Antibody Mediated
IgA Nephropathy
IgA nephropathy, first descibed in 1968, is the most common form of
primary glomerulonephritis in the world. It is an antibody-mediated
glomerular disease in which the immune deposits localize to the mesangium.
It is not certain whether the deposits form in situ or from circulating
immune complexes.
Patients with IgA nephropathy usually present with one of three syndromes:
Macroscopic hematuria concurrent with an upper respiratory infection;
so-called synpharyngitic hematuria.
Asymptomatic microscopic hematuria and variable proteinuria.
Henoch-Schonlein purpura is the systemic form of the disease process
causing IgA nephropathy, and occurs more frequently in children than
adults. Patients with Henoch -Schonlein purpura manifest skin, joint and
intestinal involvement.
A less common presentation is with the nephrotic syndrome.
These patients may have advanced disease or normal renal function. In the
latter case, the light microscopic features are of minimal change disease
but with intense mesangial staining for IgA.
Antibody Mediated
Clinical Course
Renal function progressively worsens in approximately 40% of patients, about half of whom reach end-stage renal failure after 20 years of clinically apparent disease. Nearly 30% of patients exhibit a benign course with chronic microscopic hematuria, a normal serum creatinine and proteinuria usually less than 1 gram/day. Hypertension is not uncommon and malignant hypertension develops in about 5% of patients.
Secondary deposits of IgA may occur in chronic liver disease, dermatitis herpetiformis, psoriasis, ankylosing spondylitis, celiac disease, inflammatory bowel disease, carcinoma, IgA monoclonal gammopathy, HIV infection and mycosis fungoides.
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