BB 4: Rh Blood Group System

1940

the year Karl Landsteiner and Alex Wiener discovered the Rh blood group system

004

ISBT number of Rh blood group system

Codominance

Inheritance pattern of Rh blood group

RHD gene

expressor gene of D antigen

RHCE gene

expressor gene of C, c, E, and e antigens

RHAG gene

co-expressor of Rh antigens

Fisher-Race Nomenclature

nomenclature with DCEce terminology

Wiener Nomenclature

nomenclature with Rh Hr terminology based on 8 agglutinogens

Rosenfield Nomenclature

nomenclature with no genetic basis, just the presence/absence of Rh antigens

ISBT Nomenclature

machine readable uniform nomenclature

IAT

Principle of Weak D Testing

• Blood donors

• Babies born from Rh D-negative mothers

Weak D testing is required for:

2 drops : 2 drops

Weak D Testing procedure:

Test = _ drops of Px washed red cells + _ drops of Anti-D reagent

Px washed red cells : NSS

Weak D Testing procedure:

Control = 2 drops of ____ + 2 drops of ____

DCe

Most common Fisher-Race haplotype in Asia (70%)

Fewer D Ag present (Quantitative problem)

cause of Genetic Weak D

Position effect (D is opposite to C)

cause of C Trans

Missing portion of D Ag (Qualitative problem)

cause of D Mosaic / Partial D

Px red cells are already sensitized with IgG Ab

Weak D result:

Test = 2+ Control = 2+

Why is this result invalid?

D antigen

major Rh antigen, as well as the most immunogenic

D > c > E > C > e

Immunogenicity of Rh antigens

False

True or False:

Rh antibodies activate complement.

Rh null syndrome

Lacks all Rh antigens; demonstrate mild compensated hemolytic anemia

Stomatocytosis, increase in Hb F

Rh mod

Partial suppression of Rh gene; Features similar to Rh null but less severe

Exalted D

No C/c or E/e reactivity (D—/D—); Unusually strong D expression

Cw

Originally considered an allele at the C/c locus

f

Compound antigen; c and e are in cis position

rhi

Compound antigen; C and e are in cis position

G

Present on most C(+) and D(+) positive red cells

Saline-based rgt

Rh Ag typing reagent that contains IgM Abs; Can be used on red cells coated with IgG Ab; CANNOT be used on Weak D testing

High protein-based rgt

Rh Ag typing reagent added with bovine albumin; short incubation time; can do Weak D testing

Chemically-modified rgt

Rh Ag typing reagent that contains IgG; Low protein-based; replaced Saline-reactive reagent

Monoclonal Antibodies

Rh Ag typing reagent derived from single clone of plasma cell containing both IgM/IgG