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

Recurrent pregnancy loss: what is the impact of consecutive versus non-consecutive losses?

STUDY QUESTION

Is there a different prognostic impact for consecutive and non-consecutive early pregnancy losses in women with secondary recurrent pregnancy loss (RPL)?

SUMMARY ANSWER

Only consecutive early pregnancy losses after the last birth have a statistically significant negative prognostic impact in women with secondary RPL.

WHAT IS KNOWN ALREADY

The risk of a new pregnancy loss increases with the number of previous pregnancy losses in patients with RPL. Second trimester losses seem to exhibit a stronger negative impact than early losses. It is unknown whether the sequence of pregnancy losses plays a role for the prognosis in patients with a prior birth.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study of pregnancy outcome in patients with unexplained secondary RPL included in three previously published, Danish double-blinded placebo-controlled trials of intravenous immunoglobulin (IvIg) conducted from 1991 to 2014. No other treatments were given. Patients with documented explained pregnancy losses (ectopic pregnancies and aneuploid miscarriages) were excluded.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Of the 168 patients included in the trials, 127 had secondary RPL and experienced a subsequent live birth or unexplained pregnancy loss in the first pregnancy after giving informed consent to participate in the trials (the index pregnancy). Data analyzed by multivariate analysis included the independent variables age, the number of early pregnancy losses before and after the last birth, respectively and a second trimester pregnancy loss before or after the last birth, respectively. The outcome variable was unexplained loss in the index pregnancy.

MAIN RESULTS AND THE ROLE OF CHANCE

In patients with secondary RPL, both a late and each early loss before the last birth did not significantly influence the risk of a new pregnancy loss in the index pregnancy: incidence rate ratio (IRR) 1.31 (95% CI 0.62-2.77) and IRR 0.88 (95% CI 0.70-1.11), respectively. In contrast, the impact on risk of pregnancy loss conferred by a late and by each early pregnancy loss occurring after the birth was significant: IRR 2.15 (95% CI 1.57-2.94, P < 0.0001) and IRR 1.14 (95% CI 1.04-1.24, P = 0.002), respectively.

LIMITATIONS, REASONS FOR CAUTION

Of the patients, 48% were treated with IvIg, which could influence the results. However, allocation to IvIg was random and prognostic variables were equally distributed in IvIg and placebo-treated patients.

WIDER IMPLICATIONS OF THE FINDINGS

A birth in women with secondary RPL eradicates the negative prognostic impact of previous pregnancy losses and this finding is important for our understanding of the pathogenesis. It indicates that only consecutive pregnancy losses should count in the definition of RPL.

STUDY FUNDING/COMPETING INTERESTS

There was no particular funding for this study. The authors declare that there is no conflict of interest.

TRIAL REGISTRATION NUMBER

Not applicable for two of the included randomized controlled trials. For the last trial: Clinical.Gov NCT00722475.

Intravenous immunoglobulin in the prevention of recurrent spontaneous abortion: the European experience

PROBLEM

Clinical trials of the use of intravenous immunoglobulin (IvIg) in the treatment of recurrent spontaneous abortion (RSA) in Europe were reported and discussed.

METHOD OF STUDY

A search of the published literature, combined with our own published and unpublished results, was performed.

RESULTS

Two placebo-controlled trials have been concluded in Europe. One trial found high but equal success rates in both the IvIg and the placebo group. Another trial found that IvIg treatment may increase the success rate by 24% compared with placebo but that the result was not statistically significant, which might be due to the small number of patients. Reasons for the diverse results of the two trials were discussed.

CONCLUSION

More and larger placebo-controlled trials of IvIg treatment in RSA are needed before drawing definitive conclusions.

Suppressed cell-mediated immunity and monocyte and natural killer cell activity following allogeneic immunization of women with spontaneous recurrent abortion

Spontaneous recurrent abortion (SRA) has been treated by means of immunization with paternal or third-party white blood cells, yet the immunological basis for SRA and for the role of immunization protocols in pregnancy outcome remains controversial. To elucidate this question, nine women with SRA were immunized with paternal mononuclear cells and studied before and 2 weeks after immunization. Seven women who became pregnant gave birth to live newborns. Secretion of the T helper 1 cytokines IL-2 and interferon-gamma by patients, mononuclear cells decreased, while production of IL-10 increased. The levels of natural killer and lymphokine-activated killer cell-mediated cytotoxicity were markedly decreased. Monocyte functions such as secretion of IL-1 alpha, tumor necrosis factor alpha, IL-6, and cytotoxic activity decreased concurrently with elevations in IL-10 and transforming growth factor beta secretion. Production of IL-12, a pivotal regulatory cytokine, decreased. Furthermore, B7/1 expression on patients' mononuclear cells was downregulated. This resulted in a decrease in monocyte costimulatory activity of purified T cells with soluble anti-CD3, paralleled by a decline in allogeneic proliferative responses. These results suggest that the improved pregnancy success rate in women with SRA following immunization may be partly related to suppression of cell-mediated immunity and monocyte and natural killer cell activity.

Inhibitory serum factor of lymphoproliferative response to allogeneic cells in pregnancy

INTRODUCTION

An inhibitory serum factor of mixed lymphocyte culture (MLC) has been associated with successful pregnancy after lymphocyte transfusion in women with unexplained recurrent spontaneous abortions (RSA).

OBJECTIVE

Investigate whether the inhibitory serum factor of MLC is essential for a successful pregnancy.

METHOD

Sera from 33 healthy pregnant women and from 40 women with RSA were assessed by a one-way MLC in which the woman's lymphocytes were stimulated with her partner's lymphocytes or with third party lymphocytes.

RESULTS

An inhibitory serum effect (inhibition > 50% as compared to normal serum) was detected in 45% of the pregnant women who had at least 1 previous parity, in 8% of the primigravidea, in 29% of those with one abortion and in 58% of those with more than one abortion.

CONCLUSION

MLC inhibitory serum factor does not seem to be an essential factor for pregnancy development. Therefore, it should not be considered as a parameter for the assessment of RSA patients.

Immunotherapy for recurrent pregnancy loss: analysis of results from clinical trials

PROBLEM

Up to 80% of unexplained recurrent spontaneous abortions (RSA) are thought to have an immunologic mechanism. Yet clinical trials using immunotherapy to treat women experiencing RSA have low treatment effects. The present study was undertaken to explain the low treatment effects.

METHODS

Results of clinical trials using allogeneic leukocyte immunization and intravenous (IV) immunoglobulin (Ig) are compared. The mechanisms of pregnancy loss are reviewed in light of data on frequency of karyotype abnormalities in trophoblast of failing pregnancies.

RESULTS

Results of two independent analyses using allogeneic leukocyte immunization as immunotherapy for all women with RSA revealed live birth ratios of 1.16 (P = 0.03) and 1.21 (P = 0.02). When the analysis was limited to primary aborters, the live birth ratio increased to 1.46 (P = 0.006). Live birth ratio after immunotherapy for all RSA using IVIg was 1.88 (P = 0.04). Because of low treatment effects, confounders to treatment success of maternal age and number of previous abortions were studied. Chromosomal abnormalities have been identified in 55% of concepti from RSA. The frequency of chromosomal abnormalities remained constant for up to six pregnancy losses. Women with a history of primary compared to secondary RSA had a higher frequency of karyotypically abnormal concepti (chi 2 = 4.54, P < 0.05). Risk factors for RSA also include number of previous losses.

CONCLUSION

Chromosomal abnormalities are a significant confounder when evaluating efficacy of immunotherapy for treatment of RSA. Some women with RSA have a high risk of recurrent chromosomal problems.

A comparison of flow cytometry and microcytotoxicity for the evaluation of alloimmune therapy in patients with recurrent spontaneous abortions

PROBLEM

There is substantial data that support the efficacy of paternal leukocyte immunization (PLI) for the treatment of alloimmune mediated miscarriage; however, there is confusion regarding the laboratory test that should be performed to determine levels of maternal anti-paternal leukocyte antibodies (MAPLA).

METHOD

Popular methodologies employed include: 1) microcytotoxicity (MCX), 2) mixed lymphocyte culture (MLC), and 3) cell flow cytometry crossmatch (FCXM). Cell flow cytometry crossmatch correlates well with the more difficult MLC assay although the former proves the more sensitive study. This work compares the MCX assays with FCXM. The study group consisted of ten women who had a history of three or more spontaneous abortions (SABs). All ten had very low levels (< 10%) of MAPLA as measured by FCXM. Following PLI all subjects demonstrated elevated levels (> 50%) of MAPLA by FCXM. At 12 weeks gestation, sera were simultaneously measured for MAPLA by MCX and FCXM.

RESULTS

Although all ten patients had very high levels of MAPLA by FCXM during pregnancy, five of ten had antibodies to HLA Class I and two of ten had antibodies to HLA Class II paternal antigens by MCX. Furthermore, all patients who were positive by MCX to paternal Class I antigens were also positive to Class I antigens not seen in either parent. Both patients who were positive by MCX to paternal Class II antigens were also positive to maternal Class II antigens. Notable is that all ten women eventually delivered healthy infants.

CONCLUSION

Based on this preliminary study, the MCX assay is neither sensitive or reliable enough to determine the need and/or to monitor the effectiveness of PLI. Flow cytometry should be the modality of choice when determining the need for alloimmunotherapy and to monitor the effectiveness of treatment.

MHC class II compatibility in aborted fetuses and term infants of couples with recurrent spontaneous abortion

Maternal-fetal histocompatibility for alleles at HLA class II loci, HLA-DQA1 and HLA-DQB1, was examined in 40 abortuses and 31 liveborn children of 68 couples with a history of idiopathic recurrent spontaneous abortion (RSAB) who underwent leukocyte immunization prior to the index pregnancy. Significantly more couples with RSAB shared two HLA-DQA1 alleles as compared with fertile control couples (0.18 vs. 0.03, respectively; P = 0.031). There were no differences in HLA sharing between couples with RSAB who experienced a repeat abortion in the index pregnancy as compared with couples with RSAB who were delivered of a liveborn child. Non-significant deficits of abortuses who were compatible for alleles at the HLA-DQA1 (6 observed vs. 8.5 expected; P = 0.225) and the HLA-DQB1 (7 observed vs. 9.2 expected; P = 0.254) loci were observed. A significant deficit of HLA-DQA1 compatible liveborn children was observed (1 observed vs. 5.5 expected; P = 0.0069). The overall deficit of HLA-DQA1 compatible fetuses (7 observed vs. 14.0 expected; P = 0.0018) after approximately 8 weeks gestation suggests that HLA-DQA1 compatible fetuses may be aborted early in pregnancy, prior to the time when fetal tissue can be recovered for genetic studies.

Clinical evaluation of immunotherapy in early pregnancy with x-irradiated paternal mononuclear cells for primary recurrent aborters

OBJECTIVE

The purpose of this study was to evaluate the beneficial effect of immunotherapy for the treatment of recurrent abortion.

STUDY DESIGN

We immunized 106 primary recurrent aborters, twice at around 5 and 7 weeks of gestation, with intradermal injection of approximately 100 to 200 million x-irradiated (50 Gy) paternal mononuclear cells. We injected another 38 primary recurrent aborters in the same manner with only 1 million such paternal cells, to examine the relationship between the paternal cell dose used for immunization and pregnancy outcome.

RESULTS

The pregnancy success rate (83.0%) in patients immunized with a large number of cells was significantly higher than that (55.3%) in those immunized with a small number of cells (p < 0.001). Furthermore, the frequency of twins in the former group was high (5.7%, five of 88).

CONCLUSION

This positive relationship between the paternal cell dose used for immunization in early pregnancy and the pregnancy outcome reflects the efficacy of this mode of immunotherapy for recurrent aborters.

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.

Immunologic tests in the evaluation of reproductive disorders: a critical review

OBJECTIVE

The purpose of this study was to evaluate the clinical usefulness of immunologic assays proposed to assist in the diagnosis of alloimmune causes of recurrent spontaneous abortion.

STUDY DESIGN

Human leukocyte antigen typing, maternal antipaternal lymphocytotoxic antibody testing, and mixed lymphocyte culture assays were performed on 609 couples with recurrent spontaneous abortion, 92 infertile couples, and 43 fertile couples. The frequency of HLA antigen sharing and the presence of lymphocytotoxic antibodies and mixed lymphocyte culture inhibitors was compared among the populations.

RESULTS

Sharing of two or more HLA-A, HLA-B, HLA-C, or HLA-DR antigens was observed in 41% (252/609) couples with recurrent spontaneous abortion and in 34% (31/92) with infertility compared with 63% (27/43) of fertile couples. The frequency of lymphocytotoxic antibodies to paternal cells was significantly greater in the fertile population (27/143, 63%) (p < 0.0001) than in couples with recurrent spontaneous abortion (160/609, 26%) and in infertile couples (7/92, 8%). Mixed lymphocyte culture inhibitors were also more prevalent in sera from fertile women (19/43, 44%) compared with those with recurrent spontaneous abortion (122/609, 20%) and infertile women (4/92, 4%).

CONCLUSION

Human leukocyte antigen sharing does not predict pregnancy outcome, and the presence of lymphocytotoxic antibodies and mixed lymphocyte culture inhibitors is a function of the number and duration of pregnancies. More sensitive and specific assays are needed to identify alloimmunologic causes of reproductive disorders.

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.

Immunotherapy of habitual abortion

Many cases of habitual abortion have been assumed to be due to hyporesponsiveness to the spouse's antigens encountered in pregnancy. Immunization by paternal leukocytes has been used to potentiate the immune response and prevent further miscarriages. This treatment has been highly controversial in terms of efficacy, mode of action, and side effects. More recently immunoglobulin has been used as passive immunization for similar indications. In our experience immunotherapy is effective; 80% of patients have subsequent live births. The most significant results are seen in patients with five or more abortions, in whom 66% of subsequent pregnancies develop normally compared to 20% in a control group. We have used antipaternal complement-dependent antibody (APCA) production after immunization as a marker of immune response. APCA correlates with beneficial outcome in the next pregnancy. APCA may also be associated with cytokines, which may enhance embryonic and trophoblast development. Immunoglobulin may similarly provide the relevant antibodies or cytokines. At present a large scale meta-analysis is being performed to confirm or refute the efficacy of this treatment. This meta-analysis may resolve the controversy.

The number of cells used for immunotherapy of repeated spontaneous abortion influences pregnancy outcome

One hundred and sixty-eight women were immunized on a single occasion with paternal mononuclear cells (MNC) for recurrent spontaneous abortion (RSA) and pregnancy outcomes were analysed with respect to the number of MNC given. The study was done in a prospective sequential fashion using all MNC recoverable from a unit of the spouse's blood and both patients and investigators were blinded as to the number of cells injected. Women receiving low and mid-range doses of MNC (58-305 x 10(6) and 308-567 x 10(6), respectively) had a significantly higher pregnancy success rate (57%) than those receiving the high (568-2677 x 10(6)) dose of MNC (41%). In 77 consecutive patients the diameter of the largest immediate skin flare reaction at the site of subcutaneous injection was recorded. No correlation was found between the skin flare response and the number of MNC injected. Our data suggest that a blinded trial of paternal MNC immunization comparing what appears to be optimum numbers of cells (100-550 million) to a low dose inoculum (e.g., 10 million), again noting the sizes of the skin flare reactions, might answer questions about efficacy and placebo effects of immunotherapy for RSA.

White blood cell immunization and anticardiolipin antibody levels in women with recurrent miscarriages

To determine whether WBC immunization stimulates production of anticardiolipin antibodies, anticardiolipin antibodies were measured before and 6 weeks after WBC immunization. Twenty-four non-pregnant women, who had had recurrent miscarriages for which a definitive cause could not be determined, were immunized with their partner's WBC. No significant differences in levels of anticardiolipin antibodies were detected between paired samples of sera obtained before and 6 weeks after WBC immunization. White cell immunization in nonpregnant women did not stimulate production of anticardiolipin antibodies.

Autoantibodies in women with primary recurrent spontaneous abortion of unknown etiology

A group of 153 women with 3 or more recurrent spontaneous abortions (RSAs) with unknown etiology and 90 normal multigravida controls were evaluated for antibodies to phospholipids and nuclear antigens. We demonstrate that women with recurrent spontaneous abortions showed significantly higher incidence of antibodies to phospholipids than normal multigravida controls. In contrast, the incidence of antibodies to polynucleotides and histones was not different between these two groups. These findings suggest that antiphospholipid antibodies are either epiphenomena or causally related to recurrent spontaneous abortions.

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.

Cardiolipin antibody levels are not influenced by leukocyte immunotherapy in patients experiencing recurrent spontaneous abortion

OBJECTIVE

To confirm that leukocyte immunotherapy stimulates the production of cardiolipin antibodies and to relate changes to pregnancy outcome.

PATIENTS

Fifty patients with idiopathic recurrent abortion were studied. Thirty-six patients received injections of their partners' leukocytes; 14, injected with their own cells, served as controls.

DESIGN

Cardiolipin antibodies were measured a month before and after leukocyte immunization. Patients who became pregnant were immunized a second time in early pregnancy, and cardiolipin antibodies were again measured a month later.

RESULTS

Thirty-six patients immunized with their partners' leukocytes showed no appreciable change in cardiolipin antibody levels a month after vaccination. Twenty-nine of them subsequently became pregnant and were immunized again in early pregnancy: again, no change in cardiolipin antibody level was observed. There was no difference between the minority who aborted again and the majority who subsequently had successful pregnancies nor between those who responded to immunotherapy by producing cytotoxic antilymphocyte antibodies and those who did not.

CONCLUSION

Leukocyte immunotherapy does not stimulate cardiolipin antibody production in women with normal pretreatment levels of the autoantibody.

Predictors of pregnancy success in repeated miscarriage

Factors that may have a bearing on subsequent pregnancy success or failure in patients with recurrent abortion were examined in 165 women with a history of three or more consecutive miscarriages in the first trimester. The overall success rate was 67.9%. Factors that were found to correlate significantly with success rate were length of abortion history, total number of abortions, interval from last miscarriage to present pregnancy, and whether there was any degree of subfertility. Logistic regression analysis showed that the abortion x years index and maternal age accounted for all the variation observed in our data. Where all other known causes of abortions are excluded, recurrent aborters can be subdivided into two populations--namely, those with a relatively good prognosis characterized by a short abortion history and absence of subfertility problems, compared to those with a poor prognosis namely those with a long abortion history or presence of subfertility problems. These data clearly demonstrate major differences in success rates in women depending on the number of abortions and the length of abortion history (abortion x year index), particularly in women over the age of 30 years.

Autoantibodies and pregnancy wastage

The established association between a relatively specific group of autoantibodies binding negatively charged phospholipids and poor pregnancy outcome has advanced treatment options for women with this diagnosis. Evidence for an association between systemic autoimmune disorders and otherwise unexplained obstetric complications, in the absence of a documented antiphospholipid antibody(s), is reviewed. The existence of autoantibodies with other specificities that could be related to fetal wastage has been suggested by associations between poor obstetric histories and nonspecific serologic abnormalities observed in women with no clinical signs of an autoimmune disorder. Because signs and symptoms of vasospasm such as Raynaud's phenomenon or placental infarction have been observed in women with a history of unexplained fetal demise, a search for autoantibodies recognizing antigens common to trophoblastic and vascular cell surfaces is suggested.

Treatment of recurrent aborters by immunization with paternal cells--controlled trial

A paired sequential trial was undertaken to establish whether paternal mononuclear cells improved the prognosis in couples with recurrent abortions. For this purpose, 10(7)-10(8) cells obtained from the blood of partners were injected intravenously, subcutaneously, and intra-dermally into women who had had three or more consecutive miscarriages with the same partner. Control women were given normal saline, injected in the same manner. The result of the sequential analysis showed that there was no significant beneficial effect of the cells compared to control. The overall success rate was 70% (32/46 couples). The success rate in patients given cells was 62% (13/21), while in those given saline it was 76% (19/25). While the overall success rate in this study compares with a number of other studies, we find an equally high success rate with non-immunized patients. We conclude that the value of immunization for the prevention of recurrent miscarriage has not been established.