Decrease in detectable complement receptor type 1 levels on erythrocytes from patients with psoriatic polyarthritis

The complement receptor type 1 (CR1) levels on erythrocyte membranes from 23 patients with PsA was determined by using ELISA. Six patients had an axial form, the rest had peripheral arthritis (10 polyarthritis and seven oligoarthritis). A significant decrease in levels of this receptor was found in patients with polyarthritis compared with healthy controls. Non-significant differences were found when comparing the other two groups of patients with the controls, although the mean values of CR1 were lower in the patients' group. We also found an inverse correlation between CR1 levels and articular index, but not with ESR, CRP or disease duration. No differences in the CR1 density were obtained for HLA-B27 positive and HLA-B27 negative patients.