Significance of Electron Dense Deposits in Patients with Minimal Change Nephrotic Syndrome

BACKGROUND: Minimal change nephritic syndrome (MCNS) is characterized by a lack of obvious abnormalities on light microscopy, but its electron microscopic findings include the negative immunofluorescence findings and the diffuse effacement of the epithelial cell foot processes. Rarely the presence of electron dense deposits (EDDs) has been reported, but its clinical significance remains obscure. METHODS: Eleven patients with MCNS who had the EDD deposited were enrolled in the current study. We compared the clinical characteristics, laboratory results and response to steroid treatment between the two group: the EDD group (n=11; the male-to-female ratio, 8:3) and the non-EDD group (n=13, 8:5). RESULTS: There were no significant differences in most of the laboratory results or response to steroid treatment between the two groups. The frequency of relapses per year was significantly higher in the EDD group (1.1±0.7 times vs. 0.5±0.6 times; p=0.023). These EDDs were found in the mesangium or paramesangium. With no respect to the characteristics of EDDs, our results showed that they did not cause poor treatment outcomes except for the annual frequency of relapse. CONCLUSIONS: Further large-scale studies are warrented to determine the immunologic and prognostic significance of EDDs in patients with MCNS.