The diagram is divided into three sections, each representing a different stage of the disease progression. In the top section, Foxp3 plus Treg cells with membrane CD137 support islet Treg accumulation and suppressive state, indirectly affecting Teff cells. Soluble CD137 is also present. In the middle section, membrane CD137 on Foxp3 plus Treg cells is blocked, leading to a reduction in its suppressive effect on Teff cells. Soluble CD137 is still present. In the bottom section, both membrane and soluble CD137 are blocked, resulting in a further reduction of the suppressive effect on Teff cells. The islet diagrams on the right show the increasing infiltration of Teff cells as the disease progresses.