title: A new serological reaction in patients with polymyalgia rheumatica and/or giant cell (temporal) arteritis: deposition of complement C4 and C3 components on rat kidney structures detected by indirect immunofluorescence.
abstract: Using indirect immunofluorescence deposition of complement C4 and C3 components to rat kidney medullary structures was demonstrated. This serological reaction (C4/C3-IFT) is regularly obtained with fresh sera of patients suffering from active polymyalgia rheumatica (PMR) and/or giant cell (temporal) arteritis (GCA). Sera of normal controls and of steroid-treated PMR and/or GCA patients in clinical remission have a negative C4/C3-IFT reaction. A positive conversion of the test in steroid-treated patients indicates enhanced disease activity. Because of its technical simplicity, C4/C3-IFT can be routinely used first, as a reliable serological marker in the primary diagnosis of PMR and/or GCA and second, as a sensitive criterion of disease activity in these patients. C4/C3-IFT reactivity is, however, not specific for GCA and/or PMR. Various systemic inflammatory diseases may have a positive reaction as well (e.g., certain viral and bacterial infections, malignant tumors, vasculitides, inflammatory joint diseases of different etiology). Recent experimental findings suggest that C-reactive protein (CRP) in patients' sera mediates an activation of the classical complement pathway resulting in a deposition of C4 and C3 complement components to certain rat kidney structures.
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D003167:Complement Activation; D003176:Complement C3 / Q000032:analysis*; D003181:Complement C4 / Q000032:analysis*; D005260:Female; D005455:Fluorescent Antibody Technique; D005500:Follow-Up Studies; D013700:Giant Cell Arteritis / Q000175:diagnosis*; D006801:Humans; D007668:Kidney / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011111:Polymyalgia Rheumatica / Q000175:diagnosis*; D051381:Rats; D012698:Serologic Tests
chemical_list: D003176:Complement C3; D003181:Complement C4