ANCA Dot

The ANCA Dot is a qualitative dot immunoassay for the determination of IgG antibodies against myeloperoxidase (MPO), proteinase 3 (PR3) and glomerular basement membrane (GBM) in human serum. The ANCA Dot is intended as an aid in the diagnosis of systemic vasculitis and autoimmune renal disorders in conjunction with other clinical and laboratory findings.

Systemic vasculitis (SV) pathogenesis is majorly identified by the inflammation of different blood vessel walls, and the resulting morphological changes. Anti-neutrophil cytoplasmic antibodies (ANCA) play an essential role in the serological diagnosis of SV. These antibodies are usually determined by indirect immunofluorescence using ethanol fixed human neutrophils. Cytoplasmic ANCA (cANCA) and perinuclear ANCA (pANCA) are distinguished based on the immunofluorescence pattern.

Goodpasture syndrome, a medical emergency with a high fatality rate if not treated, is characterized by glomerulonephritis, pulmonary haemorrhage and antibody formation against glomerular basement membrane (GBM). The antibodies targeted against GBM component are the primary pathogenic autoantibodies, binding along the glomerular basement membrane and inducing glomerulonephritis in all patients with Goodpasture syndrome. Their determination allows differentiating the syndrome from other causes of glomerular nephritis and pulmonary haemorrhage.

Dot immunoassays are frequently used for the determination of specific antibodies directed against multiple antigens. The test strips are coated with various antigens in consistent intervals. If antibodies are present in the patient´s sample, they bind to the respective antigens. A secondary antibody conjugated with the enzyme alkaline phosphatase detects the generated immune complexes. A colorless substrate is converted into a colored, insoluble product. The signal intensity of the precipitated reaction product is proportional to the antibody activity in the sample.