autoimmune hemolytic anemia Flashcards
immune hemolytic anemia
shortened RBC survival mediated through immune response typically humoral antibody
3 categories of hemolytic anemia
-alloimmune
-autoimmune
-drug induced (lumped with this because autocontrol and DAT are both positive)
most autoimmune antibodies react with what kind of antigens
high frequency
autoanti-I more likely
cold hemagglutinin
interfere with routine testing but otherwise unimportant
-become clinically sig as titer and reactive temp increases
who are cold hemagglutinin most common in
older patients tend to be chronic
cold agglutinins have reactivity at what temp
below 20
-don’t worry in routine testing
options for finding cold hemagglutinin
autoabsorption or prewarming
prewarming done for a screen
how to prepare a cold hemagglutinin warm incubations for ABO back typing
need to include a screening cell and read the tube without centrifugation
how to determine if cold auto relevant
pathological antibodies are reactive closer to body temp and have higher titer than benign ones
titer >1000 at 4 degrees to call relevant
most common kind of cold auto
anti-I
-confirm by testing patient plasma with cord cells which have almost no I antigen
autoanti-I= rare sequela of infectious mono
in cold hemagglutinin symptoms
extremities because colder and further away from flow
what does cold hemagglutinin look like in blood bank
screening cells positive
DAT positive
Auto 0-4+
what is paroxysmal cold hemoglobinuria
patient has a hemolytic event after exposure to cold temp
findings: intravascular hemolysis and hemoglobinuria
when is paraoxysmal cold hemoglobinuria seen
typically following viral infection : syphilis
rare
paroxysmal cold hemoglobinuria specifically caused by
biphasic antibody
bind RBC in cooler temp and when warm RBC lyse
usually IgG anti-P
Hgb can drop to 4-5
when paroxysmal cold hemoglobinuria ID it is called
Donath-Landsteiner antibody
PCH donath landsteiner test specimen
tests for biphasic antibody
serum from freshly coag blood - red tops; must have active complement
clotted and spun at 37 degrees to avoid auto absorption
donath landsteiner treatments
A tubes - 30 min ice bath, 60 min at 37
B tubes- 90 min ice bath
C tubes - 90 min at 37 degrees
3 sources of serum for donath landsteiner test
1- patient serum
2- normal serum and patient serum - controls for complement irregularities
3- normal serum
mix with normal RBCs ( have P antigen)
read hemolysis after 90 mini
normal person results for landsteiner test
no reactivity
landsteiner test results for PCH
Hemolysis in A test for patient serum (1) and patient and normal (2)
identifying characteristics of PCH
children/ young adults
hemolysis- intravascular
antibody class- IgG (anti-P)
donath landsteiner +
treatment= supportive
identifying characteristics of Cold hem. disease
elderly patients
hemolysis- extravascular
antibody class- IgM (anti-I)
treatment= avoid cold
how are most AIHA caused
warm antibody (70%)
both IgG and complement involved
(small minority caused by IgM, IgA)
