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PubMed This is a summary of 63 peer-reviewed journal articles Updated
Immunology · PLCG2-Associated Disease

PLCG2-Associated Disease (PLAID and APLAID): A Patient Guide

At a Glance

PLCG2-associated disease, including PLAID and APLAID, can cause both weak infection defenses from low B cells and antibodies and inflammation. The gene variant helps explain whether symptoms are cold-triggered or ongoing, guiding specialist care.

PLCG2-associated diseases, including PLAID and APLAID, are ultra-rare genetic disorders that disrupt the delicate balance of the immune system. These conditions occur when a change in the PLCG2 gene alters the behavior of an enzyme called PLCγ2, which serves as a vital internal messenger for many of your immune cells [1][2]. Because this enzyme is involved in so many different immune pathways, a single genetic variant can cause the body to simultaneously struggle with two seemingly opposite problems: an inability to fight off infections (immune deficiency) and inappropriate innate immune activation that can occur without infection (autoinflammation) [3][4].

The clinical symptoms of this condition exist on a spectrum, and doctors often use the terms PLAID and APLAID to describe where a patient’s symptoms primarily fall. PLAID is classically defined by its unique relationship with temperature; the faulty enzyme is relatively quiet at normal body temperature but becomes hyperactive the moment the skin is cooled, leading to cold-induced hives or swelling [5][2]. In contrast, APLAID is typically driven by variants that keep the enzyme active regardless of the temperature, which often leads to more constant and severe inflammation starting in early infancy, affecting the skin, eyes, joints, and internal organs [6][7][8]. (Loss-of-function variants also exist, presenting differently and focusing on immune deficiency).

Despite these differences, both forms of the disease share a common challenge: the immune system’s “memory” is often impaired. Many patients have low levels of B cells and protective antibodies, which makes them more vulnerable to recurring respiratory and sinus infections [9][8]. This dual nature means that treating the condition is never a one-size-fits-all process. A medication that calms inflammation might further weaken the body’s ability to fight germs, while treatments for infections must be balanced against the risk of triggering an inflammatory flare [10][11].

Because these conditions are so rare—with only a small number of families reported in the medical literature—receiving a diagnosis is often the start of a new journey toward specialized care [10]. You will likely work with a multidisciplinary team of experts, including immunologists, geneticists, and organ-specific specialists, to monitor your health and tailor a management plan to your unique genetic profile. While the diagnosis is complex, understanding the underlying mechanism in the PLCγ2 pathway is a powerful first step toward managing symptoms and improving long-term quality of life [12][3].

In this guide

6 chapters

01

Understanding Your Diagnosis: PLAID and APLAID

Learn what PLAID and APLAID mean, including symptoms, PLCG2 genetic variants, immune effects, antibody deficiency, and questions to ask your care team.

02

Symptoms and Red Flags

Learn the symptoms and red flags of PLAID and APLAID, including cold urticaria, infections, eye and lung problems, anaphylaxis, and when to seek emergency care.

03

Genetics and Diagnosis: Solving the Puzzle

Learn how PLCG2 genetic variants and immune tests diagnose PLAID and APLAID, including VUS results, deletion testing, functional assays, and family testing.

04

Managing the Immune Deficiency

Learn how PLAID and APLAID are managed with immunoglobulin therapy, preventive antibiotics, vaccines, and infection plans tailored to antibody deficiency.

05

Managing Autoinflammation and Systemic Symptoms

Learn how PLAID and APLAID autoinflammation is treated, including steroids, biologics, infection precautions, monitoring, and specialist care for symptoms.

06

Daily Living and Long-Term Monitoring

Learn how to live safely with PLCG2-associated disease, including cold-trigger precautions, epinephrine planning, lung and eye monitoring, and emotional support.

Common questions in this guide

What are PLAID and APLAID?
PLAID and APLAID are related forms on the spectrum of PLCG2-associated disease. PLAID is commonly linked to cold-triggered hives or swelling because the altered enzyme reacts abnormally to temperature changes. APLAID is more often associated with enzyme activity that stays on, causing more persistent inflammation that may begin in early infancy.
Why do people with PLCG2-associated disease get frequent infections?
The condition can reduce B cells and protective antibodies, which are important for remembering and fighting germs. This can increase the risk of recurring respiratory and sinus infections. The degree of immune deficiency can differ according to the genetic change and the person's symptoms.
Can PLCG2-associated disease cause both immune deficiency and inflammation?
Yes. A change in PLCG2 can interfere with the immune system's ability to defend against infections while also activating innate immune responses when no infection is present. This combination of immune deficiency and autoinflammation is a central feature of the condition.
How is treatment chosen for PLAID or APLAID?
Treatment is tailored to the person's genetic profile and symptoms. Medicines that calm inflammation may also make it harder to fight germs, while infection treatments must be balanced against the risk of an inflammatory flare. An immunology team monitors both problems when developing a care plan.
Which specialists should be involved in care?
Because PLCG2-associated disease is very rare, care may involve immunologists, geneticists, and specialists who treat affected organs. These clinicians can coordinate monitoring and treatment and may collaborate with a national center of excellence or an immunology research team.

Get notified when new evidence is published on PLCG2-associated antibody deficiency and immune dysregulation.

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

References

References (12)
  1. 1

    The role of PLCγ2 in immunological disorders, cancer, and neurodegeneration.

    Jackson JT, Mulazzani E, Nutt SL, Masters SL

    The Journal of biological chemistry 2021; (297(2)):100905 doi:10.1016/j.jbc.2021.100905.

    PMID: 34157287
  2. 2

    Cool-temperature-mediated activation of phospholipase C-γ2 in the human hereditary disease PLAID.

    Schade A, Walliser C, Wist M, et al.

    Cellular signalling 2016; (28(9)):1237-1251 doi:10.1016/j.cellsig.2016.05.010.

    PMID: 27196803
  3. 3

    PLCG2-associated immune dysregulation (PLAID) comprises broad and distinct clinical presentations related to functional classes of genetic variants.

    Baysac K, Sun G, Nakano H, et al.

    The Journal of allergy and clinical immunology 2024; (153(1)):230-242 doi:10.1016/j.jaci.2023.08.036.

    PMID: 37769878
  4. 4

    PLAID: a Syndrome of Complex Patterns of Disease and Unique Phenotypes.

    Milner JD

    Journal of clinical immunology 2015; (35(6)):527-30 doi:10.1007/s10875-015-0177-x.

    PMID: 26206677
  5. 5

    Splice site and de novo variants can cause PLCG2-associated immune dysregulation with cold urticaria.

    Chou SR, Bailey AC, Baysac K, et al.

    The Journal of allergy and clinical immunology 2025; (155(3)):1045-1049.e4 doi:10.1016/j.jaci.2024.06.025.

    PMID: 39667583
  6. 6

    Functional characterization of phospholipase C-γ2 mutant protein causing both somatic ibrutinib resistance and a germline monogenic autoinflammatory disorder.

    Walliser C, Wist M, Hermkes E, et al.

    Oncotarget 2018; (9(76)):34357-34378 doi:10.18632/oncotarget.26173.

    PMID: 30344948
  7. 7

    Characterization of a Novel Pathogenic PLCG2 Variant Leading to APLAID Syndrome Responsive to a TNF Inhibitor.

    Yang Z, Tao P, Han X, et al.

    Arthritis & rheumatology (Hoboken, N.J.) 2024; (76(11)):1670-1678 doi:10.1002/art.42948.

    PMID: 38965708
  8. 8

    Novel PLCG2 Mutation in a Patient With APLAID and Cutis Laxa.

    Neves JF, Doffinger R, Barcena-Morales G, et al.

    Frontiers in immunology 2018; (9()):2863 doi:10.3389/fimmu.2018.02863.

    PMID: 30619256
  9. 9

    Severe Autoinflammatory Manifestations and Antibody Deficiency Due to Novel Hypermorphic PLCG2 Mutations.

    Martín-Nalda A, Fortuny C, Rey L, et al.

    Journal of clinical immunology 2020; (40(7)):987-1000 doi:10.1007/s10875-020-00794-7.

    PMID: 32671674
  10. 10

    Overlap of familial Mediterranean fever and APLAID treated with anakinra: a case-based review.

    Akoglu G, Yaz I, Esenboga S, et al.

    Clinical rheumatology 2025; (44(12)):5143-5154 doi:10.1007/s10067-025-07760-x.

    PMID: 41114771
  11. 11

    Case Report: A Rare Case of Autoinflammatory Phospholipase Cγ2 (PLCγ2)-Associated Antibody Deficiency and Immune Dysregulation Complicated With Gangrenous Pyoderma and Literature Review.

    Wu N, Zhang B, Wang T, et al.

    Frontiers in immunology 2021; (12()):667430 doi:10.3389/fimmu.2021.667430.

    PMID: 34093563
  12. 12

    Variant in the PLCG2 Gene May Cause a Phenotypic Overlap of APLAID/PLAID: Case Series and Literature Review.

    Welzel T, Oefelein L, Holzer U, et al.

    Journal of clinical medicine 2022; (11(15)) doi:10.3390/jcm11154369.

    PMID: 35955991

This page is for informational purposes only and does not constitute medical advice about PLCG2-associated disease. Your immunologist and genetics team should interpret your genetic results and guide treatment decisions.