Jou nal o Medical Vi ology 70:475–480 (2003)
Ex Vi o Cy okine Responses Agains Pa o i us
B19 An igens in P e iously In ec ed
P egnan Women
Amanda Co co an,
1,2
Be na d P. Mahon,
2
Pe e McPa land,
3
Anne Da o en,
4
and Sean Doyle
1
*
1
Bio echnology G oup, Depa men o Biology, Na ional Uni e si y o I eland, Maynoo h, Co. Kilda e, I eland
2
Ins i u e o Immunology, Na ional Uni e si y o I eland, Maynoo h, Co. Kilda e, I eland
3
Na ional Ma e ni y Hospi al, Holles S ee , Dublin, I eland
4
I ish Blood T ans usion Se ice, S . James’ Hospi al, Dublin, I eland
Pa o i us B19 in ec ion is a signi ican cause
o e al dea h. The aim o his s udy was o
in es iga e he ole o ma e nal immune s a us in
modula ing suscep ibili y o e al B19 in ec ion.
Pe iphe al blood was ob ained om p egnan
women (n ¼199) wi h no clinical e idence o
ecen B19 in ec ion. E alua ion o ex i o T cell
esponses om 149/199 indi iduals showed
signi ican ly highe in e e on-gle els o se o-
posi i e indi iduals ollowing VP1 (268 36
e sus 103 19 pg/ml; P¼0.003) and VP2 (242 
42 e sus 91 16 pg/ml; P¼0.01) an igen s imu-
la ion. Signi ican ly highe le els o in e leukin-2
we e also obse ed in se oposi i e indi iduals
ollowing bo h VP1 (P¼0.0003) and VP2 (P¼
0.0005) s imula ion. The obse ed Th1 cellula
esponse is lowe han ha documen ed p e-
iously o non-p egnan indi iduals and s ongly
sugges s ha diminu ion o he ma e nal an i-
i al immune esponse may inc ease suscep -
ibili y o e al B19 in ec ion. J. Med. Vi ol.
70:475–480, 2003. ß2003 Wiley-Liss, Inc.
KEY WORDS: p egnancy; cellula immuni y;
e y h o i us; in e e on-g
INTRODUCTION
Human pa o i us B19 in ec ion can cause se ious
complica ions in he immunocomp omised hos includ-
ing p egnan women and indi iduals wi h unde lying
blood diso de s such as sickle cell disease [Wool e al.,
1989; Se jean e al., 1993; Heegaa d and Ho nsle h,
1995; Ta an ino and Shahidi, 1995]. Exposu e o, and
in ec ion wi h, pa o i us B19 du ing p egnancy can
lead o e al loss by ei he spon aneous abo ion o non-
immune e al hyd ops occu ing in 8–10% o in ec ions
[B own, 1989; Jo dan, 1996; Kinney e al., 1988]. B19 is
ansmi ed ac oss he placen a du ing ma e nal in ec-
ion and subsequen e al in ec ion can lead o se e e
anaemia. A e ical ansmission a e o 33–51% has
been epo ed [PHLS, 1990; Yaegashi, 2000]. B19
in ec ion du ing p egnancy o en goes unde ec ed as
many p egnan women a e asymp oma ic while o he
indi iduals expe ience symp oms such as exan hema
and a h algia [Komischke e al., 1997].
Fe al loss as a consequence o in au e ine B19
in ec ion is highes in, bu no es ic ed o, he i s
20 weeks o ges a ion [PHLS, 1990]. This suscep ibili y
could be a ibu ed, a leas in pa , o he p edilec ion o
B19 o apidly di iding e y h oid p ogeni o cells. In
he second imes e , he e al ed cell mass inc eases
h ee- o ou old and he e ec s o B19 may be u he
compounded by he educed li e span o e al ed blood
cells. The ela i e imma u i y o he e al immune
esponse a his s age may also be a con ibu o y ac o .
Cases o la e second and hi d imes e non-hyd opic
e al loss, caused by an acu e B19 in ec ion, ha e only
been epo ed ecen ly [Skjo
¨ldeb and-Spa e e al.,
2000; Tol ens am e al., 2001]. In he p esen s udy,
ollowing an examina ion o incidences o in a-u e ine
e al dea h i was ound ha 7.5% (7/93) o hi d i-
mes e and 15% (7/47) o la e second and hi d imes e
cases con ained B19 DNA in he placen al issue. These
cases we e no associa ed wi h hyd ops and no o he
explana ions o e al dea h we e e iden . Unusually,
none o he p egnan women showed clinical symp oms
o B19 in ec ion and many had delayed o absen
humo al esponses.
Speci ic an i- i al an ibody is conside ed he majo
mechanism o immune p o ec ion [Ku zman e al.,
1989; Schwa z e al., 1990], howe e , mo e ecen ly he
*Co espondence o: D . Sean Doyle, Na ional Ins i u e
o Cellula Bio echnology, Depa men o Biology, Na ional
Uni e si y o I eland, Maynoo h, Co. Kilda e, I eland.
E-mail: [email p o ec ed]
Accep ed 17 Feb ua y 2003
DOI 10.1002/jm .10420
Published online in Wiley In e Science
(www.in e science.wiley.com)
ß2003 WILEY-LISS, INC.
cellula esponse o pa o i us B19 in ec ion has been
explo ed. B19 speci ic T-cell p oli e a i e esponses o
ecen ly in ec ed and heal hy indi iduals o he capsid
an igens [ on Poblo zki e al., 1996; Co co an e al.,
2000; F anssila e al., 2001] and o he non-s uc u al
p o ein, NS1 [ on Poblo zki e al., 1996; Mi chell e al.,
2001] ha e been obse ed. T helpe cells sec e e cy o-
kines, which ha e an impo an ole in de e mining he
ou come o a p egnancy [Chaoua e al., 1990; Hill, 1991;
Tang i and Raghupa hy, 1993]. Th1 and Th2 cells a e
he majo subse s o ully di e en ia ed CD4
þ
T cells
and no mal p egnancy is domina ed by T helpe cells
ha sec e e a Th2 ype pa e n o cy okines including
in e leukin-4 (IL-4) and in e leukin-5 (IL-5) [Wegmann
e al., 1993]. Th1 cy okines, including in e e on-gamma
(IFN-g) and in e leukin 2 (IL-2), a e associa ed wi h a
poo p egnancy ou come and a e supp essed by placen-
al p oduc s such as p oges e one, p os aglandin E2 and
cy okines such as IL-4 and IL-10 [Wegmann e al., 1993;
Kelly and C i chley, 1997]. Du ing p egnancy, elimina-
ion o a i al in ec ion ia a Th1 esponse may esul in
endange ing he de eloping concep us. Cy okines ypi-
cal o a Th1 esponse, including IFN-g, IL-2, IL-6, and
IL-1bha e been epo ed upon s imula ion o T cells o
heal hy adul s wi h pa o i us B19 [Wagne e al.,
1995; Mo a e al., 1996; Co co an e al., 2000; Jo dan
e al., 2001]. Fu he mo e, Co co an e al. [2000] ha e
demons a ed ha PBMCs isola ed om no mal heal hy
indi iduals (n ¼7, comp ising 3 emales) p oduced
IFN-gle els o 610 348 pg/ml and 1765 825 pg/ml
when s imula ed wi h VP1 and VP2, espec i ely.
In his s udy, we in es iga ed i p egnancy, and he
associa ed supp ession o Th1- ype esponses, could
modula e ex i o B19-speci ic cy okine p oduc ion om
T cells isola ed om p egnan women o elucida e he
ole o hos ac o s in de e mining suscep ibili y o
B19 in ec ion.
MATERIALS AND METHODS
S udy Popula ion
Hepa inised blood specimens (n ¼199) we e ob ained
om p egnan women wi h no e idence o ecen pa -
o i us B19 exposu e o symp oms ( imes e 1 (n ¼78),
imes e 2 (n ¼80) and imes e 3 (n ¼41)). The age
ange o he olun ee s was 15–50 and he mean age was
28 yea s. The ges a ion pe iod a ied om 4 o 42 weeks.
No u he clinical da a was a ailable on he olun-
ee s. E hical pe mission o his s udy was ob ained
om he Na ional Ma e ni y Hospi al, Dublin, I eland
and w i en consen was ob ained om all olun ee s
p io o specimen collec ion.
An igen Exp ession and Pu i ica ion
Pa o i us B19 ecombinan VP1 and VP2 capsids
and NS1 we e exp essed in he baculo i us exp ession
sys em using Spodop e a ugipe a cells [B own e al.,
1990; B own e al., 1991; Ennis e al., 2001]. Capsid and
NS1 pu i ica ion ha e been desc ibed p e iously [Ke
e al., 1999; Ennis e al., 2001].
Pa o i us B19 IgG Enzyme Immunoassays
Plasma specimens we e analysed o B19 IgG speci ic
o he capsid an igens VP1 and VP2 in bo h hei na i e
(N) and dena u ed (D) con o ma ions as p e iously
desc ibed [Co co an e al., 2000]. An enzyme immu-
noassay was used o measu e he le el o eac i i y
agains B19 NS1. Resul s a e exp essed as index alues
(I.V.) ep esen ing specimen abso bance di ided by
cu -o abso bance. The cu -o was es ablished as he
abso bance þ2 SD g ea e han he mean abso bance
ob ained om a panel o B19 nega i e samples. An IV o
<1.0 was conside ed se onega i e. B19 IgG eac i i y o
con o ma ionally in ac VP1 (VP1-N) was de e mined
by a comme cial quali a i e immuno luo escen assay
(IFA). The deg ee o luo escence was g aded on a scale
o 0-4 acco ding o manu ac u e s’ ins uc ions (Bio in,
Dublin, I eland).
T cell p oli e a ion assays. Isola ed pe iphe al blood
mononuclea cells (PBMCs) we e cul u ed in iplica e
wi h pu i ied ecombinan VP1 (10 mg/ml), VP2 (10 mg/
ml) and NS1 (10 mg/ml) o 72 h . Cells cul u ed wi h
medium alone o wi h phy ohaemagglu inin (PHA: 2 mg/
ml) se ed as nega i e and posi i e con ols, espec-
i ely. The le el o B19-speci ic T cell p oli e a ion was
measu ed depending on he amoun o [
3
H]- hymidine
inco po a ion du ing he inal 4 h o cul u e [Co co an
e al., 2000].
Cy okine enzyme immunoassays. Supe na an s we e
emo ed om PBMCs cul u es, a op imal imepoin s,
o de e mine he concen a ion o IL-2 (24 h ) and IFN-g,
IL-4 and IL-5 concen a ions (72 h ). Le els o cy okine
sec e ed we e de e mined by EIA using comme cially
a ailable an ibody pai s (Pha Mingen, San Diego,
Cali o nia, USA). Concen a ions we e de e mined by
compa ing he abso bance a 405 nm o es samples
wi h a s anda d cu e o ecombinan cy okines o
known concen a ion. Le els o IL-2 a e exp essed in
e ms o index alues (specimen IL-2 (U/ml) di ided
by he mean nega i e con ol IL-2 le el (U/ml) plus 2
s anda d de ia ions) o compensa e o di e ences in
con ol IL-2 le els be ween expe imen s.
S a is ical Me hods
Cy okine sec e ion da a om di e en ea men
g oups we e compa ed by use o S uden ’s - es .
RESULTS
Se o eac i i y o S udy Popula ion
Pa o i us B19 se op e alence in he adul popula-
ion has been epo ed o be 60–70%. In his s udy,
whe e B19 se oposi i i y was de ined by he p esence
o an ibody agains VP2-N (capsid VP2), all imes e
g oups had expec ed le els o eac i i y agains VP2-N
(63–71%) (Table I), hus gi ing a ep esen a i e sample
popula ion in e ms o pas B19 in ec ion o each o he
imes e s. Le els o eac i i y agains VP1 anged om
59–68% (Table I). The low le el o an ibody eac i i y
obse ed agains linea epi opes o VP1 (35–52%) and
476 Co co an e al.
VP2 (3–15%), in he se oposi i e g oup, is indica i e o
pas in ec ion o heal hy indi iduals and also empha-
sises he impo ance o using capsid-based de ec ion
sys ems o accu a e diagnosis o pas exposu e o B19 in
p egnan women. I is known ha an ibodies agains
linea epi opes on VP2 a e unde ec able 6 mon hs pos -
in ec ion [So
¨de lund e al., 1995]. As specimens om
his coho exhibi ed he expec ed low le el o eac i i y
agains linea VP2 (Table I), i can be concluded ha
92% o se oposi i e p egnan women in his s udy did
no ha e an acu e B19 in ec ion.
S ong IFN-gResponses Domina e
he Cy okine P o ile
No all PBMCs isola ed om whole blood specimens
aken om p egnan women exhibi ed eac i i y when
s imula ed wi h posi i e con ol (PHA) in he T cell
p oli e a ion assay. Thus, subsequen da a e alua ion
in ol ed he s udy o T cell esponses om he 147/199
indi iduals wi h PHA-induced esponses. Highe le els
o he in lamma o y cy okine IFN-gwe e sec e ed by
PBMCs ob ained om se oposi i e indi iduals (n ¼99)
han in hose ob ained om se onega i e dono s
(n ¼48). Mos signi ican we e le els o IFN-g(268 
36 pg/ml) when T cells we e s imula ed wi h he immu-
nodominan capsid p o ein, VP1 (P¼0.003). Le els o
IFN-gwe e also signi ican when cells we e s imula ed
wi h he capsid p o ein VP2 (P¼0.01) and o a lesse
ex en wi h NS1 (P¼0.09) (Table II).
In o de o de e mine i he e was a imes e -
dependen pa e n in he ex i o cy okine esponse,
specimens we e e-classi ied based upon he s age o
ges a ion. IFN-gwas de ec ed in specimens ob ained
ac oss all h ee imes e s, howe e no signi ican
di e ence was obse ed in he amoun s o IFN-g
sec e ed ex i o, in esponse o all B19 an igens es ed,
ac oss he imes e s o p egnancy (Fig. 1).
B19-Speci ic IL-2 P oduc ion
by P egnan Women
Al hough signi ican ly high le els o IL-2 we e p o-
duced by PBMCs when s imula ed wi h B19 an igens,
ini ially he e was no s a is ically signi ican di e ence
be ween le els p oduced by se oposi i e (n ¼99) and
se onega i e (n ¼48) specimens due o he ac ha
h ee se onega i e specimens p oduced high le els o
IL-2 upon s imula ion. Exclusion o hese h ee speci-
mens (see Discussion) esul s in he obse ed le els
o IL-2 sec e ion being signi ican ly highe in se o-
posi i e specimens o bo h VP1 (P¼0.0003) and VP2
(P¼0.0005) s imula ion. S ong IL-2 p oduc ion was
obse ed ollowing ex i o s imula ion o PBMCs om
se oposi i e p egnan women (n ¼99) wi h VP1, VP2
and NS1, esul ing in IL-2 index alues o 1.43 0.9,
1.36 0.7 and 1.27 0.9, espec i ely (Fig. 2). In com-
pa ison, IL-2 index alues o 0.85 0.25, 0.89 0.25 and
0.83 0.29 we e e iden ollowing analysis o T cells
om se onega i e indi iduals when s imula ed wi h
VP1, VP2 and NS1 (Fig. 2). In ac , 44/99 se oposi i e
samples p oduced signi ican ly highe le els o IL-2
compa ed o se onega i e samples (P¼0.004 o VP1,
P¼0.003 o VP2) despi e he inclusion o he 3 se one-
ga i e/high IL-2 specimens in he analysis (see abo e).
Mean alues o IL-2 o hese 44 samples we e
0.407 0.049 U/ml o VP1 and 0.306 0.029 U/ml o
VP2. No di e ence was obse ed in he ex en o ex i o
IL-2 sec e ion om s imula ed PBMCs be ween ime-
s e s. Despi e he bias owa ds Th2 cy okine p oduc ion
TABLE I. An ibody Response in Plasma Ob ained F om
P egnan Women (n ¼199) Agains he B19 Capsid P o eins
VP1 and VP2*
De ec ion
an igen
T imes e
1
Posi i e
2
B19 IgG s a us (%)
posi i e
3
Posi i e
VP1-N 59 65 68
VP2-N 63 65 71
VP1-D 52 51 35
VP2-D 15 6 3
NS1-D 2 4 0
*In con o ma ionally in ac (N) and dena u ed (D) o ms, and o he B19
nons uc u al p o ein, NS1. B19 se oposi i i y was de ined by he
p esence o an ibody agains VP2-N (capsid VP2).
TABLE II. Ex Vi o IFN-gSec e ion by PBMCs Isola ed F om
Se oposi i e and Se onega i e P egnan Women A e
S imula ion Wi h Pu i ied VP1, VP2, o NS1 (10 mg/ml)
Specimen
se o eac i i y
B19-speci ic IFN-gp oduc ion
(pg/ml þSE)
VP1 VP2 NS1
Posi i e (n ¼99) 268 36 242 42 185 34
Nega i e (n ¼48) 103 19 91 16 100 17
IFN, in e e on; PBMCs, pe iphe al blood mononuclea cells.
Fig. 1. T imes e dependence o ex i o in e e on-gp oduc ion
ollowing PBMCs s imula ion wi h B19 an igens. Isola ed PBMCs we e
indi idually s imula ed wi h pu i ied B19 an igens, VP1, VP2 and NS1
o ei he medium alone o PHA as a nega i e o posi i e con ol,
espec i ely. Se onega i e (SN) and se oposi i e (SP) specimens we e
ca ego ised acco ding o imes e 1 (SP (n ¼39); SN (n ¼20)), 2 (SP
(n ¼41); SN (n ¼17)) and 3 (SP (n ¼19); SN (n ¼11)). Resul s ep esen
he mean concen a ion o in e e on-gp oduced om iplica e wells
(SE).
Ex Vi o B19-Speci ic Cy okine Responses 477
du ing p egnancy, PBMC s imula ion wi h B19 an i-
gens did no p oduce any signi ican le els o in e -
leukin-4 and -5 (da a no shown).
DISCUSSION
This s udy ep esen s he i s simul aneous e alua-
ion o bo h humo al and cellula immuni y agains
pa o i us B19 in p egnan women. The popula ion
coho exhibi ed he expec ed high le el o se oposi i i y
(63–71%) agains B19 and a signi ican ex i o Th-1
esponse agains B19 an igens, hough educed com-
pa ed o non-p egnan indi iduals. Fu he mo e, e i-
dence is p esen ed o he p esence o a cellula esponse
o pas B19 in ec ion in he absence o a de ec able
humo al esponse, which has implica ions o cu en
B19 diagnos ic p ac ices.
O e all he le el o pa o i us B19 se op e alence
amongs p egnan women in I eland was 66% (132/199).
This e alua ion compa es a ou ably wi h ha epo ed
p e iously in bo h Ge man and US (73.2%) popula ions
using iden ical es me hodology [Sea le e al., 1997; US
Food and D ug Adminis a ion, 1999]. Signi ican ly, a
lowe le el o IgG an ibody posi i i y is obse ed agains
bo h linea ised B19 VP1 and VP2, con i ming he neces-
si y o B19 IgG de ec ion sys ems o u ilise na i e B19
an igens o acili a e op imal es sensi i i y [Ke e al.,
1999]. So
¨de lund e al. [1995] ha e shown p e iously
ha an ibodies agains linea epi opes a e los wi hin
6 mon hs ollowing B19 in ec ion, hus he low le el o
an ibody posi i i y agains hese epi opes, obse ed in
he p esen s udy, con i ms u he ha he majo i y o
se oposi i e indi iduals we e in ec ed a leas 6 mon hs
p io o specimen dona ion.
Cases o ma e nal in ec ion and subsequen e al
dea h due o B19 in ec ion ha e been epo ed in all
h ee imes e s [W igh e al., 1996; Yaegashi e al.,
1998; Skjo
¨ldeb and-Spa e e al., 2000]. Al hough he
di ec pa hogenic e ec s o B19 on e al de elopmen a e
a majo cause o mo ali y, he ole o he ma e nal
immune s a us in ei he p o ec ing agains o media ing
pa o i us B19–induced e al loss is unknown. I is
gene ally accep ed ha a success ul p egnancy equi es
a Th2 esponse and ha s ong Th1 esponses a e
associa ed wi h p egnancy ejec ion [Raghupa hy, 1997;
Raghupa hy, 2001]. In e es ingly, ecen wo k by Luppi
e al. [2002] p esen s e idence o an inc ease in CD8
þ
lymphocy e equency in pe iphe al blood specimens
aken du ing he hi d imes e o p egnancy compa ed
o a con ol g oup. In his p esen s udy we show ha ex
i o s imula ion wi h B19 an igens esul s in signi ican
IL-2 and IFN-gp oduc ion om PBMC despi e he
p oposed Th2 bias o p egnancy. Compa a i e in o ma-
ion on ex i o cy okine sec e ion in esponse o
B19 an igen s imula ion is limi ed. Howe e , in he
p esen s udy, he le el o ex i o IFN-gsec e ion was
educed subs an ially om ha o no mal heal hy in-
di iduals s imula ed wi h he same an igens [Co co an
e al., 2000] whe e B19 se oposi i e adul s p oduced
IFN-gle els o 610 348 pg/ml and 1765 825 pg/ml
when s imula ed wi h VP1 and VP2, espec i ely.
In e e on-gp oduc ion by PBMCs om p egnan
women (p esen s udy) was 205 27 pg/ml wi h VP1
and 176 26 pg/ml wi h VP2 s imula ion. This is sug-
ges i e o a p egnancy-associa ed diminu ion o Th1
media ed immuni y. In ac , a ansien down- egula-
ion in he Th1 esponse is seen du ing p egnancy in
heuma oid a h i is pa ien s and his educ ion is
associa ed wi h a s a e o emission as p o-in lamma o y
cy okines cause he pa hological damage o join s
e iden du ing heuma oid a h i is [Russell e al.,
1997].
The dec ease in he cellula immune esponse o
B19 obse ed may be ele an o he ad e se ou comes
associa ed wi h B19 in ec ion du ing p egnancy. We
p opose ha his diminished Th1 esponse may
dec ease he a e o B19 clea ance, hus gi ing he i us
he oppo uni y o exhibi g ea e in ec i i y. A simila
phenomemon has been epo ed wi h Leishmania majo
pa asi ic in ec ions o gene ically esis an p egnan
mice whe eby cellula esponses agains L. majo we e
weakened due o educed IFN-gp oduc ion du ing
p egnancy and was associa ed wi h diminished clea -
ance o he pa asi e [K ishnan e al., 1996]. In addi ion,
L. majo in ec ion in hese mice caused an inc ease in
he equency o e al eso p ions. Al hough a sys emic
Th1 esponse was bene icial in igh ing in ec ion, i was
also de imen al o ges a ion, e en a a dec eased le el.
IL-2 is no p esen no mally in subs an ial le els
du ing p egnancy a ound he ophoblas [King e al.,
1995], howe e , in he p esen s udy, ex i o s imula ion
wi h B19 an igens elici ed p oduc ion o his p o-
in lamma o y cy okine. IL-2 p oduc ion has been ob-
se ed p e iously in women who we e in ec ed wi h
B19 du ing p egnancy [Jo dan e al., 2001]. Using
immunohis ochemical echniques on placen al issue
sec ions (n ¼25), IL-2 was de ec ed a he ma e nal- e al
in e ace o all women in he s udy who se ocon e ed
du ing p egnancy despi e he ou come o he p egnancy.
Howe e , i was p oposed ha in p egnancies wi h a
poo ou come IL-2 is de ec able on he e al side o he
in e ace, whe eas hose wi h a posi i e ou come end o
Fig. 2. Ex i o IL-2 p oduc ion ollowing s imula ion o isola ed
PBMC, om se oposi i e (black ba s) and se onega i e (whi e ba s)
indi iduals, wi h pa o i us B19 VP1, VP2 and NS1 an igens,
espec i ely. IL-2 esul s a e exp essed as index alues (I.V. S.E.M.)
ep esen ing he amoun o IL-2 p oduced abo e he backg ound le el
o each indi idual (I.V. ¼mean IL-2 concen a ion (U/ml)/mean IL-2
concen a ion o he nega i e con ol þ2 s anda d de ia ions).
478 Co co an e al.
ha e he IL-2 on he ma e nal side. I is well es ablished
ha some cy okines ha e ad e se e ec s on he ou come
o p egnancy, pa icula ly IFN-g, IL-2 and TNF-a. These
cy okines ac i a e cy o oxic cells such as na u al kille
(NK) and lymphokine ac i a ed kille (LAK) cells which
can kill ophoblas cells [D ake and Head, 1989] and
when hese cy okines a e adminis e ed o mice hey
cause abo ions [Kinsky e al., 1990]. In p egnan
women wi h a his o y o ecu en spon aneous abo -
ions signi ican ly highe le els o NK cells [Kwak e al.,
1995], IFN-gand IL-2 exp ession [Tang i and Raghu-
pa hy, 1993] ha e been ound when compa ed o no mal
p egnan women. IFN-gp oduc ion by B19-speci ic
T cells may also be de imen al o he concep us by
inhibi ing g anulocy e-mac ophage colony-s imula ing
ac o (GM-CSF), which is in ol ed in ophoblas
g ow h and di e en ia ion [Robe son e al., 1994].
Al hough Th1 cy okines a e impo an du ing implan-
a ion and pa u i ion o p egnan women [Haimo ici
and Ande son, 1993; Aboagye-Ma hiesen e al., 1996],
he e may be imes du ing p egnancy when he e us
is mo e sensi i e o he le el o p o-in lamma o y cy o-
kines. Ou s udy shows ha he le els o Th1 cy okines
did no signi ican ly di e o e he h ee imes e s bu
he le el o IFN-gp oduced was highes in imes e 1.
P e ious s udies ha e shown ha p o-in lamma o y
cy okines such as IFN-gcan ha e dele e ious e ec s on
he e us du ing p egnancy [Raghupa hy, 1997]. This
obse a ion, combined wi h he ela i e imma u i y o
he e us du ing imes e 1, sugges s ha an inc eased
Th1 esponse o B19 may be de imen al o he e us.
O he ac o s o be conside ed when de e mining he
e ec o cy okines caused by B19 in ec ion du ing p eg-
nancy a e heges a ional pe iod o he in ec ion, he s age
o di e en ia ion o he concep us, he le el o soluble
cy okine ecep o s and he a io o Th2 cy okines.
In e es ingly, h ee o he se onega i e dono s p o-
duced high le els o IL-2 upon ex i o B19 an igen
s imula ion. The eason o his is unclea bu ecen
e idence sugges s ha ce ain indi iduals wi h pas B19
in ec ion may possess an an igen-speci ic cell media ed
immune esponse in he absence o a humo al esponse
o he i us. Tol ens am e al. [2001] obse ed ou B19
an ibody nega i e cases ha had speci ic T cell memo y
p o en by ei he ELISpo assay o e ame binding.
These obse a ions ha e signi ican consequences o
he design o an e icacious accine o pa o i us B19 in
ha u u e subuni accines should con ain bo h B19
T cell and B cell epi opes.
P e ious s udies on B19 in ec ion du ing p egnancy
ha e ocussed on bo h he di ec e ec s o B19 on he
e us and he ma e nal humo al esponse as he majo
mechanism o p o ec ion agains B19-induced e al
dea h. Ou esul s, which show a signi ican diminu-
ion in ex i o in e e on-gsec e ion in esponse o B19
an igen s imula ion, demons a e ha cellula immu-
ni y agains B19 is a enua ed du ing p egnancy which
may ha e an ad e se e ec on an i- i al Th1- ype
esponses he eby inc easing e al suscep ibili y o
in ec ion.
ACKNOWLEDGMENTS
This s udy has been ca ied ou 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 Manage-
men o Li ing Resou ces’’, QLK2-CT-2001-00877,
‘‘Human pa o i us in ec ion: owa ds imp o ed unde -
s anding, diagnosis and he epy’’ and he I ish Heal h
Resea ch Boa d.
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