Английская Википедия:Hyper-IgM syndrome type 3
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Hyper-IgM syndrome type 3 is a form of hyper IgM syndrome characterized by mutations of the CD40 gene.[1] In this type, Immature B cells cannot receive signal 2 from helper T cells which is necessary to mature into mature B cells.
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.[2][3][4]
Signs and symptoms
Hyper IgM syndrome can have the following syndromes:[5][6]
- Infection/Pneumocystis pneumonia (PCP), which is common in infants with hyper IgM syndrome, is a serious illness.[2] PCP is one of the most frequent and severe opportunistic infections in people with weakened immune systems.
- Hepatitis (Hepatitis C)
- Chronic diarrhea
- Hypothyroidism
- Neutropenia
- Arthritis
- Encephalopathy (degenerative)
Cause
Different genetic defects cause HIgM syndrome, the vast majority are inherited as an X-linked recessive genetic trait and most sufferers are male.[3][7][8][9][10][11]
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.[12][3]
Pathophysiology
CD40 is a costimulatory receptor on B cells that, when bound to CD40 ligand (CD40L), sends a signal to the B-cell receptor.[13] 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.[5]
Diagnosis
The diagnosis of hyper IgM syndrome can be done via the following methods and tests:[5]
- MRI
- Chest radiography
- Pulmonary function test
- Lymph node test
- Laboratory test (to measure CD40)
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.[3]
References
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- ↑ Шаблон:Cite web
- ↑ 2,0 2,1 Шаблон:Cite journal
- ↑ 3,0 3,1 3,2 3,3 Шаблон:Cite journalupdate 2013
- ↑ Шаблон:Cite web
- ↑ 5,0 5,1 5,2 Шаблон:Cite web
- ↑ Шаблон:Cite journal
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite journalsubscription needed
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite web