Fc-receptor function in minimal change nephrotic syndrome of childhood.

This study was undertaken to establish whether the Fc-receptor function of circulating monocytes (CM) and/or of splenic macrophages (SM) is modified during the course of minimal change nephrotic syndrome (MCNS) of childhood. The Fc-receptor function of SM was ascertained by measuring the spleen to liver uptake ratio 40 min after IV injection of heat-damaged autologous erythrocytes labeled with 99Tc, whereas the Fc-receptor function of CM was determined by a "rosetting" test. The Fc-receptor function was followed in six girls presenting with a MCNS and receiving no therapy at the time of testing. The Fc-receptor function of SM was decreased in five patients during an acute phase of MCNS. In four of these five patients, the Fc-receptor function of CM was also altered. No significant correlations were observed between the Fc-receptor blockade and the C3, C3d, C4, C3PA or immune complex-plasma levels. The Fc-receptor blockade was persistent in three girls during remission. A prior incubation of CM with trypsin did not completely reverse the Fc-receptor blockade. Further studies are now being pursued in order to determine whether this persisting abnormality is inherited and mainly observed in relapsing nephrotic syndrome.