Abnormal reticuloendothelial function in patients with active vasculitis and idiopathic membranous glomerulopathy. A study with 99mTc-labeled heat-damaged autologous red blood cells

The use of human albumin millimicrospheres tagged with 99mTc in the evaluation of the removal capacity of the reticuloendothelial system

Liver uptake kinetics of 99mTc labelled millimicrospheres of human serum albumin (MM) was studied in 16 subjects. Every subject received four doses of MM intravenously. The uptake constant decreased progressively with increasing dose. The maximum liver removal capacity, a parameter which is independent of liver blood flow, was calculated according to the method of Iio and Wagner (1963). From these data we conclude that MM are taken up by the reticuloendothelial system (RES) with saturable kinetics, and they are suitable for clinical use to evaluate RES function in man.

Kinetic analysis of the blood clearance and organ uptake curves of IgG-coated red cells in HLA-typed controls and patients with Wegener's granulomatosis

Reticuloendothelial function and HLA type were studied in 22 controls and 15 patients with Wegener's granulomatosis (WG). IgG-coated red cells were injected intravenously and half-life times of blood disappearance and liver spleen uptake curves were related to the degree of antibody coating. Erythrocytes with 13,990 molecules of IgG per cell gave biexponential blood disappearance curves and were suitable for measuring splenic reticuloendothelial function. Half-life times thus obtained were not significantly different for individuals with the HLA-DR2 or DR3 phenotype. In WG patients with major disease activity, blood clearance of the injected cells was considerably decreased. Kinetic analysis of blood disappearance and spleen uptake curves revealed that this was partly due to a decrease in reversible trapping of the cells in the spleen. This suggests that a blocking effect of circulating immune complexes on splenic Fc receptors is not likely to be the sole cause of the observed hyposplenism.

Autoantibodies against neutrophils and monocytes: tool for diagnosis and marker of disease activity in Wegener's granulomatosis

Immunoglobulin G (IgG) autoantibodies against extranuclear components of polymorphonuclear granulocytes were detected in 25 of 27 serum samples from patients with active Wegener's granulomatosis and in only 4 of 32 samples from patients without signs of disease activity. In a prospective study of 19 patients these antibodies proved to be better markers of disease activity than several other laboratory measurements used previously. The autoantibodies were disease specific and the titres were related to the results of an in-vitro granulocyte phagocytosis test, in which 7S IgG antibodies were internalised after specific binding to the cell, resulting in gradual formation of ring-like cytoplasmic structures. This autoantibody may have a pathogenetic role in Wegener's granulomatosis. The detection of this antibody is valuable for diagnosis and estimation of disease activity.