B cells and autoimmunity: Is measuring antibody titers reliable when B cells are low?

Inara

Senior Member
Messages
449
Likes
1,068
Hi everybody,

somewhere in a post (I think by @Pyrrhus) I read that measuring virus titers is unreliable if IgM/IgG/IgA are low.

I wonder if the same applies to low B cells, specifically CD19+ and CD20+ B cells (CD20+ are depleted during Rituximab treatment if I understood correctly, and that suppresses autoimmune activity) with respect to autoimmunity markers. I don't know which antobodies CD19/CD20 produce, but I wondered if

1) there can be autoimmunity but it won't show in lab tests if CD19/CD20 are low,
or
2) having low CD19/CD20 "protects" against (at least certain forms of) autoimmunity, so having low CD19/CD20 can't lead to at least these forms of autoimmunity.

I have low/lowish CD19 and CD20 B cells, but I have Hashimoto's. In the Celltrend panel, two antibodies were positive, so there is some form of autoimmunity, but - as far as I can see it - not really severe. I wondered if autoimmunity lab tests are reliable if B cells are low. Does anybody know?

Thank you!
 

Pyrrhus

Senior Member
Messages
4,029
Likes
12,310
Location
U.S., Earth
somewhere in a post (I think by @Pyrrhus) I read that measuring virus titers is unreliable if IgM/IgG/IgA are low.

I wonder if the same applies to low B cells
I don't know of research that looks specifically at your question, but I would guess that if your B cells are abnormally low, then your antibody titers may also be abnormally low. In this situation, applying the normal reference range in a specific antibody test may be unreliable for diagnosing any pathology from that specific antibody.

I hope this helps.
 

Learner1

Senior Member
Messages
6,253
Likes
11,580
Location
Pacific Northwest
From what I understand, Hashimoto's is T cell driven immunity. Most of the other autoimmunity is driven by B cells, which make antibodies. It makes sense that if your B cells aren't very good at making antibodies, a case of autoimmunity or antibody defense can be missed.

I had 12 doctors miss EBV because I wasn't properly making antibodies. PCR tests, which look for DNA of the viruses are better. As for autoimmune antibodies, if they're low, you might have fewer symptoms.
 

Inara

Senior Member
Messages
449
Likes
1,068
That's definitely interesting. 🤔 And quite helpful. How can you spot B-cell autoimmunity then? And, if antibodies can't be really produced... how can you have B-cell autoimmunity at all? Or is it just like this:

As for autoimmune antibodies, if they're low, you might have fewer symptoms.
I will read both your posts tomorrow again. I seem to have a low concentration this evening.
 

Gingergrrl

Senior Member
Messages
15,851
Likes
46,943
@Inara

Did you mean antibody testing for viruses or autoimmune testing for autoantibodies (or both)? Also, did you mean that your B-cells are low (or non existent) from Rituximab, or another B-cell depleting drug, or did you mean that you are testing low for B-cells for some other unknown reason? I wasn't sure if I quite understood what you were asking.
 

Inara

Senior Member
Messages
449
Likes
1,068
Hi @Gingergrrl

Thank you for asking. You make good points.

I guess every substance that B cells produce and can be measured by a lab could be affected. But in my original post I only meant autoimmune testing for autoantibodies (because I didn't think of the rest).

My B cells are low/lowish due some unknown reason (I think this will get clearer in some weeks). They were not depleted by some drug, like Rituximab.

I just recalled that Rituximab aims at lowering B cells and thus improving symptoms from B cell autoimmunity, and so I wondered if low B cells (e.g. due to some immune deficiency) might lead to mild(er) autoimmunity, or if it might even protect from developping autoimmunity (because there aren't enough B cells that could produce autoantibodies). At least, that's how I understand the replies so far, it can make detecting autoimmunity (or virus antobodies like in @Learner1's case) pretty difficult.
 

Gingergrrl

Senior Member
Messages
15,851
Likes
46,943
I guess every substance that B cells produce and can be measured by a lab could be affected. But in my original post I only meant autoimmune testing for autoantibodies (because I didn't think of the rest).
@Inara I am sorry for the slow reply and your question makes sense. I would assume (but do not know for sure) that anything produced by B-cells could be affected (both antibodies & autoantibodies) in the scenario that you described.

My B cells are low/lowish due some unknown reason (I think this will get clearer in some weeks). They were not depleted by some drug, like Rituximab.
How did you discover that your B-cells were low? Did you do a test called "Lymphocyte Subset Panel"? This panel might have another name in Germany vs. the US. It measures both the Absolute Number and the Percentages of the different immune cells (CD3, CD4, CD8, NK Cells, and CD19 which are the B-cells). It would tell you what specifically was low although it would NOT tell you why it was low.

I just recalled that Rituximab aims at lowering B cells and thus improving symptoms from B cell autoimmunity, and so I wondered if low B cells (e.g. due to some immune deficiency) might lead to mild(er) autoimmunity, or if it might even protect from developping autoimmunity (because there aren't enough B cells that could produce autoantibodies).
Rituximab kills all of the B-cells so they would not only be low but they would actually be at zero (until they grow back). In my case it took around 8-9 months after my final infusion for them to fully grown back (which we measured using the Lymphocyte Subset Panel and a few other blood tests).

Your second question is interesting and I actually do not know the answer! If I understand right, you are asking if low B-cells (due to an immune deficiency and NOT from a treatment) could lead to milder autoimmunity or even be protective against developing autoimmunity and I don't know the answer. I am hoping that someone else chimes in who does know and I am curious, too.