Other blood groups

Question 1

How is the Lewis blood group formed? (Ag)

Answer 1

FUT3 (Le) gene => α-1,4-fucosyltransferase adds L-fucose on GlnNAC on Type 1 precursor => Le Ag

Question 2

Why is anti-Lea only produced in Le(a-b-) ppl?*

Answer 2

• *Anti-Leb rarely seen

Question 3

characteristics of Le Aby

Answer 3

• naturally occuring IgM (=can’t cross placenta)
• rarely clinically sig.
• can cause HTR if react at 37ºC or IAT

Question 4

why is Le Aby rarely clinically sig

Answer 4

• Le Ag poorly developed @ birth
• IgM Ab can’t cross placenta
• Aby can be neutralised w/ Le Ag in plasma
• Le AG dissociate from transfused RBC membrane

Question 5

characteristics of I blood group (Ag)

Answer 5

• CHO
• IGnT > glycosyltransferase for branching
• Ag: i (linear) ; I (branched)
• i (0-18 months); I (18+)* but some adults not convert i -> I
• precursors to Le & ABO Ag

Question 6

Characteristics of autoanti-I Aby in I blood group

Answer 6

• reacts optimally at 4ºC
• strongly agglutinates adult RBC (than cord RBC)
• cause problems in pre-t testing & reacts @ RT

Question 7

Characteristics of Pathogenic autoanti-I Aby in I blood group

Answer 7

• reacts upto 32ºC
• seen in cold agglutaninn syndrome:
  • cold @ periphery -> IgM bind to complement
  • when goes to torso = warmer -> complement activated = haemolysis

Question 8

Characteristic of compound anti-I Aby

Answer 8

• require presence of BOTH Ag (I + ABO or Le)
• e.g. Anti-HI:
  • react strongly to cells expressing BOTH H & I Ag (= O & A2 cells)
  • reacts weakly to cells expressing low levels of H or I Ag (= AB, A, cord RBC)
  • naturally occurring IgM Aby
  • Optimal react @ ≤RT
  • cause HTR (clin. sig) @ 37ºC

Question 9

common type of D variant in Australia

Answer 9

DVI

Question 10

CHaracteristics of Cw Ag

Answer 10

• described by Willis (in 1946)
• Low incidence: 1-2%
• Substitution of A -> G in RHCE

Question 11

Frequency of
• K-k+
• K+k+
• K+k-

Answer 11

• K-k+ = 91%
• K+k+ = 8.8%
• K+k- = 0.2% (hard to find ppl w/ no anti-k)

Question 12

Describe the Mcleod Phenotype (include more?)

Answer 12

• Lack XK (for optimal Kell Ag expression)
• V. rare X-linked disease
• V. weak Kell Ag expression
• Acantho, aniso, inc retic, inc osmotic fragility, dec haptoglobin

Question 13

WHy might working with kidd Aby be difficult?

Answer 13

• Dosage
• Weak
• Found in combo w/ other Aby

Question 14

why doees Anti-Lub Ab react w/ all panel cells except auto

Answer 14

bc High incidence - react w/ all cells

Question 15

Why is anti-Coa rarely encountered in the lab?

Answer 15

Coa Ag is high incidence

Question 16

Differentiate the ABO groups and subgroups

Answer 16

Use Ulex europaeus lectin => Binds to H Ag
[H]: O > A2 > B > A2B > A1 > A1B
Rxn: 4+ > 3+ > 2+ > 1+ > Neg > Neg

Question 17

Characteristics of P Blood group (Ag)

Answer 17

• CHO
• Ag: P, P1, Pk (combo of 2 Ag except P2 phenotype expresses only P)
• glycosyltransferase adds CHO residue on precursor substance

Question 18

Characteristics of Rh Blood group (Aby)

Answer 18

• Immune
• IgG
• not bind to complement
• react optimally @ 37ºC
• Detect w/ IAT
• Anti -E, -e, -C, -c demonstrate dosage
• Aby can cause HTR & HDNB

Question 19

Characteristics of Kell Blood group (Ag)

Answer 19

• Protein
• Ag: K & k (& K0*)
• Highly immunogenic
• well developed at birth
• Destroyed by reducing agents

Question 20

Characteristics of Kell Blood group (Aby)

Answer 20

• IgG
• Detect w/ IAT @ 37ºC
• Anti-K cause HTR & HDNB
• Anti-k hard to find compatible units

Question 21

Characteristics of Kidd Blood group (Ag)

Answer 21

• Ag: Jka, Jkb & Jk3
• Weakly immunogenic
• well developed at birth
• Enhanced by enzyme

Question 22

Characteristics of Kidd Blood group (Aby)

Answer 22

Anti-Jka & Anti-Jkb

• IgG
• Delayed HTR, rarely HDNB

ANti-Jk3

• react w/ Jk POS cells
• Causes HTR, mild HDNB