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.

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.

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.

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.

Environmental risk factors differ between rheumatoid arthritis with and without auto-antibodies against cyclic citrullinated peptides.

The aim of this study was to evaluate new and previously hypothesised non-genetic risk factors for serologic subtypes of rheumatoid arthritis (RA) defined by the presence or absence of auto-antibodies to cyclic citrullinated peptides (CCP). In a national case-control study, we included 515 patients recently diagnosed with RA according to the American College of Rheumatology 1987 classification criteria and 769 gender- and age-matched population controls. Telephone interviews provided information about non-genetic exposures, and serum samples for patients were tested for anti-CCP-antibodies. Associations between exposure variables and risk of anti-CCP-positive and anti-CCP-negative RA were evaluated using logistic regression. A series of RA subtype-specific risk factors were identified. Tobacco smoking (odds ratio [OR] = 1.65; 95% confidence interval: 1.03-2.64, for > 20 versus 0 pack-years) was selectively associated with risk of anti-CCP-positive RA, whereas alcohol consumption exhibited an inverse dose-response association with this RA subtype (OR = 1.98, 1.22-3.19, for 0 versus > 0-5 drinks per week). Furthermore, coffee consumption (OR = 2.18; 1.07-4.42, for > 10 versus 0 cups per day), ever use of oral contraceptives (OR = 1.65; 1.06-2.57) and having a first-degree relative with schizophrenia (OR = 4.18; 1.54-11.3) appeared more strongly associated with risk of anti-CCP-positive RA. Obesity was selectively associated with risk of anti-CCP-negative RA, with obese individuals being at more than 3-fold increased risk of this subtype compared with normal-weight individuals (OR = 3.45; 1.73-6.87). Age at menarche was the only examined factor that was significantly associated with both serologic subtypes of RA (p-trends = 0.01); women with menarche at age > or = 15 years had about twice the risk of either RA subtype compared with women with menarche at age < or = 12 years. Major differences in risk factor profiles suggest distinct etiologies for anti-CCP-positive and anti-CCP-negative RA.

International multicenter evaluation of autoantibodies to ribosomal P proteins.

Autoantibodies to the ribosomal phosphoproteins (Rib-P) are a serological feature of patients with systemic lupus erythematosus (SLE). The reported prevalence of anti-Rib-P antibodies in SLE ranges from 10 to 40%, being higher in Asian patients. The variation in the observed frequency may be related to a number of factors but is dependent in large part on the test system used to detect the autoantibodies. An association of anti-Rib-P with central nervous system involvement and neuropsychiatric manifestations of SLE has been controversial. In the present international multicenter study, we evaluated the clinical accuracy of a new sensitive Rib-P-specific enzyme-linked immunosorbent assay based on recombinant Rib-P polypeptides. The results showed that 21.3% of 947 SLE patients, but only 0.7% of 1,113 control patients, had a positive test result (P < 0.0001). The sensitivity, specificity, positive and negative predictive values, and diagnostic efficiency were determined to be 21.3%, 99.3%, 95.6%, 62.2%, and 65.3%, respectively. When evaluated in the context of participating centers, the prevalence of anti-Rib-P antibodies was found in descending frequency, as follows: China (35%) > Poland (34%) > Japan (28%) > United States (26%) > Germany (Freiburg; 23.3%) > Denmark (20.5%) > Germany (Berlin; 19%) > Mexico (15.7%) > Israel (11.7%) > Brazil (10%) > Canada (8%). The substantial data from this study indicate that the prevalence of anti-Rib-P antibodies may not be restricted to the genetic background of the patients or to the detection system but may depend on regional practice differences and patient selection. We confirm previously reported associations of antiribosomal antibodies with clinical symptoms and serological findings. Remarkably, we found a lower occurrence of serositis in Rib-P-positive lupus patients.

Clinical and laboratory characteristics of drug-induced vasculitic syndromes.

Clinical recognition of drug-induced vasculitic and lupus-like syndromes is very important because continued use of the offending drug can lead to irreversible and life-threatening vasculitic organ damage (e.g. end-stage renal disease or pulmonary haemorrhage). Withdrawal of the drug often leads to spontaneous recovery, meaning that immunosuppressive therapy can be avoided. The presence of myeloperoxidase-antineutrophil cytoplasmic antibodies, IgM anticardiolipin antibody, and antihistone antibodies in combination was found to be characteristic of drug-induced vasculitic syndromes caused by the antithyroid drugs propylthiouracil and methimazol. Clinically, skin vasculitis and arthralgias predominated and renal vasculitis was rare.

Long-term health status of Danish women with silicone breast implants.

Long-term safety data are important in the evaluation of possible adverse health outcomes related to silicone breast implants. The authors evaluated long-term symptoms and conditions and medication use among 190 Danish women with cosmetic silicone breast implants compared with 186 women who had undergone breast reduction surgery and with 149 women from the general population. Breast implant and reduction surgeries were performed from 1973 to 1988 at one public hospital and one private plastic surgery clinic. Among women with breast implants, the average implantation time was 19 years, 60 percent (n = 114) had only one implantation, and 10 percent (n = 19) had undergone explantation before the time of study (1997 to 1998). The authors found no material differences in self-reported diseases or symptoms among study groups, except for breast pain, which was reported nearly three times as often by women with implants than by women with breast reduction (odds ratio, 2.8; 95 percent confidence interval, 1.4 to 5.3). Approximately 80 percent of women in each study group reported at least one symptom. No consistent differences were observed in the seroprevalences of antinuclear antibodies or other autoantibodies. Self-reported use of psychotropic drugs was higher among women with breast implants than among either control group. The authors conclude that long-term cosmetic breast implantation may cause capsular contracture and breast pain but does not appear to be associated with other symptoms, diseases, or autoimmune reactivity. The authors' finding of excess use of drugs for treatment of depression and anxiety among women with breast implants may warrant further investigation.

Untreated silicone breast implant rupture.

Implant rupture is a well-known complication of breast implant surgery that can pass unnoticed by both patient and physician. To date, no prospective study has addressed the possible health implications of silicone breast implant rupture. The aim of the present study was to evaluate whether untreated ruptures are associated with changes over time in magnetic resonance imaging findings, serologic markers, or self-reported breast symptoms. A baseline magnetic resonance imaging examination was performed in 1999 on 271 women who were randomly chosen from a larger cohort of women having cosmetic breast implants for a median period of 12 years (range, 3 to 25 years). A follow-up magnetic resonance imaging examination was carried out in 2001, excluding women who underwent explantation in the period between the two magnetic resonance imaging examinations (n = 44). On the basis of these examinations, the authors identified 64 women who had at least one ruptured implant at the first magnetic resonance imaging examination and, for comparison, all women who had intact implants at both examinations (n = 98). Magnetic resonance images from the two examinations were compared and changes in rupture configuration were evaluated. Comparisons were also made for self-reported breast symptoms occurring during the study period and for changes in serum values of antinuclear antibodies, rheumatoid factor, and cardiolipin antibodies immunoglobulin G and immunoglobulin M. The majority of the women with implant rupture had no visible magnetic resonance imaging changes of their ruptured implants. For 11 implants (11 percent) in 10 women, the authors observed progression of silicone seepage, either as a conversion from intracapsular into extracapsular rupture (n = 7), as progression of extra-capsular silicone (n = 3), or as increasing herniation of the silicone within the fibrous capsule (n = 1); however, in most cases, these changes were minor. Some changes could be ascribed to trauma, but others seemed spontaneous. There was no increase in levels of autoantibodies during the study period in either study group. Women with untreated implant ruptures reported a significant increase in nonspecific breast changes (odds ratio, 2.1; 95 percent confidence interval, 1.2 to 3.8) compared with women without ruptures. On the basis of this first study of women with untreated silicone breast implant rupture, the authors conclude that implant rupture is a relatively harmless condition, which only rarely progresses and gives rise to notable symptoms. Even so, because of a small risk of silicone spread, the authors suggest that women with implant ruptures be followed clinically, if not operated on. Because implant ruptures often occur asymptomatically, any woman with silicone implants, regardless of rupture status, should be evaluated at regular intervals.

Antipolymer antibodies in Danish women with silicone breast implants.

OBJECTIVE: To use a new immunologic assay to evaluate antipolymer antibody (APA) levels among women with silicone breast implants (SBIs). METHODS: Women (n = 186) were identified through Danish population-based registers and categorized into six groups defined by prior breast surgery (silicone breast implantation/breast reduction/no breast surgery) and by the presence or absence of a prior hospital diagnosis of soft-tissue rheumatism (muscular rheumatism, ICD-8 codes 717.90 and 717.99). The women underwent blood tests, including an APA test, a clinical examination, and an interview focusing on rheumatic complaints. Blood samples were tested blindly. The severity of rheumatic symptoms/signs was scored from 1 (none) to 5 (severe) based on the clinical examination and interview. RESULTS: Women with SBIs did not have higher levels of APA than women without SBIs. The majority of women with SBIs had mild rheumatic complaints, and the severity of their symptoms was not related to APA levels. Among women who had previously been hospitalized because of soft-tissue rheumatism, there were more fibromyalgia cases, and their symptoms were more severe compared with those women without prior soft-tissue rheumatism; however, APA levels were not higher among these women. There was a significant difference in APA measurements resulting from between-kit variation (p less 0.01). CONCLUSIONS: Our data did not demonstrate higher APA levels among women with SBIs compared with controls. The large variation observed between the individual plates in the APA test should be evaluated in future studies.

Self-reported musculoskeletal symptoms among Danish women with cosmetic breast implants.

BACKGROUND: No epidemiological evidence of an association between silicone breast implants and connective tissue disease has been found. Based on case reports, it has been hypothesized that silicone breast implants may be associated with a unique rheumatic symptom cluster termed "atypical connective tissue disease." MATERIAL AND METHODS: We have evaluated self-reported rheumatic symptoms among women who received breast implants between 1977 and 1997 at 2 private plastic surgery clinics in Denmark. Women with other cosmetic surgery, including breast reduction, as well as women from the general population, were identified as controls. RESULTS: No statistically significant differences in mild (odds ratio [OR] = 0.9; 95% confidence interval [CI] = 0.6-1.3), moderate (OR = 0.7; 95% CI = 0.4-1.2), or severe (OR = 1.1; 95% CI = 0.6-2.1) musculoskeletal symptoms were observed when women with breast implants were compared with women with other cosmetic surgery. Compared with women from the general population, women with breast implants were statistically significantly less likely to have mild or moderate musculoskeletal symptoms (OR = 0.5; 95% CI = 0.3-0.7 and OR = 0.3; 95% CI = 0.2-0.5, respectively); for severe symptoms the deficit was not statistically significant (OR = 0.7; 95% CI = 0.3-1.3). For individual symptom groups, there was no consistent pattern of reporting among women with implants. CONCLUSION: We did not find an excess of rheumatic symptoms or symptom clusters among women with breast implants. In fact, the occurrence of mild, moderate, and severe musculoskeletal symptoms was generally lower among women with implants compared with women with other cosmetic surgery and women in the general population.

A critical evaluation of enzyme immunoassay kits for detection of antinuclear autoantibodies of defined specificities. III. Comparative performance characteristics of academic and manufacturers' laboratories.

OBJECTIVE: To analyze the performance of different commercial enzyme immunoassay (EIA) kits for measuring antinuclear antibodies (ANA) specific for dsDNA, SSB/La, Sm, and Scl-70. METHODS: EIA kits for detection of ANA from 9 commercial manufacturers were evaluated. The manufacturers were advised that they would be sent coded sera containing mixtures of the Arthritis Foundation/Centers for Disease Control reference reagents, and that they were to use their own test kits to analyze the antibody specificities of these sera and to report the data, in optical density (OD) units or their equivalent. Independently, 12 investigators in academic institutions who have done research in this field agreed to participate in a parallel study. The concentration of the antibodies and the specificities were blinded to the analysts and the coefficients of variation (CV) were computed for each participant. RESULTS: There were statistically significant differences between laboratories in terms of CV for all 9 kits tested. With the exception of one kit, there were no significant CV differences between the various autoantibody kits provided by each manufacturer and, with the exception of kits from 2 manufacturers, there were no significant differences between the various antibody kits in terms of reproducibility (CV). From the point of view of interlaboratory variability, manufacturers could be separated into either a high or low performance group. CONCLUSION: We found a disconcertingly large range of performance characteristics in the various laboratories, which could be quite detrimental in routine utilization of EIA ANA kits. Clinicians should be aware of the performance issues raised in our study, and should know and be involved in how their service laboratory assesses its own performance and the performance of commercial testing systems utilized. Manufacturers and clinical laboratories need to exercise constant quality assurance and surveillance of kit performance in the hands of medical laboratory technologists involved in routine testing.

Addendum to the International Consensus Statement on testing and reporting of antineutrophil cytoplasmic antibodies. Quality control guidelines, comments, and recommendations for testing in other autoimmune diseases.

Antineutrophil cytoplasmic antibody (ANCA) tests are used to diagnose and monitor inflammatory activity in Wegener granulomatosis, microscopic polyangiitis and its renal-limited variant (pauci-immune crescentic glomerulonephritis), and Churg-Strauss syndrome. The International Consensus Statement on testing and reporting of ANCA states that ANCA are demonstrated most readily in these conditions by using a combination of indirect immunofluorescence (IIF) of normal peripheral blood neutrophils and enzyme-linked immunosorbent assays (ELISAs) that detect ANCA specific for proteinase 3 or myeloperoxidase. The group that produced the International Consensus Statement has developed guidelines for the corresponding quality control activities, examples of comments for various IIF patterns and ELISA results, and recommendations for ANCA testing when inflammatory bowel disease and other nonvasculitic ANCA-associated autoimmune diseases are suspected.

Autoantibodies in vasculitis.

Before the mid-1980s the only autoantibody widely used to assist in diagnosing vasculitic disease was IgG antibody to the alpha(3) domain of the noncollagenous part of type IV collagen (anti-glomerular basement membrane). Since that time, antineutrophil cytoplasmic antibodies (ANCAs) directed at the azurophilic granule proteins proteinase-3 and myeloperoxidase have been established as clinically useful autoantibodies to support a diagnosis of Wegener's granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome and limited forms of these primary, small vessel necrotizing and often granulomatous vasculitides. The establishment of standardized methods for identifying those antibodies was needed before they could be used in clinical practice. The levels of both types of ANCAs tend to increase in parallel with the degree of clinical disease activity, and they decrease with successful immunosuppressive therapy. More than one assay may have to be used to discover imminent exacerbations in proteinase-3-ANCA associated syndromes. Although autoantibodies to endothelial cells may be important players in the pathogenesis of several vasculitic conditions, they have not gained clinical popularity because of lack of standardized detection methods.