LACK OF EXPRESSION OF HLA ANTIGENS ON IMMATURE GERM-CELLS FROM EJACULATES WITH ANTISPERM ANTIBODIES

PROBLEM: The lack of expression of HLA antigen on immature germ cells from ejaculates with antisperm antibodies has been reported. METHOD: The expression of human leukocyte antigens on immature germ cells from ejaculates with antisperm antibodies (ASA) was investigated by indirect immunofluorescence using a panel of monoclonal antibodies (MAb) and automated flow cytometry. Patients were divided into two groups: fertile (prevasectomic; N = 10), and ejaculates with ASA (10 samples with IgG and IgA ASA, and five semen samples with only IgG ASA). ASA were detected on sperm using the direct immunobead test. After centrifuging semen samples on a Ficoll-Hypaque gradient, round cells obtained at the gradient interface were gated by a flow cytometer. The ''immature germ cell window'' was defined in terms of cellular volume and granularity. RESULTS: The percentage of gated round cells from semen samples that reacted with anti-CD45 was always less than 5%, and with anti-CD44 less than 3%. This lack of reactivity of gated round cells with MAb specific for leukocytes and epithelial cells suggests that they were immature germ cells. Immature germ cells were unreactive with W6/32 and anti-beta-2-microglobulin MAb, which suggests that these cells do not express HLA class I molecules. Similarly, no reactivity of the immature germ cells with the MAb that recognize HLA class II molecules was found. No significant differences were observed in the expression of HLA molecules on immature germ cells between the different semen samples studied: fertile, and ejaculates with ASA. CONCLUSION: The presence of ASA in ejaculate is not associated with abnormal HLA antigen expression on immature germ cells.