Hi all - as part of the monitoring of my angioedema I had a Basophil Histamine Release blood test and it has come out in the mid range ie normal. I have tried to google it but cannot make head nor tail of the jargon! Can anyone tell me the implications for mast cell disease and/or urticaria/angioedema?

Many many thanks....

You rang?

Basophils are similar to mast cells in some ways, but different in others.  They both have high-affinity IgE receptors.  In theory, they degranulate to the same triggers.  Both play a critical role in the adaptive immune system and the healing process.  One major difference, however, is that mast cells spend their lives attached to specific organs (skin, intestines, eyes, etc...).  Basophils circulate freely in the blood.  Also, basophils release a substance called PAF (Platelet Activating Factor) which is not found in mast cells.  PAF is a powerful vasodilator... 30,000X more powerful than histamine.  It's a good thing your bone marrow doesn't produce very many basophils!  Normally, they make up less than 2% of all the blood cells in your body.  Basophils are suspected to play an important role in severe anaphylaxis.  It's just difficult to study them because they're so relatively rare... especially in mice.

But... we're talking about the basophil histamine release assay  The reason basophils are used to test "triggers" (substances that may or may not set off degranulation) is because they circulate freely in the blood.  It's much easier to get a sample of basophils than to get a sample of mast cells!  Since mast cells and basophils trigger to the same substances you can use basophils to get an approximation of what your mast cells would do.  That's the idea anyway.  For example, since my blood contains antibodies to the high-affinity IgE receptors, when you put my blood in a test tube along with "donor basophils" (basophils from a normal person) they degranulate... which is why I can no longer be a blood donor  If your blood doesn't do that, then you can rule out this kind of autoimmune disorder as the cause of your allergy symptoms... which is a good thing, even though I know how frustrating it is when all your tests keep coming back normal, normal, normal.

Heather

Riverwn wrote on 03/03/11 at 15:17:59:

Not necessarily... there could be triggers that set off your mast cells but not your basophils.  The severity of anaphylaxis also depends (in part) on your mast cell "load" and how completely/quickly your mast cells and/or basophils degranulate.  Also... co-existing factors like systemic infection, complement activation, coagulation, hormonal fluctuations, etc... can make a reaction more severe than you might expect.  This is one thing that makes our doctors rip their hair out... two people can have exactly the same lab results (tryptase, urinary histamine, prostaglandins, etc...), but one has mild reactions and the other has severe reactions.  Why??  The answer is not simple... and as usual, more research needs to be done.

Heather

Heather and Ramona - thank you both so much. Heather - you are sooo good at this stuff.

I had not seen these responses before putting the other half of my question on the baord - when you have a minute Heather could you take a look - it is about my immune system....