[Expression of Fc epsilon receptor 2 in minimal change nephrotic syndrome]

In order to clarify the mechanism for elevation of serum IgE level in minimal change nephrotic syndrome (MCNS), we investigated Fc epsilon receptor 2 (Fc epsilon R2/CD23) expression, using fluorescein isothiocyanate (FITC) labeled anti-CD20 monoclonal antibody, phycoerythrin (PE) labeled anti-CD23 monoclonal antibody and two-color flow cytometry. Moreover, serum IgE level was examined by radio-immunosorbent test. The subjects included 25 cases of MCNS, 17 cases of focal glomerular sclerosis (FGS), and 25 healthy volunteers as controls. The patients in the nephrotic stage of MCNS demonstrated significantly elevated levels of serum IgE, while those in the remission stage of MCNS showed no change in their serum IgE levels. In patients with nephrotics of MCNS, CD23+ cells, CD20+ CD23+ cells and CD23/CD20 ratio were significantly increased compared to normal controls. Furthermore, CD23/CD20 ratio in MCNS was significantly correlated with serum IgE level. Concerning FGS, there were no differences in serum IgE level and Fc epsilon R2 expression compared to those of normal controls. These results suggest that Fc epsilon R2 expression may be important in the mechanism of elevated serum IgE level in MCNS.