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Wendy asks:
“I recall being told that my 8 year old son was IgA deficient. That was after having some tests for coeliac disease when he was 3 (as we have a daughter with Coeliac Disease). He had raised IgG-gliadin antibody levels, but normal tTG. He is now having stomach aches. So I had him retested: again he had a high IgG-gliadin and normal tTG. Therefore, he was declared OK by the GP." "But I recently read if someone has an IgA deficiency, then these tests are Invalid. Can you please clarify?” Mum.
Wendy, there are several issues here: 1 - IgA deficiency is associated with coeliac disease - about 10% of coeliacs have low or absent IgA in their blood. 2- IgA deficiency can improve with age. 3 - the main blood test to make the diagnosis of coeliac disease is tTG (tissues TransGlutaminase). But this is an IgA based test. This means that those people who are deficient in IgA will have an invalid test. In other words, the IgA-based tests will give a false negative reading in someone who has IgA-deficiency. 4 – So, in those people with IgA-deficiency, the appropriate test to use is the IgG-tTG (in full: the IgG based tTG test). You have to specifically ask for this test. 5 – Your sons’ high IgG-gliadin antibody shows that he is already sensitised to gluten in his immune system. It could indicate that he does have coeliac disease – but he needs more tests. 6 – It would be a good idea to do the HLA gene marker (DQ2/DQ8). 7 - If your son has symptoms (including poor growth), then the next step is doing an endoscopy and a small bowel biopsy. |
