hello and welcome back to another future
doc house production we are continuing
our journey on hypersensitivity here we
go
type 3 we're on type 3 now this is an
immune complex hypersensitivity okay
and it's usually due to antigen-antibody
complex complexes hmm still antigen and
antibody I know it's so confusing and
it's usually this might help it's
usually systemic okay uh how to explain
this well let's talk about how this
happens how these antigen antibody
complexes form you have a foreign or
self antigen triggers the immune system
okay triggers an immune response the
antibodies are produced and they form
this antigen antibody complexes which is
what antibodies do but here's a problem
these complexes are not cleared or
removed so after the forming to be
removed they need to be cleared out in
the blood and if this doesn't happen
these complexes can trigger can cause
problems and you'll see and it can cause
inflammatory response it can lead to an
inflammatory response because these
complexes are not supposed to be in the
body anymore they suppose be removed
gone you know what just cleared out and
and this leads to a response
inflammatory response and increase in
leukocytes to the complex locations why
do I say complex locations because these
complex locations decides to deposit
themselves usually in the blood vessels
hence the systemic or they can deposit
in joints causing arthritis or the
glomeruli glomeruli of the kidneys
causing kidney disease alright here you
go it's very simple like if we just talk
about the diseases you will get
an idea of what these antibody antigen antibody
complexes do lupus systemic lupus
erythematosus this it's a big big
disease we can spend a whole video on
this so simply it's an autoimmune
disease and the antigens would be the
dsDNA and Sm antigen that would create
these antigen antibody complexes that
will lead to this this lupus in a sense
the autoimmune disease all right
there's also post strepto streptococcal
glomerulonephritis glomerulonephritis  and I
mentioned this because in type 2
hypersensitivity we have the rheumatic
disease caused by the antigens in the
cell wall okay and these antibodies
these antibodies in rheumatic fever not
only attack the antigens of the
streptococcus cell wall but the
myocardial tissues which is type 2
hypersensitivity
now again streptococcus cell wall causes
problems too in type 3 and it's the
causes the kidney problems the glomeruli
glomerulonephritis and these antigens of
the cell wall trigger this complex which
deposit themselves in the kidneys and it's
a type 3 hypersensitivity and you've got
this this disease here so don't get the
two confused okay so post streptococcus
glomerulonephritis can cause both type 2
and type 3 hypersensitivity do not get
those confused
Arthus Arthus reaction which is injected
proteins which create the antigen
antibody complexes it's very interesting
there's a whole chapter on this read it
understand it so that when you get a
question on the boards about this you'll
be like oh I got this
same thing with serum sickness usually
this happens when a horse serum is
injected into the patient usually due to
the anti-venom anti-venom that's
available or the horse serum can be part
of a vaccine or anti-venom and
as well as injected proteins so serum
sickness look it up it's quite
interesting and fascinating
polyarthritis nodosa which is caused by
the Hep B surface antigens
check it out it's you know as I
mentioned before joints arthritis and
this is reactive arthritis
these are bacterial antigens forming
antigen antibody complexes farmers lungs
inhaled antigens mode spores antigen
antibody complexes and of course these
three sub acute bacterial endocarditis
symptoms of malaria and and up shown
lien purpura now this is a big one just
you know read about it look it up I
didn't want to get into the details of
each single disease because it will just
take forever I wanted you to look them
up because you're gonna have to anyways
um especially pathophysiology
when I do decide to teach courses on
pathophysiology we're gonna get into
these in detail but that book is any of
those pathophysiology books are a
thousand pages so that's gonna be quite
a challenge
alright on the boards they're gonna ask
you about antigen antibody complexes
they're gonna not they may not ask you
to memorize that it's a type 3 because
that might be just too simple but they
need you to know about the antigen
antibody complexes that it's systemic
usually and that it can cause these
things it can deposit in the blood vessels
joints and the glomeruli
the kidneys know that um I don't know
what else they can ask here yeah you
know and know the disease's know the
diseases that the type 2
hypersensitivity are associated with
especially if I were to say something
especially Post streptococcal glomerulonephritis I've seen that on the
board exams I've seen serum sickness on
the board
and I've seen lupus well there's a lot
of questions on lupus is on the board
exam so know lupus know polyarthritis
nodosa may not be for type 2
hypersensitivity but they are on the
boards and definitely Henoch
Schonlein purpura are definite on the
board so we will talk about malaria
because I am teaching it on microbiology
series so we'll be talking about my
malaria and subacute bacterial
endocarditis and of course streptococcus
all right and that's type 2
hypersensitivity if you liked this video
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