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Contents

Blood Groups

Chapter:
Nomenclature
Author(s):

Harriet S. Meyer

Blood Groups

Blood groups are characterized by erythrocyte (red blood cell) antigens with common immunologic properties (eg, group A). Blood group systems are series of such antigens encoded by a single gene or by a cluster of 2 or 3 closely linked homologous genes1-3 (eg, ABO system).

There are about 600 recognized erythrocyte antigens.2 The International Society of Blood Transfusion (ISBT) designates around 270 blood group antigens. Of these, around 250 belong to 1 of 29 systems.3,4 (Other antigens remain in officially designated series or collections.) Some antigens are erythrocyte-specific; others appear widely, but specifically, on cells of other organs and tissues.

The discovery of blood group antigens was prompted by hemolytic disease of the newborn and transfusion reactions, but many antigens have since been implicated in infection and other disease processes1,5; whether fundamentally or incidentally is not known.6 Erythrocytes are estimated to contain millions of antigen sites.1

Traditional/Popular Nomenclature.7-10

Traditional blood group system nomenclature is typically used in medical publications. It comprises several approaches, and, therefore, sometimes the same entity (eg, a particular erythrocyte antigen) can be expressed by more than 1 term. Editors generally should follow author preference.

The principal elements named are blood group systems, antigens, phenotypes, genes, and alleles.

Blood Group Systems.

The following list shows the blood group system names and symbols. (The column of derivations of names of blood group systems is provided for background interest1,2,9,11-14 [also Geoff Daniels, PhD, written communications, May 13 and 17, 2004].)

System Name

Symbol

Derivation

ABO

ABO

Alphabetical (A and B); letter O may derive from “ohne” (German for without)

Chido/Rogers

Ch/Rg

Names of antibody makers

Colton

Co

Name of antibody maker

Cromer

Cromer

Name of antibody maker

Diego

Di

Name of antibody maker

Dombrock

Do

Name of antibody maker

Duffy

Fy

Name of antibody maker

Gerbich

Ge

Name of antibody maker

Gill

GIL

Name of antibody maker

Globoside

GLOB

Globoside synthetase

Hh

H

Concept (“heterogenetic”)

I

I

Concept (“individuality”)

Indian

In

Geographic

John Milton Hagen

JMH

Name of antibody maker

Kell

K

Name of antibody maker (Kelleher)

Kidd

Jk

Initials of infant child of antibody maker (K already in use)

Knops

Kn

Name of antibody maker

Kx

Kx

Association with Kell and X chromosome

Lewis

Le

Name of antibody maker

Lutheran

Lu

Name of antibody maker (actually Lutteran9 or Luteran13)

LW or Landsteiner/Wiener

LW

Names of investigators

MNSs

MNS

M, N: the word immune; S: location (Sydney, Australia)

U (an antigen of the MNSs system): universal

Ok

OK

Family name initials (Kobutso; letters reversed because “Ko” was in use)

P

P

Alphabetical

Raph

Raph

Name of antibody maker

Rh

Rh

Rhesus monkeys (antigens were LW antigens)

Scianna

Sc

Name of antibody maker

Xg

Xg

X chromosome and location (Grand Rapids, Michigan)

Yt or Cartwright

Yt

The ISBT prefers an all-capital style for blood group system symbols3 (see “ISBT Name and Number” in this section).

The following are examples of usage:

ABO incompatibility

A cell

type AB recipient

type O donor

Hemolytic disease of the newborn primarily occurs from incompatibilities of the Rh, ABO, or Kell blood groups.

Antigens.

Antigen terms use single or dual letters, often with a qualifier that is a letter (usually superscript) or number (subscript or typeset on the line).

A, A1, A2, Ax, B

Cra

Fya, Fyb

He

Jka, Jkb

K, k

Kpa, Kpb, Ku, Jsa, Jsb

K11, K12, K13, K14, Km

Lea, Leb, LebH, ALeb, BLeb

Lua, Lub

Lu3, Lu4, Lu5, Lu6

P1

Sc1, Sc2

Xga

The Rh system historically has used 3 alternative schemes: the Rh-Hr nomenclature, the CDE nomenclature, and the numerical nomenclature.7 Terms from the first, eg, rh′, hr″, rhx, RhA, are appropriate in historical discussions, but otherwise, the CDE and numerical nomenclatures are favored:

D, C, E, c, e, f

Ce, Cw, Cx… BARC

or

Rh1, Rh2, Rh3, Rh4, Rh5, RH6

RH7, RH8, RH9… RH52

The following are examples of antigen-term usage:

anti-Jka alloantibody

Rh(D) incompatibility

human monoclonal anti-D antibodies

Studies using anti-Ch and anti-Rg antisera have demonstrated Ch and Rg determinants on complement component C4.

Phenotypes.

In phenotypic expressions—terms that describe an individual’s blood group or type—the presence or absence of an antigen is often indicated by a plus or minus sign:

Antigen: M

Phenotype: M+

M+N+S−s+ erythrocytes

M+N+S−s+ phenotype

Lowercase letters that were superscripts in the antigen terms are set on the line in parentheses in phenotypic terms.

Antigen: Lub

Phenotype: Lu(b+)

More than 98% of the Western population is Lu(b+).

If the numerical terminology is used for the antigen, a colon is added in the phenotype.

Antigen: Sc1

Phenotype: Sc:1

the Sc:1,−2,3 phenotype

Other sample phenotypic terms include the following:

Fy(a−b+), Fy(a+b−), Fy(a−b−)

Jk(a−b+), Jk(a+b−), Jk(a+b+)

K+k−, Kp(a−b+), Js(a−b+)

Le(a−b+), Le(a+b−), Le(a−b−)

Lu(a−b+), Lu(a+b−), Lu(a+b+)

M+N+, M+, N−, M−N+, S+s+, S+s−, S−s+

P1, P2, P1k, P2k

Xg(a+), Xg(a−)

the silent phenotype Le(a−b−)

A superscript w can indicate a weak reaction:

M+w

K+w

Fy(a+w)

The ABO system is an exception: its phenotypic terms do not feature plus or minus signs; A (not A+) indicates A erythrocyte antigens; O (not A− B−) indicates the absence of A and B antigens:

Groups: O, A, B, AB, Oh, OhA

Subgroups: A1, A2, A1B, A2B

OhA individuals do not express the H determinant but do have the A allele.

Terms for Rh phenotypes, which do not feature plus and minus signs, are also in use:

D-positive (Rh positive)

D-negative (Rh negative)

DccE, DCce

RH:1,2,3

Rhnull

Absence of C, c, E, and/or e antigens is indicated with 1 or 2 minus signs14:

Dc−

D− −

Usage note: Terms such as O+ (“O positive”), A+, and AB− are common parlance as shorthand for blood of the ABO system and its Rh specificity. However, in scientific articles, use standard terms that specifically indicate Rh status:

O Rh-positive

O Rh+

or more specific designations of phenotype:

group B, D-negative

group A, Rh D-positive

In a blood group profile, elements from different systems may be separated by commas, as above, or, for more complex specificities, with semicolons:

The patient’s blood was group B, Rh positive, D+ C+ c+ E− e+; M+ N+ S− s+; P1+; Le(a−b−); K− k+; Fy(a−b+); Jk(a+b−).15(p846)

Note that in phenotypic expressions commas do not appear within elements of the same blood group system:

D+ C+ c+ E− e+

Not: D+, C+, c+, E−, e+

Commas may be dispensed with between different blood group systems in brief expressions:

K+Fy(a+)

Genes.

As with International Standard Gene Nomenclature (the “HUGO” recommendations; see 15.6.2, Genetics, Human Gene Nomenclature), ISBT gene terms are italicized. Traditional blood-group gene symbols often mixed uppercase and lowercase. However, symbols recommended by ISBT, like those of HUGO, use all capital letters.

The following list3,4,9,16 shows gene symbols associated with blood group systems.

Traditional

ISBT

HUGO

ABO

ABO

ABO

Ch/Rg

C4A, C4B

C4A, C4B

Co

AQP1

AQP1(was CO)

Cromer

DAF

CD55 (was DAF)

Di

SLC4A1

SLC4A1

Do

DO

ART4 (was DO)

Fy

FY

DARC (was FY)

Ge

GYPC

GYPC

[GIL]

AQP3

AQP3

[Globoside]

B3GALT3

B3GALT3

Hh

FUT1

FUT1

[I]

GCNT2

GCNT2

In

CD44

CD44

Jk

SLC14A1

SLC14A1

[JMH]

SEMA7A

SEMA7A

K

KEL

KEL

Kn

CR1

CR1

Kx

XK

XK

Le

FUT3

FUT3

Lu

LU

BCAM (was LU)

LW

ICAM4

ICAM4

MN or MNSs

GYPA, GYPB, GYPE

GYPA, GYPB, GYPE

Ok

BSG

BSG (previously OK, CD147)

P1

P1

A4GALT

Raph

CD151 (was MER2)

CD151

Rh

RHCE, RHD

RHCE, RHD

Sc

ERMAP

SC

Xg

XG, MIC2

XG

Yt

ACHE

ACHE

Gene symbols expressed according to ISBT4 or HUGO16 are preferred to traditional symbols.

Parenthetic synonyms are helpful:

BSG(formerly OK)

ERMAP(also called SC)

The Lutheran inhibitor gene is expressed as follows:

In(Lu) [traditional]

INLU [standard]

Do not confuse In with the traditional Indian blood group gene symbol, In (recommended gene symbol: CD44).

Alleles.

The italicized blood group symbol—ABO, MNS, RH, etc—is used for alleles (which are also distinguished by an asterisk and number). In the following example, compare the gene symbol and an allele term from the same blood group:

SC*1 [allele]

ERMAP [gene symbol]

Note that qualifiers that are subscripts in antigen terms are superscripts in allelic terms, eg, A1 antigen, A1 allele). The following are examples of genotypic terms.

A1O, A1A1, A1B, OO

MN, MM, NN, MSNs

DCe/DCe (R1R1)

DcE/dce (R2r)

dce/dce (rr)

D− −/D− −

LuaLua, LubLub, LuaLub

Lele, LeLe, lele

FyaFya, FybFyb, FyFy

Kk, KpaKpb, JsbJsb

JkaJka, JkbJkb, JkaJkb

XgaXga, XgaXg, XgXg

XgaY, XgY

For expressing alleles, the ISBT gives an option, eg, either Fya or FY*1 (with appropriate superscripts and italics). Mixing the 2 styles, however (eg, FY*A), is not appropriate (Geoff Daniels, PhD, written communications, May 13 and 17, 2004).

ISBT Name and Number.3,7,17,18

In the 1980s the Working Party on Terminology for Red Cell Surface Antigens of the ISBT developed an alphanumeric system of blood group notation, intended to provide “a uniform nomenclature that is both eye and machine readable and in keeping with the genetic basis of blood groups.”7(p273) The system does not replace traditional terminology; rather, its terms correspond to traditional terms. It is also used to assign new terms as needed. In the ISBT terminology, each blood group system has a symbol, usually of 1 to 3 capital letters, and a system number of 3 digits.

System

Antigen No. Within System

Name

Symbol

No.

001

002

003

004

ABO

ABO

001

A

B

A,B

A1

MNS

MNS

002

M

N

S

s

Rh

RH

004

D

C

E

c

Kx

XK

019

kx

Sinistral (left-hand) zeros can be dropped from system and antigen terms, and system letter symbols can be used as part of the alphanumeric term. The following, for instance, are all acceptable for blood type AB: AB

AB

ABO:1,2,3

001:1,2,3

The following are acceptable terms for the antigen A,B:

A,B

ABO3

001003

Authors may use ISBT terms in parentheses following traditional terms:

AB (1.3)

D (RH1)

Lea(007001)

The patient’s red blood cells were negative for Cromer blood system antigens Cra (CROM1) and Tca (CROM2).

In notations that use plus and minus signs to express presence and absence of particular antigens, phenotypic expressions in the numerical notation use a colon and numbers in place of letters, as in these examples:

LE:−1,2 [for Le(a−b+)]

FY:1,−2 [for FY(a+b−)]

Genotypic expressions are italicized:

FY 1/2 or FY*1/2 (for FyaFyb)

Tables of blood group systems, symbols, antigens, and ISBT numbers are available at the ISBT Committee on Terminology for Red Cell Surface Antigens website.4

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