Hi All,
I commented on a recent thread that I thought some people had PA even when Intrinsic Factor Antibody test and Parietal Cell Antibody test results were both negative.
I speculated that this could be due to an immunoglobulin deficiency leading to inability to produce certain antibodies.
I've now found this article which seems to support what I thought was possible.
There's some lovely BIG words in there Sleepybunny that seem to turn everything upside down.
I don't think I can grasp it all but thanks for finding it.
I’d like to see something less than 50 years old.
I might try to search for papers that refer to this one, to see if there’s anything more up-to-date. Especially it would be interesting to see if their people with gastric atrophy without antibodies might have H. pylori infection, and if that could affect immunoglobulin.
From: ncbi.nlm.nih.gov/pmc/articl...
H. pylori infection in dyspeptic patients with IgAD was associated with a higher prevalence of gastritis
So the subjects in the1969 paper may not have had PA without antibodies, but might have had gastritis and B12 deficiency caused by H. pylori infection.
That paper has been cited in other papers 22 times in the last 20 years. But only 6 of those mentioned PA and none of those six mentioned a connection between PA and immunoglobulin deficiencies that I could find (two of them were books, so I couldn’t read much of them).
I think this is interesting despite its age. The Ig deficiency in the subjects is interesting for one thing. Also highlighting that you don't need to have the antibodies to IF and PC to get the various conditions that can lead to a B12 deficiency, which is pernicious whether or not it is actually autoimmune Pernicious Anaemia. A greater awareness of this might mean people get more of a range of tests to find out what's actually going on instead of being dismissed as hypochondriacs following a fad.
As I pointed out in my earlier post, it’s is entirely possible that these subjects had an H. pylori infection. That causes gastritis, which causes B12 deficiency - without antibodies. And people with an Ig deficiency are more likely to have gastritis when they have H. pylori.
That’s one reason why older publications need greater scrutiny, they didn’t know some things we know now.
If there were any substance to that 1969 paper I would expect something further to have been done since then. But there has been nothing I can find in the last 20 years. As I said, only 4 papers (and 2 books) mention PA and cite the 1969 paper. And none of them build on it.
False negative PA Tests?
Negative PA Test - way forward
MMA results - supplements or further test?
IFA negative, Low Active B12 - advice please. 
PA and menopause.
