PA without IF antibodies?

[Portia1974]

Hello PA Hive Mind!

Newbie poster but have been researching my B12 def and also lurking here digesting all the amazing advice. I feel like I may have been misdiagnosed, and I now realise, probably undertreated and essentially left to languish for the last 4 years with worsening neuro symptoms and fatigue. (I can't even begin to describe how much of a shadow of my former self I feel like).

My question is this. Is it possible to have PA despite a negative IF antibody test?

As I understand the mechanism, Intrinsic Factor (needed to absorb B12 in the gut) is created in Parietal Cells in the gut. In PA the body mounts an autoimmune response against IF, kills it off, blocking the absorption of B12 in the gut. Ergo: PA.

As I mentioned, I was tested neg for IF AB. But I also understand that antibodies against the actual Parietal Cells (that create IF in the first place) are a thing. This I have NOT been tested for.

So have I understood this correctly and is it possible that I could have antibodies for parietal cells and not IF? And would that be classified as PA or something else?

I have a solid basis to believe my B12 deficiency is absorption based rather than diet related. in 2014 my b12 was 109. Loading doses ensued and once serum levels normalised (all too familiar this part it seems!) my GP concluded I was "cured" and no further treatment was necessary & stopped the jabs. I remained symptomatic then. At that time I hadn't researched any of this so just went with it and resolved to take a daily oral B12 supplement (300% RDA) to retain my "normal" serum levels. Over the next year my levels showed a sharp downward trend at each blood test (despite the oral supps). Something that I pointed out and was deflected/dismissed each time. Eventually when it was approaching borderline deficient again, the one decent GP at the surgery recognised what was going on and put me back on jabs. (2 weeks of loading then 3 monthly jabs ever since).

These were my numbers over that period:

31/7/14 - 109

25/11/14 - 592

15/4/15 - 1048 (After loading doses)

11/6/15 - 804 (oral supps only)

17/11/15 - 394 (oral supps only)

1/4/16 - 277 (oral supps only)

13/10/16 - 1379 (after loading doses)

1/5/18 - >1500 (after 3 monthly inj for 18 months)

That episode proved to me I was not absorbing in the gut.

I remain highly symptomatic. The most worrying of which is a significant worsening of neuro symptoms. I have other questions (and theories) related to functional deficiency (and other nutrient levels) that I will put in a seperate post for the sake of not turning this into any more of an essay.

But for now, based on the above, do you think I'm right in the malabsorption Dx and is it the case that they can't rule out PA without checking Parietal Cell AB also?? Or is PA only Anti IF and Anti Parietal Cell is something different altogether?

Thanks in advance and wishing everyone well.

Px

[Gambit62 Administrator]

this is a link to the BCSH guidelines for diagnosis and treatement of cobalamin and folate deficiency

onlinelibrary.wiley.com/doi...

you may find it useful to look through the commentary on the different tests and the limitations in the results they provide. Covers both GPA and IFA testing.

The standards refer to IFAB-negative PA as a result.

[wedgewood]

Both tests are notoriously unreliable . The IF because it very often shows negative when it’s positive . The same for parietal cell only the other way round . It really isn’t used anymore .Yes you can test negative with the I.F. Antibody test , and still have P.A. , It happens a lot someone will give you the link to find out about this . I haven’t got it .