Journal of Clinical Virology - Volume 82 - Supplement 1 - September 2016

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Abstracts / Journal of Clinical Virology 82S (2016) S1–S142 S99
of infections occurred after the engraftment (>30 days from TX)
(p = 0.02).
Conclusions: Among pediatric HSCT recipients, viral respiratory
infections in the post-transplant period are frequent and some-
times prolonged. Preventive measures must be tightened in this
population in order to reduce the derived morbidity and mortality.
Abstract no: 259
Presentation at ESCV 2016: Poster 157
Normalizing ELISPOT to quantify human
cytomegalovirus (HCMV) and Epstein Barr-virus
(EBV) specific T-cell response in kidney
transplant recipients
C. Fornara ∗ Cassaniti . Calarota
K.M.G. Adzasehoun , L. Scaramuzzi , G. Comolli ,
F. Baldanti
1 Molecular Virology Unit, Microbiology and Virology
Department, Fondazione IRCCS Policlinico San
Matteo, Pavia, Italy
2 Nephrology, Dialysis and Transplantation Unit,
Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
3 Molecular Virology Unit, Microbiology and Virology
Department – Experimental Research Laboratories,
Biotechnology Area, Fondazione IRCCS Policlinico
San Matteo, Pavia, Italy
4 Department of Clinical, Surgical, Diagnostic and
Pediatric Sciences, University of Pavia, Italy
Background: Herpes virus infection or reactivation are major
complications in solid organ transplant recipients. Virus-specific
T-cell response is crucial to control infection.
Methods: HCMV and EBV specific CD4+ and CD8+ T-cell
response were investigated in 29 kidney transplant recipients by
a novel approach of enzyme-linked immunospot assay (ELISPOT).
Overlapping 15-mer peptide pools of HCMV proteins immediate
early IE-1, IE-2 and phosphoprotein pp65, and of EBV lytic (BZLF1
and BMRF1) and latent (EBNA1, EBNA3a, EBNA3b, EBNA3c, LMP1
and LMP2) proteins were used for stimulation of both CD4+ and
CD8+ HCMV-specific and EBV specific T-cells, respectively. Virolo-
gical and immunological monitoring were performed for one year
of follow-up.
Results: As for HCMV infection, 13/19 (68.4%) HCMV seropos-
itive recipients showed levels of HCMV replication <100,000
DNA copies/ml blood and did not required anti-viral treatment,
while 6/19 (31.6%) HCMV-seropositive patients were treated since
showing ≥ 100,000 HCMV DNA copies/ml blood. Patients with
spontaneous control of infection showed, at 120 days after trans-
plant, levels of HCMV specific CD4+ T-cells significantly higher
with respect to patients who needed treatment. HCMV specific
T-cell response to single HCMV proteins (pp-65, IE-1, IE-2) was
examined: pretransplant number of both CD4+ and CD8 + specific
T cells directed against IE-1 showed significantly higher level in
patients controlling infection and their level remained significantly
higher until 120 days. No difference was shown for pp-65 and
IE-2 between the two groups of patients. In addition, 5 HCMV-
seronegative recipients receiving organ from HCMV seropositive
donor (D+/R−), were examined: 4/5 developed a primary infec-
tion within one month from transplantation and required antiviral
treatment. HCMV-specific CD4+ T-cells remained significant lower
with respect to patients able to control infection until 120 days after
transplantation.
As for EBV infection, 3/29 (10.3%) EBV-seropositive patients
reaching levels of EBV ≥ 10,000 DNA copies/ml blood did not
showed EBV-specific T-cell response for the entire period consid-
ered. However, EBV-specific T-cell response was detected in only
8/20 (40%) patients examined at 1 year follow-up, regardless of the
presence of EBV DNA in blood.
Conclusions: Normalizing ELISPOT may be a simple and useful
tool to performimmunologicalmonitoring in solid organ transplant
recipients and to detect herpes virus specific response. However,
while the importance of HCMV-specific T-cell response to control
HCMV infection is evident, further studies are required to better
define the role of EBV-specific T-cell response.
Abstract no: 272
Presentation at ESCV 2016: Poster 158
BK polyomavirus-seroreactivity increases with
virus replication
H.F. Wunderink ∗, E. van der Meijden ,
C.S. van der Blij-de Brouwer , H.L. Zaaijer ,
A.C.M. Kroes , J.I. Rotmans ,
J.N. Bouwes Bavinck , M.C.W. Feltkamp
1 Leiden University Medical Center, The Netherlands
2 Sanquin Blood Supply, The Netherlands
Background: BK polyomavirus (BKPyV) infection causes
nephropathy in 1–10% of kidney transplant recipients. This
condition results in graft-loss in up to 50% of cases unless immuno-
suppression is lowered. Specific antiviral treatment is not available.
In immunocompetent individuals, BKPyV resides latently in kidney
tubular epithelium after primary infection during childhood.
In order to predict which recipients will develop BKPyV
nephropathy, we recently analyzed a cohort of kidney donor-
recipient pairs prior to transplantation for several immunological
and virological parameters. That study showed a strong correla-
tion between the strength of BKPyV-seroreactivity measured in the
donor and BKPyV infection and nephropathy in the recipient
We hypothesized that BKPyV-seroreactivity of the donors mirrors
the load of infectious virus in the transplanted kidney. To further
investigate the relation between BKPyV-seroreactivity and BKPyV-
replication, we analyzed the dynamics of BKPyV-seroreactivity in
individuals that did or did not experienced a detectable BKPyV
infection.
Methods: A group of 101 kidney transplant recipients
was analyzed for BKPyV-seroreactivity (VP1-antigen; Luminex
immunoassay) and for BKPyV viremia (viral load measured by
q-PCR). Serum and blood plasma samples were obtained before
transplantation and at 3-month intervals until 18 months after. As
controls 87 healthy blood donors were analyzed with a 12-month
interval. Descriptive statistics and mixed model analysis was used
to analyze the association between measured peak BKPyV-loads
and BKPyV-IgG seroreactivity.
Results: At baseline the overall BKPyV-seropositivity was high
in both transplant recipients (92%) and blood donors (99%). The
mean baseline BKPyV-IgG level in both groups was comparable.
In 85% of the kidney recipients, BKPyV viremia was detected at
some point during follow-up, with peak viral loads ranging from10
to 579700 copies/ml, while no viremia was detected in the blood
donors. After a year, in the healthy blood donors, the mean level
of seroreactivity remained the same (p = 0.929). This was also the
case among kidney recipients without BKPyV viremia (p = 0.981).
Among kidney recipients that did develop viremia, however, a sta-
tistically significant increase in BKPyV-seroreactivity was observed