In the United States, effective treatment of NK/CTL activation associated with either alloimmune or autoimmune implantation dysfunction requires the administration of primarily Intralipid (IL)or Intravenous gamma globulin (IVIg) plus corticosteroid. Such treatment is much more likely to be successful in the case of` autoimmune implantation dysfunction where the NK/CTL activation is present in advance of the uterus being exposed to the embryo. It is not nearly as effective for the treatment of alloimmune implantation dysfunction where a DQ alpha-matching embryo will exert a sustained activation of NK/CTLs over several months of gestation.

It is presently not yet possible to recognize paternal DQ alpha in the embryo. Accordingly, in cases where the paternal DQ alpha genes only match with one of the mother’s DQ alpha’s (i.e., a partial match) there is a one out of two chance that a transferred embryo will inadvertently be a match with at least one of the mother’s DQ alpha genes. Thus IL and IVIg therapy will only prove half as likely to propagate a viable pregnancy in cases of partial DQ alpha matching as it can achieve in the treatment of NK/CTL activation associated with autoimmune implantation dysfunction. Thus we prefer to transfer only one embryo (rather than multiples) at a time in such cases, for fear of there being one DQ alpha matching embryo in the mix and so “muddying the waters” for the non-DQ alpha matching that otherwise might have propagated a healthy baby.

A real problem arises in cases of a complete match, where both paternal DQ alpha genes match with at least one of the mother’s DQ alphas. Here, every embryo will express a paternal DQ alpha gene that matches that of the mother’s. In such cases, IL therapy will rarely work. The reason is that such treatment cannot match the sustained provocation of NK/CTL activity brought about by an ever-present DQ alpha “clash.” In cases of a complete DQ alpha matching (with associated NK/CTL activation), where all the embryos will inevitably carry one or both paternal DQ alpha that match(es) the mother, there is in my opinion little hope of success, even with Intralipid/steroid therapy. In such cases, gestational surrogacy or the use of non-DQ alpha matching donor sperm may offer the only reasonable chance of a successful IVF outcome.

Some patients ask whether using an egg donor might not offer another solution in such cases. The answer is no! The matchup is between the paternal DQ alpha contribution (in the sperm) and the mother’s uterus. It is not between the sperm and the egg.

IL therapy should be administered in combination (with corticosteroids) at an adequate dosage, 7–14 days prior to planned embryo transfer, and with alloimmune implantation  dysfunction it should (ideally) be maintained, at least through the 1st half of pregnancy. The goal is to down-regulate activated NK/CTL and thereby reinstate a healthy TH-1: TH-2 cytokine balance in advance of a “competent” non-DQ alpha matching embryo reaching the uterus. Treatment of autoimmune  implantation  dysfunction requires that IL (with corticosteroids) be administered only twice, once 7–14 days prior to embryo transfer and then one more time when the beta hCG blood level has shown evidence of an appropriate  rise, thereby suggesting that healthy implantation could be in progress. Supplementation with heparinoid is indicated when there is evidence of concomitant antiphospholipid antibodies or certain types of hereditary clotting defects (thrombophilias) such as a homozygous MTHFR mutation.

The Role of PGS/PGT-A (Full Embryo Chromosomal Karyotyping) in the Treatment of Alloimmune Implantation Dysfunction

Intralipid (IL)/Prednisone therapy only addresses the implantation issue, not embryo competency (which resides in the chromosomal integrity of the embryo transferred. Moreover, as previously alluded to, with a partial DQ alpha match/NK cell activation each blastocyst transferred has a 50:50 chance of matching. Consider the fact that the transfer of a single expanded blastocyst to a young woman (who did not have a DQ alpha match) would yield at best about a 35% chance of propagating a healthy pregnancy. Now, if the woman had a partial DQ alpha match with her partner, given that  each of her embryos  embryo would have a 50:50 chance of matching (and there is currently no way to identify the DQ alpha genotype of an embryo) , the chance of a viable pregnancy would be one half of the otherwise anticipated 35% (i.e. about 17%). If on the other hand the woman’s transferred embryo had been tested and found through PGS /PGT-A (using Next Generation Gene Sequencing – NGS) to have a full component of 46 chromosomes (i.e. euploid) then the chance of a viable pregnancy would be about 32% (half of an otherwise 65% chance had she not had a partial DQ alpha match with her partner.  Now add to this equation the fact that with a partial DQ alpha match it is probably best to transfer only one embryo at a time in order to reduce the risk that the inadvertent delivery of a DQ alpha matching embryo could potentially cause activation of local uterine NK cell activation that might prejudice the implantation of all embryos being transferred.

The Role of Embryo Banking in Cases of Alloimmune Implantation Dysfunction with a Partial DQ alpha Match

Bear in mind that at best, 1:2 embryos are chromosomally normal even in young women, and this decreases further with advancing age. Furthermore, where there is a partial DQ alpha match between partners, only 50% of the embryos will be non-matching, reducing the chances of successful implantation again by half. It is advisable to only transfer one embryo at a time in such cases. Indeed, a strong case could be made for full embryo karyotyping (using CGH or NGS) to allow for the selective transfer (one at a time) of only those embryos that are chromosomally normal (euploid). In most cases, this will require biopsying the fresh embryos for CGH/NGS testing, allowing them to progress to blastocysts and then cryopreserving these for subsequent single embryo transfer.  This would allow for more competent blastocysts to be available and for a much higher success rate per blastocyst transferred and accordingly, improved IVF outcomes.

Gestational Surrogacye For Alloimmune Implantation Dysfunction

A gestational surrogate is used when there is a complete DQ alpha match with NK cell activation between the patient and the sperm provider. It has no real merit when there is only a partial match. Ordinarily, provided that an embryo recipient is NK negative, a DQa match between recipient and sperm provider should theoretically not preclude an ensuing pregnancy. Notwithstanding this, there should in our opinion be reluctance  to accept NK negative Gestational Surrogates (GS) who share a DQa match with the sperm provider……An exception could be made only if following full disclosure of this concern to both parties in advance of treatment that although unlikely, a pregnancy with a matching DQa, NK negative pair could (although unlikely) suddenly cause the newly pregnant embryo recipient to convert to NK+,  placing the pregnancy (as well as all future pregnancies) in jeopardy.

Use of a Sperm Donor in Cases of Alloimmune Implantation Dysfunction

This is an acceptable option in cases of a  partial or complete  DQ alpha match, provided that the sperm donor and the embryo recipient do not match and any coexisting NK cell/CTL activation is treated concurrently with IL/steroids.

Use of Medications in the Treatment of IID

  1. Intralipid (IL) Therapy:

About a decade ago, one of my associates,  along with a geneticist in an affiliated Reproductive immunology Laboratory, were the first to report on the potential advantage of supplanting IVIg therapy with IL. 

Intralipid (IL) is a solution of small lipid droplets suspended in water. When administered intravenously, IL provides essential fatty acids, linoleic acid (LA), an omega-6 fatty acid, alpha-linolenic acid (ALA), an omega-3 fatty acid. IL is made up of 20% soybean oil/fatty acids (comprising linoleic acid, oleic acid, palmitic acid, linolenic acid and stearic acid), 1.2% egg yolk phospholipids (1.2%), glycerin (2.25%) and water (76.5%). 

IL exerts a modulating effect on certain immune cellular mechanisms largely by down-regulating cytotoxic /activated natural killer cells (NKa). This effect is enhanced through the concomitant administration of corticosteroids such as dexamethasone, prednisone, and prednisilone, by suppressing cytotoxic/activated T-lymphocytes. This effect of IL might be due to its ability to suppress pro-inflammatory cellular (Type-1) cytokines such as interferon gamma and TNF-alpha, 

In-vitro testing has shown that IL successfully and completely down-regulates activated natural killer cells (NKa) within 2-3 weeks in 78% of women experiencing immunologic implantation dysfunction. In this regard it is just as effective as IVIg but at a fraction of the cost and with a far lower incidence of side-effects. Its effect lasts for 4-9 weeks when administered in early pregnancy.

Can in-vitro tests done in the laboratory assess for an immediate benefit of Intralipid on NKa? Since the down-regulation of NKa through IL (or IVIg) therapy can take several weeks to become detectable, it follows that there is really no benefit in trying to assess the potential efficacy of such treatment by retesting NKa in the laboratory after adding IL (or IVIg) to the sample.

Treatment of Autoimmune NKa Using Intralipid: When it comes to NKa in  IVF cases complicated by autoimmune implantation dysfunction,  the combination of daily oral dexamethasone commencing with the onset of ovarian stimulation and continuing until the 10th week of pregnancy, combined with an initial infusion of IL (100ml, 20% IL dissolved in 500cc of saline solution, 10-14 days prior to embryo transfer and repeated once more (only), as  soon as the blood pregnancy test is positive), the anticipated chance of a viable pregnancy occurring within 2 completed IVF attempts (including fresh + frozen ET’s)  in women under 40Y (who have normal ovarian reserve)  is above 80%.

Treatment of Alloimmune NKa Using Intralipid:

Partial DQ alpha Match: IVF patients who have NKa associated with a partial alloimmune implantation dysfunction (DQ alpha match between partners) we use the same IL, infusion as with autoimmune-NKa, only here we prescribe oral prednisone rather than dexamethasone until the 10th week of pregnancy and IL infusions are repeated every 2-4 weeks following the chemical diagnosis of pregnancy until the 24th week. Additionally, (as alluded to elsewhere) in such cases we transfer only a single embryo at a time. This is because in such cases, the likelihood is that one out of two embryos will “match” and we are fearful that if we transfer >1 embryo, and one of the transferred embryos “matches” it could cause further activation of uterine NK cells  and so prejudice the implantation of all transferred embryos.  Since we presently have no way of determining which embryo carries the matching paternal DQ alpha gene and thus would transfer only one embryo at a time, it follows that the anticipated viable  pregnancy rate per cycle will be much lower than with autoimmune implantation dysfunction. It also follows that the only way to improve success with a single embryo being transferred would be  to perform PGS on the embryos in advance of ET and then selectively transfer  a “chromosomally normal-euploid (“competent”) embryos.

Total (Complete) DQ alpha Match: In cases where the partners have a total alloimmune (DQ alpha) match with accompanying NKa the chance of a viable pregnancy occurring or (if it does) resulting in a live birth at term, is so small as to be an indication for using a non-matching sperm donor or resorting to gestational surrogacy would in our opinion be preferable by far.      

Contraindications and Cautions with Intralipid Infusion: IL is only contraindicated in conditions associated with severely disordered fat metabolism (e.g. severe liver damage, acute myocardial infarction and shock,

Rarely, hypersensitivity has been observed in patients allergic to soybean protein, egg yolk and egg whites and where fat metabolism may be disturbed (e.g. renal insufficiency, uncontrolled diabetes, certain metabolic disorders and in cases of severe infection (sepsis).

Adverse Reactions During Infusions of IL (Rare): These include transient fever, chills, nausea, vomiting, headache, back or chest pain with shortness of breath and cyanosis.

Composition and Storage of IL: IL should be stored at a controlled room temperature below 25°C. It should not be frozen.

IVIg versus Intralipid Therapy:  Until about a decade ago, the only effective and available way (in the US) to down-regulate activated NK cells was  through  the intravenous administration of a blood product known as immunoglobulin-G  (IVIg). The fear (albeit unfounded) that the administration of this product might lead to the transmission of viral infections such as HIV and hepatitis C, plus the high cost of IVIG along with the fact that significant side effects occurred about 20% of the time, led to bad press and bad publicity for the entire field of reproductive immunology. It was easier for RE’s to simply say “I don’t believe IVIg works” and thereby avoid risk and bad publicity. But the thousands of women who had babies because of NK cell activity being down-regulated through its use, attests to IVIg’s efficacy. But those of us who felt morally obligated to many desperate patients who would not conceive without receiving IVIG were facing an uphill battle. The bad press caused by fear mongering took its toll and spawned a malicious controversy. It was only through the introduction of IL less (than a decade ago), that the tide began to turn in favor of those patients who required low cost, safe and effective immunotherapy to resolve their IID.

  1. Corticosteroid Therapy (Prednisone, Prednisilone, and Dexamethasone)

Corticosteroid therapy has become a mainstay in the treatment of most women undergoing IVF. It is believed by most to enhance implantation due to an overall immunomodulatory effect. Some IVF programs prescribe daily oral methyl prednisolone (Medrol) while others prefer prednisone or dexamethasone, commencing 10-14 days prior to egg retrieval and continuing until pregnancy is discounted or until the 10th week of pregnancy.

  1. Heparinoid Therapy

There is compelling evidence that the subcutaneous administration  of heparin twice daily or low molecular heparin (Clexane, Lovenox) once daily, (starting  with the onset of ovarian stimulation) can improve IVF birthrate in women who test positive for APAs and can prevent later pregnancy loss when certain thrombophilias (e.g. homozygous MTHFR mutation)

  1. What About Baby Aspirin?

In my personal opinion, aspirin has little (if any) value when it comes to IID, and besides, could even reduce the chance of success. The reason for this is that aspirin thins the blood and increases the potential to bleed. This effect can last for up to a week and could complicate an egg retrieval procedure or result in “concealed” intrauterine bleeding at the time of embryo transfer, thereby potentially compromising IVF success.

  1. TH-1 Cytokine Blockers (Enbrel, Humira)

TH-1 cytokine blockers, (Enbrel and Humira) are in our opinion relatively ineffective in the IVF setting. There has to date been no convincing data to support their use. Conversely, these blockers could have a role in the treatment of a threatened miscarriage thought to be due to CTL/NK activation, but not for IVF. The reason is that the very initial phase of implantation requires a cellular response involving TH-1 cytokines. To block them completely (rather than simply restore a TH-1:TH-2 balance as occurs with IL therapy) so very early on could compromise rather than benefit implantation.

  1. Leukocyte Immunization Therapy (LIT)

The subcutaneous injection of the male partner’s lymphocytes to the mother is thought to enhance the ability for the mother’s decidua (uterus) to recognize the DQ alpha matching embryo as “self” or “friend” and thereby avert its rejection. LIT has been shown to up-regulate Treg cells and thus down-regulate NK cell activation and thereby improve decidual TH-1:TH-2 balance. Thus there could be a therapeutic benefit from such therapy. However, the same benefit can be achieved through the use of IL plus corticosteroids. Besides, IL is much less expensive, and the use of LIT is prohibited by law in the U.S.A.