Rh Blood Group System

Practice flashcards covering the history, genetics, nomenclature, and clinical significance of the Rh Blood Group System based on lecture notes.

Landsteiner and Wiener

The researchers who reported in $1940$ that an antibody made by guinea pigs and rabbits transfused with Rhesus monkey RBCs agglutinated $85\%$ of human RBCs.

Anti-LW

The name given to the antibody formed by animals against Rhesus monkey RBCs to distinguish it from the human-produced "Rh" group.

RHD gene

The gene that determines the expression of the D antigen.

RHCE gene

The gene that determines the expression of the C, c, E, and e antigens.

Fisher-Race theory

A genetic theory postulating that Rh antigens are controlled by $3$ closely linked loci ($D/d$, $C/c$, $E/e$).

Wiener theory

A theory suggesting Rh antigens are controlled by alleles at a single gene locus, with $8$ possible alleles ($R^0$, $R^1$, $R^2$, $R^z$, $r$, $r'$, $r''$, $r^y$).

Agglutinogen

According to Wiener, this is the product encoded by the Rh gene, which is made of factors that correlate with specific Rh antigens.

Rosenfield Terminology

A system suited for computerized data entry where antigens are designated by numbers (e.g., Rh1 is D, Rh2 is C, Rh3 is E).

ISBT Terminology

Specific blood group nomenclature using six-digit numbers; the first three ($004$) refer to the Rh system and the last three refer to the Rosenfield system.

D antigen

The most immunogenic antigen outside the ABO system; its presence or absence determines if a person is Rh-positive or Rh-negative.

Weak D

Red blood cells that test positive only by the indirect antiglobulin test (IAT) and not by direct immediate spin testing.

Position Effect

A cause of the weak D phenotype where the D antigen appears weak because the C antigen is inherited in the trans position to D (e.g., $Ce$ paired with $cDe$).

Partial D Antigens

Individuals who are D positive but missing parts of the D antigen; they may produce anti-D if exposed to the "whole D antigen."

Compound Antigens

Also called cis-product antigens, these are additional products formed when two genes are inherited on the same chromosome (e.g., $ce$ forming the $f$ antigen).

G Antigen

An antigen present on most $D+$ and all $C+$ cells; anti-G mimics a combination of anti-D and anti-C.

D-deletion

Phenotypes like $-D-$ or $D--$ where no reactions occur with anti-E, anti-e, anti-C, or anti-c because the RHCE genetic material is deleted or nonfunctional.

Rhnull

A rare phenotype written as $--/--$ where no Rh antigens are expressed; it results in membrane abnormalities and hemolytic anemia.

Rhmod

A phenotype similar to Rhnull where most Rh antigen expression is missing, often controlled by the RHAG gene.

Rh antibodies

Usually RBC stimulated IgG antibodies that can cross the placenta and cause severe Hemolytic Disease of the Fetus and Newborn (HDFN) or hemolytic transfusion reactions.

LW Blood Group System

A system genetically unrelated to Rh but with similar antigens; anti-LW reacts strongly with D-positive cells and weakly with D-negative cells.