A historical essay on detection of anti-neutrophil cytoplasmic antibodies.

In this essay we describe a number of the known and not so known experiences of the early anti-neutrophil cytoplasmic antibodies (ANCAs) days, explaining why and how we reached consensus on the standard indirect immunofluorescence (IIF) techniques, the naming of the two principal C- and P-ANCA patterns, why we chose to use IIF as the standard technique, how the solid phase assays have developed and where we stand today, the use of ANCA for diagnosis and the importance of using several techniques for that purpose, how ANCA titres are related to disease activity and the clinical impact of this, and finally the implications of ANCA being a natural, polyclonal antibody response against various epitopes in relation to diagnostics and disease patterns.

International recommendations for the assessment of autoantibodies to cellular antigens referred to as anti-nuclear antibodies.

Anti-nuclear antibodies (ANA) are fundamental for the diagnosis of autoimmune diseases, and have been determined by indirect immunofluorescence assay (IIFA) for decades. As the demand for ANA testing increased, alternative techniques were developed challenging the classic IIFA. These alternative platforms differ in their antigen profiles, sensitivity and specificity, raising uncertainties regarding standardisation and interpretation of incongruent results. Therefore, an international group of experts has created recommendations for ANA testing by different methods. Two groups of experts participated in this initiative. The European autoimmunity standardization initiative representing 15 European countries and the International Union of Immunologic Societies/World Health Organization/Arthritis Foundation/Centers for Disease Control and Prevention autoantibody standardising committee. A three-step process followed by a Delphi exercise with closed voting was applied. Twenty-five recommendations for determining ANA (1-13), anti-double stranded DNA antibodies (14-18), specific antibodies (19-23) and validation of methods (24-25) were created. Significant differences between experts were observed regarding recommendations 24-25 (p<0.03). Here, we formulated recommendations for the assessment and interpretation of ANA and associated antibodies. Notably, the roles of IIFA as a reference method, and the importance of defining nuclear and cytoplasmic staining, were emphasised, while the need to incorporate alternative automated methods was acknowledged. Various approaches to overcome discrepancies between methods were suggested of which an improved bench-to-bedside communication is of the utmost importance. These recommendations are based on current knowledge and can enable harmonisation of local algorithms for testing and evaluation of ANA and related autoantibodies. Last but not least, new more appropriate terminologies have been suggested.

Serum levels of lipoprotein(a) and E-selectin are reduced in rheumatoid arthritis patients treated with methotrexate or methotrexate in combination with TNF-α-inhibitor.

OBJECTIVES: To examine the effect of methotrexate (MTX) with or without tumor necrosis factor alpha (TNF-α)-inhibitors on serum lipoprotein(a) (s-Lp(a)), and to explore a possible relationship between s-Lp(a) and endothelial function (EF) in terms of serum levels of adhesion molecules and reactive hyperaemic index (RHI) in patients with rheumatoid arthritis (RA). METHODS: Serum levels of Lp(a), endothelial adhesion molecules, RHI and inflammatory markers were studied in 64 RA patients, starting with either MTX (n=34) or MTX+TNF-α-inhibitor treatment (n=30) at baseline and after 6 weeks and 6 months. RESULTS: Compared to baseline values, s-Lp(a) was significantly reduced after 6 weeks (p=0.001) and 6 months (p=0.001) in RA patients treated with MTX, and after 6 weeks (p=0.001) in the MTX+TNF-α-inhibitor group. A non-significant reduction was found after 6 months (p=0.102) in the MTX+TNFα-inhibitor group. Serum E-selectin (s-E-selectin) was significantly reduced in both RA treatment groups at both control points. S-Lp(a) correlated positively with s-E-selectin at baseline (p=0.004), and change in s-E-selectin correlated with the change in s-Lp(a) during follow-up (p6weeks= 0.008, p 6months=0.009). No association was found between s-Lp(a) and the other adhesion molecules and RHI. CONCLUSIONS: MTX or MTX combined with a TNFα-inhibitor appears to significantly reduce Lp(a). This finding indicate that s-Lp(a) might be related to systemic inflammation, or that the examined drugs might reduce s-Lp(a) by other mechanisms. Anti-inflammatory treatment might be a novel therapeutic option to decrease s-Lp(a). The associations between s-E-selectin and s-Lp(a) suggest an interaction between these factors, or a common cause.

Relations of serum COMP to cardiovascular risk factors and endothelial function in patients with rheumatoid arthritis treated with methotrexate and TNF-α inhibitors.

OBJECTIVE: To examine whether serum level of cartilage oligomeric matrix protein (S-COMP) is related to methotrexate (MTX) or to MTX and tumor necrosis factor-α (TNF-α) combination treatment for rheumatoid arthritis (RA); and to investigate whether S-COMP is related to cardiovascular risk factors including endothelial dysfunction and level of anticitrullinated protein antibodies (ACPA) in patients with RA. METHODS: Clinical and laboratory measures, including S-COMP and reactive hyperemic index (RHI), were examined in 55 consecutive patients with RA starting with either MTX (n = 34) or MTX and anti-TNF-α treatment (n = 21) at baseline, and after 6 weeks and 6 months. RESULTS: S-COMP was similar in the 2 treatment regimens during followup. We found a positive relationship between S-COMP at baseline and the use of disease-modifying antirheumatic drugs the last year preceding the study (p = 0.001), and a negative relation to current use of systemic glucocorticosteroids (p = 0.044). The nonsignificant change in S-COMP between baseline and the 6-month followup was positively and independently related to change in ACPA level (p = 0.009). There was no significant association between RHI and level of S-COMP at baseline. CONCLUSION: The cartilage turnover marker S-COMP did not change significantly after 6 months' treatment with MTX with or without a TNF-α inhibitor in patients with RA. The positive association between S-COMP and ACPA suggests that these factors might interact, and could both be contributors to an unknown link between inflammation and cartilage destruction in patients with RA. S-COMP was not related to endothelial function in patients with RA, or to other cardiovascular risk factors studied. Clinical Trials registration number NCT00902005.

Preliminary evaluation of the first international reference preparation for anticitrullinated peptide antibodies.

BACKGROUND: A lyophilised reference serum from one patient with rheumatoid arthritis (RA) diluted with serum samples from healthy subjects was evaluated as a possible first international standard for anticitrullinated peptide antibodies (ACPAs). METHODS: The authors used 12 commercial ELISAs for ACPA detection in the reference serum and for testing the linearity of the assays by studying twofold serial dilutions. To test the effectiveness of the standardisation, sera from 20 RA patients with variable antibody concentrations were analysed, and the relative concentrations were calculated using both the kit's own curve and the six dilutions of the reference serum as a calibration curve. Fifty sera from normal healthy subjects were used to calculate cut-off values for the reference serum using each commercial kit. RESULTS: The calibration curve obtained for each of the 12 methods using the reference sample dilutions as calibrator allowed harmonisation of the ACPA concentration of the 20 RA serum samples, significantly reducing the dispersion of the values. The mean coefficient of variation (CV) was reduced from 76.4% to 27.9% (p=0.018) and from 85.9% to 33.5% (p=0.028) for the medium/high and negative samples, respectively. Low positive sera CV was also reduced, but to a smaller degree, from 82.5% to 55.5% (p=0.043). CONCLUSION: This first evaluation of the behaviour of the ACPA reference serum demonstrated that it tested positive in all the assays and that it may be used as a reference standard for establishing calibration curves, reducing the dispersion of antibody values and better comparing results obtained from different methods/laboratories.

Missing links in high quality diagnostics of inflammatory systemic rheumatic diseases: It is all about the patient!

The aim of this review is to focus attention on high quality diagnostics of systemic inflammatory rheumatic diseases. Though many steps in the diagnostic process from the first visit in a doctor's office till a final diagnosis have been established a lot of things still must be done to improve quality assurance and secure fast and safe transmission of data from one step to the next. Some procedures inherent in early high quality diagnostics need to be worked out. A number of elements can be improved, some stumble stones can be removed, and a tighter collaboration between actors at different levels in the line of action in clinical and laboratory medicine can be organized. Several proposals have been made by international working groups such as the IUIS International Autoantibody Standardization Committee, and the EASI steering group in collaboration with their national EASI teams. Practical exercises carried out for more than three decades by the European Consensus Finding Study Group have proven to very useful. The review points at several principles worked out by these international expert groups can be useful in actual daily practice also in rheumatology. The hope is that the presentation will give rise to a continued discussion on how to link different parts of the diagnostic process together and strengthen collaboration between all teams involved in the diagnostic chain. The ultimate measure of success will be better clinical outcomes for patients and increased satisfaction in their families.

Autoantibodies in ANCA-associated vasculitis.

Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides are systemic or more limited conditions characterized by necrotizing destruction of small and medium-sized vessels (eg, capillaries, venules, and arterioles). ANCAs are the most predominant autoantibodies in patients affected by vasculitis, but other autoantibodies may also occur, probably reflecting pathogenetic events in affected tissue. These autoantibodies are assumed to play a role in the initiation and propagation of chronic inflammation. ANCAs are valuable for clinical diagnosis, follow-up, and guidance in therapy.

All you wanted to know about anti-CCP but were afraid to ask.

The most specific biomarker associated with the diagnosis of rheumatoid arthritis (RA) is autoantibodies to citrullinated peptides/proteins (ACPA). Though recognized as an important marker of progressive erosive disease its use has been hampered by doubt about what is a positive versus a negative reaction in the several assays that have become available commercially. This review intends to indicate that the CCP2 assay has the highest specificity and sensitivity in stratified studies that encompass sera from RA patients and non-RA inflammatory controls compared to other ACPA tests. Still, larger and strictly stratified studies are highly warranted to substantiate this conclusion.

Antinuclear antibodies: a contemporary nomenclature using HEp-2 cells.

The choice of terms used to describe indirect immunofluorescence (IIF) staining patterns of autoantibodies binding to HEp-2 cells is at present quite varied and disordered because no accurate consensus on names and descriptions exist. The aim of our study was to propose a logical and ordered IIF classification taxonomy based on 29 different selected IIF patterns. In a preliminary project carried out at Statens Serum Institut it was first shown by use of a software programme named DOORS developed by Percepton Ltd, that reading of digitized images of HEp-2 patterns on an LCD monitor could be used instead of traditional microscopy. Digitized images of HEp-2 patterns were then used in the EU supported project named CANTOR (June 1998-July 2000) aiming to reach consensus among three clinical immunology expert centres and collaborating to attain a classification version that could be used to qualitatively and quantitatively test and train image recognitions skills of laboratory technicians against expert consensus. The usability of this classification version was then tested in a course consisting of training and certification. The conclusion was that participants in the training programme clearly increased their perceptive skills using images, terms, descriptions and the graphic and statistic tools in the self-administered DOORS programme and that software-assisted training could achieve a common and accurate level of visual pattern interpretation. All results from this project were reported to the European Commission but have not previously been published in scientific literature. This communication presents the final results of agreed image classifications.

EULAR points to consider in the development of classification and diagnostic criteria in systemic vasculitis.

OBJECTIVES: The systemic vasculitides are multiorgan diseases where early diagnosis and treatment can significantly improve outcomes. Robust nomenclature reduces diagnostic delay. However, key aspects of current nomenclature are widely perceived to be out of date, these include disease definitions, classification and diagnostic criteria. Therefore, the aim of the present work was to identify deficiencies and provide contemporary points to consider for the development of future definitions and criteria in systemic vasculitis. METHODS: The expert panel identified areas of concern within existing definitions/criteria. Consequently, a systematic literature review was undertaken looking to address these deficiencies and produce 'points to consider' in accordance with standardised European League Against Rheumatism (EULAR) operating procedures. In the absence of evidence, expert consensus was used. RESULTS: There was unanimous consensus for re-evaluating existing definitions and developing new criteria. A total of 17 points to consider were proposed, covering 6 main areas: biopsy, laboratory testing, diagnostic radiology, nosology, definitions and research agenda. Suggestions to improve and expand current definitions were described including the incorporation of anti-neutrophil cytoplasm antibody and aetiological factors, where known. The importance of biopsy in diagnosis and exclusion of mimics was highlighted, while equally emphasising its problems. Thus, the role of alternative diagnostic tools such as MRI, ultrasound and surrogate markers were also discussed. Finally, structures to develop future criteria were considered. CONCLUSIONS: Limitations in current classification criteria and definitions for vasculitis have been identified and suggestions provided for improvement. Additionally it is proposed that, in combination with the updated evidence, these should form the basis of future attempts to develop and validate revised criteria and definitions of vasculitis.

The use of citrullinated peptides and proteins for the diagnosis of rheumatoid arthritis.

The presence or absence of antibodies to citrullinated peptides/proteins (ACPA) is an important parameter that helps a clinician set a diagnosis of early rheumatoid arthritis and, hence, initiate treatment. There are several commercial tests available to measure ACPA levels, although it can be difficult to decide what the best test for a given clinical question is. We analyzed literature data in which the diagnostic and other properties of various ACPA tests are compared. The results show that for diagnostic purposes the CCP2 test has the highest specificity, the highest sensitivity in stratified studies and the highest positive predictive value. For the prediction of future joint destruction the CCP2, MCV, and CCP3 tests may be used. The ability to predict the likelihood of not achieving sustained disease-modifying antirheumatic drug-free remission was highest for the CCP2 test. Finally, the levels of anti-CCP2 and anti-CCP3 (and possibly anti-mutated citrullinated vimentin) in rheumatoid arthritis patients are not significantly influenced by TNFalpha blocking agents.

Clinical and pathophysiological significance of anti-neutrophil cytoplasmic autoantibodies in vasculitis syndromes.

Necrotizing vasculitis of small blood vessels is a rare condition, but when it affects important organs it can lead to life-threatening organ damage and death. Thus, recognizing these conditions at an early stage before they spread to become systemic is a constant challenge to clinical medicine. The objectives of this review are: to give advice on clinical indications for ANCA diagnostics and laboratory procedures for highly specifically detecting the most important ANCA; to provide some data on the autoantigens involved in ANCA reactivity in small vessel vasculitides; and to discuss at the occurrence of ANCA in different vasculitic populations and at different stages of disease. One important task for the near future will be to standardize the assays used for ANCA detection/quantification and to harmonize the results given to clinicians by ensuring that international reference reagents are used by laboratories and the diagnostic industry. Finally, the author has attempted to summarize the role that ANCA are currently believed to play in the immuno-inflammatory events that take place in tissues and that affect small vessels in idiopathic vasculitis. The review concludes that the presence of ANCA is likely to become an important criterion for diagnosing idiopathic small vessel vasculitis.

Drug-induced vasculitis.

PURPOSE OF REVIEW: This review aims to draw attention to the features that distinguish drug-induced vasculitis and drug-induced lupus-like disease from those of idiopathic autoimmune syndromes, first and foremost primary vasculitides and systemic lupus erythematosus. Drug-induced vasculitis and drug-induced lupus-like disease are seen in patients treated long term with a drug, and close to 100 drugs representing all pharmacologic classes have been assumed capable of inducing such syndromes. The clinical phenotypes vary from single tissue or organ involvement to severe systemic inflammatory disease dominated by vasculitis and sometimes organ failure. RECENT FINDINGS: The recent discovery of antineutrophil cytoplasm antibodies in a large serological subset of drug-induced vasculitis/drug-induced lupus-like disease caused by long-term antithyroid drug treatment has opened new avenues for differential diagnostics. Antineutrophil cytoplasm antibodies with specificity to more than one lysosomal antigen, combined with presence of antibodies to histones and beta-2 glycoprotein 1 constitute a unique serological profile for drug-induced vasculitis/drug-induced lupus-like disease. SUMMARY: Rational use of laboratory marker profiles is likely to aid in distinguishing drug-induced from idiopathic syndromes. Hence, the use of antineutrophil cytoplasm antibodies and other autoantibodies as biomarkers of different phenotypes of drug-induced vasculitis/drug-induced lupus-like disease is the main focus of this review.

EASI - The European Autoimmunity Standardisation Initiative: a new initiative that can contribute to agreed diagnostic models of diagnosing autoimmune disorders throughout Europe.

The European Autoimmunity Standardisation Initiative (EASI) was founded 6 years ago with the intention of improving diagnostics in chronic rheumatic disorders by strengthening the collaboration between clinical and laboratory scientists responsible for autoimmune diagnostics at any given level of the health care systems in Europe. Thorough clinical work-up is frequently not the basis for the usage of laboratory tests. Old established test methods may be exchanged for new methods without the differences being communicated. Often, the optimal way of reporting laboratory results to the clinic has not been agreed upon between clinicians and laboratory scientists. An EASI international team consisting of expert rheumatologists/internists/laboratory scientists from Denmark, France, Germany, Israel, Italy, the Netherlands, Spain, and the United Kingdom meets once a year to discuss how interactions between laboratories and rheumatology clinics could be improved in practical terms, how algorithms for cost-effective and rational autoantibody testing could be harmonized, and what an international concept of standardization in this area could look like. In national EASI teams, which were founded in many European countries, clinical and laboratory experts also meet regularly to discuss how European guidelines may lead to practical improvements in their recent country-specific approaches. To enable the exchange of information and experiences, representatives of the different teams of the EASI Network will meet annually in the EASI Forum. All EASI teams will present and discuss the results of their activities with other experts in the field in an EASI Conference, which will be held biannually at the International Congress on Autoimmunity.

AutoAbSC.Org -- Autoantibody Standardization Committee in 2006.

The Autoantibody Standardization Committee was established in the early 1980s based on the recognized needs for reference human autoimmune sera that were critical for academic, clinical, and industrial laboratories. To date, 14 reference reagents are available without charge from the Biological Reference Reagents distribution center at the Centers for Disease Control and Prevention. A web site has been developed under "AutoAbSC.Org" to communicate to the wider stakeholder community and to facilitate ongoing activities in continuing the mission in autoantibody standardization.

The immune response to citrullinated proteins in patients with rheumatoid arthritis: genetic, clinical, technical, and epidemiological aspects.

This article reviews data concerning the applicability of anti-citrullinated peptide antibodies in the diagnosis, estimation of prognosis, and follow-up of patients with rheumatoid arthritis (RA). The production of anti-citrullinated peptide antibodies is closely associated with the presence of the HLA-DRB1 shared epitope, a known risk factor for development of RA, and the production may be influenced by environmental factors such as tobacco smoking. Patients who harbor this antibody from the early stage of their disease develop more severe erosive disease than patients with RA who lack the antibody. The anti-citrullinated peptide antibody level may be a reflection of disease activity, at least in the early phase of the disease. The antibody can sometimes be found several years before the onset of clinical symptoms of RA, which may represent an open window for preventive measures to be taken.

Detection of antibodies against p63 and p73 isoforms in sera from patients diagnosed with oral lichen planus.

BACKGROUND: Oral lichen planus (OLP) is a chronic inflammatory disease of oral mucosa. Despite numerous publications and intense research, the etiology of OLP is still unknown, however, autoimmunity as a possible causative factor has been discussed. METHODS: In the present study sera from 20 patients clinically and histologically diagnosed with OLP were analyzed for antibodies directed toward p53, p63, and p73 using Western blot. RESULTS: Sera from two patients reacted with all six p63 isoforms, and one also with p73. The strongest reaction was noted against the TAp63beta protein, which is the most potent transactivator of all p63 proteins and is implicated in the differentiation of stratified epithelia. CONCLUSIONS: This is the first demonstration of antibodies directed against all p63 and some p73 isoforms in sera from patients diagnosed with OLP.

Autoantibody response to BPI predict disease severity and outcome in cystic fibrosis.

BACKGROUND: Autoantibodies against bactericidal permeability increasing protein (BPI-ANCA) are frequently present in cystic fibrosis patients and have been reported to be associated to colonization with Pseudomonas (P) aeruginosa and lung damage. In the present study, we investigated BPI-ANCA as a prognostic marker and its relation to P. aeruginosa colonization and lung function. METHODS: BPI-ANCA, measured by ELISA, was examined relative to lung function and microbiological findings. The prognostic value of BPI-ANCA was assessed in 46 adult patients followed for 1.2-8.9 years. The cross-sectional investigation was performed in 366 patients (age 0.5-55). RESULTS: The presence of BPI-ANCA predicted poor prognosis. An adverse outcome occurred in 15/28 BPI-ANCA positive patients and in 2/18 BPI-ANCA negative patients (p=0.01). This result remained valid when the patients were stratified according to lung function (p=0.03). Findings of BPI-ANCA were correlated to P. aeruginosa colonization and lung damage. Development of BPI-ANCA occurred after colonization with P. aeruginosa. All colonized patients did not develop BPI-ANCA. The BPI-ANCA levels were fairly stable during the disease course, but decreased significantly following lung transplantation. CONCLUSION: BPI-ANCA responses follow colonization with P. aeruginosa and may be predictive for lung damage.

The influence of pregnancy on the development of autoimmunity in chronic lymphocytic leukemia.

To examine whether pregnancy influences the development of autoimmunity in chronic lymphocytic leukemia (CLL), we studied 591 consecutive CLL patients (202 post-menopausal women and 389 men). The mean observation time for all patients was 3.8 years, corresponding to approximately 2200 person-years of follow-up. Autoimmune manifestations were analyzed in 194 women with known obstetric history and known number of long-term sexual partners, and in the 389 male CLL patients for comparison. One hundred and fifty-nine of the CLL patients exhibited autoimmune manifestations, 38% in females and 21% in men. In female CLL patients, the frequency of autoimmunity and the number of pregnancies and the number of partners were strongly correlated. Each of the major autoimmune types approximately doubled in frequency for each additional pregnancy. The impact of pregnancy on expressed autoimmunity increased with each additional sexual partner (the odds of autoimmunity increased 11 times with each long-term sexual partner). The average numbers of pregnancies in female CLL patients with and without autoimmunity were 4.92 and 2.24, respectively (P < 0.001). Coombs' positive autoimmune anemia, a gastric ulcer with parietal cell autoantibodies and idiopathic thrombocytopenic purpura were equally common in women and men, whereas autoimmune thyroiditis, Sjögren's syndrome, rheumatoid arthritis and systemic lupus erythematosus were seen in higher rates in women than in men. The spectrum of autoimmunity suggests that pregnancy-related alloimmunization may be involved in the development of autoimmunity in CLL.