Blood Donors with McLeod Phenotype

More than 300 antigens are recognized on the red cell surface and can be classified into 4 separate categories; these are 29 genetically determined systems, 6 collections of related antigens, and the series of lo w incidence (700 series) and high incidence

Y. Tani

Japanese Red Cross Osaka Blood Center, 2-4-43, Morinomiya Joto-ku, Osaka, 536-8505, Japan, [email protected]

(901 series) antigens [2]. Among the 29 systems (Table 1), red cells which lack XK protein on the cell surface are called McLeod phenotype. McLeod phenotype is one of the rare blood cell types, defined as those that occur at a frequency of 1:1,000 or less, and was first reported by Allen et al. in 1961 [1].

In Japan, we have screened donors for rare cell types since 1987 using monoclonal antibodies (MAbs) which we have developed. Our screening strategy for McLeod phenotype is shown in Fig. 1. We do not have good MAbs against XK protein, but Kell glycoprotein is covalently linked at Cys 72 to Cys 347 of the XK protein in the red cell membrane (Fig. 2) [8] and it is well known that Kell antigen expression is markedly reduced in the absence of normal XK protein. We screen red cells by agglutination methods in an automated system such as Olympus PK7200

Table 1 The blood group systems, the genes that encode them, and their chromosomal location (ISBT, 2004) [2]

System Chromosomal CD

No. System name symbol Gene name(s) location numbers

Table 1 The blood group systems, the genes that encode them, and their chromosomal location (ISBT, 2004) [2]

System Chromosomal CD

No. System name symbol Gene name(s) location numbers

001

ABO

ABO

ABO

9q34.2

002

MNS

MNS

GYPA, GYPB, GYPE

4q31.21

CD235

003

P

P1

22q11.2-qter

004

Rh

RH

RHD, RHCE

1p36.11

CD240

005

Lutheran

LU

LU

19q13.32

CD239

006

Kell

KEL

KEL

7q34

CD238

007

Lewis

LE

FUT3

19p13.3

008

Duffy

FY

FY

1q23.2

CD234

009

Kidd

JK

SLC14A1

18q12.3

010

Diego

DI

SLC4A1

17q21.31

CD233

011

Yt

YT

ACHE

7q22.1

012

Xg

XG

XG, MIC2

Xp22.32, Yp11.3

CD99b

013

Scianna

SC

ERMAP

1p34.2

014

Dombrock

DO

DO

12p12.3

015

Colton

CO

AQP1

7p14.3

016

Landsteiner-Wiener

LW

ICAM4

19p13.2

CD242

017

Chido/Rodgers

CH/RG

C4A, C4B

6p21.3

018

Hh

H

FUT1

19q13.33

CD173

019

Kx

XK

XK

Xp21.1

020

Gerbich

GE

GYPC

2q14.3

CD236

021

Cromer

CROM

DAF

1q32.2

CD55

022

Knops

KN

CR1

1q32.2

CD35

023

Indian

IN

CD44

11p13

CD44

024

Ok

OK

BSG

19p13.3

CD147

025

Raph

RAPH

CD151

11p15.5

CD151

026

John Milton Hagen

JMH

SEMA7A

15q24.1

CD108

027

I

I

GCNT2

6p24.2

028

Globoside

GLOB

B3GALT3

3q26.1

029

GIL

GIL

AQP3

9p13.3

Kell antigen testing on the Olympus PK7200 or Toraymac GR

^ using monoclonal anti-k, anti-Ku or anti-K14 by Bromelin

Weak or Negative i

Retest for indirect antiglobulin test with polyclonal and other monoclonal anti-Kell

Weak Negative

McLeod or Kmod Ko

Flow cytometric analysis !

Scanning electron microscopy ;

Indirect antiglobulin test with anti-Kx !

XK gene analysis ;

Fig. 1 Flow chart of screening of red cells for McLeod phenotype

Mcleod Phenotype
Fig. 2 Kell/XK complex (modified from Lee et al. [8]). Kell antigen is 93 kDa type II glycoprotein consisted of 732 amino acid polypeptides and XK is 37 kDa, 444 amino acid polypeptides. They are covalently linked by a disulphide bond. (C: cysteine)

or Toraymac GR using anti-Kell MAbs (anti-k, anti-Ku and anti-K14 etc.). In the western regions of Japan from 1987 to 2005, a total of 16,160,714 donations of red blood cells (including repeat donors) were screened using mouse monoclonal anti-k (OSK5), anti-Ku (OSK32) and anti-K14 (OSK25).

We found 182 cell donations with McLeod phenotype or Kmod and 286 with Ko. Kmod red cells express Kell antigens weakly, and Ko express no Kell antigens. XK protein expression is intact or even increased in these two phenotypes as opposed to the McLeod phenotype. To identify McLeod phenotype after screening, we examine the expression level of Kell antigens by flow cytometry (Fig. 3); cell morphology (acanthocytes) by scanning electron microscopy (Fig. 4); serum creatine phosphokinase (CPK) and haptoglobin (Hp); red cells of family members (especially mothers), and the XK gene.

Although we have not examined all 182 donors, we have identified 3 donors with McLeod phenotype (2 subsequently developed McLeod syndrome [13, 16], 2 with McLeod-like phenotype (McLeod-like red cells show the same serological reactions and acanthocytes as McLeod except they weakly react with anti-Kx) [10], and more than 50 with Kmod. Nine donors are currently registered as McLeod phenotype in the whole of Japan [3, 11, 14]. Their CPK is usually high and Hp usually low (Table 2). Of note, one donor (M-1) developed McLeod syndrome 15 years after we identified him, although his CPK was within the normal range at initial screening.

Mcleod Phenotype

Red cells

Fluorescence/cell

Ko

4.5

Normal

156.0

McLeod

12.9

Mother

55.6 two peaks

Fig. 3 Kell antigen expression in McLeod male, female carrier (his mother) and Ko donors. Flow cytometry using anti-Kpb (OSK36) shows that Kell antigens are weak on red blood cells from the McLeod male and that the female carrier has a mixed population (two peaks) because XK is subject to X-chromosome inactivation

Fig. 3 Kell antigen expression in McLeod male, female carrier (his mother) and Ko donors. Flow cytometry using anti-Kpb (OSK36) shows that Kell antigens are weak on red blood cells from the McLeod male and that the female carrier has a mixed population (two peaks) because XK is subject to X-chromosome inactivation

Mcleod Phenotype

Noun alConüDl

Fig. 4 Scanning electron micrographs of acanthocytes in McLeod male and female carrier (mother). A lower percentage of acanthocytes is observed in the female carrier (JSM-5410, x1,500)

Noun alConüDl

Fig. 4 Scanning electron micrographs of acanthocytes in McLeod male and female carrier (mother). A lower percentage of acanthocytes is observed in the female carrier (JSM-5410, x1,500)

Table 2 CPK and haptoglobin

in McLeod phenotype donors

Age detected

Donor No.

(report)

CPK (U/L)

Hp (mg/dL)

References

McLeod M-1a

21 (1989)

56

n.t.

[13, 15]

M-2

45 (1994)

921

<10

[3]

M-3

31 (1995)

683

<10

[11]

M-4

29 (1995)

692

51

[14]

M-5

34 (2000)

1,937

<10

[14]

M-6

20 (2000)

282

152

[14]

M-7

27 (2000)

439

<10

[14]

M-8

? (2000)

862

<10

[14]

McLeod-likeb M-9

21 (1989)

382

<11.5

[10]

Normal

57-197

41-341

CPK creatine phosphokinase, Hp haptoglobin a Developed McLeod syndrome at 36 years old b McLeod-like: the same laboratory findings as McLeod apart from weak reaction with anti-Kx

Table 3 Differences among McLeod syndrome, chorea-acanthocytosis and non-acanthocytic chorea

Antigen expression

RBC

Possible antibodies

Kell

Kxa

Morphology

Produced

CPK

Normal Kell

N

N

N

N

N

Ko (Kell null)

(-)

Increased

N or elliptocyte

Anti-Ku

N

Kmod

Reduced

Increased

N

Anti-Ku-like

N

McLeod syndrome

Reduced

(-)

Acanthocyte

Anti-Kx, Km

N or High

McLeod carriers

Reduced to Nb

(-) to N

Acanthocyte

N

?

Chorea-acanthocytosis

N

N

Acanthocyte

N

High

Chorea

N

N

N

N

High

(non-acanthocytic)

CPK creatine phosphokinase, N normal a Anti-Kx + Km kindly gifted by Marion Reid, New York Blood Center b Flow cytometry: two peaks

CPK creatine phosphokinase, N normal a Anti-Kx + Km kindly gifted by Marion Reid, New York Blood Center b Flow cytometry: two peaks

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  • letteria calabresi
    What is the mccleod phenotype?
    4 months ago

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