Immunohistochemical Characterization of Lymphocytic Subpopulations (CD3/CD20) in Endometrium of Sub-fertile Mares

e Materials and Methods: Endometrial biopsy samples from 15 sub-fertile mares without clinical signs of endometritis and negative for uterine cytology were analysed. The samples were classified as belonging to group 2 a/b of the Kenney’s classification (1986). Characteristic findings included the presence of plasma cells and a prominent non-specific, lymphocytic infiltrate. According to the degree of clinical infertility, the mares were divided into two groups:(A) nine mares without a foal after more than three AIs and/or had shown abortion or embryo resorption;(B) six mares without a foal after no more than two AIs at the end of the breeding season. Immunohistochemistry was performed using markers for CD3 and CD20. Positive cells were counted in four randomly-selected high-power fields (HPFs).