Stimulatory Effect of CMV Immunoglobulin on Innate Immunity and on the Immunogenicity of CMV Antigens

CMV management of patients with leukopenia after CMV high-risk kidney transplantation

BACKGROUND

For CMV high-risk constellations, guidelines recommend 3-6 months of prophylaxis with valganciclovir (VGCV). Management in preventing CMV primary infection in patients developing VGCV-associated leukopenia remains challenging.

METHODS

We retrospectively analyzed the development of leukopenia during VGCV prophylaxis in 57 seronegative kidney recipients of a CMV-seropositive donor between 2008 and 2021. We analyzed CMV risk and development of CMV-specific T cells in the first post-transplant year depending on leukopenia during VGCV prophylaxis and management with CMV-IVIg.

RESULTS

Leukopenia developed in 19/57 patients, with a significant difference in leukocyte counts occurring after 10 weeks of VGCV prophylaxis compared to patients without leukopenia (p = 0.0003). VGCV discontinuation led to leukocyte reconstitution, which tended to be faster in patients receiving additional prophylaxis with CMV-IVIg after VGCV discontinuation (n = 11, p = 0.083). In the first post-transplant year, patients with leukopenia had no higher risk for severe CMV events. Interestingly, patients receiving CMV-IVIg prophylaxis showed a significantly lower peak CMV-load during primary infection (p = 0.040), with no difference in CMV-specific T-cell levels compared to patients without leukopenia or patients with additional CMV-IVIg prophylaxis (p = 0.972). Patients developing adequate CMV-specific T-cell responses less frequently underwent CMV reactivation 50 days following primary infection.

CONCLUSION

Leukopenia developed late during VGCV prophylaxis and did not result in an increased risk for CMV primary infections or severe disease. Leukopenic patients receiving CMV-IVIg tended to have a faster leukocyte reconstitution and had lower peak DNAemia, which did not adversely affect CMV-specific T-cell induction. CMV-IVIg may therefore be considered as an alternative prophylactic strategy in patients with VGCV-associated leukopenia.

Modulation of Monocyte Effector Functions and Gene Expression by Human Cytomegalovirus Infection

Monocytes are crucial players in innate immunity. The human cytomegalovirus (CMV) infection has significant impacts on monocyte effector functions and gene expression. CMV, a β-herpesvirus, disrupts key monocyte roles, including phagocytosis, antigen presentation, cytokine production, and migration, impairing their ability to combat pathogens and activate adaptive immune responses. CMV modulates monocyte gene expression, decreasing their capacity for antigen presentation and phagocytosis while increasing pro-inflammatory cytokine production, which can contribute to tissue damage and chronic inflammation. CMV also alters monocyte migration to sites of infection while promoting trans-endothelial migration, thus aiding viral dissemination. Additionally, the virus affects reactive oxygen species (ROS) production, thereby contributing to end-organ disease associated with CMV infection. Overall, these changes enhance viral persistence during acute infection and facilitate immune evasion during latency. We highlight the clinical significance of these disruptions, particularly in immunocompromised patients such as transplant recipients, where the modulation of monocyte function by CMV exacerbates risks for infection, inflammation, and graft rejection. An understanding of these mechanisms will inform therapeutic strategies to mitigate CMV-related complications in vulnerable populations.

What's New: Updates on Cytomegalovirus in Solid Organ Transplantation

Cytomegalovirus (CMV) is one of the most common infections occurring after solid organ transplantation. This high burden of disease, which incurs sizeable morbidity, may be worsening with the proportion of high-risk D+/R- solid organ transplantation recipients increasing in some regions globally. Cohort studies continue to support either universal prophylaxis or preemptive therapy as effective prevention strategies. Letermovir prophylaxis was noninferior to valganciclovir in adult high-risk D+/R- kidney transplant recipients with fewer drug-related adverse events in a recent clinical trial and has now been approved for such use in some regions. Maribavir preemptive therapy failed to demonstrate noninferiority when compared with valganciclovir in hematopoietic stem cell transplant recipients but looked promising for safety. Donor matching could be useful in prevention CMV disease with a survival advantage demonstrated in seronegative recipients waiting up to 30 mo for a seronegative kidney. Immune-guided prophylaxis resulted in fewer CMV infection episodes in lung transplant recipients when compared with fixed-duration prophylaxis in a recent clinical trial. For treatment of refractory or resistant CMV infection, maribavir was more efficacious and better tolerated when compared with investigator-initiated therapy in its registration trial for this condition. Further research regarding best treatment and prophylaxis of resistant or refractory CMV infection is needed to reflect best clinical practice choices. Optimal use of immune globulin or CMV-specific T cells for prevention or treatment of CMV disease remains undefined. Standardized definitions for the design of CMV clinical trials have been developed. In this review, we highlight recent updates in the field from data published since 2018.

Hyperimmunplasma: Gewinnung, Verarbeitung und therapeutische Anwendungen

Das Prinzip der passiven Immunisierung ist seit dem 19. Jahrhundert bekannt und wird auch bei aktuellen Pandemien als Ansatz zur Prophylaxe und Therapie eingesetzt. Der Schutz wird hierbei übertragen durch Blut, Serum oder Plasma, welche Immunglobuline gegen spezifische Krankheitserreger, Bakterientoxine oder sonstige Antigene enthalten, sowie durch aus Humanplasma industriell aufgereinigte Immunglobuline. Die aktuell verwendeten Reinigungsverfahren für Immunglobuline aus Humanplasma beruhen auf der von Edwin J. Cohn entwickelten Fraktionierung von Plasma. Zur Gewinnung von Immunglobulinen mit hohen Antikörpertitern gegen spezifische Antigene, sogenannte Hyperimmunglobuline, muss zunächst Hyperimmunplasma gezielt von ausgewählten Spendern gewonnen werden. Diese Spender haben erhöhte Antikörpertiter gegen spezifische Krankheitserreger, Bakterientoxine oder sonstige Antigene, wenn sie im Rahmen einer vorangegangenen Infektion natürlich immunisiert wurden, einen zugelassenen Impfstoff zur Immunisierung erhalten haben oder gezielt zum Zweck der Plasmaspende immunisiert wurden. Aktuell sind in Deutschland, Österreich und der Schweiz Hyperimmunglobulinprodukte für verschiedene Anwendungen im Patienten zugelassen, von denen die meisten aus humanem Blutplasma gewonnen werden. Um die Herstellung der Produkte und damit letztlich die Behandlung der Patienten gewährleisten zu können, werden resiliente Lieferketten benötigt. Hierzu bedarf es unter anderem Änderungen in den Rahmenbedingungen für die Spenderimmunisierung in Deutschland.

Effectiveness of Prophylactic Human Cytomegalovirus Hyperimmunoglobulin in Preventing Cytomegalovirus Infection following Transplantation: A Systematic Review and Meta-Analysis

Cytomegalovirus (CMV) is a common infection occurring in patients undergoing solid organ transplantation (SOT) or hematopoietic stem cell transplantation (HSCT). CMV-specific hyperimmunoglobulin (CMVIG) has been used for the past four decades and is typically administered either prophylactically or pre-emptively. The present meta-analysis evaluated CMV infection rates in SOT patients who received prophylactic CMVIG. PubMed and the Cochrane Library were searched for studies published up to October 2021. The primary endpoint was CMV infection rate. Thirty-two SOT studies were identified (n = 1521 CMVIG-treated and n = 1196 controls). Prophylactic CMVIG treatment was often associated with a lower risk of CMV infection in transplant recipients. The average CMV infection rate was 35.8% (95% confidence interval [CI]: 33.4−38.2%) in patients treated prophylactically with CMVIG and 41.4% (95% CI: 38.6−44.2%) in the control group not receiving CMVIG (p = 0.003). Similar results were observed in analyses limited to publications evaluating currently available CMVIG products (Cytotect CP and Cytogam; p < 0.001). In combination with the established safety profile for CMVIG, these results suggest that prophylactic CMVIG treatment in patients undergoing solid organ transplantation may be beneficial, particularly in those at high risk of CMV infection or disease.