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Blood Bank Case StudiesCase Studies from the reference laboratory
Jackie Ensley, MLS(ASCP)CMSBB
1
• Present various case studies and describe the approach to serologic problem solving and antibody identification.
• Determine possible causes of pan-reactivity and steps to resolve complex antibody cases.
• Briefly review serologic and molecular characteristics of antibodies identified and their respective blood group system, including clinical significance.
• Explain the various techniques and methods used in the case studies for antibody identification.
Objectives
2
• Antibody detection and identification is a complex problem-solving process
• Many techs may have a “gut-feeling” about the antibody before testing completion and intuitively know what needs to be done for antibody identificationo Be prepared to reevaluate your hypothesis if testing results do
not fit with initial assessment
Antibody Identification
3
• Use the tools available to help you detect and then identify the antibody:o Gel/solid phaseo Tube testing: saline/PeG/LISS/albumin/Room temperature/4˚Co Enzymes such as ficin, papain, trypsino Chemicals such as 0.2M DTTo Adsorption/elutiono Reticulocyte/sickle cell separationo Phenotypically similar cellso Antisera/rare antigen negative cells
Antibody Identification
4
• Know phases of reactivityo Some antibodies react best at room temperature/4˚C (M, N, P1, Lewis,
etc)o Some antigens destroyed by enzymes/chemicals (Ficin destroys Fya,
Fyb, M, N, etc)o Enzyme treatment of red cells enhances reactivity of some antibodies
such as those in the Rh system, Jka, Jkb, Lea, Leb, P1
• Know strength/pattern of reactivityo Some antigens show variable antigen expression and some antibodies
show variable reactivity and may show dosage, such as -Jka/-Jkb and -M/-N
o Note: different strengths may also indicate more than one antibody is present
Antibody Identification
5
• Besides using the blood bank techniques available to detect the antibody, also keep in mind these tips to aid you in the identification process:
o Review patient’s records, including medication, age, gender, race, diagnosis and transfusion history
o Investigate/repeat any inconsistent or contradictory reactions in the patient’s workup
o Phenotype the patient to confirm they are antigen negative for the suspected or identified antibodies
Antibody Identification
6
Case Study 1PATIENT HISTORY
• Female, 51 years old • Caucasian• Diagnosis: Anemia and GI bleedThe patient was seen on 12/12/2013. She typed as A Positive and had a negative antibody screen. She was transfused at that time.Current H/H: 7.7/ 24.8The hospital reports on 2/14/2014 a positive antibody screen in tubes with LISS (3+) with a positive autocontrol. The DAT/IgG is positive (2+). 4 out of 4 units are crossmatch incompatible. Hospital decides to send to the reference laboratory.
Case Study 1
• Reference Lab testing:– ABO/Rh performed:
– DAT Performed:
Anti-A Anti-B Anti-D A1 Cell B Cell ABO/Rh4+ 0 4+ 0 4+ A Positive
Anti-IgG/ Gel Anti-C3/ Gel
3+ 0
Plasma
Rh System Kell Duffy Kidd Lewis P MNS Lutheran
Room Temp
AHG-PeG
Cell
D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
I + + 0 0 + 0 + 0 + 0 + 0 + + 0 + 0 0 0 + 0 + 0 + 0 2+II + 0 + + 0 0 + 0 + 0 + + 0 0 + + 0 + + + + + 0 + 0 1+III 0 0 + 0 + + + + + 0 + + + + 0 0 + + + 0 + 0 0 + 0 2+Auto 0 1+
Plasma
Rh System Kell Duffy Kidd Lewis P MNS Lutheran
GELCell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
1 + + 0 0 + 0 + 0 + 0 + 0 + 0 + + 0 + + 0 + 0 0 + 2+2 + + 0 0 + 0 + 0 + 0 + 0 + + + + 0 0 0 + 0 + + + 2+3 + 0 + + 0 + + 0 + 0 + 0 + + + 0 + 0 0 + 0 + 0 + 2+4 + 0 + 0 + 0 + 0 + + + 0 0 + 0 0 + + 0 + + + + + 2+5 0 + + 0 + 0 + 0 + 0 + + + + 0 0 + 0 + 0 0 + 0 + 2+6 0 0 + + + 0 + 0 + 0 + + + + 0 + 0 + + 0 + 0 0 + 2+7 0 0 + 0 + + + 0 + 0 + 0 + + + 0 + + + 0 0 + 0 + 2+8 0 0 + 0 + 0 + 0 + 0 + + 0 0 + 0 0 + + + 0 + 0 + 2+9 0 0 + 0 + 0 + + + 0 + + 0 0 + 0 + 0 + + + + 0 + 2+10 + + 0 0 + + 0 0 + 0 + 0 + + 0 0 + + + + 0 + 0 + 2+11 + w+ 0 + 0 + 0 + 0 + 0 0 + 0 0 0 + + + 0 + 0 + 2+Auto 2+
Eluate
Rh System Kell Duffy Kidd Lewis P MNS Lutheran
GELCell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
1 + + 0 0 + 0 + 0 + 0 + 0 + 0 + + 0 + + 0 + 0 0 + 3+2 + + 0 0 + 0 + 0 + 0 + 0 + + + + 0 0 0 + 0 + + + 3+3 + 0 + + 0 + + 0 + 0 + 0 + + + 0 + 0 0 + 0 + 0 + 3+4 + 0 + 0 + 0 + 0 + + + 0 0 + 0 0 + + 0 + + + + + 3+5 0 + + 0 + 0 + 0 + 0 + + + + 0 0 + 0 + 0 0 + 0 + 3+6 0 0 + + + 0 + 0 + 0 + + + + 0 + 0 + + 0 + 0 0 + 3+7 0 0 + 0 + + + 0 + 0 + 0 + + + 0 + + + 0 0 + 0 + 3+8 0 0 + 0 + 0 + 0 + 0 + + 0 0 + 0 0 + + + 0 + 0 + 3+9 0 0 + 0 + 0 + + + 0 + + 0 0 + 0 + 0 + + + + 0 + 3+10 + + 0 0 + + 0 0 + 0 + 0 + + 0 0 + + + + 0 + 0 + 3+11 + w+ 0 + 0 + 0 + 0 + 0 0 + 0 0 0 + + + 0 + 0 + 3+
The Eluate Last Wash is negative
• Let’s look at what we know:– Phase of reactivity: AHG– Strength/pattern of reactivity: pan-reactive, about
the same strength.– Patient history: recently transfused– DAT/autocontrol: positive/reactive– Other info: eluate is also pan-reactive with same
strength
Serologic Problem Solving
Question to ask yourself: So where do we go at this point?
• Narrowed down possibilities:1. Warm autoantibody 2. Multiple antibodies in plasma (and eluate)3. Antibody to a high incidence antigen
Serologic Problem Solving
Question to ask yourself: So where do we go at this point?
Next Step:
• Reference tech decides to perform adsorption on plasma only.
Why not an adsorption on the eluate?
• The patient has been transfused in the last 3 months…
Technical Manual States that “newly developed antibodies initially detectable only in the eluate are usually detectable in the serum after about 14 to 21 days”
Blood Bank Technique: Adsorption
What is an adsorption?
Blood bank technique where red cells and plasma (or eluate) are mixed, causing antibody to be adsorbed onto the red cell surface.
Types of Adsorption:
Autologous: Patient plasma is mixed with patient cells
PATIENT MUST NOT HAVE BEEN TRANSFUSED last 3 months
Differential/Allogeneic: Patient plasma is mixed with R1R1, R2R2, and rr donor cells of known phenotypes.
Antibodies to high incidence antigens may be adsorbed out
How is an alloadsorption performed?
• Alloadsorption: Patient has been transfused or transfusion is unknown.
Patient’s Plasma + Donor RBC’s
Incubate together to adsorb the antibodies onto the donor
red cells
=
R1R1
rr
R2R2
Blood Bank Technique: Adsorption
How is an alloadsorption performed?
Incubation allows any antibody to adsorb onto the
red cells (alloantibody or autoantibody)
=
Adso
rptio
n Ce
lls- d
isca
rd
Adso
rptio
n Pl
asm
a- T
est R1R1
R2R2
rr
Centrifuge the tubes and separate the adsorbed plasma from the red cells for testing
How is an alloadsorption performed?
R1R1(D+C+E-c-e+)
R2R2(D+C-E+c+e-)
rr (D-C-E-c+e+)
Run each adsorbed plasma with panel cells to identify any antibodies. Antibodies in adsorbed plasma will depend on the phenotype of the adsorbing cell.
Example: anti-E Example: anti-E
R1R1 Adsorption Rh System Kell Duffy Kidd Lewis P MNS Lutheran
X2 PeG- Plasma
Cell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
R1R1 Cell Phenotype + + 0 0 + 0 + 0 + 0 + + 0 0 + + 0 0 0 + 0 + 0 +
1 + + 0 0 + 0 + 0 + 0 + 0 + 0 + + 0 + + 0 + 0 0 + 0√2 + + 0 0 + 0 + 0 + 0 + 0 + + + + 0 0 0 + 0 + + + 1+3 + 0 + + 0 + + 0 + 0 + 0 + + + 0 + 0 0 + 0 + 0 + 1+4 + 0 + 0 + 0 + 0 + + + 0 0 + 0 0 + + 0 + + + + + 2+5 0 + + 0 + 0 + 0 + 0 + + + + 0 0 + 0 + 0 0 + 0 + 2+6 0 0 + + + 0 + 0 + 0 + + + + 0 + 0 + + 0 + 0 0 + 2+7 0 0 + 0 + + + 0 + 0 + 0 + + + 0 + + + 0 0 + 0 + 1+8 0 0 + 0 + 0 + 0 + 0 + + 0 0 + 0 0 + + + 0 + 0 + 0√9 0 0 + 0 + 0 + + + 0 + + 0 0 + 0 + 0 + + + + 0 + 0√10 + + 0 0 + + 0 0 + 0 + 0 + + 0 0 + + + + 0 + 0 + 2+11 + w+ 0 + 0 + 0 + 0 + 0 0 + 0 0 0 + + + 0 + 0 + 2+
R2R2 Adsorption Rh System Kell Duffy Kidd Lewis P MNS Lutheran
X3 GEL
-Plasma
Cell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
R2R2 Cell Phenotype
+ 0 + + 0 0 + 0 + 0 + + 0 + 0 0 + + + 0 + 0 0 +
1 + + 0 0 + 0 + 0 + 0 + 0 + 0 + + 0 + + 0 + 0 0 + 0√2 + + 0 0 + 0 + 0 + 0 + 0 + + + + 0 0 0 + 0 + + + 0√3 + 0 + + 0 + + 0 + 0 + 0 + + + 0 + 0 0 + 0 + 0 + 0√4 + 0 + 0 + 0 + 0 + + + 0 0 + 0 0 + + 0 + + + + + 0√5 0 + + 0 + 0 + 0 + 0 + + + + 0 0 + 0 + 0 0 + 0 + 0√6 0 0 + + + 0 + 0 + 0 + + + + 0 + 0 + + 0 + 0 0 + 0√7 0 0 + 0 + + + 0 + 0 + 0 + + + 0 + + + 0 0 + 0 + 0√8 0 0 + 0 + 0 + 0 + 0 + + 0 0 + 0 0 + + + 0 + 0 + 0√9 0 0 + 0 + 0 + + + 0 + + 0 0 + 0 + 0 + + + + 0 + 0√10 + + 0 0 + + 0 0 + 0 + 0 + + 0 0 + + + + 0 + 0 + 0√11 + w+ 0 + 0 + 0 + 0 + 0 0 + 0 0 0 + + + 0 + 0 + 0√
rr Adsorption Rh System Kell Duffy Kidd Lewis P MNS Lutheran
X3 GEL
-Plasma
Cell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
r r Cell Phenotype
0 0 + 0 + 0 + 0 + 0 + 0 + + 0 0 + + 0 + + + 0 +
1 + + 0 0 + 0 + 0 + 0 + 0 + 0 + + 0 + + 0 + 0 0 + 0√2 + + 0 0 + 0 + 0 + 0 + 0 + + + + 0 0 0 + 0 + + + 0√3 + 0 + + 0 + + 0 + 0 + 0 + + + 0 + 0 0 + 0 + 0 + 0√4 + 0 + 0 + 0 + 0 + + + 0 0 + 0 0 + + 0 + + + + + 0√5 0 + + 0 + 0 + 0 + 0 + + + + 0 0 + 0 + 0 0 + 0 + 0√6 0 0 + + + 0 + 0 + 0 + + + + 0 + 0 + + 0 + 0 0 + 0√7 0 0 + 0 + + + 0 + 0 + 0 + + + 0 + + + 0 0 + 0 + 0√8 0 0 + 0 + 0 + 0 + 0 + + 0 0 + 0 0 + + + 0 + 0 + 0√9 0 0 + 0 + 0 + + + 0 + + 0 0 + 0 + 0 + + + + 0 + 0√10 + + 0 0 + + 0 0 + 0 + 0 + + 0 0 + + + + 0 + 0 + 0√11 + w+ 0 + 0 + 0 + 0 + 0 0 + 0 0 0 + + + 0 + 0 + 0√
R1R1 Adsorption Rh System Kell Duffy Kidd Lewis P MNS Lutheran
X2 PeG- Plasma
Cell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
R1R1 Cell Phenotype + + 0 0 + 0 + 0 + 0 + + 0 0 + + 0 0 0 + 0 + 0 +
1 + + 0 0 + 0 + 0 + 0 + 0 + 0 + + 0 + + 0 + 0 0 + 0√2 + + 0 0 + 0 + 0 + 0 + 0 + + + + 0 0 0 + 0 + + + 1+3 + 0 + + 0 + + 0 + 0 + 0 + + + 0 + 0 0 + 0 + 0 + 1+4 + 0 + 0 + 0 + 0 + + + 0 0 + 0 0 + + 0 + + + + + 2+5 0 + + 0 + 0 + 0 + 0 + + + + 0 0 + 0 + 0 0 + 0 + 2+6 0 0 + + + 0 + 0 + 0 + + + + 0 + 0 + + 0 + 0 0 + 2+7 0 0 + 0 + + + 0 + 0 + 0 + + + 0 + + + 0 0 + 0 + 1+8 0 0 + 0 + 0 + 0 + 0 + + 0 0 + 0 0 + + + 0 + 0 + 0√9 0 0 + 0 + 0 + + + 0 + + 0 0 + 0 + 0 + + + + 0 + 0√10 + + 0 0 + + 0 0 + 0 + 0 + + 0 0 + + + + 0 + 0 + 2+11 + w+ 0 + 0 + 0 + 0 + 0 0 + 0 0 0 + + + 0 + 0 + 2+
Autoantibody Confirmation Testing
• Patient had been transfused in the last 3 months so need to perform reticulocyte separation– Want to be testing patient cells and not donor
cells
How is a Reticulocyte Cell Separation Performed?
• Patient has been transfused so need to separate patient cells from donor red cells
Spin the sample down and fill microhematocrit tubes with the red cells.
Stopper one end of the hematocrit tube with clay.
Blood Bank Technique: Reticulocyte Cell Separation
How is a Reticulocyte Cell Separation Performed?
Clay Plug
Newer Red Cells
Older Red Cells
Air
Excess saline/plasmaBuffy Coat
Spin the microhematocrit tubes and then cut the tubes to get the reticulocytes
Blood Bank Technique: Reticulocyte Cell Separation
Autoantibody Confirmation Testing
Now that we have the retics:• DAT/IgG had been positive so perform DAT/IgG
on retics:
Retics
Anti-IgG/ tube
1+
Can not proceed with testing to identify warm autoantibody until the DAT is negative
How do we get the DAT/IgG negative?
EGA Treatment• What is EGA? – EDTA glycine acid dissociates IgG from red blood
cells so the treated red cells can be used for further testing or antigen typing using the AHG phase.
– Use when direct antiglobulin phase (DAT) is positive
– Does not impair red cell surface antigens
Blood Bank Technique: EGA Treatment
EGA Treatment• The Process– Wash IgG coated red cells thoroughly– Suspend cells briefly in EGA solution to dissociate
bound IgG antibody– Bring mixture to neutral pH– Centrifuge and wash cells with saline
• Test treated cells by performing a DAT• Limitation: destroys Kell, Era, Bg antigens
Blood Bank Technique: EGA Treatment
Autoantibody investigation
• EGA testing performed and DAT negative retics obtained
• To confirm the antibody is warm autoantibody the DAT negative retics are tested against the plasma and eluate:
Retics-Plasma Retics-Eluate
Gel Gel
2+ 3+
This is what was expected if the antibody was autoantibody! Further testing is not required, the warm autoantibody has been confirmed.
Antibody Confirmation
• Lastly need to confirm anti-Jka (JK1) by antigen typing
• Use retics so that typing patient cells and not donor cells
Anti-Jk
Tube
0
Patient types Jka negative
Results
• Patient has warm autoantibody and anti-Jka (JK1).
• Transfusion recommendations:Transfuse Jka- (JK1), AHG crossmatch least
incompatible, red blood cell products.
Kidd Blood Group System
·Daniels, G. (2013) Kidd Blood Group System, in Human Blood Groups, 3rd edition, Wiley-Blackwell, Oxford, UK.
• Located Chromosome 18
• Glycoprotein with 10 membrane spanning domains
Kidd antibodies are often difficult to work with and are a common cause of delayed hemolytic reactions
Jka (JK1) Antibody & AntigenJka Antibody Characteristics
History 1951
Clinical Significance Yes! Clinically significant·Transfusion Reactions possible, immediate or delayed hemolytic·HDN possible, mild to moderate
Antibody IgG/IgM
Other facts ·Jka has been demonstrated on fetal cells as early as 11 weeks·Antibody fades in vitro and in vivo·Can show dosage
Jka Antigen Characteristics
Occurrence Caucasians 77%Blacks 92%
Reid, Marion and Christine Lomas-Francis (2012). The Blood Group Antigen FactsBook, 3rd Edition, Elsevier.
Case Study 2PATIENT HISTORY
• Female, 38 years old • African American• DIAGNOSIS:-Severe Sepsis--blood cultures showed Finegoldia magna (normal flora of the gastrointestinal and genitourinary tract, and can be isolated from skin and the oral; often regarded as a contaminant in cultures) with subsequent cultures after that date with no growth. -Probable pneumonia -Cardiac arrest -Hypertensive-Acute respiratory failure
-Acute renal failure -Positive for influenza A
Case Study 2PATIENT HISTORY
• The patient arrived as in-patient on 1/15/2014 and was typed as B Positive with negative antibody screen. Patient was transfused 2 B Positive RBCs at that time.
• Patient was monitored and was still very ill
• On 1/24/2014 patient required another transfusion and sample was sent to hospital blood bank.
Case Study 2
• The 2nd sample was collected on 1/24/2014, 9 days after transfusion.
• Sample was sent to the reference laboratory
Hospital Results on 1/24/2014:B PositiveAll cells reactive 2+ in gelAutocontrol positive
Case Study 2
• Reference Lab testing:– ABO/Rh performed:
– DAT Performed:
Anti-A Anti-B Anti-D A1 Cell B Cell ABO/Rh0 4+ 4+ 4+ 0 B Positive
Anti-IgG/ Gel Anti-C3/ tube
W+ 0√
Plasma
Rh System Kell Duffy Kidd Lewis P MNS Lutheran
Room Temp
AHG-PeG
Cell
D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
I + + 0 0 + 0 + 0 + 0 + 0 + 0 + + 0 + + + + + 0 + 0 1+II + 0 + + 0 + + 0 + 0 + + + + + + 0 0 + 0 + 0 0 + 0 2+III 0 0 + 0 + 0 + 0 + 0 + + 0 + 0 0 + + 0 + 0 + 0 + 0 2+Auto 0 0√
Plasma
Rh System Kell Duffy Kidd Lewis P MNS Lutheran
GELCell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
1 + + 0 0 + + + + + 0 + + + + 0 + 0 W0 + + 0 0 + 2+2 + + 0 0 + 0 + 0 + 0 + + + + 0 0 + + + 0 + + 0 + 2+3 + 0 + + 0 0 + 0 + 0 + + + + 0 0 + 0 + 0 + + + + 2+4 + 0 + 0 + 0 + 0 + 0 + 0 0 + 0 0 + + + 0 + 0 0 + 2+5 0 + + 0 + 0 + 0 + 0 + + 0 + + 0 + + + 0 0 + 0 + 2+6 0 0 + + + 0 + 0 + 0 + 0 + + 0 + 0 0 + 0 + + 0 + 2+7 0 0 + 0 + + + 0 + 0 + 0 + + 0 0 + 0 0 + 0 + 0 + 2+8 0 0 + 0 + 0 + 0 + 0 + + 0 + + + 0 0 + + 0 + 0 + 2+9 0 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 0 + + + + + 0 + 2+10 0 0 + + + + + 0 + 0 + 0 + 0 + + 0 + + + + + + + 2+11 + 0 + 0 + 0 + 0 + + + 0 0 + 0 0 0 + 0 + + + 0 + 2+Auto W+
Eluate
Rh System Kell Duffy Kidd Lewis P MNS Lutheran
GELCell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
1 + + 0 0 + + + + + 0 + + + + 0 + 0 W 0 + + 0 0 + 4+2 + + 0 0 + 0 + 0 + 0 + + + + 0 0 + + + 0 + + 0 + 4+3 + 0 + + 0 0 + 0 + 0 + + + + 0 0 + 0 + 0 + + + + 4+4 + 0 + 0 + 0 + 0 + 0 + 0 0 + 0 0 + + + 0 + 0 0 + 4+5 0 + + 0 + 0 + 0 + 0 + + 0 + + 0 + + + 0 0 + 0 + 4+6 0 0 + + + 0 + 0 + 0 + 0 + + 0 + 0 0 + 0 + + 0 + 4+7 0 0 + 0 + + + 0 + 0 + 0 + + 0 0 + 0 0 + 0 + 0 + 4+8 0 0 + 0 + 0 + 0 + 0 + + 0 + + + 0 0 + + 0 + 0 + 4+9 0 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 0 + + + + + 0 + 4+10 0 0 + + + + + 0 + 0 + 0 + 0 + + 0 + + + + + + + 4+11 + 0 + 0 + 0 + 0 + + + 0 0 + 0 0 0 + 0 + + + 0 + 4+
The Eluate Last Wash is negative
• Let’s look at what we know:– Phase of reactivity: AHG– Strength/pattern of reactivity: pan-reactive, same
strength.– Patient history: recently transfused– DAT/autocontrol: positive/reactive– Other info: eluate is also pan-reactive with same
strength
Serologic Problem Solving
Question to ask yourself: So where do we go at this point?
Question to ask yourself: So where do we go at this point?
• Narrowed down possibilities:1. Warm autoantibody 2. Multiple antibodies in plasma and eluate3. Antibody to a high incidence antigen
Serologic Problem Solving
Next Step:
• Reference tech decides to perform adsorptions on plasma & eluate.
Why perform an adsorption?• To adsorb out suspected warm autoantibody
and determine if there are any alloantibodies hiding under the pan-reactivity.
R1R1 Adsorption Rh System Kell Duffy Kidd Lewis P MNS Lutheran
X3
GEL-
Plasma
X3
GEL-
Eluate
Cell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
R1R1 Cell Phenotype
+ + 0 0 + 0 + 0 + 0 + + 0 + 0 0 + + + + + + 0 +
1+ + 0 0 + + + + + 0 + + + + 0 + 0 W 0 + + 0 0 + 0 0
2+ + 0 0 + 0 + 0 + 0 + + + + 0 0 + + + 0 + + 0 + 0 0
3+ 0 + + 0 0 + 0 + 0 + + + + 0 0 + 0 + 0 + + + + 0 0
4+ 0 + 0 + 0 + 0 + 0 + 0 0 + 0 0 + + + 0 + 0 0 + 0 0
50 + + 0 + 0 + 0 + 0 + + 0 + + 0 + + + 0 0 + 0 + 0 0
60 0 + + + 0 + 0 + 0 + 0 + + 0 + 0 0 + 0 + + 0 + 0 0
70 0 + 0 + + + 0 + 0 + 0 + + 0 0 + 0 0 + 0 + 0 + 0 0
80 0 + 0 + 0 + 0 + 0 + + 0 + + + 0 0 + + 0 + 0 + 0 0
90 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 0 + + + + + 0 + 0 0
100 0 + + + + + 0 + 0 + 0 + 0 + + 0 + + + + + + + 0 0
11+ 0 + 0 + 0 + 0 + + + 0 0 + 0 0 0 + 0 + + + 0 + 0 0
R2R2 Adsorption Rh System Kell Duffy Kidd Lewis P MNS Lutheran
X3
GEL-Plasma
X3
GEL-Eluate
Cell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
R2R2 Cell Phenotype
+ 0 + + 0 0 + 0 + 0 + 0 + + + 0 + + 0 + 0 + 0 +
1+ + 0 0 + + + + + 0 + + + + 0 + 0 W 0 + + 0 0 + 0 0
2+ + 0 0 + 0 + 0 + 0 + + + + 0 0 + + + 0 + + 0 + 0 0
3+ 0 + + 0 0 + 0 + 0 + + + + 0 0 + 0 + 0 + + + + 0 0
4+ 0 + 0 + 0 + 0 + 0 + 0 0 + 0 0 + + + 0 + 0 0 + 0 0
50 + + 0 + 0 + 0 + 0 + + 0 + + 0 + + + 0 0 + 0 + 0 0
60 0 + + + 0 + 0 + 0 + 0 + + 0 + 0 0 + 0 + + 0 + 0 0
70 0 + 0 + + + 0 + 0 + 0 + + 0 0 + 0 0 + 0 + 0 + 0 0
80 0 + 0 + 0 + 0 + 0 + + 0 + + + 0 0 + + 0 + 0 + 0 0
90 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 0 + + + + + 0 + 0 0
100 0 + + + + + 0 + 0 + 0 + 0 + + 0 + + + + + + + 0 0
11+ 0 + 0 + 0 + 0 + + + 0 0 + 0 0 0 + 0 + + + 0 + 0 0
rr Adsorption Rh System Kell Duffy Kidd Lewis P MNS Lutheran
X3
GEL-Plasma
X3
GEL-Eluate
Cell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
r r Cell Phenotype
0 0 + 0 + 0 + 0 + 0 + + + 0 + + 0 0 + 0 + 0 0 +
1+ + 0 0 + + + + + 0 + + + + 0 + 0 W 0 + + 0 0 + 0 0
2+ + 0 0 + 0 + 0 + 0 + + + + 0 0 + + + 0 + + 0 + 0 0
3+ 0 + + 0 0 + 0 + 0 + + + + 0 0 + 0 + 0 + + + + 0 0
4+ 0 + 0 + 0 + 0 + 0 + 0 0 + 0 0 + + + 0 + 0 0 + 0 0
50 + + 0 + 0 + 0 + 0 + + 0 + + 0 + + + 0 0 + 0 + 0 0
60 0 + + + 0 + 0 + 0 + 0 + + 0 + 0 0 + 0 + + 0 + 0 0
70 0 + 0 + + + 0 + 0 + 0 + + 0 0 + 0 0 + 0 + 0 + 0 0
80 0 + 0 + 0 + 0 + 0 + + 0 + + + 0 0 + + 0 + 0 + 0 0
90 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 0 + + + + + 0 + 0 0
100 0 + + + + + 0 + 0 + 0 + 0 + + 0 + + + + + + + 0 0
11+ 0 + 0 + 0 + 0 + + + 0 0 + 0 0 0 + 0 + + + 0 + 0 0
Results
• Appears to be warm autoantibody• No alloantibodies were detected in the
alloadsorbed plasma or eluate
Need to confirm warm autoantibody
Autoantibody Confirmation Testing
• Patient had been transfused 9 days ago so perform reticulocyte separation.
• DAT/IgG had been positive so perform DAT/IgG on retics:
Retics
Anti-IgG/ Gel
O
Proceed with further testing to identify warm autoantibody
Autoantibody Confirmation Testing
• To confirm the antibody is warm autoantibody the retics are tested against the plasma and eluate:
Retics-Plasma Retics-Eluate
Gel Gel
0 0
This is NOT what was expected if the antibody was autoantibody! Further testing is required and now antibody to a high incidence antigen is suspected
• Narrowed down possibilities:1. Warm autoantibody 2. Multiple antibodies in plasma and eluate3. Antibody to a high incidence antigen
Serologic Problem Solving
Question to ask yourself: So where do we go at this point?
Next Step:
• Use blood bank techniques, reagents and cells to try and determine the antibody
SOME TECHNIQUES/OPTIONS AVAILABLE:
• ENZYMES (FICIN, PAPAIN, TRYPSIN, ETC)
• CHEMICALS SUCH AS DTT
• PHENOTYPE PATIENT
• RARE ANTISERA
• RARE CELLS
Ficin Panel Rh System Kell Duffy Kidd Lewis P MNS Lutheran
GEL
GEL-Ficin
Cell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
1 + + 0 0 + + + + + 0 + + + + 0 + 0 W 0 + + 0 0 + 2+ 3+2 + + 0 0 + 0 + 0 + 0 + + + + 0 0 + + + 0 + + 0 + 2+ 3+3 + 0 + + 0 0 + 0 + 0 + + + + 0 0 + 0 + 0 + + + + 2+ 3+4 + 0 + 0 + 0 + 0 + 0 + 0 0 + 0 0 + + + 0 + 0 0 + 2+ 3+5 0 + + 0 + 0 + 0 + 0 + + 0 + + 0 + + + 0 0 + 0 + 2+ 3+6 0 0 + + + 0 + 0 + 0 + 0 + + 0 + 0 0 + 0 + + 0 + 2+ 3+7 0 0 + 0 + + + 0 + 0 + 0 + + 0 0 + 0 0 + 0 + 0 + 2+ 3+8 0 0 + 0 + 0 + 0 + 0 + + 0 + + + 0 0 + + 0 + 0 + 2+ 3+9 0 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 0 + + + + + 0 + 2+ 3+10 0 0 + + + + + 0 + 0 + 0 + 0 + + 0 + + + + + + + 2+ 3+11 + 0 + 0 + 0 + 0 + + + 0 0 + 0 0 0 + 0 + + + 0 + 2+ 3+Auto
W+ 1+
0.2 M DTT Panel Rh System Kell Duffy Kidd Lewis P MNS Lutheran
GEL
GEL-0.2M DTT
Cell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
1+ + 0 0 + + + + + 0 + + + + 0 + 0 W 0 + + 0 0 + 2+ 2+
2+ + 0 0 + 0 + 0 + 0 + + + + 0 0 + + + 0 + + 0 + 2+ 2+
3+ 0 + + 0 0 + 0 + 0 + + + + 0 0 + 0 + 0 + + + + 2+ 2+
4+ 0 + 0 + 0 + 0 + 0 + 0 0 + 0 0 + + + 0 + 0 0 + 2+ 2+
50 + + 0 + 0 + 0 + 0 + + 0 + + 0 + + + 0 0 + 0 + 2+ 2+
60 0 + + + 0 + 0 + 0 + 0 + + 0 + 0 0 + 0 + + 0 + 2+ 2+
70 0 + 0 + + + 0 + 0 + 0 + + 0 0 + 0 0 + 0 + 0 + 2+ 2+
80 0 + 0 + 0 + 0 + 0 + + 0 + + + 0 0 + + 0 + 0 + 2+ 2+
90 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 0 + + + + + 0 + 2+ 2+
100 0 + + + + + 0 + 0 + 0 + 0 + + 0 + + + + + + + 2+ 2+
11+ 0 + 0 + 0 + 0 + + + 0 0 + 0 0 0 + 0 + + + 0 + 2+ 2+
Auto W+
Case Study 2• Ficin and DTT testing has helped narrow down
the possibilities. Some high incidence antigens resistant to Ficin and 0.2M DTT Treatment:
Lan ABTI PEL U Fy3
Ata MAM Dib Ge3 Fy5
Emm Oka Wrb EnaFR Era
Sda (Ficin enhanced0
Coa CO3 Vel (Ficin enhanced)
Jra (Ficin enhanced)
Consider the race of patient and start with the easiest to test for
The list is not all-inclusive. Refer to The Blood Group Antigen FactsBook by Marion E Reid and Christine Lomas-Francis for support regarding antigen/antibody reactivity.
Selected Cells Run
Rh System Kell Duffy Kidd Lewis P MNS LutheranGEL
Donor
D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub U
D1083
+ 0 + 0 + 0+ 0 + 0 + + 0 + + 0 + + 0 + 0 0 + + 0 0N1727
0 0 + 0 + 0+ 0 + 0 + 0 0 + + 0 + + + + 0 0 0 + 0 0
Rh System Kell Duffy Kidd Lewis P MNS LutheranGEL
Donor
D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub U
D1083
+ 0 + 0 + 0+ 0 + 0 + + 0 + + 0 + + 0 + 0 0 + + 0 0N1727
0 0 + 0 + 0+ 0 + 0 + 0 0 + + 0 + + + + 0 0 0 + 0 0
Eluate Testing
Plasma Testing
Patient is antigen typed with the retics and is U-
BioArray Molecular ResultsRh c +
Duffy Fya +
Dombrock Doa 0
C 0 Fyb 0 Dob +
e + MNS M + Joa +
E 0 N 0 Hy +
Kell K 0 S LS LW Lwa +
k + s LS Lwb 0
Kpa 0 Lutheran Lua 0 Scianna Sc1 +
Kpb + Lub + Sc2 0
Jsa 0 Diego Dia 0 Hemoglobin S HbS 0
Jsb + Dib + U (-)
Kidd Jka + Colton Coa +
Jkb + Cob 0
Results
• The antibody is anti-U (MNS5), not a warm autoantibody as was suspected at first.
Antigen Negative Units Requested:Two U- (MNS5) units were deglycerolized and sent to hospital
Deglycerolization
Red cells are frozen with glycerol, a cryoprotective agent that prevents cellular damage and hemolysis as well as allows them to be frozen at < -65°C for 10 years.
To deglycerolize, the red cells are warmed and then washed with decreasing % NaCl to remove the glycerol and then suspended for transfusion. Once thawed they have a shelf life of 24 hours (if an open system was used).
U (MNS5) AntibodyU Antibody Characteristics
History Anti-U was first described by Wiener et al in 1953. It was called “U” for the universal distribution of the antigen. Not ‘naturally occuring’
Clinical Significance ·Yes! Clinically significant·Transfusion Reactions possible, mild to severe·HDN possible, mild to severe
Antibody ·IgG, reacts best at 37°C/AHG·Autoanti-U is possible
Other facts Some examples of anti-U are not compatible with all U- red cells. This is because some U- red cells are actually U variant and so have small quantities of U antigen.
Reid, Marion and Christine Lomas-Francis (2012). The Blood Group Antigen FactsBook, 3rd Edition, Elsevier.
U (MNS5) AntigenU Antigen Characteristics
Occurrence Caucasians 99.9%Blacks 99%Well developed at birth
Other Facts ·All U- individuals are S-s- but not all S-s- individuals are U-. ·The S-s- phenotype not common in the Caucasian population·U negative phenotype is associated with absence of Glycophorin B (GPB)
Variants U variant is possible
Sources for further reading: ·Reid, Marion and Christine Lomas-Francis (2012). The Blood Group Antigen FactsBook, 3rd Edition, Elsevier.·Daniels, G. (2013) MNS Blood Group System, in Human Blood Groups, 3rd edition, Wiley-Blackwell, Oxford, UK.
Genetics and Biochemistry
• Genes encoding MNS system antigens reside on chromosome 4 – Responsible for the
production of glycophorin A (GPA) and glycophorin B (GPB) on red cells
Genetics and BiochemistryGlycophorin A (GPA)
M and N antigens
Glycophorin B (GPB)S, s and U antigens
GPA and GPB are the major sialic acid containing structures of the red cell
membrane.
Photo Source: http://classconnection.s3.amazonaws.com/414/flashcards/1065414/jpg/mns_biochem1330653387883.jpg
U variants
• S-s-U+ or S-s-U+var
• Almost exclusively in those of African Origin• About 50% of S-s- are U+var
• Strength of expression is variable; adsorption/elution tests may be needed to detect the U antigen
• Strong correlation of U variant antigen cells being He+ (low frequency MNSs antigen).
• Reactivity– The anti-U of S-s-U- will react with S-s-U+var
– The anti-U of U variants will not react with S-s-U- cells.
• GPB of the cell– U- cells are totally GPB-deficient– U variants have a variant GPB molecule that
doesn’t express S or s
U vs U variants
Case Study 3PATIENT HISTORY
• Female, 65 years old • African American• DIAGNOSIS: strokePatient had 45 minute seizure at nursing home before being transported to hospital. Speech was slurred upon arrival to emergency department with facial drooping.Patient has history of seizures, hypothyroidism, GERD, severe anemia, hypertension, congestive heart failure, etc.H/H: 9.9/ 32.1 Last transfusion was 10/27/2012 (>3 months)
Case Study 3• The sample was collected on 01/30/2013
• Sample was sent to the reference laboratory
Hospital Results on 1/30/2013:O PositiveAll cells reactive 2+ in gelAutocontrol not testedAdditional history includes anti-Chido and antibody in Knops system from another facility.
Case Study
• Reference Lab testing:– ABO/Rh performed:
– DAT Performed:
Anti-A Anti-B Anti-D A1 Cell B Cell ABO/Rh0 0 4+ 4+ 4+ 0 Positive
Anti-IgG/ tube Anti-C3/ tube
0√ 0√
PlasmaRh System Kell Duffy Kidd Lewis P MNS Lutheran
Room Temp
AHG-PeG
D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
+ + 0 0 + + + 0 + 0 + + 0 + + + 0 + + 0 + + 0 + 0 1+
+ 0 + + 0 0 + 0 + 0 + 0 + + 0 0 + 0 + 0 + 0 0 + 0 w+
0 0 + 0 + 0 + 0 + 0 + + + 0 + 0 + + 0 + 0 + 0 + 0 w+
0 0√
Plasma
Rh System Kell Duffy Kidd Lewis P MNS Lutheran
GELCell D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
1 + + 0 0 + + + + + 0 + + + + 0 0 0 + 0 + + 0 0 + 1+2 + + 0 0 + 0 + 0 + 0 + + + + 0 0 + + + 0 + + 0 + 1+3 + 0 + + 0 0 + 0 + 0 + + + + 0 0 + 0 + 0 + + + + 1+4 + 0 + 0 + 0 + 0 + 0 + 0 0 + 0 0 + + + 0 + 0 0 + 2+5 0 + + 0 + 0 + 0 + 0 + + 0 + + 0 + + + 0 0 + 0 + 1+6 0 0 + + + 0 + 0 + 0 + 0 + + 0 + 0 0 + 0 + + 0 + 1+7 0 0 + 0 + + + 0 + 0 + 0 + + 0 0 + 0 0 + 0 + 0 + 2+8 0 0 + 0 + 0 + 0 + 0 + + 0 + + + 0 0 + + 0 + 0 + 1+9 0 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 0 + + + + + 0 + 2+
10 0 0 + + + + + 0 + 0 + 0 + 0 + + 0 + + + + + + + 2+11 + 0 + 0 + 0 + 0 + + + 0 0 + 0 0 0 + 0 + + + 0 + 2+
Auto 0
• Let’s look at what we know:– Phase of reactivity: AHG– Strength/pattern of reactivity: pan-reactive,
different strengths.– Patient history: not recently transfused– DAT/autocontrol: negative
Serologic Problem Solving
Question to ask yourself: So where do we go at this point?
• Narrowed down possibilities:1. One antibody with different strengths2. Multiple antibodies in plasma • Keep in mind that patient has history of anti-
Chido or antibody in Knops system
Serologic Problem Solving
Question to ask yourself: So where do we go at this point?
Next Step:
• Use blood bank techniques, reagents and cells to try and determine the antibody
SOME TECHNIQUES/OPTIONS AVAILABLE:
• ENZYMES (FICIN, PAPAIN, TRYPSIN, ETC)
• CHEMICALS SUCH AS DTT
• PHENOTYPE PATIENT
• RARE ANTISERA
• RARE CELLS
Patient phenotypeRh c + Duffy Fya 0
C 0 Fyb 0
e + MNS M +
E + N 0
Kell K 0 S 0
Kidd Jka + s +
Jkb 0 Lewis Lea 0
Leb +
Some of the Selected CellsRh System Kell Duffy Kidd Lewis P MNS Lutheran
GELD C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
+ + 0 0 + + + 0 + 0 + + + + 0 + 0 + + 0 + 0 0 + 1++ + 0 + + + + 0 + 0 + + 0 + 0 0 + + 0 + 0 + 0 + Co(b+) 2++ 0 + + 0 0 + 0 + 0 + 0 + 0 + 0 + 0 + + 0 + + + 2+0 0 + 0 + + + 0 + 0 + 0 + 0 + 0 + + + 0 + 0 0 + 0+ + 0 0 + + 0 0 + 0 + + + + 0 0 + + + + 0 + 0 + w+0 0 + 0 + 0 + 0 + 0 + + + 0 + + 0 0 + + + + 0 + w++ 0 + + 0 + + 0 + 0 + + 0 + 0 0 + + + + + + 0 + 1++ + 0 0 + + + + + 0 + 0 0 + 0 + 0 + 0 + + 0 0 + 0+ + 0 0 + + + + + 0 + 0 0 + 0 + 0 0 0 + 0 + 0 + 00 0 + 0 + + + 0 + 0 + + 0 + + 0 + 0 + 0 + 0 0 + 00 0 + 0 + + + 0 + 0 + 0 + + + 0 + 0 + + 0 + 0 + Co(b+) 1+
Ficin Panel
Rh System Kell Duffy Kidd Lewis P MNS Lutheran
GEL
GEL-
Ficin
D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
+ + 0 0 + + + + + 0 + + + + 0 0 0 + 0 + + 0 0 + 1+ 1++ + 0 0 + 0 + 0 + 0 + + + + 0 0 + + + 0 + + 0 + 1+ 1++ 0 + + 0 0 + 0 + 0 + + + + 0 0 + 0 + 0 + + + + 1+ 1++ 0 + 0 + 0 + 0 + 0 + 0 0 + 0 0 + + + 0 + 0 0 + 2+ 1+0 + + 0 + 0 + 0 + 0 + + 0 + + 0 + + + 0 0 + 0 + 1+ 1+0 0 + + + 0 + 0 + 0 + 0 + + 0 + 0 0 + 0 + + 0 + 1+ 1+0 0 + 0 + + + 0 + 0 + 0 + + 0 0 + 0 0 + 0 + 0 + 2+ 1+0 0 + 0 + 0 + 0 + 0 + + 0 + + + 0 0 + + 0 + 0 + 1+ w+0 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 0 + + + + + 0 + 2+ 1+0 0 + + + + + 0 + 0 + 0 + 0 + + 0 + + + + + + + 2+ 1++ 0 + 0 + 0 + 0 + + + 0 0 + 0 0 0 + 0 + + + 0 + 2+ 1+
Auto 0 0
0.2M DTT Panel
Rh System Kell Duffy Kidd Lewis P MNS Lutheran
GEL
GEL-Ficin
GEL-DTT
D C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
+ + 0 0 + + + + + 0 + + + + 0 0 0 + 0 + + 0 0 + 1+ 1+ 0
+ + 0 0 + 0 + 0 + 0 + + + + 0 0 + + + 0 + + 0 + 1+ 1+ 0
+ 0 + + 0 0 + 0 + 0 + + + + 0 0 + 0 + 0 + + + + 1+ 1+ 0
+ 0 + 0 + 0 + 0 + 0 + 0 0 + 0 0 + + + 0 + 0 0 + 2+ 1+ 0
0 + + 0 + 0 + 0 + 0 + + 0 + + 0 + + + 0 0 + 0 + 1+ 1+ 0
0 0 + + + 0 + 0 + 0 + 0 + + 0 + 0 0 + 0 + + 0 + 1+ 1+ 0
0 0 + 0 + + + 0 + 0 + 0 + + 0 0 + 0 0 + 0 + 0 + 2+ 1+ 0
0 0 + 0 + 0 + 0 + 0 + + 0 + + + 0 0 + + 0 + 0 + 1+ w+ 0
0 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 0 + + + + + 0 + 2+ 1+ 0
0 0 + + + + + 0 + 0 + 0 + 0 + + 0 + + + + + + + 2+ 1+ 0
+ 0 + 0 + 0 + 0 + + + 0 0 + 0 0 0 + 0 + + + 0 + 2+ 1+ 0Auto 0 0
Patient History
• anti-Chido
• Knops
Reactivity
Ficin DTT
Negative Reactive
Reactivity
Ficin DTT
Weakened Negative
Knops SystemAntigen Occurrence
CaucasianOccurrence
Blacks
Kna 98% 99%
Knb 4.5% <.01%
McCa 98% 94%
McCb 0% 45%
Sla (Sl1) 98% 50-60% (30% West Africans)
Yka 92% 98%
Vil (Sl2) 0% 80%
Sl3 100% 100%
Reid, Marion and Christine Lomas-Francis (2012). The Blood Group Antigen FactsBook, 3rd Edition, Elsevier.
Available Selected Knops CellsRh System Kell Duffy Kidd Lewis P MNS Lutheran
GELD C c E e K k Kpa Kpb Jsa Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lua Lub
0 0 + 0 + + + 0 + 0 + 0 + 0 + 0 + 0 + + + + 0 + Yk(a-) 1+0 0 + 0 + 0 + 0 + + + 0 0 + 0 0 0 0 + 0 0 + 0 + Sl(a-) 0+ 0 + + + 0 + 0 + 0 + + 0 + + 0 + + + + 0 + 0 + Sl(a-) 0
Appears to be anti-Sla but due to known weak reactivity of the antibody do molecular to confirm
Molecular TestingRh c +
MNS M +
Dombrock Doa 0
C 0 N 0 Dob +
e + S 0 Joa +
E + s + Hy +
Kell K 0 Lutheran Lua 0 LW Lwa +
k + Lub + Lwb 0
Kpa 0 Diego Dia 0 Scianna Sc1 +
Kpb + Dib + Sc2 0
Jsa 0 Cromer Cra +
Jsb + Colton Coa + Knops Kna +Knb 0
Kidd Jka + Cob 0McCa +
Jkb 0 Cartwright Yta + McCb 0Duffy Fya 0 Ytb 0 Sl1 0 Fyb 0 Hemoglobin S HbS 0 Sl2 +
Knops System• Knops antigens are
located on complement receptor 1 (CR1)
• CR1 gene resides on chromosome 1
Complement Receptors
What is CR1 (CD35)?CR1 is a glycoprotein on cells that binds particles coated with C3b and C4b
Neutophils and monocytes then phagocytize those particles and processes the immune complexes.
These are transported to the liver/spleen for removal from circulation.
• Has inhibitory effect on complement activities by classical and alternative pathways so it protects the red cells from autohemolysis
What is CR1 (CD35)?
https://www.inkling.com/read/the-immune-system-peter-parham-3rd/chapter-9/antibody-production-by-b
Knops system
Structure of CR1 glycoprotein (CD35)
Knops system characteristics• Variation in antigen strength, related to CR1 red cell levels
• Generally, a reduction in antigen strength with storage of red cells as the CR1 copy per RBC may be decreased in stored samples
• High titer low avidity (HTLA) has been used to describe the antibodies
• Difficult to adsorb out antibodies
• Can be hard to distinguish antigen negative from weakly positive cells
• Clinically benign but can mask other significant antibodies
Knops System
Null phenotype: Kn(a-b-), McC(a-), Sl(a-), Yk(a-)aka Helgeson type
Knops antigens can be depressed in
cutaneous lupus erythematosus (CLE)
Cold Hemagglutinin Disease (CHAD)
Paroxysmal nocturnal hemoglobinuria (PNH)
hemolytic anemia insulin-dependent diabetes
AIDS
some malignant tumors
any condition with increased clearance of immune complexes
Sla antibody
Sla Antibody Characteristics
History Reported in 1980 and named after Swain and Langely, the first two antibody producers.
Clinical Significance No! Clinically insignificant·No Transfusion Reactions·No HDN
Antibody ·IgG, reacts best at 37°C/AHG
Other facts May be confused with anti-Fy3 because most Fy(a-b-) red cells are likely to be Sl(a-). Common antibody made by blacks.
Reid, Marion and Christine Lomas-Francis (2012). The Blood Group Antigen FactsBook, 3rd Edition, Elsevier.
Sla antigenSla Antigen Characteristics
Occurrence 98% 50-60% (30% West Africans)
Other Facts Also known as Sl1
Disease processes causing red cell CR1 deficiency can lead to false negative antigen typing. Also, variability in antigen strength has been described.
Sources for further reading: ·Reid, Marion and Christine Lomas-Francis (2012). The Blood Group Antigen FactsBook, 3rd Edition, Elsevier.·Daniels, G. (2013) MNS Blood Group System, in Human Blood Groups, 3rd edition, Wiley-Blackwell, Oxford, UK.