| pubmed-article:7362682 | pubmed:abstractText | Serologic HLA typing was carried out on 33 seropositive and 15 seronegative patients with rheumatoid arthritis (RA). Association with the DRw4 antigen was found only in seropositive RA (61%, compared with 27% in normal controls; P less than 0.05, Fisher's exact test), whereas the antigen had a normal frequency in seronegative RA patients (27%). The serum concentrations of IgM and IgE immunoglobulins were significantly higher in seropositive than in seronegative RA patients (p less than 0.01, Mann-Whitney test), whereas the concentrations of the other immunoglobulin classes and of the complement factors C3 and C4 did not show any significant differences. | lld:pubmed |
