[Flow cytometric measurement of C3b receptors (CR1) on human erythrocytes. II. E-CR1 levels in patients with various diseases and their correlation with B-CR1].

Using a novel technique previously described for measuring erythrocyte C3b receptors (E-CR1) by means of flow cytometry, we studied E-CR1 levels in patients with various diseases. We also measured C3b receptors of B cells (B-CR1) by flow cytometry, and studied the correlation between E-CR1 levels and B-CR1 levels. We have found; 1) Decreased E-CR1 levels were seen in patients with active SLE, acute leukemia, and congenital immunodeficiency syndrome. E-CR1 levels in patients with IgA nephropathy, membranoproliferative glomerulonephritis, anaphylactoid purpura, infectious mononucleosis, and viral pneumonia were statistically higher than those in normal controls. 2) Decreased E-CR1 levels in some patients with SLE were not thought to be inherited, but the E-CR1 levels of patients with diseases other than SLE appeared to be regulated in an autosomal co-dominant form of inheritance. 3) A negative correlation was observed between E-CR1 levels and B-CR1 levels in both patients with SLE and normal controls.