C-reactive protein and delayed hypersensitivity in juvenile rheumatoid arthritis.

In patients with juvenile rheumatoid arthritis (JRA), the delayed hypersensitivity found when skin-testing with a panel of memory antigens appeared to be reduced. Since C-reactive protein (CRP) has recently been shown to inhibit various parameters of cellular immunity in vitro, we tested the concentration of CRP in serum from 44 patients with JRA who had previously been tested for delayed hypersensitivity. The mean concentration of CRP in the patients was 32.2 mg/1, while in age- and sex-matched controls it was less than 5 mg/1. By scatter diagrams and statistical analysis no association was found between the concentration of CRP and various expressions of delayed hypersensitivity in vivo.