CD4 and Arthritis: These findings are consistent with a mechanism in which TRI MP decreases arthritis score by limiting immunization-induced expansion of CD4+ T cells directly and/or through an increased regulatory FoxP3-CD25+ population in the periphery, resulting in less CD4+ T cell recruitment and/or the migration of FoxP3-CD25+ T cells to the paws, and in turn less recruitment and activation of myeloid cells to produce arthritis causing inflammatory cytokines.