Molecular Biology III Flashcards
more common than B subgroups, naa ang clinically significant
A SUBGROUPS
80% of group A or AB individuals are:
Al positive
remaining 20% of group A or AB individuals
A2 or weaker subgroups
Inheritance of A1 gene elicits production of high
concentrations of ___ which then converts all H substance to Al antigen
3-N-acetylgalactosaminyltransferase
Al creates about ___ antigen sites on adult RBCs)
810000-1170000
1-8% of A2 individuals produce ___
Anti-A1
Subgroups are due to _____ at the ABO
locus.
Polymorphisms
A2 results from a single-base substitution at ___
nucleotide 1059.
A typing sera to differentiate the A subgroups
‘Dolichos biflorus
ABO ANTIBODIES can be ___ or ___
Natural or Immune
ABO ANTIBODIES Develops at ___ after birth and peaks at age ___
3-6 months after birth, age 5-10
ABO ANTIBODIES reacts at ___ temperature (** Cold antibody**)
room temperature
is present in the serum of a person who lacks the A or B antigen
Anti A or Anti B
group O possess anti ___,___,___
Anti-A, Anti-B, and Anti-AB
Most ABO antibodies are ____ and activates ___
IgM (Some are IgG) and activates complement
Complement can act as ____. So maconnect niya talaga si antibodies and red cells. Kaya visible jud ang agglutination during testing.
opsonin
Patient’s RBCs are added to sources of
commercial antisera to detect antigens on an
individual’s RBCs
“Cell grouping”
A preparation where cells are separated from the
plasma.
Cell suspension
To remove excess proteins or substances that could
affect the testing.
Cell washing
Detects ABO antibodies in the patient’s serum
using known reagent RBCs (A1 and B cells)
REVERSE GROUPING
There’s a slight connection to the technical problems, but actually what we encounter during ABO typing.
ABO DISCREPANCIES
Discrepancy that happens between forward and
backward grouping due to weakly reacting or
missing Antibodies. MORE COMMON
Group 1
group 1 discrepancies:
- Newborns and Elders
- Chronic Lymphocytic Leukemia, Lymphoma
- Using immunosuppressive drugs
- Congenital gammaglobulinemia
- Immunodeficiency status
- Bone Marrow transplant
- Chimerism
- ABO subgroups
Resolution for GROUP 1 discrepancies
Review patient’s history, Enhance serum reaction
How to enhance serum reaction
Serum + Reagent Al and B cells = Incubate
Enhance serum reaction: Incubate at ___ Temp for ____ minutes and add __ drops more plasma/ serum
Incubate at Room Temp for 15-30 minutes, add 1 or 2 drops more plasma/ serum
Enhance serum reaction: If no reaction
after centrifugation, incubate at __ for ___ minutes
4C for 15-30 minutes
Discrepancies are due to weakly reacting or
missing antigens
GROUP 2
causes of group 2 discrepancies
- Subgroups of A and B
- Disease conditions
- Increase Blood group specific soluble substances
Discrepancy due to Protein or Plasma abnormalities
GROUP 3
resolution for group 2 discrepancies
Incubate mixture at room temperature for 30
minutes
group 2 discrepancies: negative mixture
If negative, incubate at 4C for 15-30 minutes
Discrepancy due to Protein or Plasma abnormalities
GROUP 3
GROUP 3 discrepancies are caused by:
- Rouleaux formation or Pseudoagglutination
- Increase globulin
- Multiple myeloma
- Waldenstrom’s macroglobulinemia
- Advance Hodgkin’s lymphoma
- Increase fibrinogen
- Plasma expanders
- Wharton’s jelly
Red cells stack like coins
Rouleaux formation or Pseudoagglutination
How to differentiate rouleaux formation and true agglutination?
Put NSS.
During those cases, there is an increase in globulin and proteins (+ fibrinogen). When an increase in protein, it lowers down the zeta potential.
Advance Hodgkin’s lymphoma
Group 3 discrepancies resolution:
Saline replacement technique: Remove serum, replace with equal volume of saline (wash) to remove proteins
Discrepancy due to unexpected antigen reaction
or miscellaneous
GROUP 4
Group 4 discrepancies are caused by
- Cold Reactive Antibodies
- Unexpected ABO isoagglutinins
resolution for group 4 discrepancies: cold reactive antibodies
- Incubate mixture at 37C for a short period
- Washed with saline at 37C three times
and retype
for Cold Reactive Antibodies treat with ___ to disperse IgM related agglutination
0.01 M dithiothreitol
For Unexpected Isoagglutinins serum groupings can be repeated using at least ___ examples of A1, A2, B cells, O cells, and an ___ control
3 examples of A1, A2, B cells, O cells, and an autologous control (Patient’s serum, mixed
with patient’s cells)
