test (P < 0.01), but with no other symptom of antiphospholipid syndrome. The predictive values of anticardiolipin antibody determinations in unselected SLE patients were poor for all features of antiphospholipid syndrome because of high proportions of false-positive and false-negative results. As for other manifestations of SLE, positive correlations between raised antibodies to double-stranded DNA and the occurrence of anticardiolipin antibodies of the IgG isotype were observed, and anticardiolipin IgM was negatively associated with nephritis.

Novel 68 kDa autoantigen detected by rheumatoid arthritis specific antibodies

OBJECTIVE

To improve the understanding of the pathogenesis of rheumatoid arthritis (RA) by identifying novel, disease specific autoantibodies.

METHODS

Total protein preparations from synovial membranes were separated electrophoretically and immunoblotted. Sera from RA patients were screened for predominant immunoreactions by blotting. A 68 kDa antigen target of the most predominant reaction was detected and further characterised.

RESULTS

The dominant immunoreaction in most of the RA sera tested was with a 68 kDa antigen. The antigen is probably ubiquitously expressed. It has an isoelectric point of 5.1, is O-glycosylated, and is located in the endoplasmic reticulum, the cytoplasm, or both. Antibodies to the 68 kDa autoantigen were present in 64% of 167 RA patients tested, and could also be detected in seronegative RA patients, but were present in only 1% of 98 patients with other rheumatic diseases. They could not be detected in 55 healthy controls.

CONCLUSIONS

Because of its high sensitivity (64%) and specificity (99%), the anti-68 kDa autoantibody not only provides another valuable parameter for diagnosis, but also represents an antibody that may be involved in the pathological mechanisms leading to RA. This hypothesis can be tested by investigating if 68 kDa specific T cells are present in RA patients.

[Systemic lupus erythematosus in men--a different prognosis?]

A retrospective analysis of 21 male and 82 female patients with systemic lupus erythematosus (SLE) was performed in order to identify sex-linked differences in disease manifestations. As organ manifestation, cardiac involvement was assessed in 12 of 21 male patients (57%) and in 18 of 82 females (22%; p < 0.05). Renal involvement occurred in 16 male (76%) vs 26 female patients (32%; p < 0.05). Endstage renal disease developed in 5 of the 21 men (24%), but only in 6 of the 82 women (7%) with SLE. The most striking clinical result was the high frequency of thrombembolic complications in male SLE-patients. Twelve out of 21 males (57%) experienced more than 30 thrombembolic events in contrast to 9 events in 5 out of 82 females (6%; p < 0.0001). Persisting elevated IgG-anti-cardiolipin antibodies were found in 48% of male and only 16% of female patients (p < 0.05). In conclusion, these data suggest that SLE in males is characterized by more frequent and severe organ involvement and especially by striking prevalence of partly life-threatening thrombembolic complications.

Major histocompatibility complex haplotypes and complement C4 alleles in systemic lupus erythematosus. Results of a multicenter study

In a multicenter study more than 300 central European systemic lupus erythematosus (SLE) patients were examined for HLA-B, HLA-DR, and complement C4 phenotypes. For 174 SLE patients MHC haplotypes were determined by family segregation analysis, and for 155 patients C4 gene deletions were determined by TaqI restriction fragment length polymorphism. Two haplotypes, B8-C4AQ0-C4B1-DR3 and B7-C4A3-C4B1-DR2, were identified as risk factors for SLE. These findings were confirmed by applying the haplotype frequency difference (HFD) method, which uses nontransmitted haplotypes from the family study as internal controls. Furthermore, only HLA-DR2, but not DR3, B7, or B8, was significantly increased in SLE patients independently of the two risk haplotypes. C4A gene deletions, but not silent C4AQ0 alleles, were increased in SLE patients and neither C4BQ0 alleles nor C4B gene deletions were increased. The observed frequencies of homozygosity and heterozygosity for the two haplotypes and the frequencies of homozygotes for C4AQ0 and C4A deletions did not differ from the expected values, indicating that the risk for SLE is conveyed by single allele effects. In conclusion, there are two MHC-linked susceptibility factors for Caucasian SLE patients carried by the haplotypes B7-DR2 and B8-DR3. The results argue against C4Q0 alleles being the decisive factors increasing susceptibility to SLE.

[Cutaneous lupus erythematosus and cardiolipin antibodies. Incidence and clinical significance]

In recent years, the importance of antiphospholipid antibodies in systemic lupus erythematosus and various other dermatological and internal diseases has been recognized. Characteristic symptoms associated with these antibodies are venous and arterial thrombosis, recurrent fetal loss, thrombocytopenia, and haemolytic anaemia. Two antiphospholipid antibody subgroups that are clinically relevant can be discerned: anticardiolipin antibodies and lupus coagulant. In this study, 51 clinically well-characterized patients with predominantly cutaneous lupus erythematosus were screened for the presence of anticardiolipin antibodies. Anticardiolipin antibodies could be detected in only three patients. These data suggest that, in patients with cutaneous lupus erythematosus, anticardiolipin antibodies should be measured only in the presence of symptoms associated with antiphospholipid antibodies.

[Enzyme immunoassay for the detection of autoantibodies to nRNP and Sm: a rapid and sensitive alternative to current procedures]

Antinuclear antibodies are of major importance in the diagnosis of inflammatory rheumatic diseases. Sm and nRNP antibodies can be found in sera from patients with systemic lupus erythematosus and mixed connective tissue disease. Usually, these antibodies have been detected with one of the following methods: Ouchterlony immunodiffusion, passive hemagglutination or counterimmunoelectrophoresis (CIE). In this work results obtained by Ouchterlony and CIE techniques were compared with those obtained by ELISA. Purified proteins from cellular extracts (HeLa) were used as antigens for Sm- and nRNP-ELISA: D polypeptide for Sm-ELISA and the 68 kD, A, C, B,B' and D polypeptides for nRNP-ELISA. Compared with the other two techniques, ELISA was less time consuming and showed greater sensitivity. Quantitative titration proved to be of advantage in monitoring the course of the diseases mentioned above.

The genetic basis of Ro and La antibody formation in systemic lupus erythematosus. Results of a multicenter study. The SLE Study Group

Antibodies against Ro and La, including recombinant La and recombinant 60 kD-Ro, were determined by counter immunoelectrophoresis and ELISA in over 300 central European systemic lupus erythematosus (SLE) patients. The presence of both Ro and La antibodies was strongly associated with the MHC haplotype B8-C4AQ0-DR3-DQ2, the association being strongest for DR3. After exclusion of all B8-DR3 positive patients only DR3 positive patients still showed an increased incidence of Ro and La antibodies, suggesting DR3 as the primary association factor. High titers of La antibody, but not of 60 kD-Ro antibody, were also significantly associated with the presence of DR3. Other DR and DQ antigens or heterozygous DQ combinations were not significantly associated with Ro and La antibodies.

MHC gene products and anticardiolipin antibodies in systemic lupus erythematosus results of a multicenter study. SLE Study Group

Anticardiolipin antibodies (aCL) and HLA-DR antigens were determined in 314 central European patients with systemic lupus erythematosus (SLE). Both HLA-DR4 and DR7 were increased in aCL-positive patients, and aCL were significantly associated with DRw53. The association between DRw53 and aCL was also apparent in those 17 patients with SLE and the anticardiolipin syndrome. There was no association between aCL and HLA-DQ or C4 alleles in SLE.

Ankylosing spondylitis: an autoimmune disease?

Identification of several autoantibodies in serum samples from patients with ankylosing spondylitis or suspected ankylosing spondylitis is reported. Five antibodies associated with ankylosing spondylitis were identified by applying cytoimmunofluorescence and immunoblotting techniques to antigen pools from insect tissue. At least one of these antibodies was found in 82% of serum samples from patients with ankylosing spondylitis. A 36 kD drosophila antigen, which showed the most common and most dominant reaction, was further purified and isolated. Thirty two (34%) of the serum samples from 95 patients with definite ankylosing spondylitis and 12 (28%) of the serum samples from 43 patients with suspected ankylosing spondylitis reacted with this antigen. Antibodies purified from the 36 kD antigen reacted specifically with a 69 kD antigen present in separations of total protein preparations from human lymphocytes and HeLa cells. The 36 kD antibody was not found in 29 patients with rheumatoid arthritis nor in 38 apparently healthy controls. The prevalence of the 36 kD antibody was comparable in HLA-B27 positive and negative patients. In addition, the same immunoreaction was found in patients with so called 'seronegative' spondylarthropathies, particularly of the ankylosing spondylitis-type, suggesting that this antibody is specific for ankylosing spondylitis or other 'seronegative' spondylarthropathies with the typical clinical and radiological changes of ankylosing spondylitis.

Cloning and expression of antigenic epitopes of the human 68-kDa (U1) ribonucleoprotein antigen in Escherichia coli

Autoantibodies directed against the 68-kDa (U1) ribonucleoprotein antigen are mainly found in sera of patients with mixed connective tissue disease. The corresponding cDNA was fragmented into four regions coding for the major antigenic epitopes A', B', C' and D'. All the epitopes were subcloned and expressed as fusion proteins with the glutathione S-transferase in Escherichia coli using the novel expression system pGEX that allows very high yields of recombinant proteins after a single-step purification. The sera of patients with the autoimmune disease were analyzed for the expressed recombinant proteins by an immunoblotting technique. All positive sera showed a patient-specific behavior and could be divided into four groups regarding recognition of the four antigenic epitopes of the 68-kDa (U1) ribonucleoprotein antigen. The epitope B' was reactive to all patient sera positively tested and classified as the marker antigenic epitope for the mixed connective tissue disease.

Testing for association in SLE families

Systemic lupus erythematosus (SLE) is a complex disease which is partly determined by genetic factors which influence susceptibility to the disease phenotype. In this association study we try to define the high risk haplotypes which are responsible for this disease, together with other environmental factors. In many other association studies a set of SLE patients is compared to a set of controls. The basic assumption about the underlying population is that the disease and control sample should originate from the same genetic population, which is not always completely satisfied in many studies. Therefore, we analyse our family data by applying the Haplotype Frequency Difference (HFD) Method, which constructs its internal control group from those haplotypes not transmitted to the affected individual. Results partially conform with other studies, showing that the haplotypes B8 DR3 as well as B7 DR2 have a high positive association with SLE. When the DR locus was analyzed alone, we found besides the alleles DR2 and DR3 a negative association for DR1, DR5, and DR6.

[Scleroderma]

Sclerodermas may occur in two basic forms: localized sleroderma (LSc) and systemic scleroderma (SSc). Pseudoscleroderma as well as overlap syndromes have to be differentiated from these two variants. From the clinical point of view, localized scleroderma can be subdivided into type I = plaque-like LSc (= morphea), type II = linear LSc, and type III = deep LSc. According to the degree of the cutaneous involvement, systemic scleroderma can likewise be classified into type I = sclerodactylia, type II = acrosclerosis, and type III = scleroderma with primary involvement of the trunk (diffuse scleroderma). In LSc, we never find systemic involvement; SSc, in contrast, is almost always associated with Raynaud's phenomenon, changes of the esophagus, as well as an increased titer of antinuclear antibodies (Hep-2 cell test). Only 23% of our patients with LSc showed elevated ANA titers. We present and discuss data of 56 patients with LSc and 52 patients with SSc. Evidence in the literature as well as our own findings suggest that the pathogenesis of LSc is different from that of SSc. The influence of various mediators and cytokines on the collagen metabolism might be regarded as a theoretical approach in order to develop new therapeutic regimens. This is even more important since there is still no efficient mode of treatment for neither localized nor systemic scleroderma.

[Livido racemosa in detection of anti-phospholipid antibodies]

Livedo reticularis and antiphospholipid antibodies have previously been found to be associated with a subgroup of patients with systemic lupus erythematosus. We present a case of livedo reticularis accompanied by antiphospholipid antibodies, in which no other signs of any systemic or cutaneous disease could be detected.

Epitope mapping with a recombinant human 68-kDa (U1) ribonucleoprotein antigen reveals heterogeneous autoantibody profiles in human autoimmune sera

Several cDNA fragments encoding parts of the (U1)RNP specific 68-kDa autoantigen were expressed in Escherichia coli and the fusion proteins were used as substrate for localization of the autoreactive epitopes. We have identified a region of approximately 30 amino acids reacting with more than 90% (16 of 17) of all human anti-p68 sera tested, regions which carry only a few and a region with no autoepitopes. Comparative analysis of epitopes recognized on partially degraded fusion proteins indicated that the anti-p68 autoimmune response is polyclonal. It involves generation of antibodies to several epitopes including one in a region with retroviral gag protein homology speculated to play a role in the initiation of the autoimmune response. Each of the 17 sera tested contained a different set of autoantibody specificities. These data are not consistent with random mutation as a sole mechanism of anti-p68 autoantibody induction and argue for an Ag-driven autoimmune response.

Epitope mapping with a recombinant human 68-kDa (U1) ribonucleoprotein antigen reveals heterogeneous autoantibody profiles in human autoimmune sera

Several cDNA fragments encoding parts of the (U1)RNP specific 68-kDa autoantigen were expressed in Escherichia coli and the fusion proteins were used as substrate for localization of the autoreactive epitopes. We have identified a region of approximately 30 amino acids reacting with more than 90% (16 of 17) of all human anti-p68 sera tested, regions which carry only a few and a region with no autoepitopes. Comparative analysis of epitopes recognized on partially degraded fusion proteins indicated that the anti-p68 autoimmune response is polyclonal. It involves generation of antibodies to several epitopes including one in a region with retroviral gag protein homology speculated to play a role in the initiation of the autoimmune response. Each of the 17 sera tested contained a different set of autoantibody specificities. These data are not consistent with random mutation as a sole mechanism of anti-p68 autoantibody induction and argue for an Ag-driven autoimmune response.

A recombinant autoantigen derived from the human (U1) small nuclear RNP-specific 68-kd protein. Expression in Escherichia coli and serodiagnostic application

A human liver complementary DNA expression library was screened using sera from patients with high titers of autoantibodies, to search for clones expressing major autoantigens that are relevant in connective tissue diseases. One of the clones isolated expressed a major epitope(s) that was immunoreactive with anti-U1 RNP sera, as shown by several techniques. Affinity-purified autoantibodies from the cloned RNP protein specifically recognized the 68-kd U1 RNP protein of HeLa cell nuclear extracts. All sera containing anti-U1 RNP antibodies detected by immunodiffusion, counterimmunoelectrophoresis, or immunoblotting also recognized the cloned RNP protein. The RNP antigen-expressing bacterial colonies and the partially purified cloned RNP fusion protein have been applied to fast and sensitive immunologic assays for the detection and quantification of anti-U1 RNP antibodies.

[The Ha(La) antibody as a serologic marker of systemic lupus erythematosus]

Ha(La)-antibodies are detected by counterimmunoelectrophoresis (CIE) in sera of systemic lupus erythematosus (SLE) patients, but not in sera of patients with progressive systemic scleroderma (PSS) (n = 38), rheumatoid arthritis (n = 91), ankylosing spondylitis (n = 97), and other rheumatic diseases (n = 452). This antibody specificity was found in 27 out of 103 SLE patients (26%). However, 50% of SLE patients with Sjögren's syndrome (n = 12) showed the Ha(La)-antibody, suggesting a strong association in this clinical subgroup. Thus the Ha(La)-antibody can serve as a serological marker and helpful diagnostic tool for SLE. Additionally, the Ha(La)-antibody reacts with specific puffs in polytene chromosome preparations of Drosophila melanogaster. Therefore, this heterologous antigen system is suitable for the identification of Ha(La) sera.

Lung function disturbances versus respiratory muscle fatigue in patients with systemic lupus erythematosus

In 23 consecutive patients (mean age, 38.6 years) with systemic lupus erythematosus (SLE) and in 17 healthy subjects (mean age, 37.5 years) fatigue of respiratory (diaphragm, musculi intercostales externi) and leg muscles (musculus gastrocnemius) was determined comparatively by electromyography. Additionally, routine lung function parameters, including maximum inspiratory (PImax) and expiratory (PEmax) mouth pressures, were measured. The SLE patients showed lower values of vital capacity (VC), total lung capacity (TLC), thoracic gas volume (TGV), FEV1, PImax and PEmax than the healthy controls, while FEV1/VC, residual volume and specific airway conductance were not significantly different in either group. Lung compliance, corrected for TGV, was normal in the SLE group. Breathing through stenoses with increasing resistances resulted in fatigue of the diaphragm in 73% of the SLE group and in 41% of the control group. The corresponding values of the external intercostal muscles were 74% (SLE group) and 29% (control group). Electromyographic signs of respiratory and leg muscle fatigue occurred at lower loads in the SLE group than in the healthy subjects. The pattern of lung function data in patients with SLE was characteristic neither of lung restriction nor of airway obstruction. Respiratory muscle weakness can explain the decrease in TLC, VC, TGV, FEV1, PImax and PEmax.

Attempts towards a serological diagnosis of ankylosing spondylitis

Polytene chromosomes of salivary glands as well as nuclear proteins from Kc-cells of Drosophila melanogaster have been used as substrate to identify and evaluate the diagnostic value of crossreacting antibodies present in sera of AS patients. The diagnostic significance of the recently described anti-93D antibody (Lakomek et al., 1984) was confirmed by screening sera of patients with definite or suspected AS using cytoimmunofluorescence on the polytene chromosomes. In addition, four new antibodies could be identified in AS sera by immunoblotting. Simultaneous detection of these antibodies supports the diagnosis of AS and is most useful in diagnosis of early stages of this disease.

[Significant association of HLA-B8 with systemic lupus erythematosus and with specific serological markers]

Analysis of the HLA antigens of the A, B and C locus of 87 patients with systemic lupus erythematosus (SLE) revealed a significant elevation for HLA-B8 of 64% as compared to 22% in a healthy control group (n = 1850) (P less than 0.000001). Owing to the known linkage disequilibrium of this genetic marker with the HLA-A1 antigen, the HLA phenotype A1, B8 was found in 55% of the SLE patients (P less than 0.000001). Moreover, a significant association of the HLA-B8 in 82% (P less than 0.025) of Ro antibody-positive SLE patients (n = 22) and in 84% (P less than 0.025) of Ha antibody-positive patients (n = 19) was striking. A more frequent occurrence of this HLA antigen could also be detected in patients with a persistent nDNA antibody elevation and in patients with manifestation of the disease before the 40th year of life as compared to patients who manifested it later. An association of the HLA-B8 antigen with a raised disease activity of SLE can be inferred.

[Nuclear antibodies as serologic markers in progressive systemic scleroderma]

In all, 36 patients with progressive systemic sclerosis (29 women, 7 men) were studied clinically and immunologically; 15 patients had acrosclerosis (type I) and 21, sclerosis extending beyond the wrist (type II). The sera of all patients were evaluated for ANA (HEp-2-cells), Scl-70, centromere and other ENA antibodies. The centromere antigen was characterized by immunoblotting. All patients had high-titer ANA antibodies (100%); 36% of patients had the Scl-70 antibody (a marker antibody for PSS); and in 22% of our patients a centromere antibody was detected. In all cases the anti-centromere sera reacted with a 19.5-kd polypeptide and in 2 cases they reacted with 23- and 25.5-kd proteins in addition. In patients with centromere antibodies there was increased organ involvement (heart, lung, kidney) compared with patients who had anti-Scl-70 or other nuclear antibodies.

Anti-(U1)RNP and anti-Sm autoantibody profiles in patients with systemic rheumatic diseases: differential detection of immunoglobulin G and M by immunoblotting

Autoimmune sera from patients with systemic lupus erythematosus, scleroderma, or both disorders reactive with the (U1)RNP and Sm antigens were analyzed according to their IgG- and IgM-autoantibody profiles by immunoblotting with HeLa nuclear extracts. Anti-(U1)RNP-specific autoantibodies directed against the 68-kDa polypeptide were found to be predominantly of the IgG type, whereas for the other (U1)RNP-specific protein, 33 kDa, a concomitant occurrence of IgG and IgM class autoantibodies was observed for most patients. In contrast, Sm-specific anti-29/28-kDa autoantibodies were found to be more frequently of the IgM than of the IgG type, while Sm-specific anti-16-kDa antibodies of both classes were present simultaneously in most sera. Of the serum collection reported here only one (U1)RNP-specific serum has been found which lacks anti-Sm antibodies of either class. In general, preclassification of sera by immunodiffusion and counterimmunoelectrophoresis corresponds to the IgG but not to the IgM profile as determined by immunoblotting.

Scl 70 autoantibodies from scleroderma patients recognize a 95 kDa protein identified as DNA topoisomerase I

Sera of patients suffering from the autoimmune disease progressive systemic sclerosis (PSS) are known to contain autoantibodies which have been reported to recognize a 70 kDa antigenic protein, designated the Scl 70 antigen. By immunoblotting of nuclear extracts from HeLa cells with sera from scleroderma patients we observed that the size of the antigen present in such cells depends on the conditions of antigen isolation. When protease inhibitors were included in the extraction buffer, a 95 kDa protein was identified instead of a 70 kDa protein. When protease inhibitors were omitted, a number of polypeptides in the size range 66 to 95 kDa was found. Furthermore, antibodies which had been affinity purified on the 95 kDa antigen, crossreacted with the 66 to 95 kDa polypeptides. These results suggest that the smaller proteins were degradation products of the 95 kDa antigen. Immunofluorescence studies on PtK-2 cells with the antibody specific for the 95 kDa protein gave staining of nuclei, nucleoli and of chromosomes and the nucleolar organizer region in mitotic cells. Since this distribution of antigens within the nucleus was reminiscent of the intranuclear distribution of DNA topoisomerase I found by others we probed purified DNA topoisomerase I from calf thymus directly with the autoantibodies from PSS patients, and also the 95 kDa antigens of HeLa cell nuclei with antibodies raised against the bovine DNA topoisomerase I. From the crossreaction pattern observed with the different antigens and antibodies we conclude that DNA topoisomerase I is one of the antigenic components against which autoantibodies are formed in scleroderma patients.

[A serological criterion for Bechterew's disease. Demonstration of a new antibody specificity with polytene chromosomes]

A new antibody reacting with an antigen from polytene chromosomes of Drosophila melanogaster has been found in serum of patients with Bechterew's disease. This antigen-antibody system differs from other nuclear antibodies (anti-RNP, anti-Sm, anti-Ha/SS-B) in that it is not detectable by counter-immunoelectrophoresis. The antibody could be detected in 24 out of 62 Morbus Bechterew sera in which the antibody did not strictly correlate with the appearance of HLA-B27 antigen. The new antibody specificity is a specific serological finding in patients with Bechterew's disease and is therefore suitable for use as a diagnostic, and perhaps also as a prognostic test for this type of spondylarthritis till now assumed to be seronegative.

Human anti-centromere sera recognise a 19.5 kD non-histone chromosomal protein from HeLa cells

Autoimmune sera from 18 scleroderma patients were found to give a centromere positive immunofluorescence response on formaldehyde fixed HeLa cells and on chromosome spreads. Immunoblotting experiments with a protein fraction enriched in HeLa chromosomal proteins revealed that the antigenic target common to all 18 sera is a polypeptide of 19.5 kD. This polypeptide, which is not one of the core histones, is not soluble under conditions which favour the release of nuclear ribonucleoprotein particles. Antigen specific purification of autoantibodies with subsequent immunofluorescence studies confirmed that the 19.5 kD antigen is restricted to cell cycle-dependent single or double spheres at the centromere of HeLa chromosomes. Two additional polypeptides of 23 kD and 25.5 kD immunoreactive with five of the 18 centromere positive sera are not located at the centromere region, suggesting that other autoantibody systems are present in these sera.

A new serologic marker in ankylosing spondylitis

Sera of patients with ankylosing spondylitis (AS) were screened for the presence of antibodies by indirect immunofluorescence staining of polytene chromosomes of Drosophila melanogaster. Thirty-nine percent of the sera tested contained antibodies which selectively reacted with an antigen(s) present at the chromosomal locus 93D after heat shock treatment. This indicates a novel antibody specificity in a subgroup of AS patients and may provide a new aid in the diagnosis of AS.

[Incidence and diagnostic significance of reactive syphilis antibodies in systemic lupus erythematodes and other immunologic diseases]

Serum samples of 78 patients with systemic lupus erythematosus, systemic sclerosis and other immunological diseases were tested for antibodies to syphilis. Reactive or weak reactive results were observed in 10% by means of the treponema pallidum hemagglutination (TPHA) test, in 27% by the FTA-Abs test, in 40% applying the IgM-FTA-Abs test, in 10% by the VDRL test and in 3% of the cases using the cardiolipin CF test. Only in 3 patients (4%) we found an antibody pattern characteristic of syphilitic patients (TPHA and FTA-Abs test simultaneously undoubtedly reactive). Neither the comparative qualitative and quantitative determination of antibodies to ANA, nDNS and ENA (extractable salinesoluble nuclear antigen) nor elimination of nDNS and ENA antibodies, or incubation of the treponemal test antigen with DNase lead to a conclusion whether the reactive results of the TPHA, FTA-Abs, and IgM-FTA-Abs tests specifically indicate a syphilitic infection. The low incidence of reactive syphilis tests in SLE and the presence of syphilitic antibodies in other immunological diseases limitate the significance for the criterium in the diagnosis of SLE.

[A rheumatic disease register in clinical use]

A registry for the documentation of rheumatic diseases has been developed at the University of Düsseldorf. For 3 years more than 450 parameters for each patient have been documented, checked, and stored in a data bank. The registry has made a definite improvement in the diagnosis and long-term follow-up of rheumatic diseases. The use of special statistical procedures to study the frequency of various parameters in different diseases has allowed independent diagnostic criteria to be established.

Identification of human Sm and (U1) RNP antigens by immunoblotting

When HeLa nuclear extracts or ribonucleoproteins (RNPs) from rat liver nuclei were used as antigens, a monospecific anti-(U1)RNP serum recognized in each preparation only 1 polypeptide of 68 or 70 kilodalton (kd) respectively. With a serum of combined anti-Sm/(U1)RNP specificity, HeLa nuclear extracts showed 3 additional antigenic polypeptides of 29, 28, and 16 kd, whereas only 2 additional polypeptides of 27 and 16 kd were observed in rat liver RNPs. However, no antigenic reaction at 68/70 kd was detected with a monospecific anti-Sm serum, indicating that the 68/70 kd antigen is specific for anti-(U1)RNP antibodies. When commercially available ENA extract was used as antigen source only weak immunostaining in the range 70-40 kd and at 16 kd was seen. Elution experiments with anti-Sm antibodies bound to their specific polypeptides demonstrated that neither protein degradation nor cross-reaction was responsible for recognition of the 29/28 and 16 kd antigens by this serum, and that in fact 2 different autoantibody systems are involved.

[Comparison of 4 methods (immunofluorescence of antinuclear antibodies, indirect hemagglutination, immunodiffusion, counterimmunoelectrophoresis) for the differentiation and identification of nuclear antigen]

The performance of four methods (immunofluorescence of antinucleic antibodies (ANA), indirect haemagglutination, immunodiffusion and counterimmunoelectrophoresis) in the detection and differentiation of the antibodies against extractable nucleic antigen (ENA) was analysed with the aid of sera from 197 patients suffering from inflammatory diseases. Counterimmunoelectrophoresis showed the highest sensitivity and specificity for the detection and differentiation of antibodies against ribonucleoproteins (RNP), nuclear glycoprotein (Sm) and antibodies, which occur in Sicca (Sjögren) syndrome (SS-B, Ha). This method, like immunodiffusion, is suitable for demonstrating the common immunological identity of the ENA-antibody sera and the reference sera. The proof of immunological identity using the counterimmunoelectrophoresis was performed with the newly developed test system (pool procedure). This method, as compared to the procedure of Kurata & Tan ((1976) Arthritis Rheum. 19, 574-580) has certain technical advantages, and gives better identification.