Serum Immune Complex Levels Research Articles

Identification of circulating immune complexes in a subpopulation of patients with membranous glomerulonephropathy

To investigate the relationship of circulating immune complexes to membranous nephropathy, complexes were assayed by the 125I-C1q-binding assay and the Raji cell radioimmune assay in 18 patients with this disorder. Immune complexes were detected by both assays in the sera of five patients who had a concurrent renal vein thrombosis. Immunoabsorption studies established the specificity of the C1q-reactive material as immune complexes. The generation of immune complexes by the thrombotic episode was excluded by control observations in patients with other types of venous thrombosis. It is suggested that analogous to animal models, patients with membranous nephropathy and concurrent renal vein thrombosis may represent a subpopulation with a more active phase of the disease resulting in the generation of higher (and detectable) levels of serum immune complexes.

Sjögren's syndrome: a defect in reticuloendothelial system Fc-receptor-specific clearance.

To determine the functional status of reticuloendothelial system Fc receptors in patients with Sjögren's syndrome, we studied the rate of clearance from the circulation of 51Cr-labeled IgG-sensitized autologous erythrocytes in 19 patients. Fc-receptor-mediated clearance was abnormal in 12 of the 19 patients, with half-lives ranging from 80 to 356 min. There was a significant correlation between clearance rates and clinical manifestations of disease. Clearance rates tended to be normal in patients with disease limited to exocrine glands and abnormal in patients with widespread disease. In contrast, there were no correlations between the rate of clearance of IgG-sensitized erythrocytes and serum immune complex levels, serum complement component levels, or rheumatoid factor titers. The striking correlation between clearance rates and disease manifestations suggests that decreased clearance of immune complexes by defective reticuloendothelial system Fc receptors may contribute to disease pathogenesis.

Proteolytic enzyme activity of blood leukocytes and cerebrospinal fluid in multiple sclerosis.

Upon stimulation by immune complexes, the polymorphonuclear (PMN) blood secretes lysosomal hydrolases, including neutral proteinase, which is concentrated in the PMN cell. Neutral and acid proteinase activity were increased and decreased, respectively, in the circulating white cells of patients with multiple sclerosis during an exacerbation of the disease, but there was no correlation with serum immune complex levels. Neutral proteolytic activity in the cellular fraction of the cerebrospinal fluid was also found to be elevated in acute multiple sclerosis, as monitored by digestion of myelin basic protein.