Human leucocyte antigen I expression in spermatozoa from infertile men.

The expression of class I human leucocyte antigen (HLA) has been investigated by reverse transcription polymerase chain reaction (RT-PCR) and flow cytometry on human purified ejaculated spermatozoa from an infertile population. Similar investigation in a control fertile population has been performed. Among 22 fertile and 20 infertile men, 17 were selected for the study because they showed no contamination with non-sperm cells. HLA I molecules were expressed in four of nine fertile subjects (44.4%) and three of eight infertile subjects (37.5%), with no significant difference between groups. These data demonstrate for the first time the presence of class I HLA antigens on spermatozoa of infertile subjects. In addition, considering that similar results have been obtained in both fertile and infertile populations, the hypothesis that the fertilizing capacity of the spermatozoon is independent of class I HLA-antigen expression on their surface may be advanced.