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Human cytomegalovirus (HCMV) is a common cause of significant morbidity and mortality in transplant recipients after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We evaluated interferon-γ (IFN-γ) secretion by HCMV NLV-specific CD8+ T cells in HCMV-reactivated allo-HSCT recipients using an enzyme-linked immunospot (ELISPOT) assay at 3 months post-transplantation. Blood samples from 47 recipients were tested for HCMV DNAemia, HCMV pp65 antigenemia, and anti-HCMV immunoglobulins (IgG/IgM) over 3 months post-transplantation. Of the 47 transplant recipients, 26 were HLA-A*02 positive and 21 were HLA-A*02 negative. The results were essentially consistent between the 47 transplant recipients and the HLA-A*02-positive recipients. HCMV DNAemia was not linearly correlated with IFN-γ spot-forming cells (SFCs) counts; IFN-γ SFCs counts did not differ significantly between the HCMV DNAemia-positive and -negative groups, whereas the HCMV-DNA virus loads were inversely correlated with the IFN-γ SFCs counts. HCMV pp65 antigenemia was not linearly correlated with IFN-γ SFCs counts; IFN-γ SFCs counts in the HCMV pp65 antigenemia-positive and -negative groups were similar. More IFN-γ SFCs counts were detected in transplant recipients with high anti-HCMV-IgG antibody titers than in those with low anti-HCMV-IgG titers pre-transplantation in the 47 recipients. Anti-HCMV-IgG antibody titers were positively linearly correlated with IFN-γ SFCs counts in HLA-A*02-positive recipients. The HCMV infection indicators used to monitor HCMV reactivation had different values in transplant recipients. The use of the IFN-γ SFCs counts measured by ELISPOT to evaluate the risk of HCMV reactivation needs further study.

Objective To assess the rate of, and risk factors for, human cytomegalovirus viremia (HCMV) in donor+/recipient+ (HCMV serostatus matched) hematopoietic stem-cell transplantation (HSCT) recipients. Methods HCMV DNA from 144 donor+/recipient+ HSCT recipients was examined by quantitative polymerase chain reaction (qPCR). Results The cumulative incidence of HCMV viremia was 69.4% (100/144) during the 48 weeks after HSCT. In a multivariate analysis, acute graft-versus-host disease (aGVHD) was discovered to be a risk factor for the occurrence of HCMV viremia (P = .006). The cumulative incidence of HCMV viremia and increasing DNA loads were significantly associated with aGVHD occurrence (P = .001 for each). The occurrence of late-term HCMV viremia was associated with aGVHD (P = .001) and a higher DNA load during the first 12 weeks after HSCT (P = .04). Conclusions aGVHD is a risk factor for HCMV viremia. Recipients with aGVHD who have a high HCMV DNA load should be strictly monitored to prevent HCMV activation.

Human cytomegalovirus (HCMV) infection is a leading cause of morbidity and mortality in immunocompromised patients, but no specific therapeutic strategy is effective clinically, despite recent achievements. HCMV-specific T-cell therapy was thought to be helpful for the management of HCMV infection. To conduct a deep exploration, we investigated the possibility of engineering peripheral blood mononuclear cells (PBMCs) from immunocompetent and immunocompromised subjects with specific T-cell receptor (TCR) genes. CD8-positive T cells that specifically bind to NLV pentamers could be generated by transferring TCR genes to PBMCs from immunocompetent and immunocompromised subjects. The generation of functional T cells varied among transduction of different PBMCs. The numbers of IFN-γ-secreting T cells increased significantly in immunocompetent and immunodeficient PBMCs, but were unchanged in immune-reconstituted PBMCs. TCR gene transfer is a potential therapeutic strategy for controlling HCMV infection in immunocompromised patients. The transfer of TCR genes into immunocompetent and immunodeficient PBMCs would be more meaningful in response to HCMV infection than would the transfer into immune-reconstituted PBMCs.

In the present study, clonal amplifications of T-cell receptor β variable (TCR BV) linked to human cytomegalovirus (HCMV) infection were detected in recipients of allogeneic hematopoietic stem cell transplants (HSCT), and certain relationships between them were identified. Furthermore, the relationship between TCR BV sequences and HCMV infections was investigated. The results indicated that the 3 recipients of HSCT had monoclonal expansion of specific TCR BV clones following HSCT. Among these recipients, 2 suffered from pp65 and immediate early (IE) antigenemia. These patients demonstrated preferential expansion of TCR BV9 (QVRGGTDTQ) and TCR BV11 (VATDFQ). The remaining recipient did not express TCR BV9 and TCR BV11, nor did this individual have pp65 and IE antigenemia. These results suggest that expression of TCR BV9 and TCR BV11 may be associated with HCMV antigenemia, and may be involved in the immune response. The amino acid sequences 'QVRGGTDTQ' and 'VATDFQ' may be involved in HCMV reactivation in patients who have undergone HSCT. Assessment of the TCR BV families may provide valuable insight into HCMV pathogenesis and may aid in the diagnosis and therapy for HSCT recipients infected with HCMV.

T-cell responses directed against human cytomegalovirus (HCMV) glycoprotein B (gB) contribute to protective immunity against HCMV infection in both animal models and humans. However, the gB-specific human CD8 + T cell responses remain poorly understood. gB antigen-specific CD8 + T cells were stained with seven major histocompatibility complex (MHC)-peptide pentamers in 16 human leukocyte antigen (HLA)-A*1101-positive, HCMV-seropositive patients following hematopoietic stem cell transplantation (HSCT). Of these seven pentamers, the most frequent CD8 + T-cell responses were directed against the gB 332–340 peptide. These gB 332–340 -specific CD8 + T cells were strongly associated with the presence of plasma HCMV immunoglobulin M in all HSCT recipients and exhibited a probable causal relationship with the level of pp65 antigenemia. Together, these data suggest a role for gB 332–340 -specific CD8 + T cells in HCMV reactivation after HSCT. Furthermore, the pentamer assay may be valuable in detecting antigen-specific CD8 + T cells.

Background Reactivation of latent human cytomegalovirus (HCMV) is a frequent complication following allogeneic haematopoietic stem cell transplantation (HSCT). Evaluation of the quantity and function of HCMV-specific CD8+ T-cell responses after HSCT may play a crucial role in the prevention of HCMV reactivation. Objectives To investigate the mechanism of HCMV-specific T-cell immune responses after HSCT in HCMV-specific CD8+ T cells. Study design HCMV-specific CD8+ T cells were quantified using human leucocyte antigen (HLA) pentamer staining and functionally analysed by interferon-γ-enzyme-linked immunospot (IFN-γ-ELISPOT) assay with a pp65 495–503 peptide in recipients four years after HSCT. Results The absolute number of pp65 495–503 -specific CD8+ T cells did not differ significantly ( p > 0.05) between samples with antigenaemia and those without antigenaemia given a mean of 54.5/μl and 40.5/μl, respectively, in 21 HLA-A* 0201 patients after HSCT. The level of pp65 495–503 -specific CD8+ T cells > 20/μl of peripheral blood was maintained 90 days after transplantation. There was a significant difference in the spot count of IFN-γ-secreting T cells between samples with antigenaemia (mean, 507/2.5 × 10 5 PBMCs) and those without antigenaemia (mean, 216/2.5 × 10 5 PBMCs; p Conclusion pp65 495–503 -specific CD8+ T cells may not be sufficient to control HCMV reactivation in recipients after HSCT. However, the combination of pentamer and IFN-γ-ELISPOT assays may be valuable for evaluating HCMV-specific CD8+ T cells. Further studies on HCMV-specific T-cell immune responses continue to be performed for the prevention of persistent HCMV reactivation.

Summary Background Viral infections are a major cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). The effect of herpesvirus infections in human cytomegalovirus (HCMV)-seropositive (IgG-positive/IgM-negative) HSCT recipients remains poorly understood. The risk factors associated with Epstein–Barr virus (EBV), HCMV, and human herpes virus type 6 (HHV-6) infections after HSCT, both alone and in combination, were investigated in this study. Methods Peripheral blood specimens were collected from 44 HSCT recipients and examined for viral DNA using quantitative fluorescence PCR assays. Risk factors for EBV, HCMV, and HHV-6 infections were analyzed by binary logistic regression, and relationships between these viruses were analyzed using the Chi-square test. Results EBV, HCMV, and HHV-6 were detected in 50%, 45.45%, and 25% of HCMV-seropositive (IgG-positive/IgM-negative) HSCT recipients, respectively. Male sex ( p =0.007) and conditioning regimens including anti-thymocyte globulin (ATG) ( p =0.034) were strongly associated with an increased risk of EBV infection. Graft-versus-host disease (GVHD) prophylaxis with corticosteroids was a risk factor for both EBV ( p =0.013) and HCMV ( p =0.040) infections, while EBV infection ( p =0.029) was found to be an independent risk factor for HHV-6 infection. Pre-existing HHV-6 infection was associated with lower rates of HCMV infection ( p =0.002); similarly, pre-existing HCMV infection was protective against HHV-6 infection ( p =0.036). Conclusions HCMV-seropositive (IgG-positive/IgM-negative) HSCT recipients exhibited a high rate of herpesvirus infections, particularly EBV. ATG and male sex were strongly associated with an increased risk of EBV infection. GVHD prophylaxis with prednisone was found to affect both EBV and HCMV infections. Prior infection with EBV was shown to promote HHV-6 infection. Taken together, these data highlight the need for active monitoring of herpesvirus infections in patients undergoing HSCT.