CD40LG and rheumatoid arthritis: On the other hand, a recent study aimed to determine the prevalence of B19V infection in patients with RA compared to healthy controls and to assess its possible association with disease activity or severity, demonstrated that B19V DNA and an-ti-B19V IgG (but not IgM) was significantly higher in RA patients than healthy controls (p = 0.003 and p = 0.04, respectively) [83].