So what are the manifestations
of IgE antibody mediated disease?
Well, it can be everything from
things that are merely annoying.
Such as seasonal rhinitis,
to things that are much more
serious, such as food allergies.
as urticaria or Hives.
Kind of very scratchy, irritating,
mast cell degranulation within the skin.
Asthma with bronchoconstriction
and even anaphylaxis.
So those are all manifestations
and it can be from merely annoying
all the way to fail, in terms of
how many mast cells are
being activated at once.
And for things like food
allergies and anaphylaxis,
we have systemic
mast cell activation.
For seasonal rhinitis, it's
only in your nasal passages.
So you can see that these
can cause a significant amount
of disease and pathology.
So let's look at just how this
might play out at a histologic level.
On the left hand
side is normal lung.
The brighter pink rim things are
going to be the normal bronchioles.
And there isn't any inflammation,
there's no increased mucus production,
the airways themselves are open.
And that's the way it should be.
On the other hand with asthma.
Now, because of mast cell
degranulation causing bronchoconstriction,
because of the cytokines causing
now the production of increased mucus,
we are getting tight little airway
surrounded by lots of inflammatory cells.
And we have increased
And this poor
patient can't breathe.
They're trying to suck
air on little tiny straws
that are filled up with mucus
because of the action of the mast cells.
So that was all IgE
type 1 hypersensitivity.
Immediate type hypersensitivity.
Now let's talk about non IgE
antibody mediated diseases.
And this is going to be kind of
as a ramp up for the next little talk
that we're going
to have together.
Again, once we understand the
toolkit of how the immune system works,
and how the mediators are elaborated,
all this just falls out as predictable.
So if we have antibody that
binds to a particular tissue,
then we'll get
and we'll get cell lisis of
whatever that antibody is bound to
via the membrane attack
We will also have
the formation of C3b,
and antibodies that are bound with
rearrangement of their Fc component
that will allow opsonization.
Basically, whatever the antibody or
complement is bound to is now tasty.
And phagocytes, who have the appropriate
receptors will come up and try to eat it.
Now, they may be able
to eat individual cells.
Well, talk about diseases such
as autoimmune hemolytic anaemia,
where the macrophages can
actually eat an entire red cell.
However, macrophages that are trying
to eat an entire basement membrane
will actually not
be able to do so
because they can't get
their pseudo pods around it.
And then we'll have
macrophage is trying to eat
and it's trying to bring in lysosomes
to digest whatever it's eaten
and now it's going to dump that
lysosomal content onto the surface
of whatever big thing it's trying to
eat, such as a basement membrane.
Other antibody mediated diseases
includes immune complex deposition
with complement and
And immune complexes, again,
are a type 3 hypersensitivity response.
And sometimes antibodies
can block or stimulate receptors
in a variety of tissues.
And so we'll talk about those
in the coming lecture next.