MLSP 5513, TFN Med: Exam 3

Lewis group - unique

Can be lost during pregnancy

Formed into secretions

P Group - unique

Antibody may occur naturally as a cold reactive IgG in PCH

I and i Group - unique

Big only found in adults, little only found in infants and cord blood

little related to infectious mono

big related to mycoplasma pneumoniae infections

Kell Group - unique

Most immunogenic, after D

Not affected by enzymes

Primarily on RBCs and Sertoli cells

Kidd Group - unique

Antibodies activate complement

Titers drop quickly: treacherous

Associated with delayed HTR

Duffy Group - unique

When antibody is positive, so antigen is lacking, P. vivax binding site is not available = malaria resistance

MNS Group - unique

MN En(a-) resistant to P. falciparum merozoites

Renal dialysis machine sterilized with formaldehyde may allow Anti-N-like antibodies to form in patient

Lutheran Group - unique

(a-b-) cells are labile and hemolyze easily on storage

The antibody for this a demonstrates a loose mixed-field agglutination

Rh Group - unique

Some can occur without obvious immune stimulation

IgG groups

Rh, Kell, Duffy, Kidd, Ss, U, Lutheran b

IgM groups

Lewis, P, MN, Lutheran, ABO

Groups that bind complement

Kidd, Lewis, P

Groups reactive at 37C

IgG groups

Groups reactive at room temp

IgM groups

Groups that show dosage

Any that has a heterozygous possibility

Notorious: Duffy, Kidd, MN, Ss, Rh, K

Dosage

A heterozygous vs homozygous antibody can cause different reaction strength

Groups that are formed naturally

Groups that need red cell stimulation to form

Ficin

Cleaves sialic acid

Enzyme reactions

Destroyed: M, N, S, Fya, Fyb

Enhanced: Rh, Jka, Jkb

ZZAP reactions

Decreased: Duffy, Kell, Lutheran

ZZAP and WARM reagents

Mixtures of DTT and papain that destroy Kell and enzyme-destroyed antigens to allow the red cells to be used for further testing

Chloroquine diphosphate

Removes IgG from coated cells to allow cells to be used for further testing

Disulfide reducers

dithiolthreitol (DTT)

Beta-2-mercaptoethanol (2-ME)

Disulfide reduction outcome

Break J-chain of IgM

Reduced: Lutheran, ABO, MN, Lewis, P, I

Destroyed: K

Removal of IgG from cells - reason

Used when suspect auto-antibody or transfusion reaction

Eluate

Remove IgG from RBCs by removing any bound antibody. The RBCs are destroyed in the process, but the eluate with the bound antibody can be used for further testing

Gentle IgG removal

Remove bound IgG from RBCs but allow RBCs to survive the process. Both sera and cells can be used for further testing

Prewarm

Warm all reagents (cells and sera) to 37C before performing reaction to rule out any cold reactive antibodies

Why type unexpected antibodies?

They could be clinically significant

Calculation for # to type

((100-(frequency A x frequency B)) / 100) = # units requested / x units to test

ABO, Le, and Se gene releationship

Le antigen formation requires four genes and the phenotype is dependent on Se gene status.

Le by itself will create Le(a). Le and Se will create Le(b). Se modifies Le(a) to Le(b), so both are still present in secretions.

Lewis type with Se

Le(b)

Lewis type without Se

Le(a)

Secretions with Le and Se

Le(a), Le(b)

P group alloantibody disease

Can cause severe HTR and HDFN, associated with spontaneous early abortion

P group autoantibody disease

Cold reactive IgG antibody in PCH which causes in vivo hemolysis, biphasic

Follows viral infection

P group diseases

Antigens associated with:

UTI (E. coli)

Streptococcus suis - septicemia and meningitis

Human Parvovirus B19

P group clinically significant antibodies

Anti-P1, -Tja (PP1Pk), allo, auto

Cord blood cells used for anti-i ID

Little decreases as big increases over first 18 months of life

Using this helps find cold-reactive antibodies

- Anti-I, -H, -IH, -Lewis, -P

I autoantibody

Benign: naturally occurring IgM, enhanced with enzymes

Pathogenic: high titer potent IgM, broad thermal range, associated with mycoplasma pneumoniae

I alloantibody

Naturally occurring, clinically insignificant unless 37C reactive, IgG or IgM

i autoantibody

Cold reactive IgM, associated with EBV / myeloid leukemia / alcoholic cirrhosis

IgG forms expressed on infant red cells can cause HDFN

Anti- I(T) disease state

Hodgkin's Lymphoma

- recognized during transition

K/k phenotype importance

big: low frequency, very immunogenic

little: high frequency

Ko phenotype importance

rare, no RBC abnormality

- if immunized, make anti-Ku which can cause HDFN, HTR

Kx and Kell relationship

Sex-linked gene

Covalently linked together

Mutations in Kx system

If mutated and no antigen, McLeod phenotype (anemia, acanthocytes, cardiomyopathy)

- some cases, also Chronic Granulomatous Disorder

Anti-K significance and frequency

3rd most common (after ABO, Rh)

IgG

high titers can remain for years

must transfuse with negative cells - clinically significant (HDFN, HTR)

Why is Kidd called "treacherous"

Disappearing antibody

Kidd antigen function

RBC urea transporter

Jk(null) phenotype significance

Deficiency in urea transport

usually rare, but slightly more common in Polynesian populations

Enzymes on Duffy antibodies

destroyed by ZZAP and enzymes

Duffy antigens - special functions

Act as chemokine receptors

Genetics and antigen formation for MN

GYPA

Antigens carried by Glycophorin A

High in sialic acid (destroyed by neuraminidase)

Lectin = Vicia graminea

Developed at birth

Genetics and antigen formation for Ss

GYPB

Antigens carried by Glycophorin B

Less accessible to enzymes - no change

Developed at birth

Genetics and antigen formation for U

GYPB

Antigens carried by Glycophorin B

Less accessible to enzymes - no change

Can develop due to pregnancy or transfusion

Lu(null) phenotype

Inheritance of inhibitor or a silent gene

KLF1 Lu(null)

Low levels of antigen expressed, but inhibitor present

- inhibitor also affects i, P1

- no correlating antibodies

Lu(null) silent gene

Silent gene inherited in homozygous state

- no antigens

- anti-Lu3 produced

ADT vs Antibody ID tests

One is a screen, the other is a panel to concretely identify the one causing a positive screen

Circumstances to suspect unexpected antibodies

Pregnancy, incompatible crossmatch, positive ADT or DAT

Autologous control purpose

To rule out auto-antibody

Rule of 3s

Three different cells test positive and three different cells test negative for most likely antibody in a panel

Plasma choices

No worries about Rh, match type with antibodies in donor unit

Titer endpoint

Read as the reciprocal of the dilution of the last positive tube

Titer strength

use scoring of agglutination strength and score to determine overall reaction grade

- include pro-zone as 4+

Titer IgG or IgM?

Saline, room temp = IgM

37C, AHG = IgG

Or use Beta-2-mercaptoethanol and DTT - destroy IgM

Why are titers performed?

Pregnancy, test anti-sera, manage ABO incompatible transfusion, sort multiple antibodies, diagnose immunodeficiency diseases

Transfusion reaction

complication of a blood transfusion in which a severe immune response occurs

Immediate transfusion reaction

AHTR

FNHTR

TRALI

Bacterial contamination

TACO

Allergy / Anaphylaxis

Immediate afebrile

Allergy / Anaphylaxis

TACO

Delayed transfusion reaction

DHTR

TA-GVHD

PTP

Iron Overload

Delayed afebrile

PTP

Iron Overload

Mild allergic transfusion reaction

Most common transfusion reaction

Hives

Maybe due to type 1 hypersensitivity

Stop transfusion and give anti-histamines

Use washed cell product in future

Severe allergic transfusion reaction

Uncommon

Hypotension and bronchospasms

Maybe due to type 1 hypersensitivity, IgA deficiency, IgA antibodies

Stop transfusion and give epinephrine or vasopressors

Use products from IgA deficient donors

Transfusion associated circulatory overload (TACO)

Common, likely under-reported

Hypertension and dyspnea

Heart disease, elderly, and infants

Stop transfusion and give diuretics

Aliquot products and give slowly

Sepsis due to bacterial contamination

Uncommon, under-reported

High fever, hypotension, rigors, flu-like

Bacteria enter product through donor skin, or platelet stored at room temp

Stop transfusion and give antibiotics

Prevent with careful procedural attention

Febrile non-hemolytic transfusion reaction (FNHTR)

Common

Fever and chills

Secretion of cytokines by donor leukocytes

Stop transfusion and give antipyretics

Prevent with leukoreduction

Transfusion-related acute lung injury (TRALI)

Very rare

Injury occurs within 6 hours

Donor HLA and HNA activate recipient leukocytes that destroy tissue

Stop transfusion; may need to intubate

Use male-only plasma or use HLA screening of female donors

Acute hemolytic transfusion reaction (AHTR)

Very rare

Fever, chills, flank pain, DIC, hypotension hemoglobinuria, renal failure, "sense of doom"

Incompatible red cells

Stop transfusion, send unit back to lab, treat with diuretics, fluids, vasopressors, platelets, CRYO, FFP

Prevent with attention to procedures

Delayted hemolytic transfusion reaction (DHTR)

Uncommon

Fever, hyperbilirubinemia, jaundice

Anamnestic response

Stop transfusion, send unit back to lab, treat with diuretics, fluids, vasopressors, platelets, CRYO, FFP

Prevent with attention to procedures

Transfusion-associated Graft vs. Host disease (TA-GVHD)

Rare

Fever about 10-days post transfusion, skin rash, diarrhea, vomiting, marrow aplasia, infection, death

Attack recipient non-HLA graft by donor CD4, CD8, NK cells

Give immunosuppressants

Prevent by irradiating products

Post-transfusion purpura (PTP)

Rare

Thrombocytopenia and bleeding 7-10 days post transfusion after platelet products

Due to antibodies to platelet antigens

Transfuse with HPA-1a negative platelets, IVIg and therapeutic plasma exchange

Prevent with recipient platelet antibody screen

Iron overload

Rare

Liver cirrhosis, diabetes, cardiomyopathy

Occurs in tfn dependent patients who have received >100 red cell transfusions

Choose carefully who needs red cells and treat those who require more with iron chelators

Investigation of transfusion reaction

Clerical and Laboratory testing

Tests for determining transfusion reaction

1. Post-transfusion sample: observe for hemolysis

2. DAT

3. ABO/Rh on pre- and post-transfusion sample

4. GS and culture (if bacterial contamination suspected)

Additional tests for suspected acute reaction

Haptoglobin and LDH

Urine tests

Pos DAT? Perform elution

Bilirubin - direct and indirect

Repeat crossmatch and screen

Labs for Septicemia rxn

positive culture and Gram stain

Labs for Hemolytic rxn

DAT +

Hemolysis

Decreased haptoglobin, hemoglobin, hematocrit in post-transfusion sample

Hemoglobinuria in first void

Elevated bilirubin, LDH

Labs for allergic rxn

none

Labs for anaphylactic rxn

non

Labs for TACO rxn

nope

Labs for febrile rxn

nada

Enhancement reagents

LISS

PEG

Bovine albumin

Polybrene

LISS

increases antibody uptake

PEG

displaces water to concentrate antibody

- can cause non-specific agglutination

- read at IS and AHG (no 37C)

Bovine albumin

decreases zeta potential

Polybrene

Causes rouleaux

- add sodium citrate to break up all rouleaux

- what is left is true agglutination

Crossmatch positive, panel negative?

wrong ABO type

disappearing antibody

antibody not on the panel