[Frequency of anti-sperm antibodies demonstrated by classical tests for sperm antibodies in patients with unexplained infertility].

: The aim of the present investigation was to establish the frequency of sperm antibodies in patients with etiologically unexplained infertility, and to compare the demonstrated frequencies with the results from y control group of y healthy blood donors, as well as with the results of other investigators. The gelatin agglutination test of Kibrick and the tray agglutination test of Friberg were applied to test 244 sera from infertile patients and 50 sera from healthy blood donors at the Laboratory of Immunology of Reproduction, Department of Biology, Medical University of Sofia. For the infertile patients, relevant sperm antibody titers were demonstrated in 2.5% (titer > or = 16) for the Kibrick method, and in 7% (titer > or = 32) for the Fiberg method. The test of Kibrick did not reveal significant antibody titers in the healthy controls, while the test of Friberg showed sperm antibodies in 2% of the blood donors. Fisher's exact test demonstrated extremely significant correlation (p < 0.0001) between the presence of sperm antibodies in sers of patients with unexplained infertility as revealed by the tests of Kibrick and Friberg. Most often mixed agglutinates were demonstrated in the Friberg test. In contrast with the results of other investigators head-to-head agglutinins were observed more often in male sera, while tail-to-tail agglutinins--in female sera. Finally, the results from the present investigation, as well as the analyzed literature data showed a low frequency of anti-sperm immunity in the Bulgarian population. The established high degree of correlation between the tests of Kibrick and Friberg, the good reproducibility of the results and the low cost of these methods confirm their appropriate use for the diagnosis of sperm antibodies in patients with unexplained infertility.