IL1B and leukemia: Thus, a majority of studies have utilized THP-1 cells pre-stimulated with PMA, a sufficient priming stimuli for producing pro-IL-1β; however, there is accumulating evidence that the caspase-1/IL-1β activation pathway differs between primary human monocytes and the monocyte-like leukemia cell line, THP-1, and murine macrophages, cells often used to study crystal-mediated sterile inflammation22, 23.