Fig. 2From: Association between endometrial indoleamine 2,3-dioxygenase expression level and pregnancy outcomes in women undergoing first in vitro fertilization treatmentImmunohistochemical grading of the expression of IDO in endometrium. The grading was performed based on staining intensity, as described in the materials and methods, grade 1: no or weak staining and scarcely positive, IDO was localized in the stromal compartment (a); grade 2: moderately stained and focally positive, IDO was localized in surface epithelial cells (b); grade 3: strongly stained and diffusely positive, IDO was localized in glandular epithelial cells (c); scale bars = 100 µm, with insets = 10 µmBack to article page