Evidence for genetic variants proximal to the interleukin 1A gene locus was among the earliest risk regions identified for endometriosis.[26, 27] Of all the cytokine families, IL1 is most associated with damaging inflammation[45, 46, 47] and has been predicted to modulate endometriosis symptomatology.[48] In this study, IL1A/IL1B signaling was identified as a major effector driving the association between M2 macrophages and endometriosis. The gene discussed is IL1B; the disease is endometriosis.