PoM No 1, 2013

Publication of the Month

 

January 01/13: IgA deficiency in celiac disease

 

Key messages:

  • About 2% of the adult and paediatric CD patients are IgA deficient.

  • Measuring IgG serologies for routine CD diagnosis seems to be more helpful and cost effective than  the determination of total serum IgA

      

Chow MA, Lebwohl B, Reilly NR, Green PH
Immunoglobulin A deficiency in celiac disease
J. Clin. Gastroenterol. 2012; 46: 850-85

 

Background:
Selective IgA deficiency is the most common primary immunoglobulin deficiency and shows a higher prevalence in patients with celiac disease (CD) compared to the general population. This study aims to determine prevalence of selective and partial IgA deficiency in adult and paediatric CD patients and the association of IgA deficiency with autoimmune diseases.

Summary:
Both selective lgA deficiency and partial IgA deficiency show a prevalence of 2% in CD patients, equally for adults and children. The low prevalence in CD questions the need for routine measurement of total serum IgA when assessing a patient for the diagnosis of CD.
Four IgA-deficient patients were persistently positive for IgG celiac serologies (tissue transglutaminase IgG and antigliadin IgG) although adherent to a gluten-free diet (GFD) they showed normal repeat biopsy.
Adult IgA-deficient CD patients are more likely to have concomitant autoimmune diseases (29%) than CD patients with normal IgA levels (12%). There was no significant difference between selective and partial IgA deficient patients. None of the IgA deficient children showed any other known autoimmune disease.

Conclusions:
Instead of routine measurement of total serum IgA, it may be more cost effective to test only for total serum IgA levels in patients positive for IgG antibodies and negative for IgA antibodies in the initial screening panels.
Because IgA deficient patients may show persistently elevated IgG serologies the monitoring of disease course and/or success of a GFD is not reliable in these patients. Follow-up biopsy may still be necessary.

Comment:
This study confirms that IgA deficiency shows a prevalence of 2% in adults and children with celiac disease. The study also underlines that due to the low prevalence of IgA deficiency the determination of celiac specific IgG antibodies (anti-gliadin and anti-tissue transglutaminase) is more reasonable in routine CD diagnosis than determination of total serum IgA.

 

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As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.