BB AHG P2

Initial DAT

involves mixing one drop of a 3-5% washed RBC suspension with a polyspecific reagent that detects both IgG and C3D Abs

separate monospecific anti-IgG and anti-C3d

if initial testing is positive, further testing is needed using?

maternal IgG

what is presumed to be sensitizing protein in HDN?

Complement testing

what is unnecessary in HDN

False

T or F: when a DAT typing is negative during immediate spin, weak D test can be performed

• Chloroquine diphosphate

• EDTA-Glycine

• Murine Monoclonal Ab

enumerate methods for Ab removal

False

T or F: a positive DAT alone is diagnostic of immunity to hemolysis

Transfusion-related

A condition wherein a recepient alloantibody reacts with donor RBC antigen (most common)

• recipient has pre-exisiting Abs or alloantibodies against Ags on the donor’s RBCs

Donor Abs reaacts with recipient RBC antigen

a condition that occurs if the donor’s plasma contains Abs that are reactive against the recipient’s RBC antigens (less common)

1. Hapten-dependent Abs (Type 1)

2. AutoAb Formation (Type 2)

3. Drug Abs (Type 3)

Drug induced conditions can be further subtyped to:

Hapten-dependent Abs (Type 1)

the drug acts as a Hapten, so it binds strongly to the surface of a RBC. When the drug is present, these Abs (developed) bind to the drug under RBCs, leading to their destruction

Penicillin

a classic example of Type 1 drug induced condition

AutoAb Formation (Type II)

• Methyldopa

a drug-induced condition where certain drugs can trigger the production of warm autoAbs that react with the patient’s RBCs ; drug may alter the immune system

• what is a well known example of this?

Drug-dependetn Abs (Type III)

• “Innocent bystander mechanism”

• The drug causes the formation of Abs that only react with rbcs in the presence of the drug

Warm AIHA: IgG or C3 coating

the autoAbs that attack the red blood cells are typically of the IgG class and are most active at body temperature; the presence of C3 indicates that the immune response progressed to activate the complement pathway

Cold Agglutinin Syndrome (CAS): c3 caoting

characterized by IgM autoAbs that bind to red blood cells best at cold temperatures or below however, C3 is the only one detected by DAT

Paroxysmal Cold Hemoglobinuria (PCH): IgG coating

rare type of cold-reacting autoimmune hemolytic anemia and is characterized by a speific IgG autoAb

Donuth-Landsteiner antibody

What is the specific IgG AutoAb that binds to RBCs in the cold and then causes complement activation and hemolysis when the blood warms up

Hemolytic Disease of the Newborn

mother has developed IgG Abs against the Ags present on the RBCs of her fetus; typically happens when there is an incompatibility between the mother and the fetus blood types

Administration of high-dose IV gamma globulin and hypergammaglobulinemia

what in vivo phenomenon is described as non-Ab-mediated binding of immuniglobulin to RBCs in px w/ hypergammaglobulinemia

Intravenous immunoglobulin

concentrated solution of IgG Abs pooled from many healthy donors. it is used to treat various immunodeficiency and autoimmune conditions

Administration of antilymphocyte/antithymocyte globulin

what in vivo phenomenon is characterized by heterophile Abs that are present in ALG or ATG coat recipient’s RBCs. High levels of protein causing red cells to spontaneously agglutinate.

• ALG/ATG polyclonal Absare used to suppress the immune system often in the context of organ transplantation or severe autoimmune diseases

• This coting may or may not result in significant hemolysis

Ab Identification and Ab panel

(IAT) used to determine the specificity of Abs detected during antibody screening. The in vitro sensitization involves the Ab reacting with the selected Rh cells

TRUE

t or f: DAT does not require the incubation phase because of the Ag-Ab complexes formed in vivo

100-200

for IAT, there must be between ? of IgG or C3 molecules on the cell to obtain a positive reaction

IAT

is used to determine in vitro sensitization of RBCs

• Detection of incomplete Abs to potential donor RBCs

• Determination of RBC phenotyope using known antisera

• titration of incomplete Abs

Higher serum-to-cell ratios

(ratio of serum to cells) what enhances test sensitivity

40:1

(ratio of serum to cells) recommended ratio?

Increase

In detecting for weak Abs, increase or decrease serum-to-cell ratio

Albumin

Reduces zeta potential

22% bovine albumin

halved the incubation time to 30 mins from 60 mins

FALSE

T/F: albumin is a better enhancement medium than LISS

LISS (Low ionic strength saline)

enhances Ab uptake by reducing zeta potential around RBCs; shortens incubation time from 30-60 mins to 10-15 mins

Polyethylene Glycol

Enhances Ab uptake by removing water molecules around RBCs; effectively concentrates Abs for stronger reactions

Check cells (IgG sensitized group O cells)

what confirms adequate washing

Elution of low-affinity Abs

what is prevented when washing is done after incubation?

Fresh or buffered saline (pH 7.2-7.4)

ideeal saline

LIP Technique mechanism

• Low ionic conditions rapidly sensitize cells with Abs

• Polybrene induces rouleaux formation bringing sensitized cells close together

• A high ionic strength reverses rouleaux; true agglutination remains