EVALUATION OF SPERM LEUKOCYTE SUBPOPULATION BY FLOW CYTOMETRY IN INFERTILE PATIENTS WITHOUT LEUKOCYTOSPERMIA

Introduction. Leucocytospermiais considered marker of testicular and/or epididymal infection/inflammation. An increased number of sperm leukocytes may damage sperm motility and morphology and cause oxidative stress, lipid peroxidation andDNA fragmentation. However, the WHO (2010) method to evaluate leukocytes byidentifying the peroxidase enzyme, does not detect activated polymorphs, lymphocytes, macrophages and monocytes (all peroxidase-negative). Moreover,chronic inflammation may be associated to a low number of polymorphs, but with an increased number of lymphocytes in the ejaculate. Leukocyte subpopulations may be detected using specific monoclonal antibodies; thus avoiding an incorrect estimation of their number. Aim. This study was undertaken to evaluate sperm leukocyte subpopulations.Patients andMethods. Leukocyte subpopulations were evaluated in 36infertile patients(mean age: 27.9 years; range: 19-35 years) without clinical signs of infection/inflammation and a normal leukocyte concentration (<1x106mil/ml). Forty-fivehealthy, normozoospermic men (mean age: 28.6 years; range: 18-38 years) served as controls (CTL). Sperm leukocyte subpopulations were evaluated by flow-cytometry following staining with monoclonal antibodies. Coexpression of CD45/CD14/CD16 identified neutrophils and monocytes/macrophages, CD45/CD3/CD4 T-helper lymphocytes and CD45/CD3/ CD8 T-suppressor lymphocytes. Results. Out of the 93 infertile menwho accepted to participate to this study, 44 did not have any clinical sign of infection/inflammation. However, 8 of them had leukocytospermia (>1x106mil/ml) and hence were excluded. CTL had 75±10% neutrophils, 8±2% monocytes/macrophages, 11±3% T-helper lymphocytes and 6±2% T-suppressorlymphocytes in the ejaculate. Infertile patients showed a lowerpercentage of neutrophils and an increasedpercentage of T-helper and Tsuppressor lymphocytes(p<0.05 vs. CTL). In addition, 16/36 (44%) patients a higher percentage of lymphocytes compared toCTL. Conclusion. This study suggests that at least 25% of sperm leukocytes is not detected by conventional WHO 2010 method. Infertile patients without apparent signs of infection/inflammation had a higher percentage of lymphocytes, suggestive of an asymptomatic chronic (or viral) urogenital inflammation. For these reasons, we hypothesize that sperm leukocytes should be evaluated by specific monoclonal antibodies.