There is a weak positive correlation between rheumatoid factor IgM relative units/mL and patient-related pain intensity (r = 0.21, P < 0.01) and arthritis disease activity measured by the Disease Activity Score-28 (r = 0.0.19, P < 0.01), but these are no longer significant after Bonferroni adjustment. This evidence concerns the gene CD40LG and arthritic joint disease.