High-dose intravenous immunoglobulin pulse therapy in patients with progressive immunoglobulin A nephropathy: a long-term follow-up

Abstract

Summary In progressive immunoglobulin A nephropathy (IgAN), intravenous immunoglobulin (IVIg) treatment has been used to delay disease progression, but the long-term efficacy is largely unknown. We report the clinical outcomes after IVIg therapy in six male patients with progressive IgAN [median glomerular filtration rate (GFR) 31 ml/min per 1·73 m2] followed for a median observation period of 8 years. In this single-arm, non-randomized study, IVIg was given monthly at a dose of 2 g/kg body weight for 6 months. The course of renal function was assessed by linear regression analysis of GFR and proteinuria, and was compared to eight patients with IgAN (median GFR 29 ml/min per 1·73 m2) without IVIg as a contemporaneous control group. IgAN disease progression was delayed after IVIg therapy on average for 3 years. The mean loss of renal function decreased from − 1·05 ml/min per month to − 0·15 ml/min per month (P = 0·024) and proteinuria decreased from 2·4 g/l to 1·0 g/l (P = 0·015). The primary end-point (GFR < 10 ml/min or relapse) occurred 5·2 years (median; range 0·4–8·8) after the first IVIg pulse, and after 1·3 years (median; range 0·8–2·4) in the control group (P = 0·043). In Kaplan–Meier analysis, the median renal survival time with IVIg was prolonged by 3·5 years (IVIg 4·7 years versus control 1·2 years; P = 0·006). IVIg pulse therapy may be considered as a treatment option to reduce the loss of renal function and improve proteinuria in patients with progressive IgAN.