Selective immunoglobulin A deficiency
Selective immunoglobulin A deficiency | |
---|---|
The dimeric IgA molecule. 1 H-chain, 2 L-chain, 3 J-chain, 4 secretory component | |
Specialty | Immunology |
Selective immunoglobulin A (IgA) deficiency (SIgAD
Signs and symptoms
85–90% of IgA-deficient individuals are asymptomatic, although the reason for lack of symptoms is relatively unknown and continues to be a topic of interest and controversy.
IgA deficiency and common variable immunodeficiency (CVID) feature similar B cell differentiation arrests,[4] but it does not present the same lymphocyte subpopulation abnormalities.[5] IgA-deficient patients may progress to panhypogammaglobulinemia characteristic of CVID.[4] Selective IgA and CVID are found in the same family.[4]
Cause
Selective IgA deficiency is inherited in less than half of cases,[6] but has been associated with differences in chromosomes 18, 14 and 6. Selective IgA deficiency is often inherited, but fewer than half of all cases but has been associated with some congenital intrauterine infections.[4]
Pathophysiology
Pathogenesis of IgA Deficiency
‘In IgA-deficient patients, the common finding is a maturation defect in B cells to produce IgA’. ‘In IgA deficiency, B cells express IgA; however, they are of immature phenotype with the coexpression of IgM and IgD, and they cannot fully develop into IgA-secreting plasma cells’. [7]
There is an inherited inability to produce
Types include:
Type | OMIM
|
Gene | Locus |
---|---|---|---|
IGAD1 | 137100 | Unknown; MSH5 suggested[8][9] | 6p21 |
IGAD2 | 609529 | TNFRSF13B
|
17p11 |
Diagnosis
When suspected, the diagnosis can be confirmed by laboratory measurement of IgA level in the blood. SIgAD is an IgA level < 7 mg/dL with normal IgG and IgM levels (reference range 70–400 mg/dL for adults; children somewhat less).[10]
Treatment
The treatment consists of identification of co-morbid conditions, preventive measures to reduce the risk of infection, and prompt and effective treatment of infections. Infections in an IgA-deficient person are treated as usual (i.e., with antibiotics). There is no treatment for the underlying disorder.[11] All SIgAD patients, even if asymptomatic, should receive pneumococcal and influenza vaccines, but should avoid live attenuated vaccines.[12]
Use of IVIG as treatment
There is a historical popularity in using
Prognosis
Prognosis is excellent, although there is an association with
As opposed to the related condition CVID, selective IgA deficiency is not associated with an increased risk of cancer.[19]
Patients with Selective IgA deficiency rarely have severe reactions to blood transfusions.[20] Although Selective IgA deficiency is common,[21][22][23] severe reactions to blood transfusions are very rare.[20][22][24] People with selective IgA deficiency do not require special blood products unless they have a history of a severe allergic reaction to a blood transfusion.[25][26][27]
Epidemiology
Prevalence varies by population, but is on the order of 1 in 100 to 1 in 1000 people,[21] making it relatively common. SIgAD occurs in 1 in 39 to 1 in 57 people with celiac disease. This is much higher than the prevalence of selective IgA deficiency in the general population.[28] It is also significantly more common in those with type 1 diabetes.[citation needed]
It is more common in males than in females.[29]
See also
- B cell deficiency
References
- PMID 10792368.
- ^ a b Yel, L. (2010) 'Selective IgA Deficiency', Journal of Clinical Immunology, 30(1), pp. 10-16.
- S2CID 28529140.
- ^ a b c d Harrison's Principles of Internal Medicine, 17th edition, pag. 2058
- PMID 17223965.
- PMID 2193490.
- PMID 20101521.
- PMID 17409188.
- ^ Online Mendelian Inheritance in Man (OMIM): 137100
- PMID 32743511.
- PMID 37641141.
- PMID 32743511.
- ^ a b American Academy of Allergy, Asthma, and Immunology. "Five Things Physicians and Patients Should Question" (PDF). Choosing Wisely: An Initiative of the ABIM Foundation. American Academy of Allergy, Asthma, and Immunology. Retrieved August 14, 2012.
- ^ PMID 15945566. Archived from the original(PDF) on 11 November 2011. Retrieved 27 August 2012.
- ^ PMID 28041678.
- PMID 10792368.
- ISBN 978-0323044042.
- PMID 12093680.
- PMID 12452841.
- ^ PMID 15679454.
- ^ a b "IgA Deficiency: Immunodeficiency Disorders: Merck Manual Professional". Retrieved 2008-03-01.
- ^ PMID 28414063.
- PMID 27763681.
- ^ "SHOT Report, Summary and Supplement 2017". Serious Hazards of Transfusion. Retrieved 2019-04-26.
- )
- S2CID 9150295.
- ^ "IgA deficient components". transfusion.com.au. Retrieved 2019-04-26.
- PMID 18487281.
- S2CID 25545688.