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PubMed This is a summary of 38 peer-reviewed journal articles Updated
Immunology

Combined immunodeficiency due to STK4 deficiency: A Patient Guide

At a Glance

STK4 deficiency is a rare genetic combined immunodeficiency that weakens T-cell and B-cell defenses, causing recurrent infections and sometimes autoimmunity. Care combines infection prevention, antibody infusions, specialist monitoring, and possible stem cell transplantation.

Combined immunodeficiency due to STK4 deficiency (also known as MST1 deficiency) is an extremely rare genetic condition that fundamentally changes how the immune system protects the body. While symptoms typically begin in early childhood, it can occasionally present or be diagnosed in adulthood [1]. At its core, the condition is caused by mutations in the STK4 gene, which normally provides instructions for a protein that helps regulate white blood cells. Without this protein working correctly, the body’s primary defenders—particularly T cells—struggle to stay alive, move to where they are needed, and coordinate a healthy response to pathogens [2]. Because this affects both the cellular (T-cell) immune system and, in varying degrees, the humoral (B-cell) system, it is classified as a combined immunodeficiency [3].

Living with STK4 deficiency often means navigating a wide spectrum of health challenges. Patients frequently experience recurrent bacterial infections, such as pneumonia, alongside persistent viral issues like extensive skin warts [2]. Beyond just struggling to fight off external pathogens, the immune system may also become dysregulated and begin attacking the body’s own healthy tissues—a process called autoimmunity—or cause parts of the immune system, like the lymph nodes and spleen, to become enlarged [4]. This dual challenge of an under-active and over-reactive immune system requires a proactive medical strategy to keep the body in balance [2].

Managing this diagnosis is a long-term process that involves a dedicated team of specialists. While the rarity of the condition can feel isolating, modern medicine offers several layers of protection, from preventative medications and antibody infusions to advanced, potentially curative options like hematopoietic stem cell transplantation [5]. Care focuses on shielding the patient from infections while closely monitoring for signs of more serious complications, such as lymphoma, which has an increased risk in this population [6]. By working with experts in immunology, oncology, and genetics, patients and families can create a tailored plan that prioritizes safety while supporting the patient’s daily life [7].

Note: STK4 deficiency varies widely. This guide does not replace the advice of a treating immunologist.

In this guide

6 chapters

01

Understanding STK4 Deficiency

Learn what STK4 deficiency means, how MST1 loss affects T cells, infection risk, monitoring, emotional health, and treatment options, including possible HSCT.

02

Symptoms and Warning Signs

Learn STK4 deficiency symptoms, including recurrent infections, autoimmunity, lymphoma warning signs, and when fever or breathing problems need urgent medical attention.

03

The Path to Diagnosis: Genes and Lab Tests

Learn how STK4 deficiency is diagnosed through CD4 counts, immune testing, genetic sequencing, protein studies, and evaluation for similar immune disorders.

04

Daily Medical Management and Treatment

Learn how combined immunodeficiency due to STK4 deficiency is managed with immunoglobulin, infection-prevention medicines, vaccine guidance, and autoimmune care

05

Advanced Care: HSCT and Lymphoma Treatment

Learn about HSCT and lymphoma treatment for STK4 deficiency, including transplant risks, conditioning, GVHD prevention, chemotherapy, and specialist care.

06

Long-Term Care and Monitoring

Learn how long-term care for STK4 deficiency uses blood tests, specialist follow-up, lymphoma surveillance, and emotional support for patients and caregivers.

Common questions in this guide

What is STK4 deficiency?
STK4 deficiency, also called MST1 deficiency, is a rare genetic disorder that affects T cells and, to varying degrees, B cells. This can weaken protection against infections and also cause immune system overactivity, such as autoimmunity.
What infections can happen with STK4 deficiency?
People with STK4 deficiency may have repeated bacterial infections, including pneumonia, as well as persistent viral problems such as extensive skin warts. The infection pattern varies, so an immunologist can help create an individualized fever and breathing action plan.
Can STK4 deficiency cause autoimmunity or enlarged organs?
Yes. The immune system may attack healthy tissues, causing autoimmunity, and lymph nodes or the spleen may become enlarged. These problems require monitoring by the patient’s specialist team.
How is STK4 deficiency treated?
Care may include preventive medications, antibody infusions, and close monitoring for infections and immune complications. Hematopoietic stem cell transplantation is an advanced option that may be potentially curative for some patients, but suitability must be assessed individually.
Does STK4 deficiency increase the risk of lymphoma?
Yes. People with STK4 deficiency have an increased risk of lymphoma compared with the general population. Their medical team can determine appropriate monitoring and evaluate new or concerning changes.
Which specialists help manage STK4 deficiency?
Care commonly involves immunology, oncology, and medical genetics specialists, with additional experts involved when needed. The team works together to prevent infections, monitor immune dysregulation, and discuss treatment options.

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References

References (7)
  1. 1

    Epidermodysplasia Verruciformis and Vδ2 γδ T-cell Expansion in STK4 Deficiency.

    Ying W, Long X, Vandergriff T, et al.

    Journal of clinical immunology 2024; (44(8)):172 doi:10.1007/s10875-024-01780-z.

    PMID: 39110273
  2. 2

    Diversity in Serine/Threonine Protein Kinase-4 Deficiency and Review of the Literature.

    Cagdas D, Halacli SO, Tan C, et al.

    The journal of allergy and clinical immunology. In practice 2021; (9(10)):3752-3766.e4 doi:10.1016/j.jaip.2021.05.032.

    PMID: 34146746
  3. 3

    A Novel STK4 Mutation Impairs T Cell Immunity Through Dysregulation of Cytokine-Induced Adhesion and Chemotaxis Genes.

    Guennoun A, Bougarn S, Khan T, et al.

    Journal of clinical immunology 2021; (41(8)):1839-1852 doi:10.1007/s10875-021-01115-2.

    PMID: 34427831
  4. 4

    EBV Negative Lymphoma and Autoimmune Lymphoproliferative Syndrome Like Phenotype Extend the Clinical Spectrum of Primary Immunodeficiency Caused by STK4 Deficiency.

    Schipp C, Schlütermann D, Hönscheid A, et al.

    Frontiers in immunology 2018; (9()):2400 doi:10.3389/fimmu.2018.02400.

    PMID: 30386345
  5. 5

    Hematopoietic stem cell transplantation in serine/threonine kinase 4 (STK4) deficiency: Report of two cases and literature review.

    Uygun V, Keleş S, Daloğlu H, et al.

    Pediatric transplantation 2023; (27(2)):e14439 doi:10.1111/petr.14439.

    PMID: 36394186
  6. 6

    STK4 deficiency and EBV-associated lymphoproliferative disorders, emphasis on histomorphology, and review of literature.

    Saglam A, Cagdas D, Aydin B, et al.

    Virchows Archiv : an international journal of pathology 2022; (480(2)):393-401 doi:10.1007/s00428-021-03147-w.

    PMID: 34604912
  7. 7

    A unique STK4 mutation truncating only the C-terminal SARAH domain results in a mild clinical phenotype despite severe T cell lymphopenia: Case report.

    Al-Saud B, Alajlan H, Alruwaili H, et al.

    Frontiers in immunology 2024; (15()):1329610 doi:10.3389/fimmu.2024.1329610.

    PMID: 38361950

This page is for informational purposes only and does not replace medical advice. A treating immunologist and the patient’s specialist team should interpret the diagnosis and develop an individualized care plan.