Representative immunostaining for β5 subunit of the constitutive proteasome in placentas of a women with (A) idiopathic spontaneous preterm birth (sPTB, 32 weeks), (B) preeclampsia with severe features (sPE, 32 weeks) or (C) HELLP syndrome (30 weeks). Representative immunostaining for β5i subunit of the immunoproteasome in the same cases (D) sPTB, (E) sPE, and (F) HELLP syndrome. Areas of interest are marked with black arrows or arrowheads as described in results. Scale bar: 50 nm.