Human milk has immune globulin A (IgA) that protects prople from sinus, respitatory, GI, ear, skin, and some other infections. There is no treatment for people that have low levels of IgA or no IgA. There is treatment for people that have low leveles of immune globulin G (IgG), not found in breastmilk (at least not in large quantities). People can have selective IgA deficiency or a combined immune deficiency like Common Variable Immune Deficiency (CVID), the person has low levels of IgA, IgG, and IgM.
The treatment for IgG is IV gamma globulin every 3 weeks. This is a rare (orphan) disease and not much work is being done to improve treatment. The treatment has been the same for 25 or more years. It is very expensive and devistates families. If you have the IVs as a hospital OP it costs $20,000 or more every 3 weeks. It is a little less if you have it done at an infusion suite, the kind of place where they give chemo. My 3 children and I were all diagnosed with CVID 23 years ago. I have been getting the IVs every 3 weeks for 23 years.
Does drinking breastmilk work for people with IgA deficiency? If it does should there be medicine made from breastmilk that costs tens of thousands of dollars a month for people with IgA deficiency? I don't think it would work. Many people with low levels of IgA have high levels of immune globulin E (IgE), the allergy immune globulin. Some brands of IV gamma globulin has a little IgA in it and people can have an allergic or adverse reaction to the IgA. I'm thinking people could have allergic reactions to IgA from human milk especially if it was processed and concentrated. Would IgA survive the adult digestive process and prevent illness? The infant's digestive system is not the same as the adult's.
Just having IgA deficiency isn't that rare. It's estimated 1 in 400 people have it and most have very few problems. About 1 in 50,000 people have CVID. The reason they say it costs so much for the IVs for gamma globulin is that they pool the gamma globulin portion of 20,000 different people's units of blood to make the IV medicine. It doesn't take 20,000 per IV, they don't tell you how many IVs they get from the 20,000. The gamma globulin would be a tiny part of a unit of blood. It comes from paid donors and the rest of the unit is used for other things.
If we decided to treat people with low levels of IgA with human milk where would we get enough human milk? It would take huge amounts for adults. If the medical community took over and started processing the milk to remove the IgA it could cost huge amounts of money. So huge a person could loose their house, car, most of what they own, their job, and have to get divorced to Medicaid to get treated. That's what happens to most families with a member that has CVID that has to have IgG IVs. If a person is having sinus infections, horrible diarrhea and cellulitis several times a year it may be worth it to get IgA and it could save their life. Some people can have life-threatening health issues with just IgA deficiency.