Type 1 autoantibodies

Type 1 & LADA
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Hello, knowledgeable folks!
I’m back seeking the wealth of information that you all seem to have.
I’m curious about my daughter’s autoantibodies profile. She had detectable insulin and GAD autoantibodies, but no detectable islet autoantibodies at the time of diagnosis. Her most recent labs also came back negative for islet autoantibodies. Does this put her in the idiopathic, non-autoimmune mediated type 1 subgroup? Or does the presence of the other two mean her type 1 is still auto-immune mediated? I can never get any explanations from her endo. I get a “she’s type 1 just leave it at that.”

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@Eaden I can’t help that much, haven’t researched the angle you’re addressing. But…I really like your desire to “know,” and find the answer. I’m fortunate my Endo seems to appreciate the attitude andI think most of us here on FUD are similar in that regard. I’m sure you’ll get a decent reply from one of us!

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Type 1 is by definition auto-immune in origin. Autoantibodies did show up in her labs. You don’t need all the different possible kinds of autoantibodies for the diagnosis of type 1.

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There’s non-immune mediated type 1b. There’s been an uptick in cases recently too, associated with Covid. Which is what initially peaked my curiosity.
Since insulin ab and gad can be seen in other illnesses aside from type 1, I didn’t know if the islet cell ab were the primary determining factor for type 1a.

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I didn’t know about that. Shame on me for posting while ignorant. After looking through a couple papers I’m still pretty confused. One has the type 1b patients older at onset, a second has them as younger. And in the second paper, the 1b’s have the same genetic susceptibilities as the 1a’s, but lack the autoantibodies.

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You mean you don’t know about all the rare subgroups of diabetes?? Entirely joking.
See, these mention b-cell autoantibodies. Her labs show negative for those. This is where I’m left confused.

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Hi there-
As a newly diagnosed LADA with, I think, the same results as your daughter (positive for GAD65 only and low c-peptide results), I am also trying to make sense of it all.
At this point I am trying to eat well, take walks, and be gentle with myself. I was very very sick in the fall and I didn’t even know it! I feel bad for my body and want to take care of her.
I am now trying to assemble my team which isn’t easy I agree with you on that! On Wednesday I have a consult with a new endo whom I’ve heard lots of good things about so I’m hopeful.

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In most countries they only test for the GAD antibodies. UK is one. Since most type 1’s test positive for GAD, the other tests add costs so they don’t do any others. I’m not sure they even do the C-peptide all the time. Once you are positive for GAD auto antibodies and having a high A1C it’s accepted you have type 1.

I’m not even sure they have identified all the antibodies. But a true idiopathic presentation is my DE here who is considered a type 1. She doesn’t test positive for any of the antibodies, but she doesn’t make insulin. It happens, but is fairly rare. They don’t have a clue as to why it happens.

I was tested for GAD, positive high, insulin antiautobody, positve high. My endo had other tests ordered, islet autobodies was one, but once I was positive on GAD it literally says they didn’t do the other tests since a positive was already yielded. It says the insulin anti autobody test wasn’t entered into my flow chart, whatever that means. But it sounds like they don’t consider it necessary for part of my records? She handed me copies of the results when she first told me.

I know there is some research into the different genes that cause type 1. It will more likely that at some point you might give a blood or saliva test to see if they are interested in the genes she has.

But here is a list of different tests per JDRF

  • C-Peptide
    While most tests check for antibodies, this test measures how much C-peptide is in a person’s blood. Peptide levels typically mirror insulin levels in the body. Low levels of C-peptide and insulin can point to T1D
  • Glutamic Acid Decarboxylase Autoantibodies (GADA or Anti-GAD)
    This test looks for antibodies built against a specific enzyme in the insulin-producing pancreatic beta cells.
  • Insulin Autoantibodies (IAA)
    This tests looks for the antibodies targeting insulin.
  • Insulinoma-Associated-2 Autoantibodies (IA-2A)
    This test looks for antibodies mounted against a specific enzyme in beta cells. Both the IA-2A and GADA tests are common T1D antibody tests.
  • Zinc Transporter 8 (ZnT8Ab)
    This test looks at antibodies targeting an enzyme that is specific to beta cells.
  • Islet Cell Cytoplasmic Autoantibodies (ICA)
    Islet cells are clusters of cells in the pancreas that produce hormones, including insulin. This test identifies a type of islet cell antibodies present in up to 80 percent of people with T1D.
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Marie,

Thank you so much for the informative response! I really appreciate it.

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