Re: Histamine/IgE Question.

[Guest guest]

IgE binds to mast cells. Mast cells then can bind an

allergen floating along. The mast cell " explodes " and

releases histamine. Ergo allergic response.

Technically if all your IgE is mopped up by X, you

will not need any anti-histamine, as the cascade is

stopped.

This is why you reacted to the histamine alone in the

skin test. Xolair does not curb your body's reaction

to histamine. Did you react to the other allergens?

C

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[Guest guest]

Just a little more information in case you'd like to have it. IgE is a

very large protein molecule that is the " allergy antibody " floating

free in the blood (and available to be swept away by Xolair). It is Y-

shaped. The stem of the Y can bind to the surface of mast cells as well

as other cells of the immune system. The arms (V) of the Y bind to

allergens.

When IgE molecules attach by their stem ends to mast cells and then

allergen molecules bind to the arms of the IgE, the mast cell is

triggered to secrete histamine, a small protein-type molecule.

Histamine is one of a group of many molecules called immune mediators

that can cause TONS of trouble in allergic individuals.

In the upper respiratory tract, histamine causes nasal congestion,

itching, sneezing and a runny nose. In the lungs histamine causes

cough, makes the cell lining of the airways leak fluid, and triggers

narrowing of small airways (bronchoconstriction) in individuals with

asthma. In addition, histamine triggers other cells of the immune

system to cause further prolonged irritation/inflammation of

respiratory tissues.. This entire process is called the allergic

cascade.

When you have allergy skin testing, histamine is given as the " positive

control " , i.e. it shows what a positive reaction should look like when

present. Most people will react to histamine injected beneath the skin

with swelling, redness and itching even though no allergen is present.

When substances to which the patient is allergic are injected under the

skin, they bind to the arms of IgE whose stems are attached to mast

cells in the skin and histamine is released, producing the same skin

reaction as histamine alone. However, if histamine alone does not cause

this reaction in a particular patient, it becomes difficult to

interpret the results of the allergen testing at other injection sites.

Specifically, if you don't react to any injected allergens but you also

do not react to the histamine control, you cannot conclude that you are

not allergic to the allergens tested because you are not showing the

typical response to the presence of histamine.

Hoping this makes sense to you - if not, please feel free to ask

questions.

Fran

--- In , " " <grneyyedlady@...>

wrote:

>

> Could one of our " Xolair Nurses " please explain, in plain " English " ,

> the difference between IgE and Histamine. That in itself may answer

a

> few questions why people have allergic reactions to things even after

> they have been on Xolair for months/years. PLUS it will explain why

> one may need to take Anti-histamines as well as Xolair.

>

> I've been on 300mL of Xolair every two weeks, since 2005.I just had

> allergy testing done, out of curiosity. (I'm thinking he's writing

> another paper on Xolair and I'm his guinea pig) They did local

> trees, grasses, molds, animals AND a histamine. I had a " gorgeous "

> skin reaction to the histamine. My allergist did explain it to me,

> but it was in medical terms.

>

[Guest guest]

So, greyngrey - To " answer a few questions why people have allergic

reactions to things even after they have been on Xolair for

months/years. PLUS it will explain why one may need to take Anti-

histamines as well as Xolair. "

OK, having just given my long-winded explanation about IgE and

histamine: Our bodies are continuously making IgE, much of which ends

up attaching to mast cells in our upper respiratory tracts and lungs.

Only the IgE floating free in the blood can be inactivated by binding

to Xolair because the Xolair attaches to the stem of the Y-shaped IgE

molecule. When we get a Xolair (anti-IgE)injection, it moves into the

circulation, binds with any free IgE floating around at the time and,

if we're lucky, much of the IgE that is produced for a while afterwards

until that dose of Xolair is used up.

But remember that at the time of the injection, plenty of IgE is

already bound to mast cells and allergens are busy binding to the arms

of that IgE, triggering histamine release by the mast cells. The stems

of those bound IgE molecules are not available to be bound to the anti-

IgE because they're already stuck on mast cells and so we're stuck with

the histamine release and its consequences. It takes a period of time

before all those mast cell-bound IgE molecules get cleared away, and

meanwhile we're using up our Xolair dose and more IgE is always coming

down the pike and binding to mast cells unless it's picked up by anti-

IgE first.

It's a constant balancing act; the process is dynamic and never-ending.

We only get ahead of the game by eventually building up enough Xolair

to keep the circulating IgE at a low enough level that there isn't

enough to bind to mast cells to cause trouble. And then, BAM!!! We get

exposed to a burst of pollen or mold or dust mites and now we're

suddenly making a ton more IgE and the Xolair dose we're on is no

longer enough to keep things under control.

Having said all that, there's so much that nobody knows yet about long-

term Xolair treatment and what it does to the regulation of the

production rate of IgE down the road. At some point could it skyrocket

just because it's tired of being messed with? Or if we're lucky, our

bodies just might get the idea and shut it down, or something in

between. Only time and research will tell.

Fran

--- In , " " <grneyyedlady@...>

wrote:

>

> Could one of our " Xolair Nurses " please explain, in plain " English " ,

> the difference between IgE and Histamine. That in itself may answer

a

> few questions why people have allergic reactions to things even after

> they have been on Xolair for months/years. PLUS it will explain why

> one may need to take Anti-histamines as well as Xolair.

>

> I've been on 300mL of Xolair every two weeks, since 2005.I just had

> allergy testing done, out of curiosity. (I'm thinking he's writing

> another paper on Xolair and I'm his guinea pig) They did local

> trees, grasses, molds, animals AND a histamine. I had a " gorgeous "

> skin reaction to the histamine. My allergist did explain it to me,

> but it was in medical terms.

>

[Guest guest]

Let's hear it for Fran! Hip-Hip-Hooray!

Thank you for those great explanations!

Addy

Group co-owner

> >

> > Could one of our " Xolair Nurses " please explain, in

plain " English " ,

> > the difference between IgE and Histamine. That in itself may

answer

> a

> > few questions why people have allergic reactions to things even

after

> > they have been on Xolair for months/years. PLUS it will explain

why

> > one may need to take Anti-histamines as well as Xolair.

> >

> > I've been on 300mL of Xolair every two weeks, since 2005.I just

had

> > allergy testing done, out of curiosity. (I'm thinking he's

writing

> > another paper on Xolair and I'm his guinea pig) They did local

> > trees, grasses, molds, animals AND a histamine. I had

a " gorgeous "

> > skin reaction to the histamine. My allergist did explain it to

me,

> > but it was in medical terms.

> >

>

[Guest guest]

Thanks !

Yes, I did react to other allergens. Dust mites,

molds,animal dander, local trees and grasses, which

didn't surprise me at all. I had been tested for those

same things over 20 years ago. BUT one thing that I

had not been previously checked for (and that totally

surprised me) was that I have now found out that I am

allergic to tomatoes!!!

--- <carrie72583@...> wrote:

> IgE binds to mast cells. Mast cells then can bind an

> allergen floating along. The mast cell " explodes "

> and

> releases histamine. Ergo allergic response.

>

> Technically if all your IgE is mopped up by X, you

> will not need any anti-histamine, as the cascade is

> stopped.

>

> This is why you reacted to the histamine alone in

> the

> skin test. Xolair does not curb your body's reaction

> to histamine. Did you react to the other allergens?

>

> C

>

>

> Be smarter than spam. See how smart SpamGuard

> is at giving junk email the boot with the All-new

> at

> http://mrd.mail./try_beta?.intl=ca

>

>

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