The Population of CD40L-expressing Cells was Slightly but not Significant Decreased in Lymphoid Tissues of Collagen Induced Arthritic Mice Treated with Hochu-Ekki-To

Objective: To clarify the mechanism of the action of Hochu-Ekki-To (HET) on collagen-induced arthritic (CIA) mice by analyzing the CD40L-expressing cells population. Methods: CIA was induced in male DBA/1J mice by immunization with two injections of bovine type II collagen (CII). HET or water was orally administered. The subpopulations of lymphocytes obtained from lymph nodes and spleen were detected at 3 weeks after boost using flow cytometry. Results: Although the population of CD4(+)CD40L(+) cells tended to be decreased in the HET group compared to that in control mice, there was no significant difference between the two groups. These findings were observed in lymphocytes obtained from both lymph nodes and spleen. Conclusion: HET suppresses the development of CIA. These effects may be partially induced via the decrease in the population of CD4(+)CD40L(+) cells, but the role of this action is probably limited.