Figure 4.

Two phases of inflammation characterize AD. During the acute phase, OX40-OX40L ligation on activated T cells facilitates T_H2-predominant signaling and differentiation, which produces type 2 inflammatory cytokines. The shift to the chronic phase is characterized by the recruitment of T_H1, T_H17, and T_H22 cells expressing OX40. OX40-OX40L ligation on these activated T helper cell populations leads to effector cell proliferation and cytokine production that maintain the inflammatory response.