Natural killer cell activity and cytokine production after in vitro immunoglobulin treatment of lymphocytes derived from pregnant women with or without risk for spontaneous abortion

Effects of Intravenous Immunoglobulins on Human Innate Immune Cells: Collegium Internationale Allergologicum Update 2024

BACKGROUND

Intravenous immunoglobulin (IVIg) has been used for almost 40 years in the treatment of autoimmune and systemic inflammatory diseases. Numerous cells are involved in the innate immune response, including monocytes/macrophages, neutrophils, dendritic cells, mast cells, basophils, eosinophils, natural killer cells, and innate lymphoid cells. Many studies have investigated the mechanisms by which IVIg down-modulates inflammatory and autoimmune processes of innate immune cells. However, questions remain regarding the precise mechanism of action in autoimmune or inflammatory conditions. The aim of this work was to review the immunomodulatory effect of IVIg on only human innate immune cells. A narrative review approach was chosen to summarize key evidence on the immunomodulatory effects of commercially available and unmodified IVIg on human innate immune cells.

SUMMARY

Numerous different immunomodulatory effects of IVIg have been reported, with some very different effects depending on the immune cell type and disease. Several limitations of the different studies were identified. Of the 77 studies identified and reviewed, 29 (37.7%) dealt with autoimmune or inflammatory diseases. Otherwise, the immunomodulatory effects of IVIg were studied only in healthy donors using an in vitro experimental approach. Some of the documented effects showed disease-specific effects, such as in Kawasaki disease. Various methodological limitations have also been identified that may reduce the validity of some studies.

KEY MESSAGE

As further insights have been gained into the various inflammatory cascades activated in immunological diseases, interesting insights have also been gained into the mechanism of action of IVIg. We are still far from discovering all the immunomodulatory mechanisms of IVIg.

Composition and effects of seminal plasma in the female reproductive tracts on implantation of human embryos

The function of seminal plasma involves acting as a transport medium for sperm and as a means of communication between the reproductive tissues of the male and female. It is also a vital factor to prime the reproductive tracts of the female for optimal pregnancy. When the reproductive tract of the female is exposed to seminal plasma, serious alterations take place, enhancing pathogen and debris clearance observed in the uterus throughout mating. It is also capable of supporting embryo growth, promoting the receptivity of the uterus, and establishing tolerance to the semi-allogenic embryo. Moreover, seminal plasma is capable of regulating the functions of several female reproductive organs and providing an ideal condition for effective embryo implantation and pregnancy. It is believed that the health state of the offspring is affected by exposure to seminal plasma. For the treatment of infertility, assisted reproductive technologies have been extensively employed. The application of seminal plasma as a therapeutic approach to enhance the development of embryo competency and rate of implantation, receptivity of endometrium, and establishment of maternal immune tolerance in cycles of ART appears possible. Herein, current knowledge on the composition of seminal plasma and the physiological roles it possesses on various parts of the female reproductive tract are summarized. Moreover, the role of seminal plasma in the development of embryos, implantation, and the following fetal growth and survival have been reviewed in this article.

High Dose Intravenous IgG Therapy Modulates Multiple NK Cell and T Cell Functions in Patients With Immune Dysregulation

Intravenous immunoglobulin (IVIG) is an effective immunomodulatory treatment for immune dysregulation diseases. However, the mechanisms by which it reduces systemic inflammation are not well understood. NK cell cytotoxicity is decreased by IVIG in women with reduced fertility, but IVIG effects on NK cells in immune dysregulation are less clear. We hypothesized that IVIG modulation of lymphocyte function, especially in NK cells, is important for resolution of inflammation. Our aim was to identify IVIG-induced changes in a cohort of patients with Kawasaki disease (KD) and those that occur broadly in pediatric patients with various immune dysregulatory diseases. Peripheral blood mononuclear cells (PBMCs) of patients with KD or autoimmune/inflammatory diseases were phenotyped pre and post high dose IVIG treatment by flow cytometry. In KD patients, after IVIG infusion T_reg cell frequency and the proportion of activated CD25⁺ immunoregulatory CD56^bright NK cells was increased, and multiple lymphocyte subsets showed increased expression of the lymphoid tissue homing receptor CD62L. Importantly, IVIG treatment decreased the frequency of cells expressing the degranulation marker CD107a among cytotoxic CD56^dim NK cells, which was reflected in a significant reduction in target cell killing and in decreased production of multiple pro-inflammatory mediators. Interestingly, the activating receptor CD336 was expressed on a higher proportion of CD56^bright NK cells after IVIG in both KD and autoimmune/inflammatory patients while other NK receptors were increased differentially in each cohort. In autoimmune/inflammatory patients IVIG induced the proliferation marker CD71 on a higher percentage of CD56^dim NK cells, and in contrast to KD patients, CD107a⁺ cells were increased in this subset. Furthermore, when PBMCs were stimulated ex vivo with IL-2 or Candida antigen in autologous plasma, more of the CD4⁺ T cells of KD patients expressed CD25 after IVIG therapy but fewer cytotoxic T cells were degranulated based on CD107a expression. In summary, IVIG treatment in patients with immune dysregulation has multiple effects, especially on NK cell subsets and CD4⁺ T cells, which are compatible with promoting resolution of inflammation. These novel findings provide insight into the immunomodulatory actions of IVIG in autoimmune and inflammatory conditions.

Is there a Role of Intravenous Immunoglobulin in Immunologic Recurrent Pregnancy Loss?

Recurrent pregnancy loss (RPL) commonly refers to three or more miscarriages that occur before 20 weeks of pregnancy. The immunological cause of RPL could be either an auto- or alloimmune-related event or both. Because of the discovery of immunological abnormalities in RPL patients in clinical practice, several immunomodulatory therapies were introduced to maintain the immune balance at the maternal-fetal interface. Intravenous immunoglobulin (IVIg) is one of the immunomodulators. In recent years, several studies have analyzed the therapeutic effect of IVIg on RPL patients with antiphospholipid syndrome (APS) or unexplained RPL. However, their results are controversial. IVIg can be used in RPL patients with APS who have previously failed in other treatments. It is recommended that IVIg infusion could be considered used before conception in RPL patients who have cellular immune abnormalities such as increased natural killer (NK) cell counts, NK cell cytotoxicity, or increased T helper (Th)1/Th2 ratio, depending on the cut-off values of each hospital. The aim of this review was to summarize the mechanisms, efficacy, pharmacokinetics, and side effects associated with passive immunization using IVIg in immunologic RPL, according to the literature published in recent years. We hope that more obstetricians will be able to understand the timing and indication of IVIg properly in immunologic RPL patients and effectively enhance pregnancy outcomes for mothers and neonates.

Immune modulation of i.v. immunoglobulin in women with reproductive failure

Background

The mechanism of maternal immune tolerance of the semi‐allogenic fetus has been explored extensively. The immune reaction to defend from invasion by pathogenic microorganisms should be maintained during pregnancy. An imbalance between the immune tolerance to the fetus and immune activation to the pathogenic organisms is associated with poor pregnancy outcomes. This emphasizes that the immune mechanism of successful reproduction is not just immune suppression, but adequate immune modulation.

Methods

In this review, the action of i.v. immunoglobulin G (IVIg) on the immune system and its efficacy in reproductive failure (RF) was summarized. Also suggested is the indication of IVIg therapy for women with RF.

Main findings (Results)

Based on the mechanism of the immune regulation of IVIg and following confirmation of the immune modulation effects of it in various aberrant immune parameters in patients with RF, it is obvious that IVIg is effective in recurrent pregnancy losses and repeated implantation failures with immunologic disturbances.

Conclusion

The authors recommend IVIg therapy in patients with RF with aberrant cellular immunologic parameters, including a high natural killer cell proportion and its cytotoxicity or elevated T helper 1 to T helper 2 ratio, based on each clinic's cut‐off values. Further clinical studies about the safety of IVIg in the fetus and its efficacy in other immunologic abnormalities of RF are needed.

The effect of intravenous immunoglobulin passive immunotherapy on unexplained recurrent spontaneous abortion: a meta-analysis

The aim of this study was to investigate the effect of passive immunotherapy using intravenous immunoglobulin (IVIG) on unexplained recurrent spontaneous abortion (RSA). Live birth rates were analysed and binary data were calculated using risk ratio and 95% confidence interval. Meta-analysis of 11 studies showed that the difference in the live birth rate between the IVIG treatment and placebo groups was on the margin of significance (RR = 1.25, 95% CI 1.00 to 1.56, P = 0.05). Both cumulative and trial sequential meta-analyses indicated potential beneficial effect of IVIG but the evidence was inconclusive. Subgroup analysis showed that the live birth rate in primary (RR = 0.88, 95% CI 0.71 to 1.07) and secondary (RR = 1.26, 95% CI 0.99 to 1.61) RSA patients was not significantly different between the IVIG and placebo groups. Live birth rate was significantly different when IVIG was administered before conception (RR = 1.67, 95% CI 1.30 to 2.14, P < 0.0001) but not after implantation (RR = 1.10, 95% CI 0.93 to 1.29). Evidence is insufficient to support the beneficial effects of IVIG on an unexplained RSA. Further high quality studies are needed to elucidate the effectiveness of IVIG.

Role of inflammatory mediators in patients with recurrent pregnancy loss

OBJECTIVE

To examine interleukin-12 (IL-12), IL-18, IFN-γ, intracellular adhesion molecule-1 (ICAM-1), leukemia inhibitory factor (LIF), and migration inhibitory factor (MIF) levels in precisely-timed blood and endometrial tissue samples from women with idiopathic recurrent pregnancy loss (RPL).

DESIGN

Case-control study.

SETTING

University hospital.

PATIENT(S)

Twenty-one women with RPL and 20 women with proven fertility (controls).

INTERVENTION(S)

Primary endometrial cells and blood samples during the midsecretory phase (days 19-23).

MAIN OUTCOME MEASURE(S)

Detection of IL-12, IL-18, IFN-γ, ICAM-1, LIF, and MIF via enzyme-linked immunosorbent assay in both blood and endometrial tissue samples.

RESULT(S)

The blood and tissue levels of IL-12, IL-18, and IFN-γ were statistically significantly higher, and the blood and tissue levels of LIF and MIF were statistically significantly lower in patients with RPL. Only the level of tissue ICAM-1 was higher in patients with RPL. There was a strong correlation between blood and tissue level measurements of IL-12, IL-18, LIF, and MIF.

CONCLUSION(S)

Our findings support the hypothesis that inflammatory processes may contribute to pregnancy loss, possibly through their role in implantation. We found that blood and tissue levels of IL-18, LIF, and MIF, and tissue levels of IL-12, IFN-γ, and ICAM-1 have statistically significant prognostic relevance.

Joining the immunological dots in recurrent miscarriage

While raised cellular immunity mediated by T helper (Th) 1 type cells may be harmful for the developing embryo/foetus, it is likely that Th2 type immunity may be helpful. The role of natural killer (NK) cells is presently underestimated, although they are clearly important in angiogenesis and the coordinated invasion of the decidua by the trophoblast. Deficient T regulatory cell (Treg) function is evident in women with recurrent miscarriage particularly when this occurs in early pregnancy. The role of the pro-inflammatory Th17 cells is presently unclear. However, early evidence suggests that excessive Th17 activity may promote miscarriage and preterm delivery. This may relate to the ability of these cells to produce those cytokines that encourage Th1 and NK cell activity. As such recurrent miscarriage may be caused not only by chromosomal abnormalities, autoimmunity and uterine abnormalities but also by subclinical uterine infection and inflammation which by stimulating interleukin 6 favours Th17 development over Tregs. This review examines the role of these different cells in early pregnancy and suggests a schema that may join the dots of the immunological puzzle called pregnancy. Finally, suggestions are made as to how inappropriate immunity in recurrent miscarriage may be down-regulated using currently available therapies.

Intravenous immunoglobulin-based immunotherapy: an arsenal of possibilities for patients and science

The use of intravenous immunoglobulin (IVIG) concentrated from pooled healthy donors' plasma has gained increasing popularity. IVIG therapy has become important as a replacement therapy in primary and acquired humoral immunodeficiencies, and it has been extended to autoimmune, neurodegenerative and inflammatory conditions and transplantation therapy. Recurrent pregnancy failure and cancer are rather new platforms, where IVIG has shown its beneficial effects. This manuscript is focused on these two off-labelled usages. The immunomodulatory mechanisms of IVIG therapy appear as a coordinated orchestration of different functions, resulting in a synergistic effect. Treatment monitoring and detailed molecular analyses reveal how such treatments may interfere with disease pathogenesis. These finding may foster the development of novel therapeutic and/or preventive strategies. Studying this field with bidirectional bench-to-bedside and bedside-to-bench approaches fit well into 'the two-way road' paradigm of translational medicine.

Prednisolone suppresses NK cell cytotoxicity in vitro in women with a history of infertility and elevated NK cell cytotoxicity

PROBLEM

To evaluate the effect of prednisolone on NK cell cytotoxicity in vitro environment and also to compare the effect of prednisolone versus immunoglobulin-G (IVIG) on NK cell cytotoxicity using in vitro co-culture with K562 cells.

METHOD OF STUDY

The following is a prospective observational study, between August 2006 and February 2007, was carried out on blood samples from 110 patients with a history of recurrent miscarriage or recurrent failed implantation. Peripheral blood mononuclear cells containing NK cells were isolated and co-cultured with target cell K562 in three different effector-to-target (E:T) ratios of 50:1, 25:1 and 12.5:1. Prednisolone or IVIG was then added to the tube with E:T ratio of 50:1 to assess suppressive effect. The percentage killing was recorded and statistical analysis performed using Student's t-test.

RESULTS

In the experiments with an E:T ratio of 50:1 without prednisolone or IVIG in the co-culture, the mean target cell killing percentage was 26.4%. In cultures using the same E:T ratio, this killing percentage was significantly reduced in the presence of IVIG (9.9%) or prednisolone (13.6%), (P<0.001 in both analyses). On comparing the reduction in killing percentage of target cells by prednisolone versus IVIG, a slightly lower reduction in the prednisolone co-culture was noted but this was not statistically significant (P>0.05).

CONCLUSION

The results of this study show that prednisolone is able to suppress the cytolytic activity of the NK cell. Prednisolone and IVIG are almost equally effective in suppressing in vitro NK cell cytolytic activity.

Antibody therapy (IVIG): evaluation of the use of genomics and proteomics for the study of immunomodulation therapeutics

BACKGROUND AND OBJECTIVES

Intravenous immunoglobulin (IVIG) is used for an increasingly diverse number of therapeutic applications as an immunomodulation drug. Although it has demonstrated therapeutic effectiveness, the mechanism of action of IVIG in these disorders is poorly understood; this lack of understanding complicates rational clinical application and reimbursement for 'off-label' use.

MATERIALS AND METHODS

Selected literature on the clinical use of IVIG as an immunomodulation drug is reviewed. We present a brief description of DNA microarray and protein microarray technology and the application of such technologies to the study of immune system cells. The several studies on the application of DNA microarray technology to study gene expression in response to IVIG are presented.

RESULTS

There is increasing data on the use of DNA microarray and protein microarray technology to study gene expression in immune system cells including T cells, B cells, macrophages, and leucocytes. There is less information on the effect of IVIG on gene expression in immune system cells. However, there is sufficient information available to suggest that this is a practical approach with the caveat that such work will require careful experimental design and clear definition of the normal population.

CONCLUSIONS

DNA and protein microarray assays can be used to (i) provide rational indications for the clinical use of IVIG, (ii) provide for specific analysis of raw material and end product IVIG in screening for content related to immunomodulation, and (iii) accelerate the development of next generation products which would be more focused and/or targeted therapeutics.

Alterations in T-cell signal transduction molecules associated with recurrent spontaneous pregnancy loss

Clinical evidence suggests that cell-mediated immunity is altered during pregnancy and that failure to suppress the maternal immune response can lead to placentation failure, resulting in partial or total rejection of the fetus. In contrast to women experiencing recurrent spontaneous abortions (RSA), normal uncomplicated pregnancies are associated decreased T-cell proliferation and production of Th1 cytokines and increased T-cell apoptosis. This study addresses a circulating factor in normal pregnancy that may mediate these events. Sera were obtained from three groups: pregnant women who have uncomplicated term deliveries (Group 1, n = 8), pregnant women with a history of RSA, who subsequently abort (Group 2, n = 10), and age-matched non-pregnant female controls (Group 3, n = 8). Pregnancy sera were obtained between 10 and 12 weeks of gestation. Using chromatography, a CD3-zeta inhibitory factor (or analogous fraction) was isolated from each patient within each group and incubated with cultured T-cells, Jurkat and HUT-78 cells. Apoptosis was assayed by a cell-death ELISA and IL-2 production by cytokine-specific ELISA. Apoptosis regulatory proteins and signaling molecules were analyzed by western immunoblotting. Group 1 material induced a significant increase in apoptosis versus Groups 2 and 3. No significant apoptosis was observed between Groups 2 and 3. Material from Group 1 resulted in an increase in the bax expression compared to Groups 2 and 3 (P < 0.001), while no significant differences were observed in the expression of bcl-2. IL-2 secretion was inhibited 2.8-fold by material from Group 1 compared to Groups 2 and 3. Group 1 material decreased the expression of CD3-zeta, JAK3 and STAT5 compared to Groups 2 and 3 (as defined by densitometric units). Circulating materials from normal pregnancies are associated with increased lymphoid apoptosis, possibly through increased bax, and diminished production of the Th1 cytokine, IL-2. Our findings indicate that women experiencing RSA fail to suppress CD3-zeta and JAK3, suggesting a deficiency in this circulating factor that induces their suppression in normal pregnancy.

Effect of IgG therapy on lymphocyte subpopulations in the peripheral blood of Kuwaiti women experiencing recurrent pregnancy loss

Intravenously administered polyspecific IgG is being increasingly used as an immunomodulating therapy with controversial beneficial outcome. The aim of this study was to evaluate the effects of IgG infusion on peripheral T-cell subpopulations in women with recurrent pregnancy loss (RPL). Fifteen women with a history of three previous RPL between 6 and 22 weeks of gestation and positivity for the antiphospholipid antibody syndrome (APS) were randomized to one of two treatment groups: (a) an intravenous immunoglobulin therapy group (RPL-IVIg; 7 patients), 500 mg IVIg/kg/month and (b) a placebo-treated group given multivitamins (8 patients). Control groups comprised either normal pregnant women without APS (10 patients) or non-pregnant women. The T-cell markers were characterized using a monoclonal antibody panel including CD3, CD4, CD8, CD25, CD29, CD38, CD45RA, CD45RO, CD54 and HLA-DR. Analysis was performed with a two-color fluorescent-activated flow cytometer. In the first trimester, the percentage of CD4+CD25+, CD4+CD45RO+, CD8+HLA-DR+, and CD8+CD38+ populations were reduced in the multivitamin group compared to normal pregnant women (p < 0.05) while in the RPL-IVIg group only CD4+CD25+ cells were reduced (p < 0.05). By the second trimester, CD3+CD16+CD56+ was significantly higher in multivitamin- than in IVIg-treated women (p < 0.05). The percentage of CD4+HLA-DR+ was significantly higher in the two RPL groups compared to normal pregnant women (p < 0.05). IVIg therapy in women with RPL was associated with a significant reduction in CD3+CD16+CD56+ and CD4+CD25+. This may contribute to the suppression of immune-mediated processes contributing to premature abortion.

Gamma/delta T cell subsets in patients with active Mycobacterium tuberculosis infection and tuberculin anergy

Earlier data suggest that gamma/delta T cells may play an important role in the immune response to Mycobacterium tuberculosis. The aim of this study was to determine the percentage of different gamma/delta subsets in peripheral blood of active tuberculosis patients with a positive or negative tuberculin reaction. Thirty-eight patients infected with M. tuberculosis and 22 healthy controls were included in the study. Venous blood was taken before starting antimycobacterial treatment. Lymphocytes were reacted with monoclonal antibodies specific for different gamma/delta V chains (Vdelta1, Vdelta2, Vgamma9 and Vgamma4). The results were analysed in the context of tuberculin reactivity and X-ray findings. Our results revealed a selective loss of Vgamma9/Vdelta2 T cells in the peripheral blood of tuberculin-negative patients with active tuberculosis compared to healthy controls, while the ratio of Vgamma9/Vdelta2 T cells in the peripheral blood of patients with a positive skin test did not differ from that of healthy controls. These findings demonstrate a relationship between the loss of the major M. tuberculosis-reactive subset of gammadelta T cells and the absence of tuberculin reactivity. The data are consistent with the hypothesis that gammadelta T cells play a role in the protective immune response to M. tuberculosis infection.

Intravenous immunoglobulin treatment in women with recurrent abortions: increased cytokine levels and reduced Th1/Th2 lymphocyte ratio in peripheral blood

PROBLEM

The aim of this study was to investigate changes in peripheral blood Th1/Th2 cytokine levels and lymphocyte ratios after massive intravenous immunoglobulin (MIVIg) treatment for women with recurrent spontaneous abortion (RSA) of unexplained etiology.

METHOD OF STUDY

Serum Th1 (IFN-gamma, TNF-alpha) and Th2 cytokine (IL-4, IL-10) levels were assessed by ELISA methods (n = 9) and peripheral blood Th1/Th2 lymphocyte ratios (n = 4) by flow cytometry before and after MIVIg treatments in women with four or more consecutive RSA.

RESULTS

Pre-treatment serum IFN-gamma (0.06 +/- 0.09 pg/mL, mean +/- SD), TNF-alpha (0.21 +/- 0.45 pg/mL), IL-4 (0.70 +/- 1.16 pg/mL), and IL-10 (1.12 +/- 1.67 pg/mL) increased to 0.17 +/- 0.16 pg/mL, 0.77 +/- 0.28 pg/mL, 1.82 +/- 0.89 pg/mL, and 3.44 +/- 0.48 pg/mL, respectively, after MIVIg treatments (P < 0.05). CD4-positive IFN-gamma/IL-4 lymphocyte ratios (17.3 +/- 9.1) were reduced to 11.5 +/- 7.1 after treatment (P < 0.05).

CONCLUSIONS

Massive intravenous immunoglobulin treatments increased peripheral blood cytokine levels and decreased Th1/Th2 lymphocyte ratios; thus, MIVIg treatments modify the peripheral Th1/Th2 balance.

Effect of intravenous immunoglobulin treatment on the Th1/Th2 balance in women with recurrent spontaneous abortions

PROBLEM

The way by which intravenous immunoglobulin (IvIg) acts to prevent immunlogically mediated recurrent spontaneous abortions (RSA) has not been clarified. In the present study, a possible effect of IvIg on the T helper cell (Th1/Th2) balance was investigated in abortions of either alloimmune or autoimmune abnormalities.

METHOD OF STUDY

The study included 21 women treated with IvIg before conception because of a history of RSA characterized by alloimmune abnormalities (n = 15) or associated with anti-phospholipid antibodies (APA) (n = 6). Peripheral blood samples, collected before and 5 days after the first IvIg infusion, were stimulated, and Th1 and Th2 cells were detected by flow-cytometric analysis using a combination of monoclonal antibodies against T-cell surface markers and intracellular interferon (IFN)-gamma and interleukin (IL)-4. The percentage of IFN-gamma-producing (Th1) and IL-4-producing (Th2) cells and the Th1/Th2 ratio were compared between pre- and post-infusion samples.

RESULTS

A decrease of Th1 percentage in 66.6% of the cases and a concurrent Th2 percentage increase (47.61%) resulted in a decrease in the Th1/Th2 ratio in most of the cases (76.1%) (p < 0.01). Similar results were found in Group A (Th1/Th2 decreased in 60% of the cases, p < 0.05), while in Group B the effect of IvIg was not clear (Th1/Th2 increased in three and decreased in another three cases).

CONCLUSION

Our finding suggests that IvIg administration in women with alloimmune RSA enhances Th2 polarization. This is not always the case with APA-associated abortions.

Mechanisms of intravenous immunoglobulin action in the treatment of autoimmune disorders

Intravenous immunoglobulins (IVIg) are therapeutic preparations of normal human immunoglobulin (Ig) G obtained from pools of blood from more than 1000 healthy donors, and exert immunomodulatory effects in autoantibody-mediated and T-cell-mediated autoimmune disorders and systemic inflammatory diseases. IVIg mechanisms of action in autoimmune diseases have been extensively analysed during the last 15 years and include the following: (i) interaction of the IgG Fc fragment with Fc receptors on leucocytes and endothelial cells; (ii) interaction of infused IgG with complement proteins; (iii) monocyte and lymphocyte modulation of synthesis and release of cytokines and cytokine antagonists; (iv) modulation of cell proliferation and reparation; (v) neutralisation of circulating autoantibodies; (vi) selection of immune repertoires; and (vii) interaction with other cell-surface molecules on T and B lymphocytes.

Differential expression of interleukins (IL) IL-13 and IL-15 throughout the menstrual cycle in endometrium of normal fertile women and women with recurrent spontaneous abortion

Interleukins (IL)-13 and IL-15 are novel cytokines and key regulators of immune/inflammatory related responses that are critical in the outcome of various normal biological and associated abnormalities of the endometrium. The present study determined the temporal and spatial expression of IL-13 and IL-15 mRNA and protein in endometrium of normal fertile women throughout the menstrual cycle, and examined whether profiles of their expression differ from endometrium of women with unexplained recurrent spontaneous abortion (RSA). Using quantitative RT-PCR, ELISA and immunohistochemistry we found that IL-13 and IL-15 mRNA and protein are expressed in control endometrium throughout the menstrual cycle and in RSA (cycle days 21-23) with peak expression detected immediately after and prior to onset of menses, and two distinct periods corresponding to late proliferative and the early-mid secretory phases, respectively. The ratio of IL-13:IL-15 expression revealed a predominance in IL-13 expression during late proliferative/early secretory phase and IL-15 during the mid secretory phase. Compared to control endometrium, endometrium of women with RSA expresses elevated levels of IL-13 and IL-15, with IL-13:IL-15 ratio favoring IL-13. The immunoreactive IL-13 and IL-15 were localized primarily in endometrial luminal epithelial cells with an increased intensity in glandular epithelial and stromal cells in RSA. In conclusion, the results indicate that endometrium of normal fertile women expresses IL-13 and IL-15, with a distinct profile during the menstrual cycle and elevated expression in women with RSA. Although the biological significance of IL-13 and IL-15 in human endometrium and their elevated expression in RSA await investigation, these cytokines with distinct biological functions may regulate endometrial inflammatory/immune responses, tissue repair and receptivity for embryo implantation.

A model for potential tumor immunotherapy based on knowledge of immune mechanisms responsible for spontaneous abortion

Attempts to treat various cancers by immunotherapy have been tried for about 50 years. Most studies have focused on improving cytotoxic T lymphocyte (CTL) responses against various tumors. Immunotherapy has been both active and passive, and results have been modest at best. Spontaneous abortion (SAB) of pregnancies could in some ways resemble remission of a tumor. Both tumors and conceptusses are faced with a similar problem -- how to grow in a host in a vascular rich area, and yet escape immune surveillance despite both entities being an allogenic stimulus. In general, the fetus is far more immunogenic than a spontaneous tumor, and yet abortuses seem to avoid CTL responses but are sometimes invaded by natural killer (NK) cells. There are data suggesting that SAB will occur if there is inhibition of production of an immunosuppressive protein called progesterone-induced blocking factor (PIBF). This protein inhibits NK cell cytolysis and influences TH2 cytokine dominance over TH1. If some tumors avoid NK cell destruction through a PIBF mechanism, perhaps an active rejection of these tumors could be achieved by inhibiting PIBF production by treating with a progesterone receptor antagonist. Passive immunization could also be considered by conjugative radionuclide or toxic chemical to a PIBF antibody which may be tumor specific since PIBF is not produced in normal tissue. The first step should be to see if PIBF can be detected in the peripheral circulation in patients with certain tumors.