Specific T-cell receptor gene transfer enhances immune response: A potential therapeutic strategy for the control of human cytomegalovirus infection in immunocompromised patients

Secretion of IFN-γ by specific T cells in HCMV infection

One major risk for recipients undergoing allogeneic hematopoietic stem cell transplants (allo-HSCTs) is infection with the human cytomegalovirus (HCMV). For HCMV treatment, it is especially crucial to be able to differentiate between recipients who are at high risk of reactivation and those who are not. In this study, HCMV-DNA was collected from 60 HLA-A*02 allo-HSCT recipients before and after transplantation. After transplantation, the release of interferon (IFN)-γ by T cells specific to HCMV was assessed using the enzyme-linked immunospot assay (ELISPOT). The results show that the median viral load (VL) was significantly higher in the HCMV persistent-infection group compared to the non-persistent-infection group (p = 0.002), and that the late-infection rate was considerably higher in the high-VL group compared to the low-VL group (p = 0.014). The uninfected group had a considerably higher median IFN-γ spot-forming cell (SFC) count than the persistent-infection group (p = 0.001), and IFN-γ SFC counts correlated negatively and linearly with VLs (r = -0.397, p = 0.002). The immune-response groups showed significantly difference in median VL (p = 0.018), and the high immune response group had a reduced late-infection rate than the no/low immune response groups (p = 0.049). Our study showed that allo-HSCT recipients with a high VL at an early transplantation stage were at high risk for late HCMV infection. Further HCMV reactivation can be prevented by HCMV-specific T cells secreting enough IFN-γ.

Early immune surveillance to predict cytomegalovirus outcomes after allogeneic hematopoietic stem cell transplantation

Background

There is no method of predicting human cytomegalovirus (HCMV) outcomes in allogeneic hematopoietic stem cell transplant recipients clinically, leading in some cases to excessive or insufficient antiviral therapy. We evaluated the early immune response of recipients with disparate HCMV outcomes.

Methods

The HCMV outcomes of recipients were determined by long-term monitoring of HCMV DNA levels posttransplant. HCMV IgG and IgM concentrations at 1 week before and 1 week after transplantation, absolute lymphocyte counts, and HCMV-specific IFN-γ secreting cells at 1 month posttransplant were evaluated based on HCMV outcome.

Results

All recipients were negative for HCMV IgM. Significant differences between recipients with and without HCMV reactivation were observed in pre- and post-transplant HCMV IgG antibody levels, absolute lymphocyte counts, and HCMV-specific IFN-γ secreting cells (P < 0.05). HCMV IgG antibody levels significantly increased after transplantation in recipients with HCMV reactivation (P = 0.032), but not in those without reactivation. Multivariate analysis revealed that except for the absolute lymphocyte count these biomarkers were related to HCMV reactivation, independent of other clinical factors. In time-to-event analyses, lower levels of these biomarkers were associated with an increased 150-day cumulative incidence of HCMV reactivation (log-rank P < 0.05). In recipients with HCMV reactivation, the duration of HCMV DNAemia had negative correlation with HCMV-specific IFN-γ-secreting cells (P = 0.015, r = -0.372). The relationships between the peak HCMV DNA load and absolute lymphocyte count and HCMV-specific IFN-γ-secreting cells followed the same trends (P = 0.026, r = -0.181 and P = 0.010, r = -0.317).

Conclusions

HCMV IgG, absolute lymphocyte count, and HCMV-specific IFN-γ secreting cells represent the humoral and cellular immune response. Early monitoring of these immune markers could enable prediction of HCMV outcomes posttransplant and assessment of the severity of HCMV DNAemia.

Flavonoids Target Human Herpesviruses That Infect the Nervous System: Mechanisms of Action and Therapeutic Insights

Human herpesviruses (HHVs) are large DNA viruses with highly infectious characteristics. HHVs can induce lytic and latent infections in their host, and most of these viruses are neurotropic, with the capacity to generate severe and chronic neurological diseases of the peripheral nervous system (PNS) and central nervous system (CNS). Treatment of HHV infections based on strategies that include natural products-derived drugs is one of the most rapidly developing fields of modern medicine. Therefore, in this paper, we lend insights into the recent advances that have been achieved during the past five years in utilizing flavonoids as promising natural drugs for the treatment of HHVs infections of the nervous system such as alpha-herpesviruses (herpes simplex virus type 1, type 2, and varicella-zoster virus), beta-herpesviruses (human cytomegalovirus), and gamma-herpesviruses (Epstein–Barr virus and Kaposi sarcoma-associated herpesvirus). The neurological complications associated with infections induced by the reviewed herpesviruses are emphasized. Additionally, this work covers all possible mechanisms and pathways by which flavonoids induce promising therapeutic actions against the above-mentioned herpesviruses.

ELISPOT assay of interferon-γ secretion for evaluating human cytomegalovirus reactivation risk in allo-HSCT recipients

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.