ABCA4 and retinitis pigmentosa: In the same model, increased Il1β expression by subretinal macrophages is associated with increased photoreceptor apoptosis, which is ameliorated by injections of the endogenous Il1ß inhibitor, Il1ra [36].In other models, Ccl3 expression in activated macrophage/microglia is implicated in both AMD/Stargardt disease (Abca4−/−Rdh8−/− mice) and retinitis pigmentosa (Mertk-/- mice) models [40].