Immune testing for IVF – 2026 updates from a leading European clinic
Immunology might have already been on your radar – it’s an increasingly important consideration in IVF, especially for patients who haven’t found clear answers through standard fertility testing. And if that is you, you’ll know how difficult it can be to not know where to turn next.
At Clínica Tambre, our long-time go-to in Spain, this area of fertility care has been a focus for decades. With nearly 50 years of experience in assisted reproduction, the group has built a dedicated Reproductive Immunology Unit, bringing together specialists to support more complex cases with a multidisciplinary, evidence-led approach.
Spain is Europe’s largest provider of assisted reproduction, and Clínica Tambre offers high-quality, accessible care within a progressive legal framework at both of their clinic locations in Madrid and Alicante.
Dive deeper, and read on for their up-to-the-minute 101 guide to immune testing for IVF, in 2026 and beyond.
Understanding immune testing for IVF
Immune or immunology testing in a fertility and IVF context refers to a group of investigations that assess how your immune system may be interacting with embryo implantation and early pregnancy development.
As Dr. Abraham Zavala, Gynaecologist and Fertility Specialist at Clínica Tambre, explains:
“Successful embryo implantation requires a finely tuned dialogue between the embryo and the maternal immune system. Rather than simply ‘tolerating’ the embryo, the uterine immune environment actively facilitates implantation through a complex interplay of immune cells, cytokines, and signalling pathways.”
When this process is disrupted, implantation may not occur as expected, or early pregnancy complications can arise. These disruptions can happen at different levels:
- Systemic immune factors, such as antiphospholipid antibodies or thyroid autoimmunity
- Chronic inflammatory conditions, including lupus or rheumatoid arthritis
- Local uterine factors, particularly involving uterine natural killer (uNK) cells and their interaction with the embryo
Dr. Zavala highlights the growing understanding of genetic compatibility in this process:
“The interaction between maternal killer immunoglobulin-like receptors (KIR) on these NK cells and the HLA-C molecules expressed by the embryonic trophoblast is increasingly recognised as a key determinant of implantation success.”
At the same time, he emphasises a careful, evidence-based approach:
“It is important to note… that not every immune ‘abnormality’ detected in a lab test translates into a clinical problem. This is precisely why a rigorous, evidence-based approach to testing and treatment is essential.”
Who might benefit from immunology testing?
Immune testing is not recommended for every IVF patient. At Clínica Tambre, a selective approach helps ensure testing is meaningful and avoids unnecessary interventions.
Patients who may benefit include:
- Those with recurrent pregnancy loss, where guideline-supported testing (such as for antiphospholipid syndrome) is already standard
- Those with recurrent implantation failure, particularly after transferring good-quality embryos
- Patients with diagnosed autoimmune conditions, including Hashimoto’s thyroiditis or lupus
- Cases of unexplained infertility with clinical indicators of immune involvement
Dr. Zavala explains:
“We take a selective rather than universal approach to immune testing. Not every patient undergoing IVF needs an immunological work-up, and indiscriminate testing can lead to over-diagnosis, unnecessary anxiety, and unproven treatments.”
What’s new in 2026 – advances and findings
Recent developments are shaping how clinicians approach immune testing for IVF, with a stronger focus on precision and clinical relevance. These include:
1. More refined compatibility testing
One of the most important updates involves KIR/HLA-C compatibility testing.
“We now understand that it is not just the paternal HLA-C that matters; maternal HLA-C alleles are also presented on the trophoblast surface… providing a more complete picture of immune compatibility at the maternal-foetal interface.” says Dr. Zavala.
This expanded testing offers more detailed insight into how the immune system may influence implantation.
2. Clearer clinical guidance
The publication of formal recommendations by the American Society for Reproductive Immunology in 2025 marks a step forward:
“They emphasize the need for confirmed immune biomarkers before initiating treatment, rather than empirical immunosuppression.”
This supports a move away from broad, non-specific treatments towards targeted, evidence-based care.
3. Deeper insight into the endometrial environment
There is also growing interest in analysing the immune environment within the uterus itself:
“There is growing interest in characterizing the immune microenvironment of the endometrium… While still largely research-grade, these profiles may eventually help identify patients with endometrial immune dysregulation.”
4. Data-driven personalisation
At Clínica Tambre, immunology is increasingly integrated with other areas of fertility care:
“We believe that the future of reproductive medicine lies in integration, combining immunological data with embryological, genetic, and clinical information to create truly personalized treatment strategies.”
This includes using immune data alongside embryo selection and broader patient health indicators to guide decision-making.
Why Spain, for this kind of tailored support?
Spain has become a real leading destination for advanced fertility care, particularly for those of us travelling from the UK.
As a hub for innovation and experience, Spain offers:
- A high volume of IVF cycles, supporting clinical expertise
- A progressive legal framework that supports a wide range of patients
- Established pathways for international care
Tambre leads the way here for its early adoption of reproductive immunology in particular. And for UK patients exploring an IVF clinic Spain option (whether in Madrid or considering IVF clinic Alicante alternatives) their more tailored approach in complex cases make them a real standout option.
Patient experience and accessibility at the forefront
For international patients, including those travelling from the UK, immune testing and treatment can be integrated into a clear and manageable pathway.
At Clínica Tambre, this typically includes:
- An initial online consultation, where your history is reviewed in detail
- A targeted testing plan, based on your specific clinical profile
- Coordination of tests either locally or during a short visit to Spain
- A personalised treatment plan, developed with input from the Reproductive Immunology Unit
Dr. Zavala also emphasises the importance of careful interpretation:
“When immune testing is performed, results are interpreted in the context of the patient’s full clinical picture… An elevated NK cell count in isolation does not automatically warrant immunosuppressive treatment.”
What success can look like
This anonymised case* shows how targeted testing can guide treatment.
Dr. Zavala explains:
“We recently treated a 36-year-old patient who had experienced three failed IVF transfers of good-quality blastocysts… At Tambre, we performed a targeted immunological evaluation… The results revealed that she had a KIR AA genotype and her partner was HLA-C2/C2.”
Following tailored adjustments, including thyroid optimisation and a personalised transfer protocol: “On her next transfer of a single euploid blastocyst, she achieved implantation and went on to deliver a healthy baby at term.”
This reflects the value of using immunology testing selectively, and also highlights the importance of not simply attributing every case of implantation failure to immune factors.
A quick look ahead – what’s next for immunology testing in fertility?
Beyond 2026, several developments look set to shape this field further, including:
- Non-invasive immune profiling, like using uterine fluid or menstrual samples for testing
- AI-supported donor matching incorporating immune compatibility
- Targeted biologic therapies, designed specifically for reproductive use
- Large-scale European data registries, improving evidence and outcomes tracking
Dr. Zavala summarises the direction clearly. “The goal is to move reproductive immunology from an area of clinical uncertainty to one of precision medicine… where we can accurately identify which patients have immune-mediated barriers to pregnancy and offer targeted, evidence-based interventions.”
Want to know if testing is right for you?
If you’ve experienced repeated IVF challenges or unexplained outcomes, exploring immunology testing could open up a hopeful path forward.
At Clínica Tambre, this kind of care is built around a personalised, science-led approach, combining immunology, genetics and clinical expertise to support fertility journeys of all different shapes and sizes – whether you’re looking to switch clinics or restart treatment after a pause.
Book your first consult here to get the ball rolling, and discuss your individual journey to-date.
* A composite, anonymised clinical scenario representative of cases managed at Tambre. No individual patient data is disclosed.
