A medicine for treating or ameliorating a disease associated with humoral immunity in the materno-fetal relationship, for example, sterility and infertility caused by humoral immunity in the materno-fetal relationship, blood type incompatible pregnancy, or fetal hemochromatosis, the medicine including, as an active ingredient, a compound selected from the group consisting of: (i) a compound represented by Formula (I) (wherein the respective reference numerals are as described in the specification) or a pharmaceutically acceptable salt thereof, (ii) a cyclosporine, and (iii) a rapamycin derivative.