S100A9 and acrodermatitis enteropathica: To investigate the characteristics of hepatic macrophages in patients with AE, we initially examined the expression of CD68 (a marker indicating total macrophages), CD163 (a marker indicating anti-inflammatory M2 macrophages) and S100A9 (a marker indicating proinflammatory M1 macrophages) (15, 36) in AE patient liver specimens by IHC staining.