Diffuse proliferative
immunoglobulin A (
IgA) nephropathy has the potential risk for
end-stage renal disease. However, treatment of
IgA nephropathy has not been well established. To determine whether early treatment with
corticosteroids ameliorates the proliferative lesions of diffuse proliferative
IgA nephropathy, we conducted a prospective, randomized, controlled trial. Inclusion criteria were as follows: duration of abnormal urinalysis results less than 36 months,
proteinuria less than 1.5 g/d of
protein, serum creatinine level less than 1.5 mg/dL, and mesangial cell proliferation or matrix accumulation involving more than 50% of glomeruli. Twenty-one patients were randomly assigned to two groups: the
corticosteroid group and the antiplatelet group. After 1 year of treatment, repeated renal biopsy was performed in 19 patients. We evaluated glomerular filtration rate, blood pressure,
proteinuria, and histological parameters, including light microscopic findings and staining of alpha-smooth muscle actin (alphaSMA), as a marker of myofibroblast-like cells and
fibronectin EDA (
EDA-FN) as an
indicator of renal
fibrosis. After 1 year of treatment,
proteinuria significantly decreased in the
corticosteroid group. Histological findings, such as mesangial cell proliferation, mesangial matrix accumulation, and cellular crescents, showed significant improvement in the
corticosteroid group but not in the antiplatelet group. Expression of alphaSMA in glomeruli significantly decreased in the
corticosteroid group but not in the antiplatelet group.
EDA-FN did not change in either group. We conclude that early treatment with
corticosteroids for adult diffuse proliferative
IgA nephropathy is effective in reducing renal injury.