Impact of solid organ transplant status on outcomes of hospitalized patients with COVID-19 infection

Background

The COVID‐19 pandemic has caused significant morbidity and mortality in solid organ transplant (SOT) recipients. However, it remains unclear whether the risk factor for SOT patients is the immunosuppression inherent to transplantation versus patient comorbidities.

Methods

We reviewed outcomes in a cohort of SOT (n = 129) and non‐SOT (NSOT) patients (n = 708) admitted to the University of California, Los Angeles for COVID‐19 infection. Data analyses utilized multivariate logistic regression to evaluate the impact of patient demographics, comorbidities, and transplant status on outcomes. SOT patients were analyzed by kidney SOT (KSOT) versus nonkidney SOT (NKSOT) groups.

Results

SOT and NSOT patients with COVID‐19 infection differed in terms of patient age, ethnicity, and comorbidities. NKSOT patients were the most likely to experience death, with a mortality rate of 16.2% compared with 1.8% for KSOT and 8.3% for NSOT patients (p = .013). Multivariable analysis of hospitalized patients revealed that patient age (odds ratio [OR] 2.79, p = .001) and neurologic condition (OR 2.66, p < .001) were significantly associated with mortality. Analysis of ICU patients revealed a 2.98‐fold increased odds of death in NKSOT compared with NSOT patients (p = .013).

Conclusions

This study demonstrates the importance of transplant status in predicting adverse clinical outcomes in patients hospitalized or admitted to the ICU with COVID‐19, especially for NKSOT patients. Transplant status and comorbidities, including age, could be used to risk stratify patients with COVID‐19. This data suggests that immunosuppression contributes to COVID‐19 disease severity and mortality and may have implications for managing immunosuppression, especially for critically ill patients admitted to the ICU.

Leukocyte transcriptome indicators of development of infection in kidney transplant recipients

After kidney transplantation, infection and death are important clinical complications, especially for the growing numbers of older patients with limited resilience to withstand adverse events. Evaluation of changes in gene expression in immune cells can reveal the underlying mechanisms behind vulnerability to infection. A cohort of 60 kidney transplant recipients was evaluated. Gene expression in peripheral blood mononuclear cells 3 months after kidney transplantation was analyzed to compare differences between patients with infection and those who were infection-free in the first-year post-transplant. Pro-inflammatory genes such as IL1B, CCL4, and TNF were found to be downregulated in post-transplant PBMC from patients who developed infection. In contrast, genes involved in metabolism, HLA genes, and transcripts involved in type I interferon innate antiviral responses were found to be upregulated. Promoter-based bioinformatic analyses implicated increased activity of interferon regulatory factors, erythroid nuclear factor (E2), and CCAAT-enhancer-binding protein (C/EBP) in patients who developed infections. Differential patterns of gene expression were observed in patients who developed infection after kidney transplantation, with patterns distinct from changes associated with patient age, suggesting possible mechanisms behind vulnerability to infection. Assessment of gene expression in blood may offer an approach for patient risk stratification and monitoring after transplantation.

Early cytomegalovirus DNAemia and antiviral dose adjustment in high vs intermediate risk kidney transplant recipients

BACKGROUND

Cytomegalovirus (CMV) infection continues to negatively affect outcomes for solid organ transplant recipients, despite the advent of strategies for preemptive surveillance and prophylaxis. The impact is especially great for CMV seronegative recipients of donor seropositive organs, who typically lack the ability to control CMV infection at the time of transplantation.

METHODS

We reviewed episodes of CMV DNAemia in a modern cohort of kidney transplant recipients over a 3-year period at a high-volume transplant center to investigate the frequency of DNAemia during antiviral prophylaxis.

RESULTS

Despite receipt of antiviral prophylaxis per current guidelines, 75 cases of CMV DNAemia were observed in the first 100 days after transplantation. For high risk patients, median time to DNAemia was 75 days after transplantation, and the majority of patients had experienced dose-reduction of valganciclovir due to renal insufficiency. Review of CMV seropositive intermediate risk patients demonstrated DNAemia occurring earlier after transplantation compared with high risk patients with a median time of 64 days (P = .029). The impact of valganciclovir dose adjustment was less notable in the intermediate risk group.

CONCLUSIONS

Guidelines recommend beginning routine surveillance for CMV after the completion of antiviral prophylaxis. Our findings suggest that closer monitoring may be beneficial, especially for high risk patients at risk for DNAemia. Patients requiring dose adjustment of valganciclovir due to renal insufficiency may be at increased risk for CMV DNAemia. Improved methods for CMV prophylaxis and evaluation of immunologic risk for CMV DNAemia and disease are needed to improve patient outcomes after kidney transplantation.

A multi-center study on safety and efficacy of immune checkpoint inhibitors in cancer patients with kidney transplant

Immune checkpoint inhibitors (ICIs) are widely used for various malignancies. However, their safety and efficacy in patients with a kidney transplant have not been defined. To delineate this, we conducted a multicenter retrospective study of 69 patients with a kidney transplant receiving ICIs between January 2010 and May 2020. For safety, we assessed the incidence, timing, and risk factors of acute graft rejection. For efficacy, objective response rate and overall survival were assessed in cutaneous squamous cell carcinoma and melanoma, the most common cancers in our cohort, and compared with stage-matched 23 patients with squamous cell carcinoma and 14 with melanoma with a kidney transplant not receiving ICIs. Following ICI treatment, 29 out of 69 (42%) patients developed acute rejection, 19 of whom lost their allograft, compared with an acute rejection rate of 5.4% in the non-ICI cohort. Median time from ICI initiation to rejection was 24 days. Factors associated with a lower risk of rejection were mTOR inhibitor use (odds ratio 0.26; 95% confidence interval, 0.09-0.72) and triple-agent immunosuppression (0.67, 0.48-0.92). The objective response ratio was 36.4% and 40% in the squamous cell carcinoma and melanoma subgroups, respectively. In the squamous cell carcinoma subgroup, overall survival was significantly longer in patients treated with ICIs (median overall survival 19.8 months vs. 10.6 months), whereas in the melanoma subgroup, overall survival did not differ between groups. Thus, ICIs were associated with a high risk of rejection in patients with kidney transplants but may lead to improved cancer outcomes. Prospective studies are needed to determine optimal immunosuppression strategies to improve patient outcomes.

Spectrum of Coronavirus Disease 2019 Outcomes in Kidney Transplant Recipients: A Single-Center Experience

PURPOSE

We reviewed the clinical experience of kidney transplant recipients diagnosed with severe acute respiratory syndrome coronavirus 2 infection in order to understand the impact of the current coronavirus disease 2019 (COVID-19) pandemic infection on transplant recipients. Given that early reports from heavily affected areas demonstrated a very high mortality rate amongst kidney transplant recipients, ranging between 30% and 40%, we sought to evaluate outcomes at a center with a high burden of cases but not experiencing acute crisis due to COVID-19.

PROCEDURES

In this single center retrospective observational study, medical records of all kidney transplant recipients at the UCLA Medical Center were reviewed for a diagnosis of COVID-19 by polymerase chain reaction, followed by chart review to determine kidney transplant characteristics and clinical course.

MAIN FINDINGS

A total of 41 kidney transplant recipients were identified with COVID-19 positive polymerase chain reaction. Recipients had been transplanted for a median of 47 months before diagnosis. The large proportion of infected individuals were minorities (Hispanic 65.9%, black 14.6%), on prednisone, tacrolimus, and mycophenolate mofetil (95.1%, 87.8%, and 87.8%, respectively), and had excellent allograft function (median 1.25 mg/dL). The most common presenting symptoms were fever, dyspnea, or cough. Most patients were hospitalized (63.4%); mortality was 9.8% and occurred only in patients in the intensive care unit. The most common treatment was reduction or removal of antimetabolite (77.8%). Approximately 26.9% presented with AKI.

CONCLUSIONS

COVID-19 infection in kidney transplant recipients results in a higher rate of hospitalization and mortality than in the general population. In an area with a high number of infections, the mortality rate was lower compared with earlier reports from areas experiencing early surge and strain on the medical system. Minorities were disproportionately affected. Future studies are needed to determine optimal approach to treatment and management of immunosuppression in kidney transplant recipients with COVID-19 infection.

Differences in Gene Expression in Older Compared With Younger Kidney Transplant Recipients

BACKGROUND

For the growing numbers of older transplant patients, increased incidence of infection and death compared with younger patients may limit the many benefits provided by transplantation. However, little is known about age-associated immune dysfunction in the older transplant recipient.

METHODS

A cohort of 60 kidney transplant recipients, 23 older (≥ 60y) and 37 younger (30-59y), matched on antithymocyte induction and donor type (living vs deceased) was evaluated. Gene expression in peripheral blood mononuclear cells 3 months after kidney transplantation was analyzed to compare differences between older and younger patients.

RESULTS

Proinflammatory genes were upregulated in older kidney transplant patients, including cytokines IL1-β and IL-6. Downregulated genes were associated with B-cell and T-cell function, including CCR7 and CD27. Analysis of predicted transcription factor binding suggested an increase in proinflammatory transcription factor CCAAT/enhancer binding protein β-binding sites in older patients, whereas interferon regulatory factor 2 transcription factor binding sites were less prevalent.

CONCLUSIONS

Older kidney transplant recipients exhibited multiple differences in gene expression compared with younger patients, with upregulation of proinflammatory genes and downregulation of adaptive immune response genes. These findings may explain the mechanism of increased vulnerability to infection and malignancy observed in older transplant patients.

Increased Frequency of BK Virus-Specific Polyfunctional CD8+ T Cells Predict Successful Control of BK Viremia After Kidney Transplantation

BACKGROUND

BK virus infection remains an important cause of loss of allograft function after kidney transplantation. We sought to determine whether polyfunctional T cells secreting multiple cytokines simultaneously, which have been shown to be associated with viral control, could be detected early after start of BK viremia, which would provide insight into the mechanism of successful antiviral control.

METHODS

Peripheral blood mononuclear cells collected during episodes of BK viral replication were evaluated by multiparameter flow cytometry after stimulation by overlapping peptide pools of BK virus antigen to determine frequency of CD8+ and CD4+ T cells expressing 1 or more cytokines simultaneously, as well as markers of T-cell activation, exhaustion, and maturation.

RESULTS

BK virus controllers, defined as those with episodes of BK viremia of 3 months or less, had an 11-fold increase in frequency of CD8+ polyfunctional T cells expressing multiple cytokines, as compared with patients with prolonged episodes of BK viremia. Patients with only low level BK viremia expressed low frequencies of polyfunctional T cells. Polyfunctional T cells were predominantly of the effector memory maturation subtype and expressed the cytotoxicity marker CD107a.

CONCLUSIONS

Noninvasive techniques for immune assessment of peripheral blood can provide insight into the mechanism of control of BK virus replication and may allow for future patient risk stratification and customization of immune suppression at the onset of BK viremia.

Effect of diabetes and acute rejection on liver transplant outcomes: An analysis of the organ procurement and transplantation network/united network for organ sharing database

The effects of diabetic status and acute rejection (AR) on liver transplant outcomes are largely unknown. We studied 13,736 liver recipients from the United Network for Organ Sharing/Organ Procurement Transplant Network database who underwent transplantation between 2004 and 2007 with a functioning graft for greater than 1 year. The association of pretransplant diabetes mellitus (PDM), new-onset diabetes after transplant (NODAT), and AR rates on allograft failure, all-cause mortality, and cardiovascular mortality were determined. To determine the differential and joint effects of diabetic status and AR on transplant outcomes, recipients were further stratified into 6 groups: neither (reference, n = 6600); NODAT alone (n = 2054); PDM alone (n = 2414); AR alone (n = 1448); NODAT and AR (n = 707); and PDM and AR (n = 513). An analysis with hepatitis C virus (HCV) serostatus was also performed (HCV recipients, n = 6384; and non-HCV recipient, n = 5934). The median follow-up was 2537 days. The prevalence of PDM was 21.3%. At 1 year after transplant, the rates of NODAT and AR were 25.5% and 19.4%, respectively. Overall, PDM, NODAT, and AR were associated with increased risks for graft failure (PDM, hazard ratio [HR] = 1.31, P < 0.01; NODAT, HR = 1.11, P = 0.02; AR, HR = 1.28, P < 0.01). A multivariate Cox regression analysis of the 6 recipient groups demonstrated that NODAT alone was not significantly associated with any study outcomes. The presence of PDM, AR, NODAT and AR, and PDM and AR were associated with higher overall graft failure risk and mortality risk. The presence of PDM was associated with higher cardiovascular mortality risk. The analyses in both HCV-positive and HCV-negative cohorts showed a similar trend as in the overall cohort. In conclusion, PDM and AR, but not NODAT, is associated with increased mortality and liver allograft failure. Liver Transplantation 22 796-804 2016 AASLD.

Co-infections of malaria and soil-transmitted helminths in localities with different levels of urbanisation in the Mount Cameroon region

Malaria co-exists with intestinal helminths and they have different effects on infected individuals. A total of 235 and 208 children from Ekona and Great Soppo respectively of both sexes aged 4–14 years were enrolled into a cross-sectional study.Capillary blood was collected for detection and determination of malaria parasitaemia as well as PCV. Stool samples were collected for quantitative determination of helminth ova by Kato-Katz technique.The prevalence of malaria and helminths was higher in Ekona than Great Soppo. In Great Soppo, Trichuris was the most prevalent helminth than Great Soppo and an association was found between these co-infections. More children were co-infected in Ekona and co-infecting species were Ascaris and Plasmodium falciparum.The prevalence of malaria and intestinal helminths as well as co-infection was lower in Great Soppo than in Ekona, probably due to increased urbanization in Great Soppo than Ekona.

Predictors of between-method differences in cardiac output measurement using thoracic electrical bioimpedance and thermodilution

OBJECTIVES

To evaluate the usefulness of transthoracic electrical bioimpedance in trending changes in cardiac output after cardiac surgery, and to identify predictors of differences between cardiac output measured by thermodilution and transthoracic electrical bioimpedance methods.

DESIGN

Prospective repeated-measures study.

SETTING

University-affiliated tertiary care center.

PATIENTS

Thirty-four adult patients undergoing elective cardiac surgery with routine pulmonary artery catheter placement.

INTERVENTIONS

Simultaneous paired cardiac output measurements by transthoracic electrical bioimpedance and thermodilution were made at four time points: within 2 hrs of intensive care unit (ICU) admission; when the patient reached a normothermic temperature; after extubation; and 24 hrs after ICU admission.

MEASUREMENTS AND MAIN RESULTS

Mean measurements by each method over time did not differ, except at ICU admission, when compared by repeated-measures analysis of variance. For each time point, bias and precision between methods were calculated. Bias calculations ranged from 0.02 to 0.21 L/min/m2. Precision calculations ranged from 1.06 to 1.52 L/min/m2. Predictors of between-method differences identified by a multiple regression model of hemodynamic variables were: increased systemic vascular resistance index, decreased mean arterial pressure (MAP), and the presence of atrial or ventricular pacing.

CONCLUSIONS

While mean postoperative cardiac output measurements did not differ by method over time, agreement between transthoracic electrical bioimpedance and thermodilution methods was poor in the immediate postoperative period, with precision calculations indicative of clinically significant differences. Increased systemic vascular resistance index and decreased MAP were predictive of larger between-method differences.