Associations Between Rheumatoid Factor (RF) and Disease Duration and Scores From Cytokine-Loaded Factors Associated With Experimental Activation. Associations ranged from positive (red) to negative (blue) for visit 1, visit 2, and the change between visits. * indicates P<.05; **, P<.01; ***, P<.001; CD3/CD28, anti-CD3 and anti-CD28 microbeads; CpG, cytosine-phosphate-guanine oligonucleotide ODN2006; Medium, RPMI 1640 medium with 10% fetal calf serum; PHA, phytohemagglutinin; PMA/Ion, phorbol 12-myristate 13-acetate–ionomycin; SEA/SEB, staphylococcal enterotoxins A and B.