| Abstract: | We analysed the occurrence of anti-neutrophil cytoplasmic antibodies (ANCA) in sera of 191 patients with glomerulonephritis (76 females and 115 males) by the standard indirect immunofluorescence method (IIF). The presence of ANCA was demonstrated in sera of 4.4% (8/181) patients with idiopathic glomerulonephritis (GN) and in 30% (3/10) of patients with rapidly progressive glomerulonephritis (RPGN), as a form of renal limited vasculitis. In the experimental part of our study we analysed the influence of GN ANCA-negative sera on the neutrophil function in vitro and compared with the effect of ANCA-positive sera (titre > or = 4:40) from systemic vasculitis (SV) patients with renal involvement. The activation of neutrophils was established by reactive oxygen species (ROS) production and the ability of superoxide anion to reduce ferrocytochrome c. Among 30 ANCA-negative GN sera 20% (6/30) revealed the ability to activate neutrophils isolated from healthy donor. Remaining ANCA-negative GN sera and all sera from normal healthy individuals (negative control group) did not affect the neutrophil function and did not induce the superoxide anion production. Their effect was similar to the second negative reference system without serum. Only 33% (3/9) of high titre ANCA-positive sera (> or = 1:40) from SV patients were able to activate neutrophils and to produce the superoxide anion with following ferrocytochrome c reduction, but the effect of activation was most powerfully expressed (three times greater than by GN ANCA-negative sera). The remaining ANCA-positive sera and all SV ANCA-negative sera did not affect the neutrophil function in vitro. These experimental data indicate that the presence of ANCA in GN sera is not necessary to induce neutrophil activation in vitro. On the other hand the influence of the SV ANCA-positive sera was most powerful expressed, although only 33% of sera were able to activate neutrophils in vitro. Our results indicate that not always ANCA presence in serum was connected with the ability to neutrophil activation in vitro. It is possible that in ANCA-negative sera other factors were able to activate neutrophils in vitro, but the effect of activation was markedly lower. |
