Laboratori Sperimentali Of Ricerca

Pavia, Italy

Laboratori Sperimentali Of Ricerca

Pavia, Italy
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Revello M.G.,Science Ostetricia e Ginecologia | Genini E.,Science Virologia e Microbiologia | Gorini G.,Science Virologia e Microbiologia | Klersy C.,Servizio di Biometria e Epidemiologia Clinica | And 2 more authors.
Journal of Clinical Virology | Year: 2010

Background: The interpretation of a positive IgM antibody result to human cytomegalovirus (HCMV) in a pregnant woman is of major importance for the correct management of the pregnancy. Determination of HCMV-specific IgG avidity is considered an useful approach for distinguishing IgM antibody due to primary HCMV infection from IgM antibody elicited during non-primary infection. Objective: Comparative evaluation of eight commercial HCMV IgG avidity assays currently available in Europe. Study design: A panel of 198 sequential samples collected from 65 pregnant women at 0-90, 91-180, and >180 days after the onset of primary HCMV infection was retrospectively tested by Abbott, BioMérieux, Bio-Rad, DiaSorin, Diesse, Euroimmun, Radim, and Technogenetics HCMV IgG avidity assays according to the manufacturer's instructions. Results: None of the 198 samples tested yielded identical scores by the kits under evaluation. The Euroimmun and Radim assays showed the best correlation with expected results in terms of low (0-90 days), intermediate (90-180 days) and high (>180 days) avidity results, respectively. The best accuracy in diagnosing a recent (<90 days after the onset) or non-recent (>180 days after the onset) primary HCMV infection was shown by Radim followed by Euroimmun and Diesse. The best correlation with a well established in-house developed HCMV IgG avidity assay was shown by Radim. Conclusions: HCMV IgG avidity kits need to be improved and standardized. In the meantime, highly specific IgM assays are preferable for screening purposes in pregnant women. © 2010 Elsevier B.V.

Gerna G.,Laboratori Sperimentali Of Ricerca | Lilleri D.,Laboratori Sperimentali Of Ricerca | Chiesa A.,Science Virologia e Microbiologia | Zelini P.,Science Virologia e Microbiologia | And 7 more authors.
American Journal of Transplantation | Year: 2011

Control of human cytomegalovirus (HCMV) infection during the posttransplant period was investigated in 134 solid-organ transplant recipients by monitoring in parallel virologic and immunologic parameters for at least 1 year of follow-up. Virologic monitoring was achieved by determining HCMV DNAemia with real-time PCR, using the threshold of 300 000 DNA copies/mL blood as a cutoff for starting preemptive therapy. Immunologic monitoring included measurement of HCMV-specific CD4+ and CD8+ T cells by cytokine flow cytometry, using HCMV-infected dendritic cells as a stimulus. HCMV infection was diagnosed in 110 (82%) and required treatment in 49 (36%) patients. At 12 months after transplantation 'protective' immunity (≥0.4 CD4+ and CD8+ HCMV-specific T cells/lL blood) was achieved in 115/129 (89%) patients. During the entire study period, 122 patients reconstituting HCMV-specific CD4+ and CD8+ T-cell immunity at 60 days posttransplant onward were able to control HCMV infection, except for one patient who developed HCMV disease because of a rejection episode. Patients reconstituting HCMV-specific CD8+ only did not control HCMV infection. In conclusion, the presence of both HCMV-specific CD4+ and CD8+ T cells ≥ 0.4/lL blood appears to be protective against HCMV disease. This result does not apply to patients undergoing antirejection treatment, or reconstituting HCMV-specific CD8+ T cells only. © Copyright 2011 The American Society of Transplantation.

Furione M.,SS Virologia Molecolare | Rognoni V.,SS Virologia Molecolare | Sarasini A.,SS Virologia Molecolare | Zavattoni M.,SS Virologia Molecolare | And 3 more authors.
Journal of Medical Virology | Year: 2013

Following primary human cytomegalovirus (HCMV) infection, virus-specific IgG antibody shift from low to high avidity with individual variations in the rate of avidity maturation. The kinetics of the avidity maturation of IgG specific for HCMV nuclear antigen in pregnant women with primary infection was investigated. Absorbance values used for avidity index calculation of 286 sequential sera collected from 69 pregnant women with primary HCMV infection were retrieved. Percent difference in absorbance values of IgG antibody bound to the solid phase after urea treatment (IgG avidity) between early (T1, 0-90, median 31 days) and late (T2, 91-180, median 136 days) serum samples was calculated for each woman. Three groups of women were identified: 24/69 (34.8%) women showed high (>100%) avidity increase between T1 and T2 (pattern H), 29/69 (42%) low (<50%) increase (pattern L), and 16/69 (23.2%) intermediate increase (pattern I). Avidity values in T1 samples were significantly higher in women with pattern L compared to women with pattern H (P=0.01). Altogether, 28/69 (40.6%) women transmitted HCMV infection to their fetuses. Fetal infection preferentially occurred (P<0.01) in women with pattern H (15/24, 62.5%) compared with women with pattern L (7/29, 24.1%). In conclusion, different patterns of IgG avidity maturation can be detected following primary HCMV infection. Pregnant women with pattern H (rapid IgG avidity increase) appear to be at higher risk for fetal infection, whereas, pregnant women developing early antibody with high avidity appear to be at a lower risk of vertical transmission. © 2013 Wiley Periodicals, Inc.

Revello M.G.,Servizio di Virologia | Revello M.G.,Laboratori Sperimentali Of Ricerca | Gerna G.,Laboratori Sperimentali Of Ricerca
Reviews in Medical Virology | Year: 2010

Human cytomegalovirus (HCMV) has been routinely isolated from and propagated in vitro in human embryonic lung fibroblast (HELF) cell cultures, while in vivo it is known to infect predominantly endothelial and epithelial cells. In recent years, genetic determinants of the HCMV tropism for endothelial/epithelial cells were identified in the UL131A/UL130/UL128 locus of HCMV genome of wild-type strains. UL131A-UL128 gene products form a complex with glycoprotein H (gH) and L (gL) resulting in a gH/gL/UL131A-UL128 complex that is required for HCMV entry into endothelial/epithelial cells. In contrast, virus entry into fibroblasts has its genetic determinants in the complex gH/gL/gO (or gH/gL). During primary HCMV infection, the neutralising antibody response measured in endothelial cells (EC) is potent, occurs very early and is directed mostly against combinations of two or three gene products of the UL131A-128 locus. On the contrary, neutralising antibodies measured in fibroblasts appear late, are relatively weak in potency and are directed against gH and gB. The T-cell immune response to UL131A-UL128 gene products remains to be investigated. Recently, a role has been proposed for neutralising antibody in conferring prevention/protection against HCMV infection/disease in pregnant women with primary HCMV infection. However, the level of cooperation between humoral immunity and the well-established T-cell protection remains to be defined. Copyright © 2010 John Wiley & Sons, Ltd.

Gerna G.,Laboratori Sperimentali Of Ricerca | Lilleri D.,Laboratori Sperimentali Of Ricerca | Lilleri D.,Institute for Research in Biomedicine | Fornara C.,Laboratori Sperimentali Of Ricerca | And 5 more authors.
Journal of General Virology | Year: 2015

The comparative long-term kinetics of human cytomegalovirus (HCMV) load and HCMV-specific antibody responses in the immunocompetent and immunocompromised solid-organ transplanted host during primary HCMV infection was investigated. In total, 40 immunocompetent subjects and 17 transplanted patients were examined for viral load as well as for IgG antibody responses to HCMV glycoproteins gH/gL/pUL128L, gH/gL and gB, and neutralizing antibodies in ARPE-19 epithelial cells and human fibroblasts. In parallel, the CD4+ and CD8+ HCMV-specific T-cell responses were determined by cytokine flow cytometry. Transplanted patients reached significantly higher viral DNA peaks, which persisted longer than in immunocompetent subjects. The ELISA-IgG responses to the pentamer, gH/gL and gB were significantly higher in primary infections of the immunocompetent until six months after onset, with the two antibody levels then overlapping from six to 12 months. Antibody levels neutralizing infection of epithelial cells were significantly higher in transplanted patients after six months, persisting for up to a year after transplantation. This trend was not observed for antibodies neutralizing infection of human fibroblasts, which showed higher titres in the immunocompetent over the entire one-year followup. In conclusion, in immunocompromised patients the viral load peak was much higher, while the neutralizing antibody response exceeded that detected in the immunocompetent host starting six months after onset of follow-up, often concomitantly with a lack of specific CD4+ T cells. In this setting, the elevated antibody response occurred in the presence of differentiated follicular helper T cells in the blood, which decreased in number as did antibody titres upon reappearance of HCMV-specific CD4+ T cells. © 2015 The Authors.

Lilleri D.,Laboratori Sperimentali Of Ricerca | Kabanova A.,Institute for Research in Biomedicine | Lanzavecchia A.,Institute for Research in Biomedicine | Gerna G.,Laboratori Sperimentali Of Ricerca
Journal of Clinical Immunology | Year: 2012

Purpose: Recently, human cytomegalovirus (HCMV) UL128-131 locus gene products have been found to be associated with glycoprotein H (gH) and glycoprotein L (gL) to form a pentameric glycoprotein complex gH/gL/pUL128-130-131, which is present in the virus envelope and elicits production of neutralizing antibodies. Purpose of this study was to verify whether in vitro activities of these antibodies may correlate with protection in vivo. Methods: By using potently neutralizing human monoclonal antibodies (mAbs) targeting 10 different epitopes of the pentameric complex, a competitive ELISA assay was developed, in which the pentamer bound to the solid-phase was reacted competitively with human sera and murinized human mAbs. In addition, inhibition of virus spreading (plaque formation and leukocyte transfer) by neutralizing human mAbs and sera was investigated. Results: In the absence of any reactivity of sera from HCMV-seronegative subjects, antibodies to all 10 epitopes were detected in HCMV-seropositive individuals. During primary HCMV infection in pregnancy antibodies to some epitopes showed a trend towards an earlier appearance in mothers not transmitting the virus to the fetus as compared to transmitting mothers. In addition, the activity of neutralizing human mAbs and sera in blocking virus cell-to-cell spreading and virus transfer to leukocytes from infected endothelial cells was shown to develop during the convalescent phase of primary infection. Conclusions: Dissection of the neutralizing/inhibiting activities of human sera may be helpful in the study of their protective role in vivo. In particular, neutralizing antibodies to the pentamer may be a surrogate marker of protection in vivo. © 2012 Springer Science+Business Media, LLC.

Gerna G.,Laboratori Sperimentali Of Ricerca | Lilleri D.,Laboratori Sperimentali Of Ricerca | Furione M.,S.S. Virologia Molecolare | Baldanti F.,S.S. Virologia Molecolare
New Microbiologica | Year: 2011

Human cytomegalovirus (HCMV) still causes major viral complications in the post-transplant period of both solid-organ (SO) and hematopoietic stem cell (HSC) transplant (T) recipients (R). Diagnosis of HCMV infection is mostly made by real-time PCR-based methodologies, which allow quantification of viral DNA in both blood and, if required, organ tissues or local secretions. HCMV infection/disease can be prevented by either universal prophylaxis or preemptive therapy. The latter approach has mostly been used in European Transplantation Centers upon reaching predetermined cut-off levels of viral load, predictive of high risk for HCMV disease. In our Department, these cut-offs are higher for SOTR (3×l0 5 DNA copies/ml whole blood) and lower for HSCTR (3×l0 4 DNA copies/ml). Antiviral therapy is continued until viral DNA disappearance from blood or tissues. However, the authentic long-term control of HCMV infection is achieved when HCMV-specific CD4 + and CD8 + T-cells are detected in blood or tissues. Proposed immunological cut-off levels conferring protection are: one HCMV-specific CD4 + and three CD8 + T-cells/μl blood for HSCTR, and 0.4 HCMV-specific T-cells/μl for both CD4 + and CD8f in SOTR. However, anti-rejection in SOTR and anti-GvHD in HSCTR steroid therapies make patients susceptible to HCMV infection, even in the presence of protective levels of specific T-cells.

Gerna G.,Laboratori Sperimentali Of Ricerca
Future Microbiology | Year: 2012

Using the murine CMV animal model and the well-established model of Cre-lox-P-mediated green-fluorescence tagging of endothelial cell (EC)-derived mouse CMV to quantify the role of infected ECs in transplantation-associated CMV dissemination (in mice expressing Cre recombinase under the control of either the Tie2 or the Tek promoter selectively expressed in vascular EC-Tie-Cre and Tek-Cre mice), it was shown that EC-derived virus contributed to 50% of the total viral load during primary infection, and there was no preference for dissemination of EC-derived viruses over viruses produced by other cell types. In addition, during secondary viremia, there was only a negligible contribution of EC-derived virus to dissemination to other organs. These results are novel in the methodology employed and are somewhat interesting. However, the data are limited to the mouse model with a short-term follow-up, and the immunodeficient host has not yet been studied. In humans, these conclusions must be taken with caution. First, in primary infection occurring through natural routes, epithelial cells are infected first, then ECs, unless primary infection occurs through blood transfusion, in which case endothelial vascular cells may become infected first. In both cases, the virus transport occurs through the intervention of leukocytes, namely monocytes and polymorphonuclear leukocytes. As monocytes differentiate to macrophages, they become highly susceptible to human CMV replication inside organ tissues, while polymorphonuclear leukocytes are active in virus capturing from infected endothelial vascular cells and transporting to distant sites. © 2012 Future Medicine Ltd.

Piralla A.,S.S. Virologia Molecolare | Lilleri D.,Laboratori Sperimentali Of Ricerca | Sarasini A.,S.S. Virologia Molecolare | Marchi A.,University of Pavia | And 4 more authors.
Diagnostic Microbiology and Infectious Disease | Year: 2012

The epidemiology of picornavirus infections along with associated risk factors for lower respiratory tract infections (LRTI) and duration of virus shedding were investigated in 985 hospitalized patients in the period October 2008-September 2009. One-third of patients were human rhinovirus (HRV)-positive. Of 336 HRV-associated episodes, 153 (45.5%) were sustained by HRV-A, 31 (9.2%) by HRV-B, and 93 (27.7%) by HRV-C, while 7 episodes showed multiple HRV types and 52 were sustained by undefined HRV species. Independent risk factors for LRTI included high viral load and age less than 5 years. Twenty (2.1%) patients were enterovirus (EV)-positive (12 had EV-68, 7 EV-104, and 1 E-13 infection). Half of the EV-positive patients had a LRTI and were younger with respect to patients with upper RTI (median 18 months versus 37 years; P < 0.001). HRVs are often the cause of LRTI in children less than 5 years, frequently in association with a high viral load. © 2012 Elsevier Inc.

Piralla A.,S.S. Virologia Molecolare | Baldanti F.,S.S. Virologia Molecolare | Gerna G.,Laboratori Sperimentali Of Ricerca
Journal of Clinical Microbiology | Year: 2011

Human rhinovirus species C (HRV-C) was the second most common HRV species detected in hospitalized patients in Italy with acute respiratory disease during a 1-year surveillance period. Sequencing of the picornavirus VP4/VP2 region allowed molecular typing of HRV-A and HRV-B and provisional typing of HRV-C. Copyright © 2011, American Society for Microbiology. All Rights Reserved.

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