Very technical vaccine immunity question

[2boyzmama]

What role does IgM play in acquisition of immunity from a vaccine?

My son has Primary Immune Deficiency. It's expressed itself in low t-cells, but in his last two immune function labs, he's also had low IgM. His other Igs are normal (IgA, IgG). He has been referred to a Hematologist/Oncologist for interpretation, because having low IgM but normal IgA and IgG is nearly unheard of (200-300 cases worldwide according to a Pubmed article I read)

So far we have not vaccinated, figuring that even if we felt the benefits outweighed the risks, he is not likely to mount an immune response. How does the low IgM play into that assumption? Is it more likely that he won't respond? Or does IgM have nothing to do with vaccine immunity?

[Otto]

A very technical question, indeed. I don't know that it's well understood whether IgM is more a marker or mediator of immunogenic response.

[2boyzmama]

Originally Posted by Otto

A very technical question, indeed. I don't know that it's well understood whether IgM is more a marker or mediator of immunogenic response.

Exactly! From what I understand right now, t-cells are the first level of response. IgM is the first immunoglobulin, then IgG and IgA. So first of all, it's counterintuitive that he'd have low IgM but normal IgG and IgA. No one quite understands that.

Unfortunately, IVIG therapy doesn't work with low IgM. If he had CVID with all three Igs low, then IVIG might help. So not only is this a very strange/rare immune deficiency subset, it's also apparently untreatable. Thankfully up to this point he hasn't had any severe illness or infections. He's had LOTS of illnesses and infections, a few requiring hospitalization, but none severe.

Most of his specialists think that he should be vaccinated with the non-live vaccines at least. They agree that he may not get full benefit, but he may get partial benefit, and none of them think there's any risk.

[EdnaMarie]

I would ask the ladies at justthevax.blogspot.com. They know their stuff.

I am sorry about your son. I hope he continues to be free of serious illness!