Jou nal o Medical Vi ology 78:125–128 (2006)
Es ablishmen o Func ional B Cell Memo y Agains
Pa o i us B19 Capsid P o eins May be Associa ed
Wi h Resolu ion o Pe sis en In ec ion
A. Co co an,
1
B. C owley,
2
C. Dewhu s ,
3
B.L. Pize ,
3
and S. Doyle
1
*
1
Depa men o Biology and Na ional Ins i u e o Cellula Bio echnology, Na ional Uni e si y o I eland,
Maynoo h, Co. Kilda e, I eland
2
Depa men o Clinical Mic obiology, S . James Hospi al, Dublin, I eland, and Na ional Vi us Re e ence Labo a o y,
Uni e si y College, Dublin, I eland
3
Depa men o Pedia ic Oncology, Royal Li e pool Child en’s Hospi al-Alde Hey, Li e pool, UK
Pa o i us B19 (B19) in ec ion can occu du ing
acu e lymphoblas ic leukemia and pe sis en
i al in ec ion can occu despi e in a enous
immunoglobulin adminis a ion. He e, e idence
is p esen ed ha esolu ion o pe sis en B19
in ec ion in an acu e lymphoblas ic leukemia
pa ien may be associa ed wi h he simul aneous
s eng hening o an igen-speci ic B cell memo y
agains he B19 capsid p o ein VP2 and diminu-
ion in he memo y esponse agains he B19
non-s uc u al p o ein 1 (NS1). De e mina ion
o an igen-speci ic B cell memo y s a us may
enhance he se ological and molecula analyses
o pe sis en B19 in ec ion. J. Med. Vi ol. 78:
125–128, 2006. ß2005 Wiley-Liss, Inc.
KEY WORDS: ALL; immunocomp omised; B
cell ELISpo ; leukemia; e y h o-
i us
INTRODUCTION
Pa o i us B19 (B19) is he causa i e agen o disease
in bo h immunocompe en and immunocomp omised
indi iduals [B oliden, 2001; Co co an and Doyle, 2004].
Speci ically wi h espec o he immunocomp omised
s a us, he e ha e been a numbe o ecen epo s o
B19-associa ed disease in acu e lymphoblas ic leukemia
o child en [Heegaa d and Schmiegelow, 2002; Sa asan
and Ozdei , 2003; Ke e al., 2003a; Fa e e al., 2004].
Al hough i has been sugges ed ha childhood acu e
lymphoblas ic leukemia may be associa ed wi h p io
B19 exposu e [Sa asan and Ozdei , 2003], his causal
link emains unp o en. In ac , ecen wo k by Isa e al.
[2004] has shown ha B19 exposu e, in u e o, is unlikely
o be associa ed wi h he subsequen onse o acu e
lymphoblas ic leukemia, as judged by he absence o
de ec able B19 DNA om Gu h ie ca ds o child en
(n ¼54) who subsequen ly wen on o de elop acu e
lymphoblas ic leukemia.
Adminis a ion o in a enous immunoglobulin is he
main ea men o he symp oms associa ed wi h pe -
sis en B19 in ec ion, such as pancy openia and ch onic
anemia, in immunocomp omised pa ien s [B oliden,
2001] al hough he bene i o in a enous immunoglo-
bulin adminis a ion in acu e lymphoblas ic leukemia
pa ien s has ecen ly been ques ioned [Fa e e al.,
2004]. Concei ably, he cu en lack o s anda diza ion
o B19 IgG le els p esen in in a enous immunoglobu-
lin may be esponsible o his unce ain y wi h espec
o e icacy. To da e, mos s udies on he pa e n o B19
se ology and i aemia du ing acu e lymphoblas ic
leukemia ha e ocused solely on he de ec ion o B19
IgG and IgM and i al DNA [Heegaa d and Schmiege-
low, 2002; El-Mahallawy e al., 2004; Fa e e al., 2004].
Two ecen epo s [Ke e al., 2003a; Fa e e al., 2004]
ha e alluded o impo ance he o e all indi idual
pa ien esponse, and by implica ion he cellula
immune esponse, in success ul e adica ion o B19
in ec ion. E idence is p esen ed in his epo ha he
es ablishmen o B cell memo y is coinciden wi h he
clea ance o ci cula ing B19 and esolu ion o B19-
associa ed symp oms.
METHODS
A p e iously well 5-yea -old gi l p esen ed wi h
py exia, cough, b uising, and a pu pu ic ash. Bone
ma ow examina ion con i med he diagnosis o CD10
þ
G an sponso : Commission o he Eu opean Communi ies;
G an numbe : QLK2-CT-2001-00877.
A. Co co an’s p esen add ess is Bio in, 93, The Rise, Moun
Me ion, Co. Dublin, I eland.
*Co espondence o: D . S. Doyle, Depa men o Biology and
Na ional Ins i u e o Cellula Bio echnology, Na ional Uni e -
si y o I eland, Maynoo h, Co. Kilda e, I eland.
E-mail: [email protected]
Accep ed 30 Sep embe 2005
DOI 10.1002/jm .20513
Published online in Wiley In e Science
(www.in e science.wiley.com)
ß2005 WILEY-LISS, INC.
acu e lymphoblas ic leukemia and she commenced on
induc ion chemo he apy wi h he MRC ALL 97 ( 99)
p o ocol ( egimen B). A e induc ion he apy she
s a ed consolida ion chemo he apy. She esponded
well, bu in week 17 she was anemic and a bone ma ow
aspi a e showed e y h oid hypoplasia. O e he ollow-
ing 4 weeks she became ans usion-dependen , equi -
ing nine packed ed cell ans usions. Subsequen bone
ma ow aspi a es con i med e y h oid hypoplasia wi h
no elapse o acu e lymphoblas ic leukemia. Chemo he -
apy was commenced on T ¼3 mon hs ( ela i e o T ¼0
o ini ial B19 se ological and nucleic acid es ing) and
also adminis e ed a mon hs 3, 16, and 19. Pa en al
pe mission was ob ained o specimen collec ion.
To al B19-speci ic IgG o capsid VP2 (VP2-N) was
de e mined by comme cial EIA (Bio in In e na ional,
Dublin, I eland). B19 IgM was assessed acco ding o
B own e al. [1989]. B19 IgG eac i i y agains linea -
ized VP1 (VP1-D), VP2 (VP2-D), and NS1 was de e -
mined using immunoassay o ma s as desc ibed
p e iously [Co co an e al., 2000]. B19 DNA le els we e
assessed as desc ibed p e iously [Hicks e al., 1995;
B aham e al., 2004] and we e quan i ied using a B19
DNA In e na ional S anda d p epa a ion [Saldanha
e al., 2002]. In addi ion, cell p oli e a ion s udies and
cy okine quan i a ion we e ca ied ou as desc ibed
elsewhe e [Co co an e al., 2000]. B cell memo y was
analyzed using a B19-speci ic B cell ELISpo assay as
desc ibed by Co co an e al. [2004]. B ie ly, ni ocellu-
lose-lined pla es (96 well) (Millipo e, Bed o d, MA) we e
coa ed wi h ei he capsid VP2 (VP2-N; 10 mg/ml),
dena u ed VP2 (VP2-D; 10 mg/ml), dena u ed VP1
(VP1-D; 10 mg/ml), NS1 (10 mg/ml), o abbi an i-human
IgG (Dako A/S, Glos up, Denma k) (10 mg/ml) in 50 mM
sodium ca bona e bu e pH 9.6, o e nigh a 48C ( abbi
an i-human IgG acili a es de ec ion o o al IgG-
sec e ing B cells o insu e ha memo y B cell ac i a ion,
ia S aphylococcus au eus Cowan s ain 1 cells and IL-2,
had occu ed). Pla es we e washed wi h phospha e-
bu e ed saline (PBS) and blocked (20%( / ) FCS in
RPMI medium). Cells (pos -ac i a ion), a 1 10
7
,
110
6
,110
5
, and 1 10
4
cells/well we e added o
he pla es and sec e ed IgG was de ec ed using bio iny-
la ed abbi an i-human IgG/s ep a idin-conjuga ed
alkaline phospha ase (Sigma-Ald ich, Do se , UK
1
) and
BCIP/NBT p ecipi a ing subs a e (Sigma-Ald ich).
Spo s we e a e aged om iplica e wells and esul an
da a epo ed as he mean numbe o spo o ming cells
(SFC)/million s a ing cells.
RESULTS
Ini ial se ological es ing (T ¼0), using a B19 VP2
capsid-based immunoassay, o B19 IgG/M p o ed
nega i e, howe e B19 DNA posi i i y was con i med
by bo h eal- ime PCR and by do blo hyb idiza ion
[Hicks e al., 1995; B aham e al., 2004] (Fig. 1).
T ea men wi h in a enous immunoglobulin was com-
menced, and al hough loga i hmic educ ions in B19
i al load we e obse ed pos - ea men , i al clea ance
was no achie ed, as judged by a con inual ele a ion
in plasma B19 DNA le els, un il mon h 31 (Fig. 1).
Se ological analysis o a specimen ob ained om he
indi idual a T ¼1 (Fig. 1) demons a ed he p esence o
high le els o in a enous immunoglobulin-de i ed B19
VP2 IgG (index alue 5.76; eac i i y >o ¼1.1), in
addi ion o de ec ing he p esence o B19 NS1 IgG (Index
alue 3.22). No IgG was de ec ed which was eac i e
agains linea epi opes o ei he VP1 o VP2 p o eins
(VP1-D and VP2-D; da a no shown). A T ¼2, he B19
VP2 IgG index alue was 2.31, while ha o B19 NS1
had dec eased o 0.77 (se onega i e s a us).
F eshly isola ed pe iphe al blood mononuclea cells
(PBMCs), om he T1 specimen, we e s imula ed
ex i o, wi h bo h B19 VP1 and VP2 p o eins. Al hough
phy ohaemagglu inin (PHA) s imula ion esul ed in
signi ican s imula ion index (SI (mean s anda d
de ia ion): 1062.92 508.81, n ¼3), no de ec able T cell
s imula ion was e iden ollowing exposu e o PBMCs o
ei he VP1 (SI: 0.3 0.2) o VP2 (SI: 1.7 0.7). Cy okine
analysis o cul u e supe na an s likewise indica ed a
de ici in he p esence o cy okines associa ed wi h
ei he a Th1 (in e e on-g) o Th2 (IL-4 and IL-5)
immune esponse ollowing B19 an igen s imula ion
(da a no shown). In e e on-gwas de ec able in cul u e
supe na an s ollowing PBMC s imula ion wi h PHA
(da a no shown). Subsequen analysis o a second
specimen (T2) ob ained 5 mon hs a e he ini ial
sample, demons a ed he con inued absence o a
de ec able cellula immune esponse agains bo h B19
VP1 and VP2 p o eins. In e es ingly, signi ican PBMC
p oli e a ion was e iden ollowing s imula ion wi h
B19 NS1 p o ein (SI: 8.7 1.7) (Fig. 2A). Again,
howe e , he e was no e idence o B19-speci ic cy okine
p oduc ion (IL-2, in e e on-g, IL-4, and IL-5) agains
B19 VP1, VP2, o NS1 p o eins.
J. Med. Vi ol. DOI 10.1002/jm
1.00E+00
1.00E+01
1.00E+02
1.00E+03
1.00E+04
1.00E+05
1.00E+06
1.00E+07
1.00E+08
1.00E+09
1.00E+10
1.00E+11
1.00E+12
0 5 10 15 20 25 30 35 40
Time (Mon hs)
B19 DNA (IU/ml)
IVIG
IVIG
IVIG
IVIG
IVIG
T1 T2
Fig. 1. E ec o mul iple in a enous immunoglobulin adminis a-
ion on se um pa o i us B19 le els (B19 DNA (IU/ml)). Ini ial
se ological and i ological analyses we e pe o med a T ¼0. Speci-
mens o analysis o T cell immuni y and B cell ELISpo we e ob ained
a T ¼1 (22 mon hs) and 2 (27 mon hs), espec i ely. Chemo he apy
was commenced on T ¼3 mon hs ( ela i e o T ¼0 o ini ial B19
se ological and nucleic acid es ing), chemo he apy was also adminis-
e ed a mon hs 3, 16, and 19. IVIG: In a enous immunoglobulin.
126 Co co an e al.
I can be seen om Figu e 2B ha no B cell memo y is
e iden agains ei he linea epi opes o B19 VP1 o VP2
p o eins, howe e signi ican B cell memo y is de ec -
able agains he B19 NS1 p o ein (123.3 20.2 SFC/10
6
cells; mean SD) in specimen T1. In addi ion, a small
hough de ec able le el o B cell memo y was de ec able
agains B19 VP2 capsid p o ein (5.3 5.7 SFC/10
6
cells;
mean SD). In e es ingly, upon analysis o specimen
T2, i was obse ed ha he memo y B cell le el agains
he NS1 p o ein had diminished ( en old). Howe e , he
le el o de ec able memo y agains capsid VP2, and o a
lesse ex en he VP1 unique egion, had inc eased wi h
espec o he ini ial analysis, (VP2-N: 13 2, VP1-D:
32, VP2-D: 1.7 0.6, NS1-D: 9 3.6 SFC/10
6
cells).
This appa en de elopmen o a unc ional hos esponse
agains pa o i us B19 capsid p o ein VP2 was accom-
panied by a esolu ion o i al disease symp oms and
diminu ion o plasma B19 DNA le els o less han 10
2
IU
B19 DNA/ml.
DISCUSSION
Pe sis en in ec ion wi h pa o i us B19 (B19) is
desc ibed in an acu e lymphoblas ic leukemia pa ien
despi e he adminis a ion o in a enous immunoglo-
bulin he apy. The pe sis en B19 in ec ion was asso-
cia ed wi h he de ec ion o NS1 IgG eac i i y, in
addi ion o e idence o T cell immuni y and B cell
memo y di ec ed agains B19 NS1. Fu he mo e,
e idence is p esen ed ha he es ablishmen and
enhancemen o B cell memo y, di ec ed agains he
capsid p o eins o B19, was associa ed wi h diminu ion
o B19 i emia and esolu ion o ela ed disease
symp oms in he acu e lymphoblas ic leukemia pa ien .
I is e iden ha mul iple adminis a ion o in a e-
nous immunoglobulin h oughou he ea men pe iod
was insu icien o elimina e B19 i aemia, indeed he
i al load emained be ween 10
3
and 10
10
IU B19 DNA/
ml un il he inal in a enous immunoglobulin ea -
men a mon h 23. The p ecise o igin (i.e., pa ien - o
in a enous immunoglobulin-de i ed) o B19 VP2 IgG
de ec able in specimen T1 is unclea , al hough he
p esence o B19 NS1 IgG does indica e ha pa ien
an ibody p oduc ion capabili y was in ac . None heless,
he use o in a enous immunoglobulin he apy o he
elimina ion B19 i aemia emains unp o en, indeed
a ecen s udy [Fa e e al., 2004], which epo ed
a iable success wi h in a enous immunoglobulin
ea men in acu e lymphoblas ic leukemia, ecom-
mended he ea men only in cases o pe sis en
pancy openia o clinical mani es a ions o B19 in ec ion.
Howe e , in a enous immunoglobulin he apy has
been shown o be success ul o he ea men o B19-
associa ed ch onic a igue synd ome [Ke e al., 2003b].
Ul ima ely, he e icacy o in a enous immunoglobulin
he apy o he elimina ion o B19 i emia will only
become appa en when he le el o B19 IgG p esen in
in a enous immunoglobulin p epa a ions is epo ed
in e ms o B19 IgG IU/ml as p e ious s udies ha e
indica ed a iable B19 IgG le els (64.7 17.5 IU/ml;
(n ¼30)) in pooled sol en -de e gen ea ed plasma
[Daly e al., 2002].
Al hough ini ially hough o be a ma ke o pe sis en
in ec ion only [ on Poblo zki e al., 1995], he de ec ion
o NS1 IgG has also been shown o be p esen du ing
acu e B19 in ec ion in 61%–69% o indi iduals
[Hemaue e al., 2000; Ennis e al., 2001]. Mo eo e ,
signi ican T cell esponses o NS1 ha e also been
epo ed in ecen ly in ec ed indi iduals and pa ien s
who de eloped ch onic a h opa hy ollowing B19
in ec ion [Mi chell e al., 2001]. I is clea om he
p esen s udy, howe e , ha immuni y o NS1 does
no appea o be consis en wi h clea ance o B19
in ec ion, a leas in his indi idual su e ing om acu e
J. Med. Vi ol. DOI 10.1002/jm
A
0
2
4
6
8
10
VP1 VP2 NS1 PHA
S.I.
T2
B T1
T2
SFC/ 10^6 cells
0
10
20
30
40
VP2-N VP2-D VP1-D NS1
0
10
20
30
40
VP2-N VP2-D VP1-D NS1
Fig. 2. E alua ion o PBMC p oli e a i e esponse and an igen-
speci ic B cell memo y in acu e lymphoblas ic leukemia. A: Speci ic
p oli e a i e esponse o human pa o i us B19 p o eins VP1 (VP1-D),
VP2 (VP2-N), and NS1 in addi ion o he posi i e con ol mi ogen,
phy ohaemaggul inin (PHA), a T ¼2. Resul s a e exp essed as
s imula o y indices (SI) and a e he mean SD o iplica e wells.
B: Pa o i us B19-an igen-speci ic B cell memo y a T ¼1 and 2.
Resul s o B cell memo y a e exp essed as B19-speci ic spo - o ming
cells (SFCs)/numbe o s a ing cells and a e he mean SD o
iplica e wells. Indi idual ELISpo mic opla es we e coa ed wi h he
ollowing B19 p o eins: na i e (capsid) VP2 (VP2-N), dena u ed VP2
(VP2-D), dena u ed VP1 (VP1-D), and NS1. Human IgG de ec ion
using abbi an i-human IgG was used o con i m ha o al B cell
ac i a ion had occu ed (da a no shown). No e: B19 NS1 p o ein
esponse ¼123.3 20.2 SFC/10
6
cells in specimen T1.
B19 Memo y and Pe sis en In ec ion 127
lymphoblas ic leukemia. In addi ion, he p esence o
high i e B19 VP2 IgG, in he absence o de ec able
cellula immuni y, also appea s o be insu icien o
comple ely amelio a e B19 i aemia.
Howe e , he es ablishmen o B cell memo y agains
capsid VP2, and o a lesse ex en VP1, may play a ole in
he clea ance o B19 i emia. We ha e p e iously
epo ed e idence o B cell memo y agains B19 capsid
p o eins in immunocompe en indi iduals [Co co an
e al., 2004], and he da a p esen ed abo e ep esen he
i s de e mina ion o a simila pa e n o B cell memo y
in acu e lymphoblas ic leukemia, coinciden wi h he
esolu ion o B19 i aemia and symp oms. Assessmen
o an igen-speci ic B cell memo y also acili a es dis-
c imina ion be ween in a enous immunoglobulin- and
indi idual-de i ed B19 IgG, espec i ely, which is
signi ican in de e mining he se ocon e sion s a us
o he indi idual. In e es ingly, no e idence o B cell
memo y was e iden agains B19 NS1 in i e immuno-
compe en indi iduals [Co co an e al., 2004] he eby
sugges ing ha he p esence o B cell memo y agains
his p o ein may be indica i e o memo y dys unc ion
in acu e lymphoblas ic leukemia. Resolu ion o B19
i aemia o less han 10
2
IU/ml B19 DNA in he pa ien
was coinciden wi h a h ee old inc ease in de ec able B
cell memo y agains capsid VP2 (and a en old educ ion
wi h espec o NS1).
In conclusion, we sugges ha de e mina ion o
an igen-speci ic B cell memo y should accompany he
se ological and molecula in es iga ion o pe sis en
B19 i aemia, and associa ed disease mani es a ions, in
immunocomp omised indi iduals.
ACKNOWLEDGMENTS
This wo k was pe o med wi h inancial suppo om
he Commission o he Eu opean Communi ies, speci ic
RTD p og amme ‘‘Quali y o Li e and Managemen o
Li ing Resou ces,’’ QLK2-CT-2001-00877, ‘‘Human pa -
o i us in ec ion: owa d imp o ed unde s anding,
diagnosis and he apy.’’
REFERENCES
B aham S, Gandhi J, Bea d S, Cohen B. 2004. E alua ion o he Roche
Ligh Cycle pa o i us B19 quan i ica ion ki o he diagnosis o
pa o i us B19 in ec ions. J Clin Vi ol 31:5–10.
B oliden K. 2001. Pa o i us B19 in ec ion in pedia ic solid-o gan and
bone ma ow ansplan a ion. Pedia T ansplan 5:320–330.
B own KE, Buckley MM, Cohen BJ, e al. 1989. An ampli ied ELISA o
he de ec ion o pa o i us B19 IgM using monoclonal an ibody o
FITC. J Vi ol Me hods 26:189–198.
Co co an A, Doyle S. 2004. Ad ances in he biology, diagnosis and hos -
pa hogen in e ac ions o pa o i us B19. J Med Mic obiol 53:459–
475.
Co co an A, Doyle S, Wald on D, Nicholson A, Mahon BP. 2000.
Impai ed gamma in e e on esponses agains pa o i us B19 by
ecen ly in ec ed child en. J Vi ol 74:9903–9910.
Co co an A, Mahon BP, Doyle S. 2004. B cell memo y is di ec ed owa d
con o ma ional epi opes o pa o i us B19 capsid p o eins and he
unique egion o VP1. J In ec Dis 189:1873–1880.
Daly P, Co co an A, Mahon BP, Doyle S. 2002. High-sensi i i y PCR
de ec ion o pa o i us B19 in plasma. J Clin Mic obiol 40:1958–
1962.
El-Mahallawy HA, Mansou T, El-Din SE, Ha ez M, Abd-el-La i S.
2004. Pa o i us B19 in ec ion as a cause o anemia in pedia ic
acu e lymphoblas ic leukaemia pa ien s du ing main enance
chemo he apy. J Pedia Hema ol Oncol 26:403–406.
Ennis O, Co co an A, Ka anagh K, Mahon BP, Doyle S. 2001.
Baculo i us exp ession o pa o i us B19 (B19V) NS1: U ili y in
con i ming ecen in ec ion. J Clin Vi ol 22:55–60.
Fa e S, Cassino i P, Popo ic MB. 2004. Pe sis en human pa o i us
B19 in ec ion in child en unde main enance chemo he apy o
acu e lymphocy ic leukaemia. J Pedia Hema ol Oncol 26:497–
503.
Heegaa d ED, Schmiegelow K. 2002. Se ologic s udy on pa o i us B19
in ec ion in childhood acu e lymphoblas ic leukaemia du ing
chemo he apy: Clinical and hema ologic implica ions. J Pedia
Hema ol Oncol 24:368–373.
Hemaue A, Gigle A, Sea le K, Beckenlehne K, Raab U, B oliden
K, Wol H, Ende s G, Mod ow S. 2000. Se op e alence o
pa o i us B19 NS1-speci ic IgG in B19-in ec ed and unin ec -
ed indi iduals and in in ec ed p egnan women. J Med Vi ol 60:
48–55.
Hicks KE, Bea d S, Cohen BJ, Clewley JP. 1995. A simple and sensi i e
DNA hyb idiza ion assay used o he ou ine diagnosis o human
pa o i us B19 in ec ion. J Clin Mic obiol 33:2473–2475.
Isa A, P i akis P, B oliden K, Gus a sson B. 2004. Human pa o i us
B19 DNA is no de ec ed in Gu h ie ca ds om child en who ha e
de eloped acu e lymphoblas ic leukaemia. Pedia Blood Cance
42:357–360.
Ke JR, Ba ah F, Cunni e VS, Smi h J, Vallely PJ, Will AM, Wynn RF,
S e ens RF, Taylo GM, Clea o GM, Eden OB. 2003a. Associa ion
o acu e pa o i us B19 in ec ion wi h new onse o acu e
lymphoblas ic and myeloblas ic leukaemia. J Clin Pa hol 56:873–
875.
Ke JR, Cunni e VS, Kellehe P, Be ns ein RM, B uce IN. 2003b.
Success ul in a enous immunoglobulin he apy in 3 cases o
pa o i us B19-associa ed ch onic a igue synd ome. Clin In ec
Dis 36:e100–e106.
Mi chell LA, Leong R, Rosenke KA. 2001. Lymphocy e ecogni ion o
human pa o i us B19 non-s uc u al (NS1) p o ein: Associa ions
wi h occu ence o acu e and ch onic a h opa hy? J Med Mic obiol
50:627–635.
Saldanha J, Lelie N, Yu MW, Hea h A, B19 Collabo a i e S udy G oup.
2002. Es ablishmen o he i s Wo ld Heal h O ganiza ion
In e na ional S anda d o human pa o i us B19 DNA nucleic
acid ampli ica ion echniques. Vox Sang 82:24–31.
Sa asan S, Ozdei O. 2003. Pa o i us B19 in ec ion and acu e
lymphoblas ic leukaemia. B J Haema ol 120:166–171.
on Poblo zki A, Hemaue A, Gigle A, Puchhamme -S ockl E, Heinz
FX, Pon J, Laczika K, Wol H, Mod ow S. 1995. An ibodies o he
nons uc u al p o ein o pa o i us B19 in pe sis en ly in ec ed
pa ien s: Implica ions o pa hogenesis. J In ec Dis 172:1356–
1359.
J. Med. Vi ol. DOI 10.1002/jm
128 Co co an e al.