Future Directions in the Treatment of IgA Nephropathy

Abstract

IgA nephropathy (IgAN) is the most common primary glomerulonephritis yet its etiology remains uncertain. Recent data suggest a structural aberration of the IgA molecule in IgAN that may exert pathophysiologic effects on target cells, reduce clearance of IgA-immune complexes (IC), or favor mesangial IC trapping. Mesangial reactivity to immune complexes triggers off the release of cytokines and the alteration of prostaglandin and thromboxane A₂ production promoting mesangial cell proliferation. Angiotensin II-induced mesangial cells contraction with efferent arteriolar vasodilatation initiates glomerular injury and eventually lead to glomerulosclerosis following increased local production of transforming growth factor-β (TGF-β) and platelet-derived growth factor (PDGF). This paper highlights the potential therapeutic strategies in the future. These strategies include: (i) decreasing the synthesis of IgA-IC; (ii) limiting the mesangial uptake of IgA-IC; (iii) antagonizing the effect of PDGF and TGF-β to reduce mesangial proliferation and glomerulosclerosis; and (iv) reducing the noxious glomerular injury due to infiltrating neutrophils. The effective treatment of IgAN requires a better clarification of the pathogenesis of the nephropathy. Future therapeutic attempts to slow down the renal deterioration should target at prevention of mesangial IgA deposition and the amelioration of inflammatory injury induced by infiltrating neutrophils and the released cytokines.