Association of Donor and Recipient Cytomegalovirus Serostatus on Graft and Patient Survival in Liver Transplant Recipients

Cytomegalovirus immunity in high-risk liver transplant recipients following preemptive antiviral therapy versus prophylaxis

CMV-specific T cells, NK cells, and neutralizing antibodies (nAbs) were assessed in a randomized trial of CMV prevention with preemptive antiviral therapy (PET) versus prophylactic antiviral therapy (PRO) in donor-seropositive/recipient-seronegative (D+R-) liver transplant recipients (LTxR) at 100 days (end of intervention) and at 6 and 12 months after transplant. The PET group had significantly increased numbers of circulating polyfunctional T cells, NK cells, and nAbs compared with the PRO group at day 100, and several CMV immune parameters remained significantly higher by 12 months after transplant. Among PET recipients, preceding CMV viremia (vs. no preceding viremia) was associated with significantly higher levels of most CMV immune parameters at day 100. Higher numbers of CMV-specific polyfunctional T cells and NKG2C+ NK cells at day 100 were associated with a decreased incidence of CMV disease in multivariable Cox regression. The strongest associations with protection against CMV disease were with increased numbers of CMV-specific polyfunctional CD4+ T cells, CD3negCD56dimCD57negNKG2Cpos cells, and CD3negCD56dimCD57posNKG2Cpos NK cells. Our results suggest that PET is superior to PRO for CMV disease prevention by allowing low-level CMV replication and associated antigen exposure that is promptly controlled by antiviral therapy and facilitates enhanced CMV protective immunity in D+R- LTxR.

Asian Pacific Association for the Study of the Liver clinical practice guidelines on liver transplantation

Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.

Patient years lost due to cytomegalovirus serostatus mismatching in the scientific registry of transplant recipients

Background

The cytomegalovirus (CMV) mismatch rate in deceased donor kidney transplant (DDKT) recipients in the US remains above 40%. Since CMV mismatching is common in DDKT recipients, the cumulative effects may be significant in the context of overall patient and graft survival. Our primary objective was to describe the short- and long-term risks associated with high-risk CMV donor positive/recipient negative (D+/R-) mismatching among DDKT recipients with the explicit goal of deriving a mathematical mismatching penalty.

Methods

We conducted a retrospective, secondary analysis of the Scientific Registry of Transplant Recipients (SRTR) database using donor-matched DDKT recipient pairs (N=105,608) transplanted between 2011-2022. All-cause mortality and graft failure hazard ratios were calculated from one year to ten years post-DDKT. All-cause graft failure included death events. Survival curves were calculated using the Kaplan-Meier estimation at 10 years post-DDKT and extrapolated to 20 years to provide the average graft days lost (aGDL) and average patient days lost (aPDL) due to CMV D+/R- serostatus mismatching. We also performed an age-based stratification analysis to compare the relative risk of CMV D+ mismatching by age.

Results

Among 31,518 CMV D+/R- recipients, at 1 year post-DDKT, the relative risk of death increased by 29% (p<0.001), and graft failure increased by 17% (p<0.001) as compared to matched CMV D+/R+ group (N=31,518). Age stratification demonstrated a significant increase in the risk associated with CMV mismatching in patients 40 years of age and greater. The aGDL per patient due to mismatching was 125 days and the aPDL per patient was 100 days.

Conclusion

The risks of CMV D+/R- mismatching are seen both at 1 year post-DDKT period and accumulated throughout the lifespan of the patient, with the average CMV D+/R- recipient losing more than three months of post-DDKT survival time. CMV D+/R- mismatching poses a more significant risk and a greater health burden than previously reported, thus obviating the need for better preventive strategies including CMV serodirected organ allocation to prolong lifespans and graft survival in high-risk patients.

Current Perspectives on the Management of Herpesvirus Infections in Solid Organ Transplant Recipients

Solid organ transplant recipients (SOTRs) are at high risk of human herpesvirus (HHV)-related morbidity and mortality due to the use of immunosuppressive therapy. We aim to increase awareness and understanding of HHV disease burden in SOTRs by providing an overview of current prevention and management strategies as described in the literature and guidelines. We discuss challenges in both prevention and treatment as well as future perspectives.

Increasing Proportion of High-risk Cytomegalovirus Donor-positive/Recipient-negative Serostatus in Solid Organ Transplant Recipients

BACKGROUND

Cytomegalovirus (CMV) donor-positive/recipient-negative (D+R-) serostatus is independently associated with worse allograft and patient survival across solid organ transplant (SOT) types. We characterized trends in CMV D+R- serostatus among adult SOT recipients performed in the United States.

METHODS

Donor (D) and recipient (R) CMV serostatus and demographic factors were obtained from the Scientific Registry of Transplant Recipients for persons ≥18 y undergoing a first SOT between January 1, 2000, and December 31, 2020. The proportions of D+R- SOTs over time were assessed using Chi square for trend and modeled through 2040. Factors associated with D/R seropositivity were assessed using logistic models.

RESULTS

Among 472 549 SOTs, the average proportion of D+R- SOTs increased significantly among kidney, liver, heart, and lung between 2000 to 2009 and 2010 to 2020: 18.0% to 18.3% ( P  = 0.034), 19.4% to 21.8% ( P  < 0.001), 22.2% to 25.5% ( P  < 0.001), and 23.6% to 27.0% ( P  < 0.001), respectively. The increased proportion over time resulted from a disproportionate increase in R- (34.9% to 37.0% for all organ types, P  < 0.001) and a smaller corresponding change in D+ (60.8% to 60.3%, P  < 0.001).

CONCLUSIONS

The proportion of high-risk CMV D+R- SOTs increased significantly across all organs and is projected to continue to increase. These findings inform population-level strategies to mitigate the negative impact of CMV D+R- in SOT.

Immunohistochemistry Staining-Proven Cytomegalovirus Colitis in Living Donor Liver Transplantation

Background and Aims: Cytomegalovirus (CMV) infection is a common occurrence in liver transplantation (LT) even in an era of preventive strategies. However, the diagnosis of CMV colitis remains challenging. This study aimed to focus on the clinical significance of endoscopic biopsy-proven CMV colitis in patients following living donor liver transplantation (LDLT). Methods: From January 2007 to December 2021, a total of 55 CMV colitis cases were retrospectively enrolled and divided into a non-LDLT group in 53 and an LDLT group in 2 cases. Clinical demographics, diagnostic measurement, histopathology, and anti-viral therapy were investigated. Results: There were 1630 cases undergoing LDLT in the period 2007-2021, with only 2 recipients being confirmed to have CMV colitis in 2021 (2/114, 1-year incidence: 1.75%). Comparisons between the 53 non-LDLT cases and 2 LDLT cases are as follows: Serum anti-CMV immunoglobulin M (IgM) was shown to be positive (n = 3, 5.5% vs. n = 0, p = 1.0) and negative (n = 20, 37.7% vs. n = 2, 100%, p = 0.16); anti-CMV immunoglobulin G (IgG) was positive (n = 19, 35.8% vs. n = 2, 100%, p = 0.14) and none were negative; CMV DNAemia was shown to be detectable (n = 14, 26.4% vs. n = 1, 50%, p = 0.47) and undetectable (n = 14, 26.4% vs. n = 1, 50%, p = 0.47). Among the two recipients with CMV colitis, one had CMV DNAemia and the other had no CMV DNAemia upon the development of symptoms; negative anti-CMV-IgM and positive anti-CMV-IgG were observed both pre-transplant and post-transplant; finally, CMV colitis was documented based on the presence of inclusion bodies and positive immunohistochemistry (IHC) staining in histology. Conclusion: Patients with immunocompromised status, in particular organ transplantation, may have positive serum anti-CMV IgM/IgG antibodies both before and after transplantation. This study emphasized the fact that endoscopic biopsy with IHC staining may be a more powerful tool for making an accurate diagnosis of CMV colitis in the setting of living donor liver transplantation.

Pathogenesis of human cytomegalovirus in the immunocompromised host

Human cytomegalovirus (HCMV) is a herpesvirus that infects ~60% of adults in developed countries and more than 90% in developing countries. Usually, it is controlled by a vigorous immune response so that infections are asymptomatic or symptoms are mild. However, if the immune system is compromised, HCMV can replicate to high levels and cause serious end organ disease. Substantial progress is being made in understanding the natural history and pathogenesis of HCMV infection and disease in the immunocompromised host. Serial measures of viral load defined the dynamics of HCMV replication and are now used routinely to allow intervention with antiviral drugs in individual patients. They are also used as pharmacodynamic read-outs to evaluate prototype vaccines that may protect against HCMV replication and to define immune correlates of this protection. This novel information is informing the design of randomized controlled trials of new antiviral drugs and vaccines currently under evaluation. In this Review, we discuss immune responses to HCMV and countermeasures deployed by the virus, the establishment of latency and reactivation from it, exogenous reinfection with additional strains, pathogenesis, development of end organ disease, indirect effects of infection, immune correlates of control of replication, current treatment strategies and the evaluation of novel vaccine candidates.