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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 Immunoglobulin M (IgM) levels and a considerable deficiency in Immunoglobulins G (IgG), A (IgA) and E (IgE). As a consequence, people with HIGM have decreased concentrations of serum IgG and IgA and normal or elevated IgM, leading to increased susceptibility to infections.[8][7][9]

Hyper IgM syndrome
IgM scheme.svg
Immunoglobulin M
Specialty Immunology Edit this on Wikidata
Types Hyper-IgM syndrome type 1,2,3,4 and 5[1][2][3][4][5]
Diagnostic method MRI, Chest radiography[6]
Treatment Allogeneic hematopoietic cell transplantation[7]

Contents

Signs/symptomsEdit

Among the presentation consistent with hyper IgM syndrome are the following:[6][10]

 
Pneumocystis pneumonia

CauseEdit

 
Class switch recombination

Different genetic defects cause HIgM syndrome, the vast majority are inherited as an X-linked recessive genetic trait and most sufferers are male.[7]

IgM is the form of antibody that all B cells produce initially, before they undergo class switching due to exposure to a recognized antigen. 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 they can't switch to a different antibody. This results in an overproduction of IgM antibodies and an underproduction of IgA, IgG, and IgE.[11][7]

PathophysiologyEdit

CD40 is a co-stimulatory receptor on B cells that, when bound to CD40 ligand (CD40L), sends a signal to the B-cell receptor.[12] When there is a defect in CD40, this leads to defective T-cell interaction with B cells. Consequently, humoral immune response is affected. Certain insults, usually from encapsulated bacteria and toxin, then have a greater opportunity to damage the body.[6]

DiagnosisEdit

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

TypesEdit

Five types of hyper IgM syndrome have been characterized:

TreatmentEdit

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]

See alsoEdit

ReferencesEdit

  1. ^ a b "OMIM Entry - # 308230 - IMMUNODEFICIENCY WITH HYPER-IgM, TYPE 1; HIGM1". www.omim.org. Retrieved 16 November 2016. 
  2. ^ a b "OMIM Entry - # 605258 - IMMUNODEFICIENCY WITH HYPER-IgM, TYPE 2; HIGM2". omim.org. Retrieved 16 November 2016. 
  3. ^ a b "OMIM Entry - # 606843 - IMMUNODEFICIENCY WITH HYPER-IgM, TYPE 3; HIGM3". www.omim.org. Retrieved 16 November 2016. 
  4. ^ a b "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". www.omim.org. Retrieved 2 January 2018. 
  6. ^ a b c d "X-linked Immunodeficiency With Hyper IgM Clinical Presentation: History, Physical, Causes". emedicine.medscape.com. Retrieved 27 November 2016. 
  7. ^ a b c d e Johnson, Judith; Filipovich, Alexandra H.; Zhang, Kejian (1 January 1993). "X-Linked Hyper IgM Syndrome". GeneReviews(®). University of Washington, Seattle. Retrieved 12 November 2016. update 2013
  8. ^ a b 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. 
  9. ^ "Hyper-Immunoglobulin M (Hyper-IgM) Syndromes | NIH: National Institute of Allergy and Infectious Diseases". www.niaid.nih.gov. Retrieved 27 November 2016. 
  10. ^ 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. 
  11. ^ Reference, Genetics Home. "X-linked hyper IgM syndrome". Genetics Home Reference. Retrieved 27 November 2016. 
  12. ^ Reference, Genetics Home. "CD40 gene". Genetics Home Reference. Retrieved 27 November 2016. 
  13. ^ 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. subscription needed

Further readingEdit

External linksEdit

Classification
External resources