CD40LG and rheumatoid arthritis: While the sICAM-1 levels in all the RA patients did not present a significant correlation with the levels of antibodies against antigens of P. mirabilis, in the subgroup of RA patients treated with biologic agents, a statistically significant correlation was shown between sICAM-1 concentration and IgM antibodies against HpmB (r = 0.506, p<0.02).