Been getting IVIG infusions every 4 weeks. Recent testing performed 5/12/26 indicates my levels are now in normal...

Your IVIG Response and What "Normal Range" Means for Your Situation

This is genuinely good news on the surface — your immunoglobulin levels are now normal — but given your specific situation (MDS, post-allo-HSCT, CVID diagnosis, and that CD34+ chimerism loss), we need to unpack what this actually means for you.

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What Your IgG Subclass Results Show

Your lab results indicate:

• IgG1, IgG2, IgG3, IgG4 — all within normal ranges
• Total IgG — within normal range
• Clinical interpretation — "your immune system is working properly to make protective antibodies"

This is the objective lab finding. But context matters enormously.

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The Critical Question: Why Are Your Levels Normal?

Here's what you need to understand: Normal immunoglobulin levels after IVIG infusions don't necessarily mean your CVID is resolved. There are two possible explanations:

Possibility 1: IVIG Is Working (Temporary Correction)

• The IVIG infusions you've been receiving every 4 weeks are replacing the antibodies your body can't make
• Your levels are normal because of the replacement therapy, not because your B cells have started producing adequate antibodies on their own
• If you stop IVIG, your levels will likely drop again over the coming weeks/months

Possibility 2: Your B Cells Have Recovered (True Reconstitution)

• Your donor B cells (from your February 2025 transplant) have successfully engrafted and matured
• Your immune system is now genuinely producing adequate antibodies on its own
• Stopping IVIG might be appropriate because you no longer need replacement therapy

These are fundamentally different scenarios, and your team needs to have determined which one applies to you.

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The Timing Concern: Your CD34+ Chimerism Loss

Here's where this gets complicated for your specific case:

You reported that your donor CD34+ cells dropped from 86% to 0% — a significant loss of donor stem cells. This happened around the same timeframe as your IVIG discontinuation.

This raises a critical question:

If your CD34+ chimerism is at 0% (meaning you've lost donor stem cells), how are your B cells producing normal immunoglobulins?

Two Scenarios:

Scenario A: Your own (recipient) B cells are recovering

• Your CD34+ loss means you've lost donor hematopoietic stem cells
• But your own B cells may be reconstituting and producing antibodies
• This would explain normal IgG levels despite CD34+ loss
• However: This raises concerns about MDS relapse — your own cells are coming back, which could include dysplastic MDS cells

Scenario B: Residual donor B cells are functioning

• Some donor B cells may have matured before the CD34+ loss occurred
• These mature B cells can continue producing antibodies even if stem cell chimerism is lost
• This is more favorable for graft function
• However: You'd still want to understand why CD34+ chimerism was lost

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What You Need to Know About Stopping IVIG

Before your team discontinued IVIG, they should have determined:

1. Is this true B-cell reconstitution or IVIG-dependent?

   • Did they do repeat testing after a gap in IVIG to see if levels stayed normal?
   • Or did they assume normal levels = no need for IVIG?

2. What is your complete chimerism picture?

   • You know CD34+ is at 0%, but what about:
     • Myeloid chimerism (neutrophils, monocytes)?
     • T-cell chimerism (CD3+ cells)?
     • B-cell chimerism specifically?
   • If B-cell chimerism is donor-derived and stable, stopping IVIG might be reasonable
   • If B-cell chimerism is recipient-derived, that's a different story

3. What's your infection risk profile?

   • Even with normal IgG levels, CVID patients can have functional antibody defects
   • You might have normal quantities but poor quality antibodies
   • Your infection history matters

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The Broader Context: Your Recent Health Events

Your medical profile shows:

• Recent myocardial infarction (MI) — a serious cardiac event
• Mouth sores — could indicate infection or other complications
• CD34+ chimerism loss — concerning for graft instability
• CVID diagnosis — January 2026, 11 months post-transplant

Stopping IVIG during a period of graft instability is worth questioning. Infections are a known risk factor for:

• Cardiac events (infection-triggered MI)
• Graft destabilization
• MDS relapse

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Critical Questions to Ask Your Team

Before accepting that IVIG discontinuation is appropriate, ask:

1. "My CD34+ chimerism is at 0%. How does this affect my B-cell function and my need for IVIG?"

2. "What is my B-cell chimerism specifically? Is it donor-derived or recipient-derived?"

3. "Did you test my immunoglobulin levels after a gap in IVIG infusions to confirm they stay normal without replacement therapy? Or are these levels normal because I'm still receiving IVIG?"

4. "Do I have functional antibody testing, or just quantitative IgG levels? Can my antibodies actually protect me against infections?"

5. "Given my recent MI and mouth sores, what's my current infection risk? Should I be on prophylactic antibiotics?"

6. "What's my plan if my immunoglobulin levels drop after stopping IVIG? Can I restart quickly if needed?"

7. "How does my CD34+ chimerism loss affect my risk for MDS relapse? Could my own B cells be producing antibodies while dysplastic MDS cells are also returning?"

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What "Normal Range" Doesn't Tell You

Your lab report says your immune system is "working properly to make protective antibodies." But this conclusion may be premature because:

• Normal quantity ≠ normal function — you could have adequate amounts but poor quality antibodies
• IVIG-dependent normal ≠ true recovery — your levels might drop once infusions stop
• Chimerism context matters — if your CD34+ is at 0%, the source of your B cells is unclear
• Infection history matters — have you had infections despite "normal" IgG levels?

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Bottom Line

Your normal immunoglobulin levels are encouraging, but they need to be interpreted in the context of:

1. Your CD34+ chimerism loss — which suggests graft instability
2. Your CVID diagnosis — which may not be "cured" by one normal lab result
3. Your recent health events — MI and mouth sores suggest ongoing complications
4. Your MDS relapse risk — which increases if your own cells are reconstituting

Don't assume that normal IgG levels = CVID resolved = IVIG no longer needed. These are separate questions that require careful clinical reasoning.

I'd recommend:

• Getting a copy of your complete chimerism panel (CD34+, myeloid, T-cell, B-cell)
• Asking explicitly whether your normal IgG is IVIG-dependent or true reconstitution
• Discussing your infection risk profile given your recent health events
• Having a plan to restart IVIG quickly if your levels drop

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This information is for educational purposes only. Always consult your healthcare team for personalized medical advice and decisions.