Among untreated RA patients with active disease (Disease Activity Score 28-C-reactive protein = 5.6 ± 0.89) an expanded population of peripheral GM-CSF+ B (4.1 ± 2.2%) and T (3.4 ± 1.6%) cells was detected compared with both disease (1.7 ± 0.9%, p < 0.0001 and 1.7 ± 1.3%, p < 0.0001, respectively) and healthy (0.3 ± 0.2%, p < 0.0001 and 0.6 ± 0.6%, p < 0.0001) controls. Here, CRP is linked to rheumatoid arthritis.