Found this in response to an ABC article discussing the issue of post-tick allergic reaction to red meat. Note also the risk when eating marshmallows containing gelatin.
"drjones :
26 Feb 2014 3:28:33pm
Hi Dr Karl,
I suffer from this and am an immunologist. The allergy first came up for me in 2004. I was stumped because one of the tricky symptoms is that the anaphlylaxis is delayed, occurring 4-6 hours after the meat meal. Typically anaphlyaxis occurs very rapidly after allergen exposure.
It was my dear beloved (a very smart lady and also an ex-immunology graduate) who figured out it was red meat - this was in 2006- before Sharyn van Neunan et al had cracked it. It was doubly hard to crack because she is a vegartarian, and consequently I only used to eat red meat infrequently anyway. The other complex thing is that it is only RARE red meat that is the issue- well cooked meat is ok. So I had instances of eating red meat (eg in a well cooked moussaka) with no issues, but then had the reaction after a rare serving of meat. In fact we did a RAST test with a piece of rare lamb to prove it- the allergist/immunologist that we did this for was very impressed (since prior he'd tested all sorts of other allergens to no avail)!
This allergy has another concern- it makes the patient potentially ineligible to receive the blockbuster biologic monoclonal antibody drugs like Rituxan, Erbitux and Hercepitn, because these drugs have alpha-gal on them. They are proteins that get made using a mammalian cell line. The cells (CHO cells of hamster origin) put alpha-gal on the antibodies. This problem has recently been published:
PS> The bit about well cooked red meat not causing the reaction is interesting because cooking does not break down the alpha-gal- it modifies the meat protein. So the immune system needs to see both the protein and the alpha-gal to go into anaphylaxis..."
