Progesterone-induced blocking factor and interleukin 4 as novel therapeutics in the treatment of recurrent pregnancy loss

Abstract

Recurrent pregnancy loss (RPL) is defined as at least three consecutive pregnancies ending in a miscarriage. RPL affects around 1–3% of child-bearing couples. In up to half of cases the etiology of RPL cannot be identified; many such cases are believed to be caused by alterations of the mechanisms involved in the development of immune tolerance of the fetus as a semi-allograft. One of the key proteins involved in the regulation of the immune system during pregnancy is progesterone-induced blocking factor (PIBF). Here we present our hypothesis according to which recombinant PIBF could be used in the treatment of immune system-mediated RPL. An alternative to PIBF could be interleukin (IL)-4; the rationale for the use of IL-4 in RPL is that immunomodulatory effects of PIBF are mediated by α subunit of IL-4 receptor. Both PIBF and IL-4 exert some immunomodulatory effects that could be beneficial in patients with RPL.