To assess the impact of increased steatosis and fibrosis on hepatocellular inflammation, tissue sections were probed for myeloperoxidase (MPO, a marker of activated neutrophils), F4/80 (a marker of infiltrating macrophages and resident Kupffer cells), B220 (a B cell marker) and CD3 (a lymphocyte marker). The gene discussed is MPO; the disease is steatosis.