Development of an EliSPOT assay for HSV-1 and clinical validation in lung transplant patients.

Cellular immunity plays a major role in the control of HSV-1 infection/reactivation with a potential impact on the clinical-therapeutic management of immunocompromised patients, such as transplant recipients. Herein, we quantitatively evaluated T-cell response directed at HSV-1 by a newly developed IFN-γ EliSPOT assay in 53 patients (including 45 lung transplant recipients and eight subjects in waiting list). Overall, 62.2% of transplant patients and 62.5% of subjects on the waiting list showed a response to HSV-1 with no significant difference in the level of virus-specific cellular immunity. Response tended to be lower in the first three months posttransplantation with a progressive recovery of pretransplantation status by the second year and in the presence of HSV-1 DNA positivity in bronchoalveolar lavage. As expected, no response was found in seronegative patients. No significant difference in the level of response according to IgM and IgG status was found. Further studies are required to define the role of HSV-1 specific immune response for the clinical-therapeutic management of lung transplant patients and in other clinical settings and to define cut-off levels discriminating between absence/low and strong response to be related to the risk of viral infection/reactivation.

Evaluation of polyomavirus BK cellular immune response by an ELISpot assay and relation to viral replication in kidney transplant recipients.

The failure of immune surveillance may be associated with polyomavirus BK reactivation, potentially leading to the development of nephropathy in kidney transplantation. BK-specific cellular immune response may be used to modulate immunosuppressive therapy, but few studies have investigated the topic. Herein, we serially evaluated BK-specific response in 149 kidney transplant recipients and found that only 14/149 (9.4%) were responders. Episodes of viral reactivation (viremia and/or viruria) occurred only in non-responder patients. The frequency of BK-specific immune response appears to be lower than that for other persistently infecting viruses such as cytomegalovirus.

In vitro CMV-infection model in fresh and glycerolized skin graft.

Viral infections, especially cytomegalovirus (CMV), are a cause of death in burned patients. Aim of this study was to perform an in vitro CMV-infection model comparing fresh and glycerol-treated fibroblasts and keratinocytes. Cells were plated in plates for the two conditions. Each plate was set up with CMV dilutions. Immunofluorescence and real time PCR assays were performed. The assays were negative in both fresh and glycerolized keratinocytes. For fibroblasts, CMV-DNA was positive in both conditions and immunofluorescence test only in fresh cells. Glycerol at 85% confirms its strong virucidal effect as reported also for other viruses.

Non-organ-specific and anti-endothelial antibodies in relation to CMV infection and acute rejection in renal transplant recipients.

The presence of non-organ-specific (NOSA) and anti-endothelial antibodies (AECAs) and the onset of rejection in relation to cytomegalovirus (CMV) infection was investigated in 96 renal transplant recipients: 48 CMV pp65-antigenemia-negative (group 1) and 48 positive (group 2). The presence of autoantibodies (autoAbs) was evaluated before and following renal transplantation (first three months) by indirect immunofluorescence. Before transplantation, none of the patients was positive to AECAs, while eight (8.3%) were positive to NOSAs. Post-transplantation, AECA were found in none of patients from group 1 vs. 15/48 (31.2%) from group 2 (p<0.05); NOSAs were detected in 9/48 (18.8%) and 9/48 patients from group 1 and 2, respectively. An acute rejection was diagnosed in ten cases: six of interstitial type (antigenemia-, and AECA-negative; two NOSA-positive); four of vascular type (all of them NOSA-negative, 3/4 antigenemia-, and AECA-positive). CMV infection did not seem to be significantly associated with the appearance of NOSAs, while there was a significant correlation with the occurrence of AECAs. No significant correlation was found between acute rejection and the occurrence of NOSAs, while 75% of the cases of vascular rejection was associated to CMV infection and AECA-positivity, suggesting the pathogenic role of CMV-mediated endothelial damage.

Quantitative RT real time PCR and indirect immunofluorescence for the detection of human parainfluenza virus 1, 2, 3.

Human parainfluenza viruses (HPIVs) are distributed worldwide and are involved mainly in the pathogenesis of respiratory tract infections. The development and optimization of three quantitative reverse transcription real time polymerase chain reactions (RT Real Time Qt-PCRs) and an indirect immunofluorescence (IFA) for the detection and quantitation of HPIV-1, -2 and -3 in clinical samples are described. Efficiency, sensitivity, specificity, inter- and intra-assay variability and turnaround time of the two methods were compared. These assays have been validated on 131 bronchoalveolar lavage specimens. Based on the results obtained, the molecular methods represent a valid and rapid tool for clinical management and should be included in diagnostic panels aimed to evaluate suspected respiratory tract infections.

Reverse transcriptase-polymerase chain reaction to evaluate human cytomegalovirus lytic gene expression.

This paper describes the development of four Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) assays devised to evaluate lytic (UL123, immediate-early; UL54, early; UL65, late; and UL99, true late) human cytomegalovirus (HCMV) transcripts. Subsequently, the assays have been validated evaluating the HCMV lytic gene expression in 28 samples (peripheral blood leukocytes, PBLs) from 14 renal transplant recipients. Although the assessment of HCMV transcriptional profile could be useful to evaluate viral reactivation state, further studies on dynamics of viral transcripts in different clinical settings are needed to determine the role of transcriptional profiling in virological monitoring and therapeutic management in immunocompromised patients.

Evaluation of two set of primers for detection of immediate early gene UL123 of human cytomegalovirus (HCMV).

Human cytomegalovirus (HCMV) is a widespread agent causing a life-long persistent and generally asymptomatic infection in immunocompetent individuals. In contrast, immunocompromised subjects are the most susceptible group to experience HCMV disease. First genes to be expressed during the replication cycle are the immediate early (IE) genes, the products of which have pleiotropic effects on host cell metabolism. Aim of this study was to compare two set of primers in the optimization and standardization of a RT-PCR assay for qualitative detection of mRNA encoded by the IE gene UL123 (IE1). The RT-PCR assays were then used to evaluate the UL123 gene expression in 29 peripheral blood leukocyte (PBL) samples obtained from 14 renal transplant recipients. In particular, 21/29 (72.4%) were positive with set A of primers vs. 24/29 (82.8%) with set B. Only one sample were negative with set B and positive with set A. Twenty-four of 29 samples (82.8%) were pp65-antigaenemia positive: 21 mRNA-UL123 positive with set A vs. 22 with set B; all viraemia-positive patients were mRNA-UL123 positive with both set A and B. Five of 29 samples were pp65-antigaenemia negative: 1 mRNA-UL 123 positive with set A vs. 2 with set B; all of them were viraemia-negative. These two RT-PCR assays could provide a reliable, rapid and sensitive system enabling the detection and identification of UL123 transcripts and could be usefully employed to study the pathogenesis of HCMV-related diseases.

Double-step PCR assay to quantify Epstein-Barr viral load in peripheral blood.

Posttransplant lymphoproliferative disorders (PTLD) are a severe complication arising in solid organ transplant patients. A strong correlation between Epstein-Barr virus (EBV) infection, the grade and type of immunosuppression, and the development of PTLD has been recognized. This article describes the development of a double-step polymerase chain reaction (PCR) assay for the quantification of EBV-deoxyribonucleic acid (DNA) to monitor EBV infection. Screening of samples containing >/=10(3) viral genomes/10(5) peripheral blood mononuclear cells (PBMC) or 100 micro L serum by a semiquantitative PCR assay is followed by quantification of the samples containing a high number of viral genomes in a quantitative-competitive (QC)-PCR assay. Screening by semiquantitative PCR selects samples with a high number of viral genomes for use in the more labor-intensive and expensive QC-PCR assay and thus provides a handy means for quantitative DNA analysis of large numbers of samples. Our double-step PCR assay can be employed in EBV viral load measurement in PBMC and serum samples to monitor transplanted patients at risk to develop PTLD.