Serum allograft inflammatory factor-1 is a novel marker for diabetic nephropathy

Abstract Aims Recent studies have identified macrophage-mediated injury as an important component in the development of diabetic nephropathy. The aim of this study was to investigate the correlations between serum allograft inflammatory factor-1 (AIF-1) concentration, which is a marker of activated macrophages, and diabetic nephropathy. Methods Serum AIF-1 concentrations were measured in 284 patients with type 2 diabetes. We evaluated relationships of serum AIF-1 concentrations to degree of urinary albumin excretion (UAE) or estimated glomerular filtration rate (eGFR) in univariate and multivariate linear regression analyses. Results Serum AIF-1 concentrations positively correlated with logarithm of UAE ( r = 0.260, P < 0.0001), whereas serum AIF-1 concentrations inversely correlated with eGFR ( r = −0.312, P < 0.0001). Mean serum AIF-1 concentration was higher in patients with macroalbuminuria than that in patients with normoalbuminuria ( P = 0.0001) or that in patients with microalbuminuria ( P = 0.0093). In multivariate linear regression analyses, serum AIF-1 concentrations were independently correlated with logarithm of UAE ( β = 0.213, P = 0.0120) and with eGFR ( β = −0.286, P = 0.0011). Conclusions Serum AIF-1 concentration correlated with albuminuria and eGFR in patients with type 2 diabetes and it could be a marker of diabetic nephropathy as well as activated macrophages.