Lowered expression of C3b receptor (CR1) on erythrocytes of rheumatoid arthritis patients.
The number of C3b receptors (CR1) on erythrocytes (E) has been quantitated by whole cell enzyme-linked immunosorbent assay (ELISA), using a monoclonal anti-CR1 antibody, in 46 healthy individuals as controls, 58 having rheumatoid arthritis (RA) and 3 hereditary angioedema patients. The mean value of CR1 in RA (381/E) was significantly lower (p < 0.001) when compared to normal controls (646/E). In hereditary angioedema patients CR1 numbers (620/E) were found to be comparable to normal values. No significant difference was found between normal male (708/E) and female (598/E) subjects. Among the patient groups, those on steroid therapy (352/E) showed no change compared to others not receiving such therapy (408/E). The cumulative frequency curve of CR1 in the normal population showed maximum inflection at 32% and 82%. This led us to conclude that there is a trimodal distribution of receptors in the control population. Such a contention is well supported by frequency histogram, when a small group interval (0-50) was chosen. However, if large group intervals (0-100 or 0-150) were considered, a very close approximation to unimodal pattern was obtained. The factors actually contributing to low receptor numbers are yet to be elucidated.
Kumar
A
A
Department of Biochemistry, All India Institute of Medical Sciences, New Delhi.
Malaviya
A N
AN
Srivastava
L M
LM
D000293:Adolescent; D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D004912:Erythrocytes / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017463:Receptors, Complement 3b / Q000032:analysis*; D012016:Reference Values
D017463:Receptors, Complement 3b