May ELISA tests replace IIF in the diagnostic work-up of patients with suspected ANCA-associated vasculitis? The answer is clearly yes according to recently published results of the European Vasculitis Study Group.1
ANCA / vasculitis diagnostics
Systemic lupus erythematosus (SLE) is a chronic inflammatory disease with manifold manifestations. SLE belongs to the family of autoimmune disorders, diseases that occur, when a mislead immune system attacks the body’s own structures. SLE can affect almost any organ system, thus its presentation and course are highly variable, and diagnosis and therapy may be challenging.
With the intention to classify SLE patients for research and surveillance studies and to support clinicians in confirming a diagnosis, a set of clinical and laboratory classification criteria has been developed and released by the American College of Rheumatology (ACR). The first classification criteria for SLE were originally published in 1971 [1,2]. They have been updated 1982  and 1997  to incorporate new immunologic knowledge and improve patient classification. In contrast to the 1987 criteria, the 1997 criteria have not been validated.
The most recent addendum to the classification criteria for SLE dates from 2012, when the Systemic Lupus International Collaborating Clinics (SLICC) group published a revision and validation of the ACR criteria .
HEp2 cells are held dear in autoimmune diagnostics. They are invaluable for people engaged in analysing autoantibodies, as E. coli is for molecular biologists or mice for toxicologists.
In spite of a wide range of other suitable methods and technologies, determination of autoantibodies with indirect immuno-fluorescence assays (IFA) on human epithelioma (HEp2) cells still contributes significantly to the diagnosis of autoimmune diseases. The widely recognised advantages of this method are high sensitivity and a broad spectrum of antibodies that can be analysed simultaneously. In addition to mere detection of antibodies a characteristic fluorescence pattern and staining of metaphase and cytoplasmic cells offer supplementary information.
When an autoimmune disease is suspected, the HEp-2 test usually is the first line test. Any positive result is then followed up by a step-wise diagnostic approach, including other immunological tests like ELISA (enzyme-linked immunosorbent assay) for single antibody specificities or immunoblot tests.
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The web community GRÜNER CLUB AUTOIMMUN is a voluntary association of scientists, laboratory specialists, medical doctors, students and immunofluorescence enthusiasts from Austria. In their internet blog these experienced IFT professionals discuss questions, ideas and concepts of immunofluorescence tests in autoimmune disease diagnostics.
In a recent posting my Austrian colleague Barbara Fabian, community manager of GRÜNER CLUB AUTOIMMUN, refered to the relationship between the formation of autoantibodies against glomerular basal membrane (GBM) and ANCA (antibodies against cytoplasmic antigens of neutrophil granulocytes). The article was originally written in German language, but we had it translated for the not German speaking readers of the Autoimmunity Blog.
Autoantibodies against Glomerular Basal Membrane and Myeloperoxidase in Crescentic Glomerulonephritis
by Barbara Fabian, Vienna
Crescentic Glomerulonephritis (CGN) is an autoimmune disease of the kidney that leads to vasculitis of the capillaries in the glomeruli. The appearance of characteristic autoantibodies or antibody complexes is indicative of CGN and allows for the differentiation of three groups:
The GRÜNER CLUB AUTOIMMUN blog featured a fine post about the history of indirect immunofluorescence. In that article my Austrian colleague Barbara Fabian, community manager of GRÜNER CLUB AUTOIMMUN, described in great detail how indirect immunofluorescence technology, or: IFT, and also referred to as IIF assay, has become an indispensible tool of autoimmune disease diagnostics over the last two decades, and how IFT has become a standard laboratory technique used in serological autoimmune diagnostics.
Without further ado I have translated Barbara’s post in order to make you this text, and especially the interesting images, available. – Here it is:
The Development of Indirect Immunofluorescence Technology (IFT)
by Barbara Fabian, MSc, Community Manager of GRÜNER CLUB AUTOIMMUN
Over the last 20 years, the detection of autoantibodies has developed into an indispensible component of autoimmune diagnostics. Along with serological and clinical data, autoimmune status has become an important building block in the formation of diagnoses. (more…)
It’s Great When There’s Something to Celebrate!
Last week we had such an occasion at ORGENTEC Diagnostika. The February issue of the Annals of the Rheumatic Diseases, the EULAR Journal, included the results of a clinical evaluation study of our Anti-PR3 hs ELISA. The results are very gratifying for us and reflected well on our product.
The subject of the article? – The effectiveness of our test for the diagnosis of ANCA-associated vasculitis, abbreviated as AAV. This term encompasses autoimmune diseases characterized by the presence of antineutrophil cytoplasmic antibodies, known as ANCA. These diseases include Wegener’s granulomatosis (WG), microscopic polyangiitis (MPA), and Churg-Strauss syndrome (CSS). (more…)