Pathogenesis (disease development)
Immunoglobulin A (IgA) nephropathy is the most common cause of adult idiopathic glomerulonephritis.
The pathogenesis of mesangial IgA glomerulonephritis has not been fully elucidated. IgA immune complexes are thought to be deposited in the glomerular mesangium, where they maintain an inflammatory response. This leads to scarring, which in turn can lead to functional impairment of the kidney.
Note: IgA nephropathy leads to immunoglobulin G (IgG) autoantibody formation in most cases. The autoantibody deposition in turn leads to activation of the systemic renin-angiotensin-aldosterone system (RAAS) as well as complement activation. This explains hypertension (high blood pressure) on the one hand and glomerular inflammation with hematuria (blood in the urine) and proteinuria (increased excretion of protein with the urine) on the other.
Etiology (causes)
Biographic causes
- Genetic burden from parents, grandparents (dominantly inherited disease with polygenetic background).
Disease-related causes
- Idiopathic (> 90%)
- Autoimmune disease such as systemic lupus erythematosus (SLE).
- Bacterial endocarditis (endocarditis).
- Granulomatosis with polyangiitis (GPA), formerly Wegener’s granulomatosis – necrotizing (tissue dying) vasculitis (vascular inflammation) of the small to medium-sized vessels (small vessel vasculitides), which is accompanied by granuloma formation (nodule formation) in the upper respiratory tract (nose, sinuses, middle ear, oropharynx) as well as the lower respiratory tract (lungs)
- Hepatitis B/C (inflammation of the liver).
- HIV
- Infection with ß-hemolytic streptococci (bacteria).
- Liver cirrhosis (irreversible damage to the liver and a pronounced remodeling of liver tissue), severe liver disease.
- Food allergy especially to gluten (gluten enteropathy).
- Schönlein-Henoch purpura (synonyms: Anaphylactoid purpura; Acute infantile hemorrhagic edema; Schönlein-Henoch disease; Purpura anaphylactoides; Purpura anaphylactoides; Purpura Schönlein-Henoch (PSH); Seidlmayer cocard purpura; Schönlein-Henoch purpura; Vasculitis allergica; IgA vasculitis) – immunologically mediated vasculitis (inflammation of the (mostly) arterial blood vessels) of the capillaries and pre-capillary and post-capillary vessels, usually without complications; as a multisystem disease, it preferentially affects the skin (purpura/spontaneous, small-spot skin, subcutaneous, or mucosal hemorrhages), joints (arthralgias/joint pain), intestines (vasculitic lesions of the intestinal wall), and kidneys
