Natural killer activity and antibody-dependent cell-mediated cytotoxicity in primary glomerular diseases

This study was performed to investigate the role of cell-mediated immunity in primary glomerular diseases (PGD), by estimating natural killer (NK) activity from peripheral blood mononuclear cells (PBMC) assayed against K562 cells, and antibody-dependent cell-mediated cytotoxicity (ADCC) activity from PBMC assayed against chicken red blood cells. The proportion of PBMC was examined by flow cytometry using the monoclonal antibodies OKT and Leu series. NK activity in patients with nephrotics of minimal change nephrotic syndrome (MCNS), membranous glomerulonephritis (MGN) and membranoproliferative glomerulonephritis (MPGN) was significantly lower compared to those of the normal controls. In addition, ADCC activity in patients with nephrotics of MPGN was significantly lower compared to the normal controls. The sera from patients with diminished NK activity inhibited NK activity of PBMC from healthy individuals. Furthermore, OKM1 positive lymphocytes were significantly higher in the MCNS, MGN and MPGN patients and Leu7 positive lymphocytes were significantly higher in the MPGN patients. These data suggest that several mechanisms contribute to the defects of NK and ADCC activities in patients with PGD, and the defects in NK and killer cells are common in patients with nephrotics of MCNS, MGN and MPGN, and may be important in the pathogenesis of PGD.