IL6 and ovarian hyperstimulation syndrome: In addition, other systemic and local vasoactive substances, including interleukin (IL)−2, IL-6, IL-8, IL-10, IL-18, angiotensin II, histamine, prolactin, prostaglandins, insulin-like growth factor (IGF) 1, and transforming growth factor (TGF) b, are also directly and indirectly involved in the pathogenesis of OHSS [4, 8–10].