High-dose immunoglobulin therapy for severe IgA nephropathy and Henoch-Schönlein purpura

To determine if polyvalent IgG is promising therapy for severe IgG nephropathy.

Open prospective cohort study.

Referral nephrology unit.

11 adult patients with severe IgA nephropathy (9 who had idiopathic disease and 2 who had Henoch-Schönlein purpura) and indicators of poor prognosis.

Patients were given high-dose immunoglobulins (2 g/kg each month) for 3 successive months, followed by intramuscular immunoglobulins (preparation content, 16.5%; 0.35 mL/kg every 15 days) for another 6 months.

Histologic changes were analyzed by comparing pre- and post-therapy renal biopsy specimens blindly, using an activity index (14-point scale), a sclerosis index (10-point scale), and a semiquantitative immunofluorescence test of immune deposits. Proteinuria, hematuria, leukocyturia, enzymuria, and global renal function (creatinine and polyfructosan clearances) were evaluated before and after intervention.

Proteinuria (median level before intervention, 5.20 g/d; median level after intervention, 2.25 g/d), hematuria, and leukocyturia decreased substantially. The decrease in glomerular filtration rate was greatly slowed or stopped (median rate of decline in glomerular filtration before, -3.78 mL/min per month; after, 0 mL/min per month). The histologic index of activity (median index before, 5; after, 2) and the staining intensity of glomerular IgA and C3 deposits also decreased. Immunoglobulin therapy was well tolerated.

Immunoglobulin therapy may be effective in treating severe IgA nephropathy and protecting renal function. However, prospective controlled trials must confirm these preliminary results.