Inspired by the hypothesis that SOCS-1 might modulate the negative effect of hCG on IL-2 production in OHSS patients, we designed the present pilot exploratory case series, aimed to evaluate the expression of IL-2 and its suppressor, SOCS-1, in the PBMCs of patients suffering from severe OHSS, and to examine whether their expressions differ when compared to PBMCs originated from normal early pregnant women (without OHSS). The gene discussed is IL2; the disease is ovarian hyperstimulation syndrome.