Skip to content
How It Works
Explore
Ask a Question Resources Pricing
Who It's For
Patients
Decode results, prep for appointments, weigh options.
Caregivers & advocates
Carry the research load for someone you love.
Providers & clinicians
Resources for patients in your practice.
Log In Sign Up
PubMed This is a summary of 7 peer-reviewed journal articles Updated
Pediatric Immunology · TYK2 Deficiency

Considering a Transplant (HSCT)

At a Glance

For children with severe TYK2 deficiency, a bone marrow transplant may be discussed when infections are life-threatening or uncontrolled despite standard treatment. It is not routine and can cause graft-versus-host disease, treatment-related organ damage, infertility, transplant failure, or death.

For children with the most severe forms of TYK2 deficiency, doctors may discuss a Hematopoietic Stem Cell Transplant (HSCT), commonly known as a bone marrow transplant [1][2].

HSCT is not a routine or standard treatment for every child with this condition. Because the procedure carries severe, life-threatening risks and evidence in TYK2 deficiency is limited to rare case reports, it is typically reserved for those with profound, recurrent infections that cannot be controlled with standard medications, or for children who develop severe complications like lymphoma (a type of blood cancer) [1][3].

How HSCT Works to Rebuild the Immune System

The goal of HSCT is to replace the child’s defective immune system with a healthy one from a donor [2].

  • The Problem: In TYK2 deficiency, the immune cells—which are born in the bone marrow—are missing the TYK2 “switchboard” protein [4].
  • The Solution: During a transplant, the patient’s own immune cells are cleared away (usually with intense chemotherapy), and healthy stem cells from a donor are infused [2].
  • The Result: If the transplant is successful, these new donor cells grow and create a functional, donor-derived immune system. However, it is important to note that HSCT is not guaranteed to normalize all immune biology, reverse existing organ damage, or eliminate every infection risk forever [2].

Successes and Outcomes

Because TYK2 deficiency is so exceptionally rare, there are very few documented cases of patients undergoing HSCT [2]. In one notable published case report, a young boy with a history of severe infections received a transplant from an unrelated donor [2].

  • Rebuilding the System: Following the transplant, his immune system began to function more normally, and his laboratory tests showed that his cells were responding correctly to immune signals [2].
  • Fewer Infections: Over a four-year follow-up period, the child experienced significantly fewer severe infections than he had before the procedure [2].

Understanding the Risks

HSCT is a major medical undertaking with several serious potential complications. It is vital to weigh these against the risks of the disease itself.

  • Transplant-Related Mortality and Graft Failure: The procedure itself carries a risk of death due to severe infection while the immune system is wiped out, or if the new donor cells fail to grow and engraft.
  • Graft-Versus-Host Disease (GVHD): One of the most significant risks is GVHD [2]. This occurs when the new donor immune cells (the “graft”) recognize the patient’s body (the “host”) as foreign and begin to attack it [2]. In the documented case report of the TYK2-deficient boy, he did not experience sudden (acute) GVHD, but he did develop chronic GVHD [2]. This affected multiple organs and required ongoing medical management by specialists [2].
  • Conditioning Toxicity: The “conditioning” phase (the chemotherapy used to prepare the body for the new cells) can have long-term effects on organ function and carries a high risk of causing permanent infertility [2].
  • Autoimmune Issues: Some patients may develop autoimmune conditions after a transplant, such as autoimmune thyroiditis, where the new immune system attacks the thyroid gland [2].

Making the Decision

Deciding whether to proceed with HSCT involves a deep partnership between your family and a specialized transplant center experienced in Inborn Errors of Immunity.

  • Mild vs. Severe: For many patients, especially those with “partial” deficiencies who respond well to antibiotics, the risks of HSCT may be considered far too high [5][3].
  • High-Risk Scenarios: If a child has recurrent, life-threatening pneumonia, brain infections, or certain viral-driven cancers, the experimental option of HSCT may be discussed by expert specialists as a potential path forward, though it is not a universally established protocol [1][6].

Your child’s specific genetic “blueprint” and their clinical history will be the most important factors in determining if HSCT is the right choice [7][2].

Common questions in this guide

When is a bone marrow transplant considered for a child with TYK2 deficiency?
HSCT may be discussed for a child with profound, recurrent, life-threatening infections that cannot be controlled with standard medicines, or with severe complications such as lymphoma. It is not routine for every child with TYK2 deficiency. The decision depends on the child’s TYK2 variants, infection history, response to treatment, and overall health.
Can HSCT fully correct TYK2 deficiency?
A successful transplant can replace the child’s immune cells with donor-derived cells that function more normally. However, HSCT may not normalize every immune function, reverse damage already caused to organs, or remove all future infection risk.
What are the most serious risks of HSCT for TYK2 deficiency?
Risks include life-threatening infection while the immune system is weakened, failure of donor cells to grow, and death related to transplant. Graft-versus-host disease can occur when donor immune cells attack the child’s tissues. Conditioning chemotherapy can damage organs and cause permanent infertility, and autoimmune problems may develop afterward.
What is graft-versus-host disease after a transplant?
Graft-versus-host disease occurs when donor immune cells see the child’s tissues as foreign and attack them. It can be acute or chronic, affect several organs, and require long-term treatment and monitoring.
How successful is HSCT in TYK2 deficiency?
TYK2 deficiency is rare, so evidence comes from very few case reports and cannot provide reliable success rates. In one published case, a child had more normal immune test results and fewer severe infections over four years, but that experience does not predict what will happen for every child.
How do doctors decide whether HSCT is worth the risk?
The transplant team weighs the severity and frequency of infections, response to medicines, the child’s TYK2 variants, complications such as organ damage or lymphoma, and the risks of transplant. The family’s goals and the center’s experience with similar immune deficiencies are also important.
What should families ask before considering HSCT?
Families can ask about center-specific survival and complication rates, donor options, graft-versus-host disease monitoring, fertility effects, and alternatives to transplant. They should also discuss how their child’s infection history and genetic findings change the balance of benefits and risks.

Get notified when new evidence is published on Susceptibility to infection due to TYK2 deficiency.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.

References

References (7)
  1. 1

    A Novel Homozygous Mutation Causing Complete TYK2 Deficiency, with Severe Respiratory Viral Infections, EBV-Driven Lymphoma, and Jamestown Canyon Viral Encephalitis.

    Roussel L, Pham-Huy A, Yu AC, et al.

    Journal of clinical immunology 2023; (43(8)):2011-2021 doi:10.1007/s10875-023-01580-x.

    PMID: 37695435
  2. 2

    Successful Immune Reconstitution in a Patient with a TYK2 Deficiency after Allogeneic Stem Cell Transplantation from Unrelated Donors.

    Gao Y, Wang Y, Zhou L, et al.

    Journal of clinical immunology 2024; (44(7)):152 doi:10.1007/s10875-024-01753-2.

    PMID: 38896258
  3. 3

    The Child with Recurrent Mycobacterial Disease.

    Reed B, Dolen WK

    Current allergy and asthma reports 2018; (18(8)):44 doi:10.1007/s11882-018-0797-3.

    PMID: 29936646
  4. 4

    Human TYK2 deficiency: Mycobacterial and viral infections without hyper-IgE syndrome.

    Kreins AY, Ciancanelli MJ, Okada S, et al.

    The Journal of experimental medicine 2015; (212(10)):1641-62 doi:10.1084/jem.20140280.

    PMID: 26304966
  5. 5

    Mycobacterium Intracellulare Infection Associated with TYK2 Deficiency: A Case Report and Review of the Literature.

    Guo W, Feng X, Yang M, et al.

    Infection and drug resistance 2020; (13()):4347-4353 doi:10.2147/IDR.S279438.

    PMID: 33293838
  6. 6

    Disseminated tuberculosis associated with deficient interleukin-23/tyrosine kinase 2 signalling.

    Ojuawo O, Allen R, Hagan G, Piracha S

    BMJ case reports 2022; (15(8)) doi:10.1136/bcr-2022-250479.

    PMID: 35999022
  7. 7

    Impaired IL-23-dependent induction of IFN-γ underlies mycobacterial disease in patients with inherited TYK2 deficiency.

    Ogishi M, Arias AA, Yang R, et al.

    The Journal of experimental medicine 2022; (219(10)) doi:10.1084/jem.20220094.

    PMID: 36094518

This page is for informational purposes only and does not constitute medical advice. Decisions about HSCT for TYK2 deficiency should be made with your child’s immunology and transplant team.

Guide contents Susceptibility to infection due to TYK2 deficiency
Research & Literature
04 Treatment, Prevention, and Managing Risk 06 Building Your Care Team and Long-Term Monitoring