Human Herpesvirus 6 as an Indicator of Cytomegalovirus Infection and Its Attributable Disease Symptoms in Liver Transplant Recipients

Cytokine Dynamics and Herpesvirus Interactions in Pediatric Liver and Kidney Transplant Recipients: The Distinct Behavior of HCMV, HHV6, HHV7 and EBV

Pediatric solid organ transplant (SOT) recipients face a challenging balance between immunosuppression and graft rejection. While Epstein-Barr Virus (EBV) and cytomegalovirus (HCMV) are known contributors to post-transplant lymphoproliferative disease and graft rejection, respectively, the roles of herpesvirus 6 and 7 (HHV6 and HHV7) and the impact of these herpesviruses on cytokine levels remain unclear, leading to gaps in clinical practice. In this associative study, we measured 17 cytokines using a Bio-Plex assay in a meticulously curated plasma sample pool (N = 158) from pediatric kidney and liver transplant recipients over a one-year follow-up period. The samples included virus-negative and virus-positive cases, either individually or in combination, along with episodes of graft rejection. We observed that the elevation of IL-4, IL-8, and IL-10 correlated with graft rejection. These cytokines were elevated in samples where HCMV or HHV6 were detected alone or where EBV and HHV7 were co-detected. Interestingly, latent EBV, when detected independently, exhibited an immunomodulatory effect by downregulating cytokine levels. However, in co-detection scenarios with β-herpesviruses, EBV transitioned to a lytic state, also associating with heightened cytokinemia and graft rejection. These findings highlight the complex interactions between the immune response and herpesviruses in transplant recipients. The study advocates for enhanced monitoring of not only EBV and HCMV but also HHV6 and HHV7, providing valuable insights for improved risk assessment and targeted interventions in pediatric SOT recipients.

Risk factors and outcome of concurrent and sequential multiviral cytomegalovirus, Epstein-Barr virus, BK virus, adenovirus and other viral reactivations in transplantation

PURPOSE OF REVIEW

Reactivation of viral infections occurs frequently in immunosuppressed populations, particularly in solid organ (SOT) or allogeneic haematopoietic cell (HCT) transplant patients. Concurrent and sequential multivirus infections are common, yet risk factors and outcomes remain unclear. This review aims to identify the patients vulnerable to multivirus infections and characterize the impact of increased viral burden to formulate prevention and treatment strategies.

RECENT FINDINGS

Incidences of up to 89% in SOT and 36% in HCT have been reported for two viruses, and 32% in SOT and 28% in HCT for at least three viruses. Risk factors appear related to an increased burden of immunosuppression, with most viral coinfections occurring within 12 months of transplantation. Direct viral complications such as cytomegalovirus disease are more frequent in coinfected patients, with documented prolonged duration of viraemia, higher viral load and increased end-organ disease. Graft dysfunction, acute rejection and graft-vs.-host disease (GVHD) have also been associated. Increased mortality is reported in the HCT population.

SUMMARY

Multivirus infections occur in a significant proportion of transplant patients and is linked to immunosuppressive burden. There is increasing evidence that this leads to worse graft and patient outcomes. Further prospective studies are required to further comprehensively characterise viral epidemiology, mechanisms and treatment strategies to ameliorate this risk.

Post-Liver Transplant Cytomegalovirus (CMV) Reactivation, Graft, and Patient Survival Rates in Iranian Population

Background: Human cytomegalovirus (CMV) is the major complication of viral infection in immunocompromised patients. This opportunistic infection is associated with high morbidity and mortality in transplanted recipients. Objectives: The present study aimed to determine CMV burden and assess the clinical outcome in the liver recipients with CMV reactivated infection at Nemazi Hospital, Shiraz, Iran. Methods: This retrospective study examined 657 patients who underwent liver transplantation during 2014 - 2017 to identify the CMV infection, morbidity, and mortality rates. To this end, the medical records of such patients were reviewed, and their rejection/survival rates were analyzed. Accordingly, the CMV infection was diagnosed by Taq-Man real-time PCR assays. Results: In this study, 151 (23%) had CMV reactivation at least one year after liver transplantation. Viremic patients had a viral burden between 300 - 738790 copies/mL. In this study, 41 persons (6.2%) died, and 58 liver transplant patients (8.8%) had rejection experience up to one year after their operation. Among the 41 dead patients, 21 and 20 cases were with and without CMV-reactivation, respectively. The results demonstrated that the mortality rate was significantly higher in the CMV-infected patients than the non-CMV-infected counterparts. In contrast, the graft survival rate was not significantly different between the two groups (P ≤ 0.05). Conclusions: In the present study, CMV infection can serve as a significant mortality predictor in LT patients.