Effect of sperm-immobilizing antibodies bound to the surface of ejaculated human spermatozoa on sperm motility in immunologically infertile men

Anti-sperm Antibodies as an Increasing Threat to Male Fertility: Immunological Insights, Diagnostic and Therapeutic Strategies

It is a fact that sperm possess antigenic properties. Substantial scientific research suggests that specific antibodies that attach to sperm antigens can induce infertility in both humans and other species. Antisperm antibodies (ASA) represent a significant etiology of infertility in humans, leading to immunoinfertility. The association between ASA and infertility is multifaceted. The observation of sperm agglutination, although not conclusive for the diagnosis of immunological infertility, may suggest the presence of ASA. Nevertheless, ASA may also manifest in the lack of any sperm agglutination. Managing ASA from an andrological perspective depends on the underlying cause and the specific approaches healthcare professionals adopt. The precise etiology of male infertility resulting from ASA remains unclear. Current research has examined the impact of ASA and its prevalence among infertile males to understand the relationship between ASA and changes in semen parameters. However, the findings have been inconclusive. Numerous techniques have been documented for the management of immunoinfertility. This review examines the importance of ASA in the context of infertility, encompassing the postulated mechanisms underlying the development of ASA, the various assays employed for detecting them, and the available treatments.

Sex difference in anti-sperm antibodies

Background

Some diseases have sex differences. There have been no reports on the relationship between anti‐sperm antibodies (ASA) and sex differences.

Methods

ASA are detected by sperm‐immobilization test using patients' sera in women. In men, the ASA testing is generally performed by direct‐immunobead test.

Main findings

Sperm‐immobilizing antibodies in women inhibit sperm migration in their genital tract and exert inhibitory effects on fertilization. ASA bound to sperm surface in men also show inhibitory effect on sperm passage through cervical mucus. The fertilization rate of IVF significantly decreased when sperm were coated with higher numbers of ASA. For women with the antibodies, it is important to assess individual patients' SI₅₀ titers. In patients with continuously high SI₅₀ titers, pregnancy can be obtained only by IVF. For men with abnormal fertilizing ability by ASA, it is necessary to select intracytoplasmic sperm injection. Production of sperm‐immobilizing antibodies is likely to occur in women with particular HLA after exposure to sperm. The risk factors for ASA production in men are still controversial.

Conclusion

Attention to sex differences in specimens, test methods and the diagnosis of ASA should be paid. For patients with ASA, treatment strategies have been established by considering sex difference for each.

Application of computer-aided sperm analysis (CASA) for detecting sperm-immobilizing antibody

PROBLEM

Since the 1970s, anti-sperm antibodies have been studied as a pathogenic factor contributing to infertility. The complement-dependent sperm-immobilization test (SIT) and quantitative SIT have been used as effective tools for detecting anti-sperm antibodies in clinical settings. These tests have been carried out traditionally by manually counting the number of motile sperm through eye estimation.

METHOD OF STUDY

In this study, we developed a novel method using computer-aided sperm analysis. The results were compared with those obtained by the traditional method.

RESULTS

The results were identical and 25 of 78 samples tested were positive and 53 samples were negative for sperm-immobilizing (SI) antibodies based on both methods. For SI-positive samples, the values of SI₅₀ obtained using the two methods correlated closely with high co-efficiency.

CONCLUSION

Using the novel method, manually counting the number of motile spermatozoa becomes unnecessary. The novel method presented here will increase the objectivity and convenience of using the SIT as a clinical indicator.

In vitro and in vivo studies evaluating antisemen antibodies as a potential spermicidal agent in hamsters

OBJECTIVE

To determine the spermicidal activity of antisemen antibodies in the hamster model.

DESIGN

Prospective, controlled study.

SETTING

Advanced preclinical sciences center.

ANIMAL(S)

Subgroups of 10 and 14 golden hamsters.

INTERVENTION(S)

Ex vitro and in vivo treatment of sperm with antisemen antibodies or normal rabbit serum.

MAIN OUTCOME MEASURE(S)

The EC(50) value of antisemen antibodies, the time required for 50% motility loss of progressively motile spermatozoa exposed to antisemen antibodies, the average sperm mitochondrion fluorescence intensity, the rate of fertilization, and the scoring of histologic changes in the hamster vaginal tissue.

RESULT(S)

The EC(50) value of antisemen antibodies was found 70 microg/mL, and the time required for 50% motility loss of progressively motile spermatozoa exposed to antisemen antibodies (at 70 microg/mL) was 5 minutes; for the experimental and control groups, the average fluorescence intensities of sperm mitochondria were respectively 180.28 +/- 82.24 and 309.74 +/- 148.37, the fertilization rates in vitro were 0.09% and 45%, the rates of fertilization with intrauterine sperm injection were 0 and 15.0%. There was a significant difference between two groups. None of the four hamsters that received antisemen antibodies in gel-polyoxyl-40-stearate had epithelial disruption characteristic of inflammation.

CONCLUSION(S)

Antisemen antibodies possess appreciable spermicidal potential, which may be explored as an effective constituent of spermicide.

Incidence of antisperm antibodies in males with systemic autoimmune diseases

PROBLEM

To investigate if systemic autoimmune diseases could be one of the risk factors for developing antisperm antibodies (ASA) in males.

METHOD OF STUDY

Antisperm antibodies in the sera of 70 males with systemic autoimmune diseases and 80 healthy controls were examined, by using the indirect-immunobead test (I-IBT). The sperm immobilization test (SIT) was also performed to detect sperm immobilizing antibodies to the patients who were positive in I-IBT.

RESULTS

Among 70 males with systemic autoimmune diseases, five were I-IBT positives, with incidence of 7.1%. However, no positives existed in 80 healthy males. Compared with the healthy controls, the incidence of ASA in males with systemic autoimmune diseases was significantly higher (P = 0.020). None of these five ASA-positive patients had sperm immobilizing antibodies.

CONCLUSION

The incidence of ASA in males with systemic autoimmune diseases was significantly higher than in the healthy controls. Systemic autoimmune diseases may be one of the risk factors for developing ASA in men.

Diagnosis and treatment of immunologically infertile males with antisperm antibodies

The presence of antisperm antibodies (ASA) can reduce fecundity in both males and females. The present review describes a strategy, established by investigations of the diverse inhibitory effects of ASA on fertility, for the appropriate diagnosis and treatment of infertile males with ASA. For infertile males with ASA, diagnosis using the direct-immunobead test (D-IBT), the postcoital test (PCT) and the hemizona assay (HZA) should be carried out as the basis for decision-making. If the patient with ASA has an abnormal hemizona index, it seems reasonable to advise selecting intracytoplasmic sperm injection-embryo transfer (ICSI-ET) as a primary treatment. However, it has been shown that some immunologically infertile males with normal fertilizing ability established pregnancy by timed intercourse (TI) or intrauterine insemination (IUI). In such patients with ASA having normal hemizona index, TI or IUI can be selected based on the PCT result. Therefore, the treatment strategy for males with ASA is similar to that for infertile males with oligozoospermia or asthenozoospermia. In conclusion, it should be emphasized that a diversity of ASA exists and their effects on fertility in infertile males. Although there is an argument that routine testing for ASA in males is not always necessary, one should be aware that in some cases of failed IUI or IVF, ICSI is selected afterward because of the diagnosis of ASA. (Reprod Med Biol 2005; 4: 133-141).