Increased urinary excretions of immunoglobulin g, ceruloplasmin, and transferrin predict development of microalbuminuria in patients with type 2 diabetes.

M icroalbuminuria is generally considered as the best available noninvasive predictor of diabetic nephropathy. However, several studies have shown that increases in certain urinary proteins (immunoglobin G [IgG] [1–3], transferrin [Tf] [4–7], and ceruloplasmin [CRL] [3,8]) were found in normoalbuminuric diabetic patients. Recently, we reported that in normoalbuminuric diabetic patients, there was a strong linear correlation among these urinary proteins (9). To assess whether increased urinary excretions of IgG, CRL, and Tf can predict development of microalbuminuria, we conducted a 5-year follow-up study of type 2 diabetic patients with normoalbuminuria at baseline.