Hyper-IgM syndrome type 2

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Hyper IgM syndrome type 2
IgM scheme.svg
Immunoglobulin M
TypesHyper-IgM syndrome type 1,2,3,4 and 5 [1] [2] [3] [4] [5]
Diagnostic method MRI, Chest radiography and genetic testing [6]
TreatmentAllogeneic hematopoietic cell transplantation [7]

Hyper IgM syndrome type 2 is a rare disease. Unlike other hyper-IgM syndromes, type 2 patients identified thus far did not present with a history of opportunistic infections. One would expect opportunistic infections in any immunodeficiency syndrome. The responsible genetic lesion is in the AICDA gene found at 12p13. [8]

Contents

Hyper IgM syndromes

Hyper IgM syndromes is a group of primary immune deficiency disorders characterized by defective CD40 signaling; via B cells affecting class switch recombination (CSR) and somatic hypermutation. Immunoglobulin (Ig) class switch recombination deficiencies are characterized by elevated serum IgM levels and a considerable deficiency in Immunoglobulins G (IgG), A (IgA) and E (IgE). As a consequence, people with HIGM have an increased susceptibility to infections. [9] [7] [10]

Signs and symptoms

Hyper IgM syndrome can have the following syndromes: [6] [11]

Cause

Class switch recombination Class switch recombination.png
Class switch recombination

Different genetic defects cause HIgM syndrome, the vast majority are inherited as an X-linked recessive genetic trait and most with the condition are male. [7] [1] [2] [3] [12] [4]

IgM is the form of antibody that all B cells produce initially before they undergo class switching. Healthy B cells efficiently switch to other types of antibodies as needed to attack invading bacteria, viruses, and other pathogens. In people with hyper IgM syndromes, the B cells keep making IgM antibodies because can not switch to a different antibody. This results in an overproduction of IgM antibodies and an underproduction of IgA, IgG, and IgE. [13] [7]

Pathophysiology

CD40 is a costimulatory receptor on B cells that, when bound to CD40 ligand (CD40L), sends a signal to the B-cell receptor. [14] When there is a defect in CD40, this leads to defective T-cell interaction with B cells. Consequently, humoral immune response is affected. Patients are more susceptible to infection. [6]

Diagnosis

The diagnosis of hyper IgM syndrome can be done via the following methods and tests: [6]

Treatment

In terms of treatment for hyper IgM syndrome, there is the use of allogeneic hematopoietic cell transplantation. Additionally, anti-microbial therapy, use of granulocyte colony-stimulating factor, immunosuppressants, as well as other treatments, may be needed. [7]

Related Research Articles

Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that affect the patient's immune system. Examples of these extrinsic factors include HIV infection and environmental factors, such as nutrition. Immunocompromisation may also be due to genetic diseases/flaws such as SCID.

<span class="mw-page-title-main">X-linked agammaglobulinemia</span> Medical condition

X-linked agammaglobulinemia (XLA) is a rare genetic disorder discovered in 1952 that affects the body's ability to fight infection. As the form of agammaglobulinemia that is X-linked, it is much more common in males. In people with XLA, the white blood cell formation process does not generate mature B cells, which manifests as a complete or near-complete lack of proteins called gamma globulins, including antibodies, in their bloodstream. B cells are part of the immune system and normally manufacture antibodies, which defend the body from infections by sustaining a humoral immunity response. Patients with untreated XLA are prone to develop serious and even fatal infections. A mutation occurs at the Bruton's tyrosine kinase (Btk) gene that leads to a severe block in B cell development and a reduced immunoglobulin production in the serum. Btk is particularly responsible for mediating B cell development and maturation through a signaling effect on the B cell receptor BCR. Patients typically present in early childhood with recurrent infections, in particular with extracellular, encapsulated bacteria. XLA is deemed to have a relatively low incidence of disease, with an occurrence rate of approximately 1 in 200,000 live births and a frequency of about 1 in 100,000 male newborns. It has no ethnic predisposition. XLA is treated by infusion of human antibody. Treatment with pooled gamma globulin cannot restore a functional population of B cells, but it is sufficient to reduce the severity and number of infections due to the passive immunity granted by the exogenous antibodies.

Hypogammaglobulinemia is an immune system disorder in which not enough gamma globulins are produced in the blood. This results in a lower antibody count, which impairs the immune system, increasing risk of infection. Hypogammaglobulinemia may result from a variety of primary genetic immune system defects, such as common variable immunodeficiency, or it may be caused by secondary effects such as medication, blood cancer, or poor nutrition, or loss of gamma globulins in urine, as in nonselective glomerular proteinuria. Patients with hypogammaglobulinemia have reduced immune function; important considerations include avoiding use of live vaccines, and take precautionary measures when traveling to regions with endemic disease or poor sanitation such as receiving immunizations, taking antibiotics abroad, drinking only safe or boiled water, arranging appropriate medical cover in advance of travel, and ensuring continuation of any immunoglobulin infusions needed.

Common variable immunodeficiency (CVID) is an immune disorder characterized by recurrent infections and low antibody levels, specifically in immunoglobulin (Ig) types IgG, IgM, and IgA. Symptoms generally include high susceptibility to foreign invaders, chronic lung disease, and inflammation and infection of the gastrointestinal tract. CVID affects males and females equally. The condition can be found in children or teens but is generally not diagnosed or recognized until adulthood. The average age of diagnosis is between 20 and 50. However, symptoms vary greatly between people. "Variable" refers to the heterogeneous clinical manifestations of this disorder, which include recurrent bacterial infections, increased risk for autoimmune disease and lymphoma, as well as gastrointestinal disease. CVID is a lifelong disease.

<span class="mw-page-title-main">CD40 (protein)</span> Mammalian protein found in Homo sapiens

Cluster of differentiation 40, CD40 is a type I transmembrane protein found on antigen-presenting cells and is required for their activation. The binding of CD154 (CD40L) on TH cells to CD40 activates antigen presenting cells and induces a variety of downstream effects.

Hypergammaglobulinemia is a medical condition with elevated levels of gamma globulin. It is a type of immunoproliferative disorder.

Hyperimmunoglobulinemia E syndrome (HIES), of which the autosomal dominant form is called Job's syndrome or Buckley syndrome, is a heterogeneous group of immune disorders. Job's is also very rare at about 300 cases currently in the literature.

<span class="mw-page-title-main">CD154</span> Protein-coding gene in humans

CD154, also called CD40 ligand or CD40L, is a protein that is primarily expressed on activated T cells and is a member of the TNF superfamily of molecules. It binds to CD40 on antigen-presenting cells (APC), which leads to many effects depending on the target cell type. In total CD40L has three binding partners: CD40, α5β1 integrin and integrin αIIbβ3. CD154 acts as a costimulatory molecule and is particularly important on a subset of T cells called T follicular helper cells. On TFH cells, CD154 promotes B cell maturation and function by engaging CD40 on the B cell surface and therefore facilitating cell-cell communication. A defect in this gene results in an inability to undergo immunoglobulin class switching and is associated with hyper IgM syndrome. Absence of CD154 also stops the formation of germinal centers and therefore prohibiting antibody affinity maturation, an important process in the adaptive immune system.

<span class="mw-page-title-main">Hyper IgM syndrome</span> Primary immune deficiency disorders

Hyper IgM syndrome is a rare primary immune deficiency disorders characterized by low or absent levels of serum IgG, IgA, IgE and normal or increased levels of serum IgM.

<span class="mw-page-title-main">Hyper-IgM syndrome type 1</span> Medical condition

Hyper IgM syndrome type 1 (HIGM-1) is the X-linked variant of the hyper IgM syndrome.

<span class="mw-page-title-main">Hyper-IgM syndrome type 5</span> Primary immune deficiency disorder

The fifth type of hyper-IgM syndrome has been characterized in three patients from France and Japan. The symptoms are similar to hyper IgM syndrome type 2, but the AICDA gene is intact.

Primary immunodeficiencies are disorders in which part of the body's immune system is missing or does not function normally. To be considered a primary immunodeficiency (PID), the immune deficiency must be inborn, not caused by secondary factors such as other disease, drug treatment, or environmental exposure to toxins. Most primary immunodeficiencies are genetic disorders; the majority are diagnosed in children under the age of one, although milder forms may not be recognized until adulthood. While there are over 430 recognized inborn errors of immunity (IEIs) as of 2019, the vast majority of which are PIDs, most are very rare. About 1 in 500 people in the United States are born with a primary immunodeficiency. Immune deficiencies can result in persistent or recurring infections, auto-inflammatory disorders, tumors, and disorders of various organs. There are currently limited treatments available for these conditions; most are specific to a particular type of PID. Research is currently evaluating the use of stem cell transplants (HSCT) and experimental gene therapies as avenues for treatment in limited subsets of PIDs.

An immune disorder is a dysfunction of the immune system. These disorders can be characterized in several different ways:

<span class="mw-page-title-main">IgG deficiency</span> Form of immune disorder

IgG deficiency is a form of dysgammaglobulinemia where the proportional levels of the IgG isotype are reduced relative to other immunoglobulin isotypes.

<span class="mw-page-title-main">Humoral immune deficiency</span> Medical condition

Humoral immune deficiencies are conditions which cause impairment of humoral immunity, which can lead to immunodeficiency. It can be mediated by insufficient number or function of B cells, the plasma cells they differentiate into, or the antibody secreted by the plasma cells. The most common such immunodeficiency is inherited selective IgA deficiency, occurring between 1 in 100 and 1 in 1000 persons, depending on population. They are associated with increased vulnerability to infection, but can be difficult to detect in the absence of infection.

<span class="mw-page-title-main">Hyper-IgM syndrome type 3</span> Primary immune deficiency disorder

Hyper-IgM syndrome type 3 is a form of hyper IgM syndrome characterized by mutations of the CD40 gene. In this type, Immature B cells cannot receive signal 2 from helper T cells which is necessary to mature into mature B cells.

<span class="mw-page-title-main">Hyper-IgM syndrome type 4</span> Medical condition

Hyper-IgM syndrome type 4 is a form of Hyper IgM syndrome which is a defect in class switch recombination downstream of the AICDA gene that does not impair somatic hypermutation.

<span class="mw-page-title-main">DOCK8 deficiency</span> Medical condition

DOCK8 deficiency, also called DOCK8 immunodeficiency syndrome, is the autosomal recessive form of hyperimmunoglobulin E syndrome, a genetic disorder characterized by elevated immunoglobulin E levels, eosinophilia, and recurrent infections with staphylococcus and viruses. It is caused by a mutation in the DOCK8 gene.

Nuclear factor-kappa B Essential Modulator (NEMO) deficiency syndrome is a rare type of primary immunodeficiency disease that has a highly variable set of symptoms and prognoses. It mainly affects the skin and immune system but has the potential to affect all parts of the body, including the lungs, urinary tract and gastrointestinal tract. It is a monogenetic disease caused by mutation in the IKBKG gene. NEMO is the modulator protein in the IKK inhibitor complex that, when activated, phosphorylates the inhibitor of the NF-κB transcription factors allowing for the translocation of transcription factors into the nucleus.

References

  1. 1 2 "OMIM Entry – # 308230 – Immunodeficiency With Hyper-IgM, TYPE 1; HIGM1". omim.org. Retrieved 16 November 2016.
  2. 1 2 "OMIM Entry – # 605258 – Immunodeficiency With Hyper-IgM, TYPE 2; HIGM2". omim.org. Retrieved 16 November 2016.
  3. 1 2 "OMIM Entry – # 606843 – Immunodeficiency With Hyper-IgM, TYPE 3; HIGM3". omim.org. Retrieved 16 November 2016.
  4. 1 2 "OMIM Entry – # 608106 – Immunodeficiency With Hyper-IgM, TYPE 5; HIGM5". omim.org. Retrieved 16 November 2016.
  5. "OMIM Entry – 608184 – Immunodeficiency With Hyper-IgM, Type 4; HIGM4". omim.org. Retrieved 2 January 2018.
  6. 1 2 3 4 "X-linked Immunodeficiency With Hyper IgM Clinical Presentation: History, Physical, Causes". emedicine.medscape.com. Retrieved 27 November 2016.
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  8. Revy P, Muto T, Levy Y, et al. (September 2000). "Activation-induced cytidine deaminase (AID) deficiency causes the autosomal recessive form of the Hyper-IgM syndrome (HIGM2)". Cell. 102 (5): 565–75. doi:10.1016/S0092-8674(00)00079-9. hdl: 11655/14257 . PMID   11007475. S2CID   13092588.
  9. 1 2 Etzioni, Amos; Ochs, Hans D. (1 October 2004). "The Hyper IgM Syndrome—An Evolving Story". Pediatric Research. 56 (4): 519–525. doi: 10.1203/01.PDR.0000139318.65842.4A . ISSN   0031-3998. PMID   15319456.
  10. "Hyper-Immunoglobulin M (Hyper-IgM) Syndromes | NIH: National Institute of Allergy and Infectious Diseases". niaid.nih.gov. Retrieved 27 November 2016.
  11. Davies, E Graham; Thrasher, Adrian J (27 November 2016). "Update on the hyper immunoglobulin M syndromes". British Journal of Haematology. 149 (2): 167–180. doi:10.1111/j.1365-2141.2010.08077.x. ISSN   0007-1048. PMC   2855828 . PMID   20180797.
  12. Lougaris V, Badolato R, Ferrari S, Plebani A (2005). "Hyper immunoglobulin M syndrome due to CD40 deficiency: clinical, molecular, and immunological features". Immunol. Rev. 203: 48–66. doi: 10.1111/j.0105-2896.2005.00229.x . PMID   15661021. S2CID   6678540.subscription needed
  13. Reference, Genetics Home. "X-linked hyper IgM syndrome". Genetics Home Reference. Retrieved 27 November 2016.
  14. Reference, Genetics Home. "CD40 gene". Genetics Home Reference. Retrieved 27 November 2016.