Immunological factors in infertility

[Proteasomes on thyroid tissue allotransplantation under induction of donor specific tolerance in rats]

The proteasomes in the liver of August rats (RT1C) were investigated 30 days after the allotransplantation of Wistar rat (RT1u) thyroid tissue under renal capsule with/without induction of donor specific tolerance by donor splenocyte intraportal administration. The level of the total proteasome pool, immune proteasomes containing the LMP2 and/or LMP7 subunits, proteasome 19S- and 11S-regulators was defined. The intact and sham-operated August rats were used as control groups. The level of all immune proteasome forms and 11S regulator increased while the level of the total proteasome pool and 19S regulator decreased in the liver of experimental animals compared to the control groups that indicated changes of liver functional state after transplantation. The 19S/11S ratio increased in the liver of non-tolerated rats compared to tolerated animals. In the liver of tolerated rats with survived transplants, the quantity of mononuclear cells, expressing the immune subunit LMP2, greatly increased in comparison with control and non-tolerated animals. Study of the survived transplants showed the increase of the ratio of LMP2/LMP7 immune subunits and 19S/11S regulators in them compared to the tissue replacing the rejected transplants. In the control intact thyroid tissue, the immune proteasomes were almost not revealed, while 19S/11S ratio was maximal. Thus, the development of the immune reaction or its suppression is accompanied by change of the balance between different proteasome forms. The immune subunit LMP7 and 11S regulator are connected with the response against donor tissue. On the contrary, the immune subunit LMP2 and 19S regulator are likely to be important for the immune tolerance development and survived tissue functioning. The low content of the immune proteasomes in the follicle cells was found by immunofluorescence assay. The formation of antigens for major histocompatibility complex class I molecules was impaired by low immune proteasome content that led to immunological tolerance to hormone-producing follicle cells.

Influence of antiphospholipid antibodies on pregnancy outcome in women undergoing in vitro fertilization and embryo transfer

PROBLEM

Antiphospholipid antibodies (APA) are thought to be involved in recurrent pregnancy loss. Therefore, we investigated the impact of APA on pregnancy outcome in women undergoing in vitro fertilization and embryo transfer (IVF-ET).

METHOD OF STUDY

Blood samples taken from 54 Korean women referred for IVF were tested for the presence of APA, anticardiolipin antibody IgG and IgM and lupus anticoagulant. The standard gonadotropin-releasing hormone agonist long protocol was used for ovarian stimulation.

RESULTS

Nine patients (16.7%) were positive and 45 (83.3%) were negative for APA. There were no significant differences between the two groups in clinical characteristics such as age, infertility duration, and response to controlled ovarian hyperstimulation. However, pregnancy outcome significantly differed between the two groups (p < 0.05). The APA positive group and APA negative group had abortion rates of 62.5% and 20.0%, respectively and delivery rates of 37.5% and 80.0%, respectively.

CONCLUSION

The presence of APA in women undergoing IVF-ET was associated with a poor pregnancy outcome.

Drug intervention in early pregnancy after assisted reproductive technology

Implantation in humans is a complex, closely regulated, highly selective and relatively poorly understood process. Humans have the highest rate of miscarriage in mammals and various pharmacological manipulations have been used to minimize pregnancy losses in both spontaneous pregnancies and pregnancies resulting from assisted reproduction technology. The widespread application of protocols using numerous drugs in assisted reproduction treatment has led to an increasing number of pregnancies exposed to these drugs. The vast majority of these protocols have been based on data from a few observational and often retrospective clinical studies. This paper reviews the recent literature on drug interventions in early pregnancy after assisted reproduction treatment. It is concluded that there are still numerous issues about the safety of most drugs for both the women and their fetus. In many cases, the benefits are theoretical and the possible long-term side-effects are untested. There is an urgent need for more epidemiological studies and randomized controlled trials to explore the use, efficacy and side-effects of both old and new drugs in early pregnancy after assisted reproduction treatment.

Infertile matings and sperm competition: the effect of "nonsperm representation" on intraspecific variation in sperm precedence patterns

In theoretical and experimental approaches to the study of sperm competition, it is often assumed that ejaculates always contain enough sperm of good quality and that they are successfully transferred and used for fertilization. However, this view neglects the potential effects of infertility and sperm limitation. Permanent or temporal male infertility due to male sterility, insemination failures, or failures to fertilize the ova implies that some males do not achieve sperm representation in the female reproductive tract after mating. A review of the literature suggests that rates of nonsperm representation may be high; values for the proportion of infertile matings across 30 insect species vary between 0% and 63%, with the median being 22%. I simulated P2 (the proportion of offspring fathered by the second male to copulate with a female in a double-mating trial) distributions under a mechanism of random sperm mixing when sample sizes and rates of male infertility varied. The results show that nonsperm representation can be responsible for high intraspecific variance in sperm precedence patterns and that it can generate misleading interpretations about the mechanism of sperm competition. Nonsperm representation might be a common obstacle in the studies of sperm competition and postcopulatory female choice.

Antisperm immunity in assisted reproduction

Antisperm antibodies (ASA) can impair the fertilising capacity of human spermatozoa, acting negatively on sperm motility and cervical mucus penetration, and at the level of in vitro gamete interaction. Several methods attempt to improve the potentially deleterious effects of ASA-mediated infertility: by decreasing ASA production, by removing ASA already bound to sperm, artificial insemination (AIH) and fertilisation (IVF, ICSI). Only ICSI seems able to overcome the problem, with fertilisation and pregnancy rates of ASA-positive patients undergoing this technique in the same range as ASA-negative patients. As immunological infertility is relatively rare, literature in the field is quite scarce and more studies need to be conducted to confirm that embryo quality is not impaired.

Antisperm antibodies associated with infertility: properties and encoding genes of target antigens

Infertility among couples of reproductive age is a perplexing condition when the cause is indeterminate. These cases are classified as unexplained infertility. In a subset of subjects, antisperm antibodies with sperm agglutinating and/or immobilizing activities have been detected in the blood or fluids of the reproductive tract. These cases are designated as immunologic infertility although a cause and effect relationship of the antibodies to infertility has not been established. In this review, seven target sperm antigens to antibodies associated with infertility and their encoding genes are described. The antisperm antibodies (ASAs) examined were obtained from infertile women or were monoclonal antibodies (mAb) raised against human sperm proteins. All the ASAs studied possessed potent sperm agglutinating and/or immobilizing activities. The target antigens were isolated from human and other mammalian sperm, and the encoding genes identified. The seven antigens are YWK-II, BE-20, rSMP-B, BS-63 (nucleoporin-related), BS-17 (calpastatin), HED-2 (zyxin), and 75- kDa. Each antigen is a distinct and separate entity and is produced by different cells of the reproductive tract, (e.g., germ cells, epididymal epithelial cells, and Sertoli cells). No single predominant target component has been found to interact with the ASAs. It is proposed that immunologic infertility is the consequence of the combined actions of multiple ASAs in immobilizing and/or agglutinating spermatozoa, blocking spermegg interaction, preventing implantation, and/or arresting embryo development.

Autoantibody screening for infertility: explaining the unexplained?

Several laboratories currently offer panels of serum autoantibody assays to screen women with unexplained infertility and those undergoing in vitro fertilization (IVF). Offering these tests implies that they have predictive value for the outcome of proposed infertility treatments such that the results of the testing would alter clinical management. Because screening for antiphospholipid antibodies adds expense to already costly procedures, it is an appropriate time to review the justification for the use of these panels.

Impact of age on reproductive outcome in women with recurrent spontaneous abortions and infertility of immune etiology

The objective of this paper is to determine whether age has any impact on conception rate, pregnancy outcome, or autoimmune status in women with recurrent spontaneous abortions (RSA) and infertility of immune etiology. One hundred twenty-four women with 3 or more RSA and 36 women with unexplained infertility were prospectively studied. Maternal antipaternal lymphocyte antibodies and autoantibodies to phospholipids and nuclear antigens were tested. All achieved an adequate alloimmune recognition after lymphocyte immunization and followed for 1 year with optimal preconception autoimmune treatment. Conception rate and pregnancy outcome were prospectively studied. 1) 10.1% of women with RSA and 30.6% of women with infertility failed to achieve a pregnancy after 1 year of trial (P = 0.0084); 2) in women with RSA, the number of previous fetal death after 28 weeks of gestation was significantly higher in women who failed to achieve a pregnancy within 1 year when compared to women who became pregnant (P = 0.0296). Conception rate was not different with advancing age; 3) women with infertility demonstrated significantly higher incidence of anti-phosphatidylethanolamine antibody when compared to women with RSA (P = 0.052); 4) in women with infertility, those who failed to achieve a pregnancy were significantly older (P = 0.0012) and demonstrated a higher incidence of autoantibodies to phosphatidic acid than women with infertility who became pregnant (P = 0.0339); 5) the subsequent spontaneous abortion rate while on optimal immune therapy was the same in the women with RSA (39.3%) and women with infertility (32%). Spontaneous abortion rate of women with RSA or infertility was not different among four age groups; 6) the presence of anticardiolipin antibody (P = 0.0055) and higher gravidity (P = 0.0354) correlated significantly with pregnancy failure in women with a history of infertility. The prevalence of auto-antibodies to phospholipids and nuclear components was not different among four age groups in women with RSA or infertility. Age does not affect pregnancy outcome or conception rate in women with RSA. In women with infertility of immune etiology, conception rate was significantly reduced over age 40 although pregnancy outcome was no different with advanced age.

Detection of antibodies toward epididymal sperm antigens--an obligatory step in evaluation of human immunologic infertility?

PROBLEM

To test the relative impact of epididymal versus ejaculated sperm in immunologic infertility.

METHOD

Human antibody binding to epididymal and ejaculated spermatozoa was compared by flow cytometry (FCM) since it allows quantitative analysis of viable sperm while ignoring nonsperm cells. To select sera for FCM, GAT, TAT, and ELISA were applied on 145 sera from fertile men, idiopathically infertile and varicocele patients.

RESULTS

All GAT/TAT-positive infertile patients, a representative group of varicocele patients and the fertile control, were assessed by FCM. Higher reactivity toward epididymal sperm revealed 18/22 sera while only four out of them bound to ejaculated sperm stronger than the control. All varicocele sera were positive against epididymal while negative against ejaculated spermatozoa.

CONCLUSIONS

Epididymal sperm antigens may play a predominant role in some cases of immunologic infertility. Such patients might not be adequately diagnosed and respectively treated due to the limitations of diagnostic procedures applying only ejaculated spermatozoa.