Immunosuppressive treatment using tacrolimus promotes pregnancy outcome in infertile women with repeated implantation failures

Problem We aim to investigate whether the peripheral blood T helper (Th) 1 cell level could predict pregnancy outcome in patients who have experienced repeated implantation failure ( RIF , three or more) after ART cycles. Method of study This is a prospective cohort study of total 124 women with RIF who showed elevated Th1/Th2 ( CD 4 + IFN ‐γ + / CD 4 + IL ‐4 + ) cell ratios (≥10.3) and received tacrolimus at Sugiyama Clinic between November 2011 and July 2016. Patients were divided into three groups as per Th1 cell levels: Th1 level of <22.8 as Low; 22.8 to <28.8 as Middle, and 28.8 or greater as High group. The study patients received daily dose of tacrolimus 1‐3 mg based on initial Th1/Th2 cell ratio. Results The clinical pregnancy rates of Low, Middle, and High groups were 48.8%, 43.9%, and 33.3%, respectively ( P = NS ), with tacrolimus treatment. The ongoing pregnancy/delivery rate of Low group (46.3%) was significantly higher than that of High group (21.4%, P <.05). Middle group (34.3%) had higher success rate than High group, albeit without statistical significant. Conclusion We confirm our previous report that Th1/Th2 ratio can predict ART outcomes in patients with RIF and immunosuppressant treatment with tacrolimus, and peripheral blood Th1 cell levels were negatively correlated with pregnancy outcome.