Expression of complement 3 receptors (CR1 and CR3) on neutrophils and erythrocytes in patients with IgA nephropathy.
Expression of C3 receptors (CR1 and CR3) on neutrophils (PMN) was measured in 26 patients with IgA nephropathy (IgA N), 17 normal persons, and 8 patients with non-IgA glomerulonephritis (non-IgA GN) by fluorescence activated cell sorting after labeling with monoclonal antibodies. Mean channel fluorescence for both CR1 and CR3 on PMN was significantly higher in IgA N patients than in either control group (p less than 0.01). (CR1 mean +/- SD 42.5 +/- 10.4 in IgA N, 31.7 +/- 11.5 in normal controls, 27.8 +/- 9.0 in non-IgA GN; CR3 94.0 +/- 16.5, 75.0 +/- 16.6 and 76.7 +/- 15.6, respectively.) No differences were found between the two control groups or between IgA N patients with normal and impaired renal function. These results imply that PMN are activated in IgA N patients. The expression of CR1 and CR3 of PMN may be upregulated by immune complexes (ICs), enhancing both phagocytosis of C3b- or iC3b-coated particles, and absorptive pinocytosis of soluble ICs containing C3b or iC3b. Erythrocyte CR1 and CR3 expression was measured by ELISA and found to be slightly but significantly lower in IgA N patients than in the other 2 groups (CR1 85.3 +/- 28.4 in IgA N, 113.1 +/- 28.8 in normal controls, 109.4 +/- 28.2 in non-IgA GN, p less than 0.02; CR3 80.9 +/- 20.0, 100.4 +/- 19.9, 101.2 +/- 24.9, respectively, p less than 0.05).
Tao
K
K
Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia.
Nicholls
K
K
Rockman
S
S
Kincaid-Smith
P
P
D000328:Adult; D000368:Aged; D004797:Enzyme-Linked Immunosorbent Assay; D004912:Erythrocytes / Q000032:analysis*; D005260:Female; D005922:Glomerulonephritis, IGA / Q000097:blood* / Q000209:etiology / Q000276:immunology; D006801:Humans; D016177:Macrophage-1 Antigen; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000032:analysis*; D010587:Phagocytosis / Q000276:immunology; D011951:Receptors, Complement / Q000032:analysis*
D016177:Macrophage-1 Antigen; D011951:Receptors, Complement