Anne writes about her son who may have an immune deficiency and what  
impact her breastmilk has on him.
She asks (my responses are marked with **):

"If an infant has an immune deficiency - specifically igA or igG and  
is breastfed, what does
his body do with the igA and igG that he ingests through his mother's  
breastmilk?

** His body will enjoy the benefits of the IgA (mostly) and IgG  
antibodies in your breastmilk. These antibodies are very stable  
proteins designed to survive the digestive tract. They act by binding  
to pathogens in his digestive tract, coating them & preventing the  
pathogens from binding to the epithelial cells lining his digestive  
tract. In essence, they can prevent him from getting infected  (or  
greatly reduce the level of infection). There are also many other  
things beside antibodies in the breastmilk that provide protection  
against disease including lactoferrin, oligosaccharides (sugars),  
defensins (anti-bacterial proteins), etc. A good reference for all  
the immune properties in milk is the book by Lars Hanson entitled  
"The Immunobiology of Human Milk" published in 2004.**

Is there a chance that his body will produce anti-A (antibodies to igA)?

** No, his body will not make anti-IgA antibodies. They will just  
pass through his digestive tract, protecting him as they move  
through.***

So my question from a hypothetical standpoint regarding breastfeeding  
is =
IF he has an immune deficiency - is breastfeeding the only thing  
keeping him from gett=
ing really sick?

** It is certainly protecting him from many things, and may be why it  
has taken a long time to get a proper diagnosis**

If his body really isn't producing these immunoglobulins and he's  
getting=
  them from my breastmilk - are they enough to replace what he would  
be making himself o=
r just enough to boost his immunity?

** Breastmilk is "designed" by nature to compensate for the  
immunological immaturity of normal infants (all infants are born with  
an immune system that is not fully developed. But Nature didn't  
intend for breastmilk to be able to compensate for immunodeficiency  
that is greater than the normal course of development. And, as you  
have seen, your son has experienced many infections during his life.  
However,  he would have had even more if he wasn't breastfed. **

The longer I breastfeed - what happens to the igA and igG levels - do  
the=
y stay the same, increase, decrease?

** There is evidence to suggest that as older babies nurse less ( and  
take in smaller volumes of milk) the concentration of antibodies in  
the milk increases. I don't have all my references at home, but I can  
try to look this up for you**

If breastmilk is part of what is keeping him healthy (beyond the  
normal benefits for the average child) do I need to keep  
breastfeeding him forever? (help me find the humor please!)

Will I be pumping a glass of milk for him daily when I'm 50 or 60?

**Well, don't hurry to wean right now! But you may not have to pump  
when you are 60 either. There are good treatments available for some  
immune deficiencies.

  I gather from your subject line that he is deficient in IgG, IgA,  
IgM, and IgE. This sounds like a defect in his B lymphocytes which  
are the cells that produce antibodies. One type of immunodeficiency  
is called X-linked aggamaglobulinemia (more common in boys than in  
girls because it's due to a gene on the X chromosome and boys only  
get one copy of that chromosome).  People with B cell defects can  
resist many pathogens successfully, although they will be more  
susceptible to staphylcocci and streptococci (types of bacteria). In  
these patients, the infections can be suppressed with antibiotics and  
with monthly infusions of human immunoglobulin. The human  
immunoglobulin is pooled from many donors and therefore has  
antibodies against many infections. **

I hope this is helpful. Feel free to email off-list if you would like  
further information.

Warmly, Laurie Shornick, Ph.D., Immunologist

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