Inhibition of complement-dependent lymphocyte rosette formation by sera of patients with chronic glomerulonephritis.

It has been demonstrated that activated C3 products might bind to lymphocyte C3 receptors and inhibit subsequent complement-dependent lymphocyte rosette formation. Sera from patients with various types of chronic glomerulonephritis (GN) have been tested in a complement-dependent rosette inhibition assay using normal donors' lymphocytes as reacting cells. Control subjects consisted of healthy donors and patients with miscellaneous renal and general diseases. Most sera of membranoproliferative GN and of systemic lupus erythematosus, and two-thirds sera of focal glomerolosclerosis patients, significantly inhibited rosette formation. Only 15-40 percent sera of patients with other types of GN were inhibitory. Serum inhibiting activity usually correlated with low serum C3 level (P less than 0.0005), although inhibition could be observed with normal serum C3. However, no correlation was found between a patient's own complement-dependent lymphocyte rosette count and his serum inhibitory activity. These results extend previous findings and suggest that the complement-dependent rosette inhibition assay can be used routinely to detect serum activated complement components either free or bound to immune complexes.