Treatment of recurrent spontaneous abortion by immunization with paternal lymphocytes: correlates with outcome

Allogeneic lymphocytes immunotherapy in female infertility: Lessons learned and the road ahead

The endometrium is an essential tissue in the normal immunologic dialogue between the mother and the conceptus, which is necessary for the proper establishment and maintenance of a successful pregnancy. It's become evident that the maternal immune system plays a key role in the normal pregnancy's initiation, maintenance, and termination. In this perspective, the immune system contributes to regulating all stages of pregnancy, thus immunological dysregulation is thought to be one of the major etiologies of implantation failures. Many researchers believe that immune therapies are useful tactics for improving the live births rate in certain situations. Lymphocyte immunotherapy (LIT) is an active form of immunotherapy that, when used on the relevant subgroups of patients, has been shown in multiple trials to dramatically enhance maternal immunological balance and pregnancy outcome. The primary goal of LIT is to regulate the immune system in order to create a favorable tolerogenic immune milieu and tolerance for embryo implantation. However, there are a plethora of influential factors influencing its therapeutic benefits that merit to be addressed. The objective of our study is to discuss the mechanisms and challenges of allogeneic LIT.

Lymphocyte immunotherapy in the treatment of recurrent miscarriage: systematic review and meta-analysis

PURPOSE

Recurrent miscarriage (RM) affects up to 2-3% of couples of reproductive age. There are several causes for this condition, including immunologic. The embryo is considered an allograft, subject to the rejection mechanisms of the maternal immune system. Immunotherapy involving immunization with lymphocytes is considered in cases of idiopathic RM. However, there is still no consensus regarding the efficacy and safety of this therapy.

METHODS

This systematic review and meta-analysis evaluated the data available in the literature regarding the efficacy and safety of the use of immunotherapy with lymphocytes in couples with history of RM. Searches in PubMed/Medline, SCOPUS, and Cochrane Library databases were conducted, using the following keywords: "recurrent miscarriage," "lymphocyte immunotherapy," and "meta-analysis." Statistical analyses were performed using Review Manager 5.3 (RevMan), version 5.3.

RESULTS

Six published meta-analysis were retrieved; two found no improvements in the rate of live births after the use of immunization with lymphocytes in the treatment of RM, and four found a beneficial effect of the use of immunotherapy with lymphocytes in cases of RM, with significant improvements in the rate of live births.

CONCLUSION

Data available in the literature supports the efficacy and safety of immunotherapy with lymphocytes in cases of RM without an identified cause.

Characterization of mixed lymphocyte reaction blocking antibodies (MLR-Bf) in human pregnancy

BACKGROUND: It is known that during normal pregnancy and after immunotherapy blocking antibodies are developed, these antibodies inhibit mixed lymphocyte reaction and are also anti-mitogenic in nature. Mixed lymphocyte reaction blocking antibodies are specific to the husband's lymphocytes. In the present study an attempt has been made to characterize the mixed lymphocyte reaction blocking antibodies in normal pregnancy and in women with recurrent spontaneous abortion after immunotherapy. METHODS: Serum was obtained from women of different gestational windows of pregnancy (Ist, IInd, IIIrd trimesters and post delivery period of normal pregnancy), recurrent spontaneous aborters from pre and post immunization. Healthy (male and females) controls were screened for the presence of mixed lymphocyte reaction blocking antibodies. The standard mixed lymphocyte reaction technique was used to evaluate the inhibitory effect of serum in the mixed lymphocyte reaction. Each serum was tested for cytotoxic antibodies. Immunoglobulin G and its isotypes were isolated according to the standard protocol. RESULTS: In the present study we have observed that there was significant inhibition of proliferation response when immunoglobulin G from different trimesters of pregnancy were added to one way mixed lymphocyte reaction or to phytohemagglutinin activated lymphocyte proliferation assay. Similar pattern was seen when immunoglobulin G isolated from adequately immunized women with recurrent spontaneous abortion was used. It was further confirmed that amongst all the isotypes of immunoglobulin G, only immunoglobulin G-3 was found to be positive for the inhibitory effect. CONCLUSIONS: Present study indicates that mixed lymphocyte reaction blocking antibodies are immunoglobulin G-3 in nature. It is developed during pregnancy and also after immunotherapy in women with recurrent spontaneous abortion who subsequently have the successful pregnancy.

Relationship between MLR blocking antibodies and the outcome of the third pregnancy in patients with two consecutive spontaneous abortions

To determine the relationship between mixed lymphocyte culture reaction (MLR) blocking antibodies (BAbs), immunological humoral factors, which generated in pregnant women and the outcome of pregnancy, the natural outcome of the third pregnancy in fifty-five patients with primary twice consecutive abortion was evaluated, and MLR-BAbs in sera were examined during their third pregnancy. The third pregnancy in 39 of 55 patients (70.9%) continued successfully, and remaining 16 patients (29.1%) experienced repeated abortion at the first trimester. Out of these 55 patients, MLR-BAbs were examined in 27 (17 with successful outcome and 10 with repeated abortion). The positive rate of MLR-BAbs was 82.4% in patients with successful outcome (15 of 17 cases), and that in patients with repeated abortion was 10% (one of 10 cases). The positive rate of MLR-BAbs was significantly higher in the successful pregnancy group compared with that in the repeated abortion group (p < 0.001). The blocking effect on MLR significantly increased along with the prenatal course in patients with successful outcome. Thus, MLR-BAbs are strongly associated with the outcome of pregnancy in patients with primary twice consecutive spontaneous abortions.

Clinical and immunological condition of newborns of mothers treated for recurrent spontaneous abortions with paternal lymphocytes immunization

OBJECTIVE

The aim of this study was to evaluate the clinical condition at birth and some laboratory parameters in newborns of mothers treated for recurrent spontaneous abortion (RSA) of unknown etiology with paternal lymphocytes immunization.

STUDY DESIGN

The study comprised 104 newborns delivered by 102 women with RSA, who underwent alloimmunization and 90 randomly chosen control newborns. The following parameters were analysed in two groups of newborns: general condition at birth, physical development, course of adaptation period, values of hematological and immunological (percentage of CD3, CD4, CD8, CD19 and CD3/CD25 lymphocytes, chemiluminescence of neutrophils at rest and stimulated with opsonized zymosane) parameters in umbilical arterial blood.

RESULTS

No statistically significant differences were noted between the two groups of newborns as to the duration of pregnancy, birth weight, general condition at birth, occurrence of complications in the adaptation period and values of studied hematological and immunological parameters.

CONCLUSION

These results suggest that immunization with paternal lymphocytes in women with RSA of unknown etiology not only creates better prognosis for the outcome of the pregnancy, but is also safe for the fetus and the newborn.

Enhancement of the expression of progesterone receptor on progesterone-treated lymphocytes after immunotherapy in unexplained recurrent spontaneous abortion

PROBLEM

The immunological mechanism of an effective immunotherapy with paternal lymphocytes for unexplained recurrent spontaneous abortion (RSA) is not yet clear. Previous studies revealed that progesterone plays an important role in maintaining normal pregnancy and lower expression of progesterone receptor (PGR) on lymphocytes was found in RSA. Therefore, it was of interest to investigate whether immunotherapy for RSA would be able to enhance the expression of PGR on lymphocytes of RSA.

METHOD

PGR expression on lymphocytes was analyzed with indirect immunofluorescence using flow cytometry.

RESULTS

There was no change of PGR expression on PBL of RSA between pre- and post-immunotherapy (P > 0.05), while in the presence of 10.0 micrograms/ml progesterone for 24 h, PGR expressed on PBL on post-immunotherapy was increased significantly as compared with that of pre-immunotherapy in successful cases (P < 0.05) and decreased in abortive cases (P < 0.05). Most PGR was expressed on both CD4+ and CD8+ lymphocyte subsets. In successful cases, CD8+PGR+ subset of post-immunotherapy was found to be increased significantly (P < 0.05) in comparison with that of pre-immunotherapy.

CONCLUSION

The data in the present study suggest that immunotherapy for RSA induced a higher expression of PGR on progesterone-treated lymphocytes, which may be involved in successful pregnancy.

Fertility among women with recurrent spontaneous abortions--the effect of paternal cell immunization treatment

PROBLEM

The risk of women whose chief complaint is recurrent spontaneous abortions (RSA) for secondary infertility (infecundability) has not been evaluated prospectively. The effect of paternal mononuclear cell immunization on conception rates is unknown.

METHOD

Two hundred women whose chief complaint was RSA were randomly assigned to be immunized with paternal mononuclear cells either before or after (up to 6 postmenstrual weeks) conception. Fertility rates (both conception and live birth) were evaluated for the group immunized before conception and compared to those for the control group, who were not immunized until after conception, using life table and multiple logistic regression analyses.

RESULTS

Prospectively ascertained, age-related conception rates for nonimmunized RSA controls appeared to be similar to those for general populations. Immunization before pregnancy had no significant effect (power +/- 14%) on rates of conception (66% before, 77% after) or time to conceive (median weeks before 19.5, after 27.0). Live birth rates (before 59%, after 63%) were also similar for both groups (P = 0.7).

CONCLUSION

Women whose only prior complaint was RSA were not at high risk for secondary infecundability, and immunization did not alter either conception rates or time to conceive. Postponement of immunization until after conception did not affect live birth rates for women selected for study because they did not have a history of prior infecundability or early repeated miscarriages.

Treatment of recurrent spontaneous abortions by immunization with paternal lymphocytes induces immunosuppression by placental isoferritin

PROBLEM

The immunological mechanism leading to an effective vaccination of unexplained habitual aborters with paternal lymphocytes is not yet elucidated. Since previous studies revealed that immunosuppression by placental isoferritin (PLF) may play an important role in the down regulation of the immune system during pregnancy, it was of interest to investigate whether alloimmunization activates immunosuppression by PLF.

METHOD

The immunosuppressive effect of PLF or anti-PLF CM-H-9 monoclonal antibody (MAb) was studied by a one-way mixed lymphocyte reaction (MLF) of alloimmunized women and their husbands.

RESULTS

It was found that vaccination of the women with paternal lymphocytes resulted in in vitro immunosuppression by PLF as well as by CM-H-9 MAb, reaching the highest effect after three vaccinations (38 +/- 8 and 42 +/- 10%, respectively). The increase in PLF immunosuppressive effect was accompanied by the appearance of serum antipaternal human leukocyte antigen cytotoxic antibodies. However, there was no correlation between the degree of suppression and titer of antibodies. The study group was too small to reach a significant correlation between degree of immunosuppression and pregnancy outcome.

CONCLUSIONS

Although it may be of value to measure the inhibitory effect of PLF in one-way MLR as an index of immunosuppression, further studies are needed to establish whether it is a relevant predictor of a successful pregnancy.

Flow cytometric crossmatch and early pregnancy loss in women with a history of recurrent spontaneous abortions who underwent paternal leukocyte immunotherapy

OBJECTIVE

The purpose of our study was to evaluate the clinical significance of flow cytometric crossmatch in managing women with unexplained recurrent spontaneous abortions who have been immunized with paternal leukocytes.

STUDY DESIGN

Two-color flow cytometric crossmatch was performed after immunotherapy in 69 women with recurrent spontaneous abortions to detect maternal immunoglobulin G antibodies against paternal T lymphocytes. A positive flow cytometric crossmatch was determined by a > or = 20 channel increases (256 channel linear scale-log amplification) in the fluorescence intensity of the T-cell peak. We analyzed the clinical correlation between flow cytometric crossmatch results and subsequent pregnancy outcome in those patients using the Fisher exact test.

RESULTS

In 46 subsequent pregnancies among 69 immunized women the incidence of early subsequent pregnancy wastage was only 6 (17.1%) of 35 in flow cytometric crossmatch-positive patients and 7 (63.6%) of 11 in flow cytometric crossmatch-negative patients (p < 0.01).

CONCLUSIONS

These data indicate that a two-color T cell flow cytometric crossmatch predicts subsequent pregnancy outcome in patients undergoing immunotherapy for recurrent spontaneous abortion.

Treatment of recurrent spontaneous abortion by immunization with paternal lymphocytes: results of a controlled trial

PROBLEM

It remains unclear whether maternal immunization with paternal lymphocytes prior to conception improves the reproductive outcome in women with recurrent abortion in whom all secondary causes have been excluded.

METHOD

A double-blind placebo controlled trial was instituted in women with unexplained recurrent spontaneous abortion, comparing immunization with 400 million paternal to 400 million maternal (autologous) lymphocytes. The groups were compared in a paired sequential trials chart, by logistic regression, and, in addition, a meta-analysis of this and other published trials was carried out.

RESULTS

The live birth rate among pregnancies in paired couples with paternal lymphocyte immunization was 68% compared to 47% in the women who received their own cells. The results bordered on, but did not achieve, statistical significance. The women in each group were thoroughly investigated to exclude known causes of recurrent pregnancy loss and appeared to have been well matched in all variables. Women with lymphocytotoxic antibodies against paternal lymphocytes were excluded. Unlike our previous study there was not association between the time to conception and the chance of a successful outcome. Indeed, the time to conception was relatively short, 12 wk in all groups. The meta-analysis supported an overall modest favorable experience with paternal cells.

CONCLUSION

The study is consistent with a general trend favoring paternal over maternal lymphocyte immunization but reinforces the need for larger multicenter controlled trials as well as more detailed biological study in humans to understand the nature of the maternal-fetal interface and its breakdown.

Is an additional vaccination necessary for a successful second pregnancy in unexplained recurrent aborters who were successfully immunized with their husband's lymphocytes before the first pregnancy?

PROBLEM

Is an additional immunotherapy necessary or not for patients who have obtained successful results after initial immunotherapy?

METHODS

The successive pregnancy outcome was analyzed in 22 patients out of 29 unexplained recurrent aborters who had undergone immunotherapy with their husband's lymphocytes according to our previously reported protocol (Takakuwa et al., Am J Reprod Immunol Microbiol. 10:1-9, 1986; Takakuwa et al., Am J Reprod Immunol. 23:37-41, 1990) and had obtained successful outcome between January 1983 and December 1989. In addition, the alteration of blocking antibodies (BAbs), which was evaluated by a one-way mixed lymphocyte culture reaction (MLR) blocking assay between the spouses, was analyzed in 26 patients out of 29.

RESULTS

None of the 22 patients underwent further immunotherapy because a significantly high titer of MLR-BAbs had been detected before the new pregnancy. In 19 out of the 21 patients (90.5%), pregnancy was successful.

CONCLUSION

Additional immunotherapy is not necessary for patients who have obtained successful results after the initial immunotherapy and are positive for MLR-BAbs after their first delivery.

Predictors for live birth after unexplained spontaneous abortions: correlations between immunologic test results, obstetric histories, and outcome of next pregnancy without treatment

Our objective was to determine whether results from tests for maternal serum antinuclear antibodies, cytotoxic antibodies to paternal lymphocytes, parental histocompatibility types, and blocking factors for maternal-paternal mixed lymphocyte reactions were predictive of pregnancy outcome without immunologic treatment. Pregnancy outcome data from 95 women with a history of unexplained recurrent spontaneous abortions who underwent immunologic tests at Jefferson Medical College were evaluated with multiple logistic regression analyses. The number of prior spontaneous abortions, history of another relevant diagnosis, parental sharing of one histocompatibility antigen, and maternal age were related to the outcome of the next pregnancy in women given no immunologic treatment (p = 0.05). No significant correlation was found between results from the immunologic tests or other history characteristics evaluated and outcome of the next pregnancy. The immunologic tests evaluated were not clinically useful predictors of pregnancy outcome.

The role of blocking factors and antipaternal lymphocytotoxic antibodies in the success of pregnancy in patients with recurrent spontaneous abortion

OBJECTIVE

To elucidate the role of mixed lymphocyte reaction blocking factors (BF) and complement-dependent antipaternal lymphocytotoxic antibodies on the outcome of pregnancy in unexplained recurrent spontaneous aborters.

DESIGN

A controlled study of immunotherapy in which the treated group was immunized with the husband's or a third party donor's lymphocytes and the control group received autologous lymphocytes.

SETTING

Tertiary care institution.

PATIENTS

Forty-three patients in the control group and 48 patients in the treated group.

INTERVENTION

The before and after immunization levels of BF and antipaternal lymphocytotoxic antibodies were measured.

MAIN OUTCOME MEASURES

The existence or changing pattern of BF and antipaternal lymphocytotoxic antibodies levels before and after immunization had no influence on the pregnancy outcome in either group of patients.

CONCLUSION

Neither BF nor antipaternal lymphocytotoxic antibodies is essential for successful pregnancy. They probably reflect the immunological response of the mother to exposure to fetal antigens.

Update on immunotherapy for recurrent pregnancy loss

Results of recent, randomized, placebo-controlled clinical trials have raised questions about the efficacy of immunotherapy for recurrent spontaneous abortion (RSA). Most of the clinical trials have shown a 70% successful pregnancy rate with immunotherapy. The controversy comes from variations in success rates in the control populations, which have ranged from 29% to 76%. Explanations for these variations includes small sample sizes and heterogeneity by the populations studied as well as cointervention by the placebo. A meta-analysis has been proposed to investigate these explanations. Because the trials have largely used husband's leukocytes for immunization, alternative forms of immunotherapy have been sought. Two treatments that have been proposed but have not completed testing a randomized, placebo-controlled trials are intravenous immunoglobulin (IVIG) and immunization with seminal plasma. A safe and efficacious method is needed to treat recurrent spontaneous abortion; it is hoped that results of proposed studies will answer this controversy.

Influence of immunotherapy on the cellular immunity of unexplained recurrent aborters

Changes in lymphocyte subsets in whole blood were analyzed sequentially by flow cytometry with an automated leukocyte differential system in 15 patients with unexplained recurrent spontaneous abortions, each of whom underwent vaccination(s) with her husband's lymphocytes. Mitogen responses of peripheral blood lymphocytes (PBL) were also examined in these patients. The reactivity of PBL against mitogens revealed no significant change in each patient before and after vaccination(s) with her husband's lymphocytes. The CD4:8 ratio was observed to decrease significantly during 22 and 28 days after the first vaccination with a significant increase in the percentage of T suppressor-cytotoxic (CD8) cells. This change was also observed after the second vaccination. The percentages of other subsets did not change significantly after vaccination(s). In 11 patients out of 15, the pregnancy continued successfully and correlated with a predominance of Ts/c (CD8) over TH/I (CD4) cells in the first trimester. These changes in lymphocyte subsets may indicate the induction of immune enhancing mechanisms and it is suggested that continuation of the predominance of Ts/c cells induced by immunotherapy might be important for the successful maintenance of pregnancy.

A possible mechanism of immunotherapy for patients with recurrent spontaneous abortions

The mechanism of the beneficial effect of immunotherapy for human reproductive wastage remains to be elucidated. Induction of blocking antibodies such as anti-HLA class II antibodies and anti-idiotypic antibodies was investigated as the mechanism of specific immunosuppression in pregnancy. We reported the changes in the mixed lymphocyte reaction (MLR), T-cell subsets, and generation of anti-idiotypic antibodies after immunotherapy compared to before immunotherapy. MLR was significantly (P less than 0.001) inhibited after the immunization. The mean inhibition rate was 50.2%, suggesting that MLR blocking antibodies were induced by immunotherapy. Binding of autoantibodies to alloactivated maternal lymphoblasts against the paternal lymphocytes was detected in postimmunization cases in two-color flow-cytometric experiments. This suggests that anti-idiotypic antibodies were induced by the immunotherapy. The percentage of cytotoxic T-cells was significantly decreased (P less than 0.05) and the percentage of suppressor T-cells was significantly increased (P less than 0.01) after the immunotherapy, suggesting that a cell-mediated immune response was induced by the immunotherapy.

Interpretation of blocking activity in maternal serum depends on the equation used for calculation of mixed lymphocyte culture results

Immunosuppressive blocking factors in maternal serum are usually determined by inhibition of mixed lymphocyte cultures (MLC), but reports on the importance of these factors for successful pregnancy are conflicting. Here we measured serum blocking activity in men, non-pregnant nulliparous women, non-pregnant multiparous women, women with normal pregnancies, and in women who had had recurrent spontaneous abortions and were treated with leucocyte immunizations. Three different equations were used for calculation of blocking activity: blocking effect index (BEI); stimulation index (SI); and blocking index (BI). By all three methods of calculation, significantly lower levels of blocking activity were noted for men and women compared with pregnant women and multiparae. In the patients with a history of recurrent spontaneous abortions blocking activity as determined by BEI and BI increased into the positive range after treatment with infusions of third-party donor leucocytes in a statistically significant number of women (P less than 0.05). However, blocking activity as determined by BEI had a higher predictive value for successful pregnancy than did that determined by BI or SI. Our data suggest that the equation used for calculating BEI is superior to other methods for the determination of blocking activity when monitoring the response to leucocyte immunization in women with recurrent spontaneous abortion. However, these results also cast doubt on the importance of blocking antibodies in histories of recurrent abortion, since pregnancies occurred in the absence and spontaneous abortions occurred in the presence of blocking activity.

Paternal mononuclear cell immunization therapy for repeated miscarriage: predictive variables for pregnancy success

Pregnancy outcomes for 125 women with unexplained recurrent abortion conceiving after immunologic testing for possible paternal leukocyte immunization were analyzed. Pregnancy success was related to the number of previous miscarriages (relative risk 0.36 for each additional miscarriage after 3), a history of a late pregnancy loss (relative risk 0.18), any other relevant treated or untreatable diagnosis (relative risk 0.27), immunization with paternal mononuclear cells (relative risk 5.6), and time in weeks from test date to LMP of the next pregnancy (relative risk 0.93 for each additional week). The significant difference in pregnancy outcomes between women given a single immunization and nonimmunized women reflected a larger difference between those in each group conceiving within 12 weeks of initiating tests for inclusion in the treatment program. The latter observation suggests that any effect from a single immunization in prevention of recurrent miscarriage is of relatively short duration.