IL1B and acne: Supporting a key position for PA in shaping the inflammatory environment, we confirmed that PA is a more potent stimulator of interleukin (IL)1 beta (IL1B) and tumor necrosis factor alpha (TNFA) cytokine production than Propionibacterium acnes (P. acnes), the commensal bacterium which has been associated with acne, in in vitro differentiated monocyte-derived macrophages (16).