Infection in Organ Transplantation

Enhancing longevity of immunoisolated pancreatic islet grafts by modifying both the intracapsular and extracapsular environment

Type 1 diabetes mellitus (T1DM) is a chronic metabolic disease characterized by autoimmune destruction of pancreatic β cells. Transplantation of immunoisolated pancreatic islets might treat T1DM in the absence of chronic immunosuppression. Important advances have been made in the past decade as capsules can be produced that provoke minimal to no foreign body response after implantation. However, graft survival is still limited as islet dysfunction may occur due to chronic damage to islets during islet isolation, immune responses induced by inflammatory cells, and nutritional issues for encapsulated cells. This review summarizes the current challenges for promoting longevity of grafts. Possible strategies for improving islet graft longevity are also discussed, including supplementation of the intracapsular milieu with essential survival factors, promotion of vascularization and oxygenation near capsules, modulation of biomaterials, and co-transplantation of accessory cells. Current insight is that both the intracapsular as well as the extracapsular properties should be improved to achieve long-term survival of islet-tissue. Some of these approaches reproducibly induce normoglycemia for more than a year in rodents. Further development of the technology requires collective research efforts in material science, immunology, and endocrinology. STATEMENT OF SIGNIFICANCE: Islet immunoisolation allows for transplantation of insulin producing cells in absence of immunosuppression and might facilitate the use of xenogeneic cell sources or grafting of cells obtained from replenishable cell sources. However, a major challenge to date is to create a microenvironment that supports long-term graft survival. This review provides a comprehensive overview of the currently identified factors that have been demonstrated to be involved in either stimulating or reducing islet graft survival in immunoisolating devices and discussed current strategies to enhance the longevity of encapsulated islet grafts as treatment for type 1 diabetes. Although significant challenges remain, interdisciplinary collaboration across fields may overcome obstacles and facilitate the translation of encapsulated cell therapy from the laboratory to clinical application.

Assessment of an exhaled breath test using ultraviolet photoionization time-of-flight mass spectrometry for the monitoring of kidney transplant recipients

Continuous monitoring for immunosuppressive status, infection and complications are a must for kidney transplantation (KTx) recipients. Traditional monitoring including blood sampling and kidney biopsy, which caused tremendous medical cost and trauma. Therefore, a cheaper and less invasive approach was urgently needed. We thought that a breath test has the potential to become a feasible tool for KTx monitoring. A prospective-specimen collection, retrospective-blinded assessment strategy was used in this study. Exhaled breath samples from 175 KTx recipients were collected in West China Hospital and tested by online ultraviolet photoionization time-of-flight mass spectrometry (UVP-TOF-MS). The classification models based on breath test performed well in classifying normal and abnormal values of creatinine, estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN) and tacrolimus, with AUC values of 0.889, 0.850, 0.849 and 0.889, respectively. Regression analysis also demonstrated the predictive ability of breath test for clinical creatinine, eGFR, BUN, tacrolimus level, as the predicted values obtained from the regression model correlated well with the clinical true values (p < 0.05). The findings of this investigation implied that a breath test by using UVP-TOF-MS for KTx recipient monitoring is possible and accurate, which might be useful for future clinical screenings.

An allosteric inhibitor of sirtuin 2 deacetylase activity exhibits broad-spectrum antiviral activity

Most drugs used to treat viral disease target a virus-coded product. They inhibit a single virus or virus family, and the pathogen can readily evolve resistance. Host-targeted antivirals can overcome these limitations. The broad-spectrum activity achieved by host targeting can be especially useful in combating emerging viruses and for treatment of diseases caused by multiple viral pathogens, such as opportunistic agents in immunosuppressed patients. We have developed a family of compounds that modulate sirtuin 2, an NAD+-dependent deacylase, and now report the properties of a member of that family, FLS-359. Biochemical and x-ray structural studies show that the drug binds to sirtuin 2 and allosterically inhibits its deacetylase activity. FLS-359 inhibits the growth of RNA and DNA viruses, including members of the coronavirus, orthomyxovirus, flavivirus, hepadnavirus, and herpesvirus families. FLS-359 acts at multiple levels to antagonize cytomegalovirus replication in fibroblasts, causing modest reductions in viral RNAs and DNA, together with a much greater reduction in infectious progeny, and it exhibits antiviral activity in humanized mouse models of infection. Our results highlight the potential of sirtuin 2 inhibitors as broad-spectrum antivirals and set the stage for further understanding of how host epigenetic mechanisms impact the growth and spread of viral pathogens.

Preemptive Therapy in Cryptococcosis Adjusted for Outcomes

Cryptococcosis is one of the most serious opportunistic diseases in patients living with HIV. For this reason, early diagnosis and appropriate treatment are important.

OBJECTIVES

The aim of the study was to understand the development of patients diagnosed with cryptococcosis by detection of Cryptococcus antigen in serum by lateral flow assay (CrAg LFA) without nervous system involvement and with treatment in accordance with the results.

MATERIALS AND METHODS

A retrospective, longitudinal, analytical study was performed. Seventy patients with cryptococcosis initially diagnosed by serum CrAg LFA without meningeal involvement between January 2019 and April 2022 were analyzed for medical records. The treatment regimen was adapted to the results of blood culture, respiratory material, and pulmonary tomography imaging.

RESULTS

Seventy patients were included, 13 had probable pulmonary cryptococcosis, 4 had proven pulmonary cryptococcosis, 3 had fungemia, and 50 had preemptive therapy without microbiological or imaging findings compatible with cryptococcosis. Among the 50 patients with preemptive therapy, none had meningeal involvement or cryptococcosis recurrences to date.

CONCLUSION

Preemptive therapy avoided progression to meningitis in CrAg LFA-positive patients. Preemptive therapy with dose adjustment of fluconazole in patients with the mentioned characteristics was useful despite the use of lower doses than recommended.

Impact of Invasive Pulmonary Aspergillosis in Critically Ill Surgical Patients with or without Solid Organ Transplantation

BACKGROUND

Critically ill patients, especially those who have undergone solid organ transplantation (SOT), are at risk of invasive pulmonary aspergillosis (IPA). The outcome relevance of adequately treated putative IPA (pIPA) is a matter of debate. The aim of this study is to assess the outcome relevance of pIPA in a cohort of critically ill patients with and without SOT.

METHODS

Data from 121 surgical critically ill patients with pIPA (n = 30) or non-pIPA (n = 91) were included. Cox regression analysis was used to identify risk factors for mortality and unfavourable outcomes after 28 and 90 days.

RESULTS

Mortality rates at 28 days were similar across the whole cohort of patients (pIPA: 31% vs. non-pIPA: 27%) and did not differ in the subgroup of patients after SOT (pIPA: 17% vs. non-pIPA: 22%). A higher Sequential Organ Failure Assessment (SOFA) score and evidence of bacteraemia were identified as risk factors for mortality and unfavourable outcome, whereas pIPA itself was not identified as an independent predictor for poor outcomes.

CONCLUSIONS

Adequately treated pIPA did not increase the risk of death or an unfavourable outcome in this mixed cohort of critically ill patients with or without SOT, whereas higher disease severity and bacteraemia negatively affected the outcome.

Advancing cell-based cancer immunotherapy through stem cell engineering

Advances in cell-based therapy, particularly CAR-T cell therapy, have transformed the treatment of hematological malignancies. Although an important step forward for the field, autologous CAR-T therapies are hindered by high costs, manufacturing challenges, and limited efficacy against solid tumors. With ongoing progress in gene editing and culture techniques, engineered stem cells and their application in cell therapy are poised to address some of these challenges. Here, we review stem cell-based immunotherapy approaches, stem cell sources, gene engineering and manufacturing strategies, therapeutic platforms, and clinical trials, as well as challenges and future directions for the field.

Mutations in latent membrane protein 1 of Epstein-Barr virus are associated with increased risk of posttransplant lymphoproliferative disorder in children

Epstein-Barr virus (EBV)-positive posttransplant lymphoproliferative disorder (PTLD) results in significant morbidity and mortality in pediatric transplant recipients. Identifying individuals at an increased risk of EBV-positive PTLD could influence clinical management of immunosuppression and other therapies, improving posttransplant outcomes. A 7-center prospective, observational clinical trial of 872 pediatric transplant recipients evaluated the presence of mutations at positions 212 and 366 of EBV latent membrane protein 1 (LMP1) as an indicator of risk of EBV-positive PTLD (clinical trials: NCT02182986). DNA was isolated from peripheral blood of EBV-positive PTLD case patients and matched controls (1:2 nested case:control), and the cytoplasmic tail of LMP1 was sequenced. Thirty-four participants reached the primary endpoint of biopsy-proven EBV-positive PTLD. DNA was sequenced from 32 PTLD case patients and 62 matched controls. Both LMP1 mutations were present in 31 of 32 PTLD cases (96.9%) and in 45 of 62 matched controls (72.6%) (P = .005; OR = 11.7; 95% confidence interval, 1.5, 92.6). The presence of both G212S and S366T carries a nearly 12-fold increased risk of development of EBV-positive PTLD. Conversely, transplant recipients without both LMP1 mutations carry a very low risk of PTLD. Analysis of mutations at positions 212 and 366 of LMP1 can be informative in stratifying patients for risk of EBV-positive PTLD.

Cutaneous infections from viral sources in solid organ transplant recipients

INTRODUCTION

Solid organ transplant recipients (SOTRs) are susceptible to various dermatological complications caused by long-term immunosuppressive therapy. Of these complications, viral infections are noteworthy because of their high prevalence and the potential morbidity associated with viral carcinogenesis.

OBJECTIVES

To evaluate the occurrence of cutaneous viral infections in SOTRs and their correlation with clinical features, transplant type, and the length and intensity of immunosuppressive therapy.

METHODS

This retrospective cohort study included SOTRs followed up at the Department of Dermatology in a tertiary hospital. The outcomes analyzed were the occurrence of cutaneous viral infections, including human papillomavirus (HPV) infection, herpes simplex, herpes zoster, molluscum contagiosum, Merkel cell carcinoma, Kaposi's sarcoma, and cytomegalovirus, and the occurrence of HPV-related neoplasms. Clinical variables, such as length and intensity of immunosuppression, type of transplanted organ, and comorbidities, were analyzed as possible risk factors for cutaneous viral infections in SOTRs.

RESULTS

A total of 528 SOTRs were included in this study, among which 53.8% had one or more viral infections. Of these, 10% developed a virus-associated malignancy (HPV-associated carcinoma, Merkel cell carcinoma, or Kaposi's sarcoma). The higher risk of viral infections among SOTRs was associated with cyclosporine intake (1.40-fold higher risk) and younger age at transplantation. The use of an immunosuppressive regimen, including additional drugs, was associated with a higher risk of genital HPV infection (1.50-fold higher risk for each incremental drug).

CONCLUSIONS

The occurrence of cutaneous viral infections in SOTRs is directly associated with the duration and intensity of immunosuppressive therapy. Patients at higher risk were those taking drugs with a stronger impact on cellular immunity and/or those on an immunosuppressive regimen comprising various drugs.

Infections after organ transplantation and immune response

Organ transplantation has provided another chance of survival for end-stage organ failure patients. Yet, transplant rejection is still a main challenging factor. Immunosuppressive drugs have been used to avoid rejection and suppress the immune response against allografts. Thus, immunosuppressants increase the risk of infection in immunocompromised organ transplant recipients. The infection risk reflects the relationship between the nature and severity of immunosuppression and infectious diseases. Furthermore, immunosuppressants show an immunological impact on the genetics of innate and adaptive immune responses. This effect usually reactivates the post-transplant infection in the donor and recipient tissues since T-cell activation has a substantial role in allograft rejection. Meanwhile, different infections have been found to activate the T-cells into CD₄⁺ helper T-cell subset and CD₈⁺ cytotoxic T-lymphocyte that affect the infection and the allograft. Therefore, the best management and preventive strategies of immunosuppression, antimicrobial prophylaxis, and intensive medical care are required for successful organ transplantation. This review addresses the activation of immune responses against different infections in immunocompromised individuals after organ transplantation.

Blood–Brain Barrier Biomarkers before and after Kidney Transplantation

Kidney transplantation (KT) may improve the neurological status of chronic kidney disease (CKD) patients, reflected by the altered levels of circulating BBB-specific biomarkers. This study compares the levels of neuron specific enolase (NSE), brain-derived neurotrophic factor (BDNF), neurofilament light chain (NfL), and circulating plasma extracellular vesicles (EVs) in kidney-failure patients before KT and at a two-year follow up. Using ELISA, NSE, BDNF, and NfL levels were measured in the plasma of 74 living-donor KT patients. Plasma EVs were isolated with ultracentrifugation, and characterized for concentration/size and surface protein expression using flow cytometry from a subset of 25 patients. Lower NSE levels, and higher BDNF and NfL were observed at the two-year follow-up compared to the baseline (p < 0.05). Male patients had significantly higher BDNF levels compared to those of females. BBB biomarkers correlated with the baseline lipid profile and with glucose, vitamin D, and inflammation markers after KT. BBB surrogate marker changes in the microcirculation of early vascular aging phenotype patients with calcification and/or fibrosis were observed only in NSE and BDNF. CD31+ microparticles from endothelial cells expressing inflammatory markers such as CD40 and integrins were significantly reduced after KT. KT may, thus, improve the neurological status of CKD patients, as reflected by changes in BBB-specific biomarkers.

Isolated massive histiocytes renal interstitial infiltration: a case report of an unexpected cause of acute kidney injury in a kidney transplant recipient

BACKGROUND

Acute kidney injury is a frequent cause of hospital readmission in kidney transplant recipients (KTR), usually associated with infections and graft rejection. Herein, we report a case of an unusual cause of acute kidney injury in a KTR (massive histiocytes renal interstitial infiltration).

CASE PRESENTATION

A 40-year-old woman was submitted to a second kidney transplant. One year after surgery, she presented asthenia, myalgia, and fever, haemoglobin 6.1 g/dL; neutrophils: 1.3 × 109/µL; platelets: 143 × 109/µL; blood creatinine 11.8 mg/dL, requiring dialysis. A kidney biopsy revealed diffuse histiocytic infiltration, which was assumed due to dysregulated immunological activation triggered by infections. The patient had multiple infections, including cytomegalovirus infection (CMV), aspergillosis, bacteraemia, and urinary tract infections, which could trigger the immune response. Haemophagocytic lymphohistiocytosis (HLH) was ruled out. The present case highlights the occurrence of isolated massive renal interstitial infiltration of histiocytes that does not meet the criteria for HLH or other related pathologies.

CONCLUSIONS

Renal histiocyte activation and infiltration may have been initiated by an immunological mechanism similar to what occurs in HLH and infectious processes. The present case highlights the occurrence of isolated massive renal interstitial infiltration of histiocytes that does not meet the criteria for HLH or other related pathologies.

Delta Neutrophil Index as a New Early Mortality Predictor after Liver Transplantation

Background: Patients with liver disease display numerous defects of the immune system, so infection is a frequent complication of both acute and chronic liver disease. These infections are independently associated with poor outcomes after liver transplantation. Our objective was to evaluate the delta neutrophil index (DNI), a new inflammation marker, as a predictor of survival after liver transplantation (LT). Methods: This observational study retrospectively evaluated the records of 712 patients who underwent LT from January 2010 to February 2018. DNI was evaluated at pre-transplantation and 1, 7, 14, and 30 days after operation. Statistical analysis was performed using the T-test or chi-square test, and logistic regression analysis. Results: The mean MELD score was 16.7 ± 9.4 (0–48). There were 125 mortality cases (17.8%) after liver transplantation. Mean DNI was 1.61 at pre-transplantation, 3.94 one day after operation, 2.67 seven days after operation, 1.61 fourteen days after operation, and 1.64 thirty days after operation, respectively. In multivariate analysis, DNI seven and fourteen days after operation was revealed as an independent prognostic factor for mortality after liver transplantation (p = 0.040 and p < 0.0001). Conclusions: The DNI is a simple and reliable predictor of patient mortality after liver transplantation.

The value of 18 F-FDG PET/CT quantitative indexes in the diagnosis of nondestructive posttransplant lymphoproliferative disorders after pediatric liver transplantation

BACKGROUND

Posttransplant lymphoproliferative disease (PTLD) is a serious complication after pediatric liver transplantation (pLT), which may lead to death. ¹⁸ F-FDG PET/CT is rarely considered in PTLD after pLT and lacks clear diagnostic guidelines, especially in the differential diagnosis of nondestructive PTLD. The aim of this study was to find a quantifiable ¹⁸ F-FDG PET/CT index to identify nondestructive PTLD after pLT.

METHODS

This retrospective study collected the data of patients who underwent pLT, postoperative lymph node biopsy, and ¹⁸ F-FDG PET/CT at Tianjin First Central Hospital from January 2014 to December 2021. Quantitative indexes were established using lymph node morphology and the maximum standardized uptake value (SUVmax).

RESULTS

A total of 83 patients met the inclusion criteria and were included in this retrospective study. To distinguish between PTLD-negative cases and nondestructive PTLD cases, according to the receiver operating characteristic curve, (the shortest diameter of the lymph node at the biopsy site [SDL]/the longest diameter of the lymph node at the biopsy site [LDL])*(SUVmax at the biopsy site [SUVmaxBio]/SUVmax of the tonsils [SUVmaxTon]) had the maximum area under the curve (0.923; 95% confidence interval: 0.834-1.000), and the cutoff value was 0.264 according to the maximum value of Youden's index. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 93.6%, 94.7%, 97.8%, 85.7%, and 93.9%, respectively.

CONCLUSIONS

(SDL/LDL)*(SUVmaxBio/SUVmaxTon) has good sensitivity, specificity, positive predictive and negative predictive values, and accuracy, and can be used as a good quantitative index for the diagnosis of nondestructive PTLD.

Biomarker-Development Proteomics in Kidney Transplantation: An Updated Review

Kidney transplantation (KT) is the optimal therapeutic strategy for patients with end-stage renal disease. The key to post-transplantation management is careful surveillance of allograft function. Kidney injury may occur from several different causes that require different patient management approaches. However, routine clinical monitoring has several limitations and detects alterations only at a later stage of graft damage. Accurate new noninvasive biomarker molecules are clearly needed for continuous monitoring after KT in the hope that early diagnosis of allograft dysfunction will lead to an improvement in the clinical outcome. The advent of “omics sciences”, and in particular of proteomic technologies, has revolutionized medical research. Proteomic technologies allow us to achieve the identification, quantification, and functional characterization of proteins/peptides in biological samples such as urine or blood through supervised or targeted analysis. Many studies have investigated proteomic techniques as potential molecular markers discriminating among or predicting allograft outcomes. Proteomic studies in KT have explored the whole transplant process: donor, organ procurement, preservation, and posttransplant surgery. The current article reviews the most recent findings on proteomic studies in the setting of renal transplantation in order to better understand the effective potential of this new diagnostic approach.

Infection and clinical xenotransplantation: Guidance from the Infectious Disease Community of Practice of the American Society of Transplantation

This guidance was developed to summarize current approaches to the potential transmission of swine-derived organisms to xenograft recipients, health care providers, or the public in clinical xenotransplantation. Limited specific data are available on the zoonotic potential of pig pathogens. It is anticipated that the risk of zoonotic infection in xenograft recipients will be determined by organisms present in source animals and relate to the nature and intensity of the immunosuppression used to maintain xenograft function. Based on experience in allotransplantation and with preclinical models, viral infections are of greatest concern, including porcine cytomegalovirus, porcine lymphotropic herpesvirus, and porcine endogenous retroviruses. Sensitive and specific microbiological assays are required for routine microbiological surveillance of source animals and xenograft recipients. Archiving of blood samples from recipients, contacts, and hospital staff may provide a basis for microbiological investigations if infectious syndromes develop. Carefully implemented infection control practices are required to prevent zoonotic pathogen exposures by clinical care providers. Informed consent practices for recipients and their close contacts must convey the lack of specific data for infectious risk assessment. Available data suggest that infectious risks of xenotransplantation are manageable and that clinical trials can advance with carefully developed protocols for pretransplant assessment, syndrome evaluation, and microbiological monitoring.

Opportunistic Infections Post-Lung Transplantation: Viral, Fungal, and Mycobacterial

Opportunistic infections are a leading cause of lung transplant recipient morbidity and mortality. Risk factors for infection include continuous exposure of the lung allograft to the external environment, high levels of immunosuppression, impaired mucociliary clearance and decreased cough reflex, and impact of the native lung microbiome in single lung transplant recipients. Infection risk is mitigated through careful pretransplant screening of recipients and donors, implementation of antimicrobial prophylaxis strategies, and routine surveillance posttransplant. This review describes common viral, fungal, and mycobacterial infectious after lung transplant and provides recommendations on prevention and treatment.

The Role of Pretransplant Infections in Pediatric Receiving LDLT in Indonesia: A 7-y Retrospective Study

Liver transplantation is the definitive treatment for pediatric end-stage liver disease. Infections posttransplantation might significantly affect the outcome of the surgery. This study aimed to identify the role of pretransplant infection among children who underwent living donor liver transplantation (LDLT) in Indonesia.

Methods

This is an observational, retrospective cohort study. A total of 56 children were recruited between April 2015 and May 2022. Patients were categorized into 2 according to the presence of pretransplantation infections requiring hospitalization before the surgery. Diagnosis of posttransplantation infection was observed for up to 1 y based on the clinical features and laboratory parameters.

Results

The most common indication for LDLT was biliary atresia (82.1%). Fifteen of 56 patients (26.7%) had a pretransplant infection, whereas 73.2% of patients were diagnosed with a posttransplant infection. There was no significant association between pretransplant and posttransplant infection in all 3-time points (≤1 mo, 2-6 mo, and 6-12 mo). The most common organ involvement posttransplantation was respiratory infections (50%). The pretransplant infection did not significantly affect posttransplant bacteremia, length of stay, duration of mechanical ventilation, initiation of enteral feeding, hospitalization cost, and graft rejection.

Conclusions

Our data showed that pretransplant infections did not significantly affect clinical outcomes in post-LDLT procedures. A prompt and sufficient diagnosis and treatment before and after the LDLT procedure is the best way to obtain an optimal outcome.

Ventilator-Associated Pneumonia in Immunosuppressed Patients

Immunocompromised patients-including patients with cancer, hematological malignancies, solid organ transplants and individuals receiving immunosuppressive therapies for autoimmune diseases-account for an increasing proportion of critically-ill patients. While their prognosis has improved markedly in the last decades, they remain at increased risk of healthcare- and intensive care unit (ICU)-acquired infections. The most frequent of these are ventilator-associated lower respiratory tract infections (VA-LTRI), which include ventilator-associated pneumonia (VAP) and tracheobronchitis (VAT). Recent studies have shed light on some of the specific features of VAP and VAT in immunocompromised patients, which is the subject of this narrative review. Contrary to previous belief, the incidence of VAP and VAT might actually be lower in immunocompromised than non-immunocompromised patients. Further, the relationship between immunosuppression and the incidence of VAP and VAT related to multidrug-resistant (MDR) bacteria has also been challenged recently. Etiological diagnosis is essential to select the most appropriate treatment, and the role of invasive sampling, specifically bronchoscopy with bronchoalveolar lavage, as well as new molecular syndromic diagnostic tools will be discussed. While bacteria-especially gram negative bacteria-are the most commonly isolated pathogens in VAP and VAT, several opportunistic pathogens are a special concern among immunocompromised patients, and must be included in the diagnostic workup. Finally, the impact of immunosuppression on VAP and VAT outcomes will be examined in view of recent papers using improved statistical methodologies and treatment options-more specifically empirical antibiotic regimens-will be discussed in light of recent findings on the epidemiology of MDR bacteria in this population.

Cytomegalovirus Infection Management in Multivisceral and Intestinal Transplant: A Dual Institution Study

Intestinal transplant and multivisceral transplant were originally in pediatric populations and are relatively new procedures in adults. Despite increasing success rates in the immediate post-transplant period, infectious complications and acute and chronic rejection remain significant causes of morbidity and mortality. Previous research has shown cytomegalovirus (CMV) is the main cause of infection in this population. Due to the limited patient population, incidence of CMV viremia ranges widely and there is lack of universal protocol for treatment. This dual institution retrospective chart review between Henry Ford Hospital and Duke University analyzed adult intestinal and multivisceral transplant recipients between 2009 and 2019. Of the 32 patients identified and included in the study, 15 had CMV infection (46.9%). Of those with CMV infection, 5 (33.3%) had donor positive (D+)/recipient positive (R+) status; 5 had D-/R+; 4 had D+/R-; and one had D-/R-. There was no significant difference between mortality in those who had reported infection and not (80% vs 76.5%). The data from this study show significant rates of CMV viremia in patients undergoing intestinal transplant/multivisceral transplant with almost half of our study population having documented infection within 1 year of transplant, stressing the importance for universal protocol into CMV viremia treatment.

Relationship between Cytomegalovirus Viremia and Long-Term Outcomes in Kidney Transplant Recipients with Different Donor Ages

OBJECTIVES

To explore the Cytomegalovirus (CMV) burden on the long-term post-transplant course in different donor ages, we evaluated the incidence and risk factors for CMV in our kidney-transplanted patients (KTs) with extensive adoption of expanded-criteria donors (ECDs).

METHODS

Retrospective evaluation of 929 consecutive first KTs (49.5% receiving an organ from a donor ≥ 60 years) performed between 01-2003 and 12-2013. Overall survival was estimated using Kaplan-Meier curves; cumulative incidence function was additionally analyzed to consider the potential role of death with a functioning graft as a competitive event with graft dysfunction and to avoid overestimation. Apart from regular DNAemia monitoring in all patients, prophylaxis was adopted in high-risk groups (D+/R- or recipients of anti-thymocyte globulin induction), with pre-emptive therapy in the remaining groups.

RESULTS

CMV incidence was 19.5% (4-34.9% according to serostatus combination: D-/R-, D-/R+, D+/R+, D+/R-). Donor and recipient age, recipient pre-transplant hypertension, DR antigen compatibility, cold ischemia time, and post-transplant early complications, including rejection, urologic and renal artery stenosis, and lower renal function and proteinuria ≥ 0.5 g/day at one year after KT were associated with CMV. CMV determined lower death-censored graft survival (DCGS) (p < 0.01), with a prominent effect in R+ (p < 0.01) and without impact in R- (p = 0.32 in D-/R- and p = 0.006 in D+/R-). Interestingly, CMV occurrence influenced DCGS only in KTs who received grafts from donors < 50 or 50-69 years old (p < 0.01), while it was not significant with older donors (p = 0.07). The analysis of the cumulative incidence of graft loss accounting for death as a competing risk confirmed all these findings. In multivariate analysis, CMV replication/disease in the first year was an independent predictor for DCGS (HR 1.73 [1.3-2.3]).

CONCLUSIONS

In a large population with extensive ECD adoption, CMV viremia in the first year demonstrates its harmful effect with an independent role for graft loss and significant impact among R+ recipients and KTs with donors < 70 years.

Impact of HLA polymorphisms on the susceptibility to SARS-CoV-2 infection and related mortality in patients with renal replacement therapy

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection could present in a clinical spectrum of varying severity. Human leukocyte antigen (HLA) is a crucial component of the viral antigen presentation pathway and immune response to the virus. Therefore, we aimed to assess the impact of HLA allele polymorphisms on the susceptibility to SARS-CoV-2 infection and related mortality in Turkish kidney transplant recipients and wait listed patients, along with clinical characteristics of the patients. We analysed data from 401 patients with clinical characteristics according to presence (n = 114, COVID+) or absence of SARS-CoV-2 infection (n = 287, COVID-) who had previously been HLA typed to support transplantation. The incidence of coronavirus disease-19 (COVID-19) was 28 %, and the mortality rate was 19 % in our wait listed/ transplanted patients. Multivariate logistic regression analysis showed that a significant HLA association between HLA- B*49 (OR = 2.57, 95 % CI, 1.13-5.82; p = 0.02) and HLA- DRB1*14 (OR = 2.48, 95 % CI, 1.18-5.20; p = 0.01) with SARS-CoV-2 infection. Besides, in COVID + patients, HLA-C*03 was correlated to mortality (OR = 8.31, 95 % CI, 1.26-54.82; P = 0.03). The new finding from our analysis suggests that HLA polymorphisms could be associated with the occurrence of SARS-CoV-2 infection and COVID-19 mortality in Turkish patients with renal replacement therapy. This study may provide new information for the clinician to identify and manage sub-populations at risk in the setting of the current COVID-19 pandemic.

Abdominal infection combined with pneumoperitoneum after renal transplantation: A case report

INTRODUCTION

Abdominal infection combined with pneumoperitoneum after renal transplantation is rare, clinically confusing, and easily misdiagnosed by physicians as gastrointestinal perforation.

PATIENT CONCERNS

A 54-year-old man experienced abdominal pain and distension together with signs of peritoneal irritation after cadaveric renal transplantation. CT and standing abdominal plain film showed a large pneumoperitoneum in the abdominal cavity and the patient underwent an exploratory laparotomy but no gastrointestinal perforation was found.

DIAGNOSIS

No gastrointestinal perforation was found during the operation. In the search for the infectious agent, ascites culture was negative while next-generation sequencing was positive, suggesting the presence of intestinal flora ectopic to abdominal infection with anaerobic respiration fermentation leading to large amounts of gas.

INTERVENTIONS

The patient underwent exploratory laparotomy without gastrointestinal perforation, and then underwent abdominal lavage, placed abdominal drainage tube, and conducted culture and next-generation sequencing examination of ascites.

OUTCOMES

Postoperative symptoms were relieved and intestinal function recovered. After 3 months of outpatient follow-up, the patient had stable transplanted kidney function and was in good spirits and sleeping well, with a good appetite, soft and regular stools, no abdominal pain and distension, and no fever.

CONCLUSION

Patients after kidney transplantation should be wary of abdominal infection being misdiagnosed as gastrointestinal perforation.

Corticosteroids and Outcomes in Solid Organ Transplant Recipients Infected With Severe Acute Respiratory Syndrome Coronavirus 2

Objective

To examine outcomes in organ transplant and nontransplant patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the initial 22 months of the pandemic.

Patients and Methods

We used Optum electronic health records to compare outcomes between an adult transplant group and a propensity-matched nontransplant group that tested positive for SARS-CoV-2 from February 1, 2020, to December 15, 2021. Baseline characteristics, hospitalization, intensive care unit admission, mechanical ventilation, renal replacement therapy, inpatient, and 90-day mortality were compared between the transplant and nontransplant groups and among specific transplant recipients. Cox proportional analysis was used to examine hospitalization and mortality by organ transplant, medical therapy, sex, and the period of the pandemic.

Results

We identified 876,959 patients with SARS-CoV-2 infection, of whom 3548 were organ transplant recipients. The transplant recipients had a higher risk of hospitalization (30.6% vs 25%, respectively; P<.001), greater use of mechanical ventilation (7.8% vs 5.6%, respectively; P<.001), and increased inpatient mortality (6.7% vs 4.7%, respectively; P<.001) compared with the nontransplant patients. The initiation of mechanical ventilation was significantly more frequent in the transplant group. After adjustment for baseline characteristics and comorbidities, the transplant group had a higher risk of hospitalization (odds ratio, 1.38; 95% confidence interval, 1.19-1.59), without a difference in mortality. In the transplant group, lung transplant recipients had the highest inpatient mortality (11.6%).

Conclusion

Among patients with SARS-CoV-2 infection, the transplant recipients were at a higher risk of hospitalization and inpatient mortality; however, mortality was mainly driven by advanced age and comorbidities rather than by transplant status or immunosuppressive medications. Lung transplant recipients had the greatest inpatient and 90-day mortality.

Evaluation of an Abnormal Liver Panel After Liver Transplantation

Abnormal liver tests are common after liver transplantation. The differential diagnosis depends on the clinical context, particularly the time course, pattern and degree of elevation, and donor and recipient factors. The perioperative period has distinct causes compared with months and years after transplant, including ischemia-reperfusion injury, vascular thrombosis, and primary graft nonfunction. Etiologies seen beyond the perioperative period include biliary complications, rejection, infection, recurrent disease, and non-transplant-specific causes. The evaluation begins with a liver ultrasound with Doppler as well as appropriate laboratory testing and culminates in a liver biopsy if the imaging and laboratory testing is unrevealing.

Specificities of Meningitis and Meningo-Encephalitis After Kidney Transplantation: A French Retrospective Cohort Study

Kidney transplant recipients develop atypical infections in their epidemiology, presentation and outcome. Among these, meningitis and meningoencephalitis require urgent and adapted anti-infectious therapy, but published data is scarce in KTRs. The aim of this study was to describe their epidemiology, presentation and outcome, in order to improve their diagnostic and management. We performed a retrospective, multicentric cohort study in 15 French hospitals that included all 199 cases of M/ME in KTRs between 2007 and 2018 (0.9 case per 1,000 KTRs annually). Epidemiology was different from that in the general population: 20% were due to Cryptococcus neoformans, 13.5% to varicella-zoster virus, 5.5% to Mycobacterium tuberculosis, and 4.5% to Enterobacteria (half of which produced extended spectrum beta-lactamases), and 5% were Post Transplant Lymphoproliferative Disorders. Microorganisms causing M/ME in the general population were infrequent (2%, for Streptococcus pneumoniae) or absent (Neisseria meningitidis). M/ME caused by Enterobacteria, Staphylococci or filamentous fungi were associated with high and early mortality (50%-70% at 1 year). Graft survival was not associated with the etiology of M/ME, nor was impacted by immunosuppression reduction. Based on these results, we suggest international studies to adapt guidelines in order to improve the diagnosis and the probabilistic treatment of M/ME in SOTRs.

PREBIOTIC: a study protocol of a randomised controlled trial to assess prebiotic supplementation in kidney transplant recipients for preventing infections and gastrointestinal upset - a feasibility study

BACKGROUND

Modulating the microbiota in the large intestine of kidney transplant recipients through prebiotic supplementation may prevent infectious complications from occurring. To date, there have been no interventional trials which have investigated this novel treatment in kidney transplantation. The aim of PREBIOTIC is to assess the feasibility of performing a randomised controlled trial of prebiotics in reducing infections and gastrointestinal symptoms in kidney transplant recipients.

METHODS

Sixty kidney transplant patients will be recruited to a double-blind, placebo-controlled, randomised feasibility trial. Patients will be provided with prebiotic therapy or placebo for 4 to 6 weeks. Outcomes will include recruitment, adherence, tolerance, retention, laboratory parameters (including serum indoxyl sulphate, ρ-cresyl sulphate and stool collection), patients' self-assessed quality of life, gastrointestinal symptoms and clinical outcomes.

DISCUSSION

This trial will assess the feasibility of prebiotic supplementation in kidney transplant recipients. Prebiotics not only may alter the gut microbiota and their inherent metabolism and production of uraemic toxins but also may prevent infections from occurring in kidney transplant recipients.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry number ACTRN12618001057279p. The date of registration was 25th June 2018, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375370&isReview=true .

Effects of periodontal pathogen-induced intestinal dysbiosis on transplant immunity in an allogenic skin graft model

Periodontal disease can induce dysbiosis, a compositional and functional alteration in the microbiota. Dysbiosis induced by periodontal disease is known to cause systemic inflammation and may affect transplant immunity. Here, we examined the effects of periodontal disease-related intestinal dysbiosis on transplant immunity using a mouse model of allogenic skin graft in which the mice were orally administered the periodontal pathogen Porphyromonas gingivalis (Pg). For 6 weeks, the Pg group orally received Pg while the control group orally received phosphate-buffered saline solution. After that, both groups received allogenic skin grafts. 16 s rRNA analysis of feces revealed that oral administration of Pg significantly increased three short chain fatty acids (SCFAs) producing genera. SCFA (acetate and propionate) levels were significantly higher in the Pg group (p = 0.040 and p = 0.005). The ratio of regulatory T cells, which are positively correlated with SCFAs, to total CD4+ T cells in the peripheral blood and spleen was significantly greater (p = 0.002 and p < 0.001) in the Pg group by flowcytometry. Finally, oral administration of Pg significantly prolonged skin graft survival (p < 0.001) and reduced pathological inflammation in transplanted skin grafts. In conclusion, periodontal pathogen-induced intestinal dysbiosis may affect transplant immunity through increased levels of SCFAs and regulatory T cells. (198 words).

Trained immunity - basic concepts and contributions to immunopathology

Trained immunity is a functional state of the innate immune response and is characterized by long-term epigenetic reprogramming of innate immune cells. This concept originated in the field of infectious diseases - training of innate immune cells, such as monocytes, macrophages and/or natural killer cells, by infection or vaccination enhances immune responses against microbial pathogens after restimulation. Although initially reported in circulating monocytes and tissue macrophages (termed peripheral trained immunity), subsequent findings indicate that immune progenitor cells in the bone marrow can also be trained (that is, central trained immunity), which explains the long-term innate immunity-mediated protective effects of vaccination against heterologous infections. Although trained immunity is beneficial against infections, its inappropriate induction by endogenous stimuli can also lead to aberrant inflammation. For example, in systemic lupus erythematosus and systemic sclerosis, trained immunity might contribute to inflammatory activity, which promotes disease progression. In organ transplantation, trained immunity has been associated with acute rejection and suppression of trained immunity prolonged allograft survival. This novel concept provides a better understanding of the involvement of the innate immune response in different pathological conditions, and provides a new framework for the development of therapies and treatment strategies that target epigenetic and metabolic pathways of the innate immune system.

Microbiological and Clinical Outcomes of Methicillin-Susceptible Staphylococcus aureus Isolated in Lung Transplant Perioperative Donor and Recipient Respiratory Cultures

Staphylococcus aureus is one of the most common organisms isolated from respiratory secretions in lung transplant donors and recipients perioperatively. Within the first 90 days after lung transplantation, methicillin-susceptible Staphylococcus aureus (MSSA) infections have been associated with increased mortality and acute and chronic rejection. However, it is unclear whether respiratory cultures positive for MSSA at the time of transplantation can lead to clinically significant infection. The aim of this study was to assess the microbiological and clinical outcomes for lung transplant recipients (LTRs) with positive perioperative donor or/and recipient respiratory cultures for MSSA. A retrospective study was conducted evaluating MSSA-positive respiratory cultures at the time of lung transplantation from donors and/or recipients from January 1, 2008, to December 30, 2019. Patients who did not have a bronchoalveolar lavage at 2 weeks after the lung transplant or died within 2 weeks of lung transplant were excluded. The main outcome was MSSA eradication at 2-week bronchoscopy. Recipients were evaluated for MSSA infections at the 12-week period after the transplant. Of the 1,678 individuals who underwent lung transplantation, 218 LTRs had S. aureus isolated in perioperative donor or recipient respiratory cultures, and 29 were subsequently excluded. Of the remaining 189 LTRs, MSSA eradication at the 2-week bronchoscopy was achieved in 186 (98.4%) recipients. During the 12-week follow-up, 15 (7.9%) recipients were diagnosed with MSSA pneumonia; concurrent MSSA bacteremia was noted in one recipient. No anastomotic infection, empyema, or lung abscess related to MSSA was diagnosed during the follow-up period.In LTRs, the rate of MSSA eradication at 2-week post-transplant recipients is high, and it is associated with a low rate of infectious complication within the first 12 weeks after transplant. Most of the recipients received a combination therapy with at least one agent active against MSSA. More studies to evaluate the optimal antimicrobial stewardship policies regarding the regimen and duration of antibiotic therapy for these patients are needed.

Locally controlled release of immunosuppressive promotes survival of transplanted adult spinal cord tissue

Transplantation of adult spinal cord tissue (aSCT) is a promising treatment for spinal cord injury (SCI) basing on various types of neural cells and matrix components inside aSCT. However, long-term systemic administration of immunosuppressors (e.g. tacrolimus, TAC) is required for the survival of allogeneic tissue, which often associated with severe side effects such as infection, liver damageand renal failure. In this study, a triglycerol monostearate (TGM)-based TAC delivery system (e.g. TAC@TGM) with high drug loading concentration was developed, which possessed injectable properties as well as sustainable and immune-responsive drug release behaviors. In complete transected SCI model, locally injected TAC@TGM could reduce the infiltration of inflammation cells, enhance the survival of transplanted aSCT (e.g. Tuj-1⁺ and NF⁺ neurons) and promote the recovery of locomotor function. Moreover, controlled release of TAC by TAC@TGM attenuated side effects of TAC on liver and kidneys compared with traditional systemic administration. More importantly, the developed TAC@TGM system provided a facile single dose of long-term immunosuppressive effect not just for aSCT transplantation, but also for other tissue/organ and cell transplantations.

A consensus conference to define the utility of advanced infectious disease diagnostics in solid organ transplant recipients

The last decade has seen an explosion of advanced assays for the diagnosis of infectious diseases, yet evidence-based recommendations to inform their optimal use in the care of transplant recipients are lacking. A consensus conference sponsored by the American Society of Transplantation (AST) was convened on December 7, 2021, to define the utility of novel infectious disease diagnostics in organ transplant recipients. The conference represented a collaborative effort by experts in transplant infectious diseases, diagnostic stewardship, and clinical microbiology from centers across North America to evaluate current uses, unmet needs, and future directions for assays in 5 categories including (1) multiplex molecular assays, (2) rapid antimicrobial resistance detection methods, (3) pathogen-specific T-cell reactivity assays, (4) next-generation sequencing assays, and (5) mass spectrometry-based assays. Participants reviewed and appraised available literature, determined assay advantages and limitations, developed best practice guidance largely based on expert opinion for clinical use, and identified areas of future investigation in the setting of transplantation. In addition, attendees emphasized the need for well-designed studies to generate high-quality evidence needed to guide care, identified regulatory and financial barriers, and discussed the role of regulatory agencies in facilitating research and implementation of these assays. Findings and consensus statements are presented.

Acute hepatitis as an independent form of mixed (herpetic and new coronavirus) infections in a child

To date, the association of SARS-CoV-2 infection with the reactivation of herpes viruses has been determined. This has been proven not only by the results of laboratory studies, but also by a clinically confirmed subsequent manifestation of the herpetic process. The article describes a clinical case of Epstein–Barr viral and cytomegalovirus infections reactivation after COVID-19. The child was diagnosed with anicteric form of hepatitis of herpetic etiology. Hepatitis, moderate anicteric form. During treatment, the patient’s condition improved. Complete clinical recovery with normalization of the activity of alanine and aspartate aminotransaminases occurred 1 month after the onset of the disease, but the level of lymphocytes and gamma-glutamyl transpeptidase still remained moderately elevated. According to the ultrasound of the abdominal organs, the size of the liver returned to normal. The presented case illustrates that mixed infections are a quite possible situation during the COVID-19 pandemic, which must be taken into account when working with such patients. 

Curative islet and hematopoietic cell transplantation in diabetic mice without toxic bone marrow conditioning

Mixed hematopoietic chimerism can promote immune tolerance of donor-matched transplanted tissues, like pancreatic islets. However, adoption of this strategy is limited by the toxicity of standard treatments that enable donor hematopoietic cell engraftment. Here, we address these concerns with a non-myeloablative conditioning regimen that enables hematopoietic chimerism and allograft tolerance across fully mismatched major histocompatibility complex (MHC) barriers. Treatment with an αCD117 antibody, targeting c-Kit, administered with T cell-depleting antibodies and low-dose radiation permits durable multi-lineage chimerism in immunocompetent mice following hematopoietic cell transplant. In diabetic mice, co-transplantation of donor-matched islets and hematopoietic cells durably corrects diabetes without chronic immunosuppression and no appreciable evidence of graft-versus-host disease (GVHD). Donor-derived thymic antigen-presenting cells and host-derived peripheral regulatory T cells are likely mediators of allotolerance. These findings provide the foundation for safer bone marrow conditioning and cell transplantation regimens to establish hematopoietic chimerism and islet allograft tolerance.

Management of early graft candidiasis in a kidney transplant recipient

Balancing adequate immunosuppression with the risk of infection after renal transplantation remains a challenge. The presence of comorbidities adds to the challenge. Although infrequent, invasive fungal infections result in high morbidity and mortality risk in renal transplant recipients. This can be attributed to the intense immunosuppression in the first 6 months after renal transplantation, minimal symptomatology and the high mortality associated with fungal infections.

Due to minimal available evidence, clinical judgement guides management of graft candidiasis. There is a need to develop evidence-based management guidelines for the treatment of fungal infections in renal transplants. Here, we report a case of early-onset candidiasis in a transplanted kidney and present the histological findings, multidisciplinary discussions and treatment given.

Cladophialophora Bantiana Brain Abscess and Concurrent Pulmonary Cryptococcus Neoformans Infection in a Patient Twenty Years After Renal Transplantation

Recipients of solid organ transplants are at risk for a variety of infections due to their immunocompromised status. The types of infections are often correlated to the timing from their transplant. After about six to twelve months, transplant recipients remain at risk for typical community acquired pathogens, late viral infections, and fungal infections including atypical molds such as Cladophialophora bantiana. C. bantiana is a dematiaceous fungus that has a predilection for infecting the brain and is the most common cause of cerebral phaeohyphomycosis - a term used to describe infections caused by molds that produce dark cell walls. Patients with cerebral abscesses due to C. bantiana infections have an estimated mortality of about 70%. Improved outcomes have been seen in patients who receive both surgical and antifungal therapy. While there are no clear guidelines on antifungal therapy, most cases have been treated with combination amphotericin B, a triazole (itraconazole, voriconazole, or posaconazole) with flucytosine sometimes in conjunction as well. This case describes a patient with C. bantiana brain abscess and concurrent Cryptococcus neoformans pulmonary infection that occurred twenty years after his kidney transplantation. He was treated successfully with two craniotomies for cerebral abscess debridement and liposomal amphotericin B followed by planned lifelong voriconazole.

Multiple Post-SARS-COV2 Infectious Complications in Kidney Transplant Recipient

A forty-seven-year-old recipient in late period after kidney transplantation with chronic estimated glomerular filtration rate (eGFR) 30 mL/min/1.73 m2, fully vaccinated against COVID-19 was diagnosed with SARS-CoV-2 infection in November 2021. After an initially mild course of the disease, he developed multiorgan failure requiring periodic respiratory and dialysis therapy. Covid-19 disease was complicated by multiple infections such Clostridioides difficile infection, Streptococcus epidermidis bacteriemia, Klebsiella pneumoniae and Candida glabrata urinary tract disease, cytomegalovirus infection and oral candidiasis. In a short period, he was readmitted to the hospital twice with recurrent Klebsiella pneumoniae urosepsis. One of those hospitalizations was also complicated by another COVID-19 infection that was confirmed with non-reactive neutralizing antibody. Due to severe infections the patient required individualized modification of immunotherapy; however, due to their recurrence it was finally decided to be discontinued. The patient was also reintroduced to hemodialysis therapy and no infections occurred since then.

Outcomes of acute ischemic stroke in kidney transplant recipients: An analysis of US Nationwide inpatient sample

A kidney transplant is often the treatment of choice for end-stage kidney disease, compared with a lifetime on dialysis. Kidney transplant recipients (KTRs) have a reduced risk for new strokes than patients with chronic kidney disease (CKD) G5 treated by dialysis (CKD G5D). However, the benefit of Kidney transplant on post-stroke hospitalization outcomes has not been well studied. This study aimed to evaluate the outcomes of hospitalization after acute ischemic stroke (AIS) in KTRs and patients with CKD G5D. This retrospective study used patient data from the US Nationwide Inpatient Sample database. From 2005 to 2018, patients hospitalized with AIS were classified into 3 groups, including KTRs (n = 1,833), patients with CKD G5D (n = 26,767), and those without CKD (CKD-free, n = 986,945). Patients with CKD G1–G4 or unspecified stage, and graft failure requiring dialysis were excluded. In-hospital mortality, medical complications, transfer to nursing homes, and length of stay (LOS) were compared. Compared to CKD-free group, KTRs had no significant higher risks for in-hospital mortality, transfer to nursing homes, and LOS, but a greater risk for medical complications after adjusting for relevant factors. CKD G5D group had higher risks for in-hospital mortality (adjusted odds ratio (aOR): 2.04, 95% confidence interval (CI): 1.93–2.15), medical complications (aOR: 1.49, 95% CI: 1.45–1.54), and transfer to nursing homes (aOR: 1.10, 95% CI: 1.07–1.13), and a 0.07 day (95% CI: 0.06–0.08) longer LOS than CKD-free group. In conclusion, the outcomes of AIS hospitalization were more favorable in KTRs as compared with CKD G5D. Furthermore, the risks for in-hospital mortality, transfer to long-term care facilities, and LOS were not significantly different between KTRs and CKD-free patients.

Long-term respiratory outcomes following solid organ transplantation in children: A retrospective cohort study

BACKGROUND

Solid-organ transplantation (SOT) has become commonly used in children and is associated with excellent survival rates into adulthood. Data regarding long-term respiratory outcomes following pediatric transplantation are lacking. We aimed to describe the prevalence and nature of respiratory pathology following pediatric heart, kidney, and liver transplant, and identify potential risk factors for respiratory complications.

METHODS

Retrospective review involving all children under active follow-up at the provincial transplant service in British Columbia, Canada, following SOT.

RESULTS

Of 118 children, 33% experienced respiratory complications, increasing to 54% in heart transplant recipients. Chronic or recurrent cough with persistent chest x-ray changes was the most common clinical picture, and most infections were with nonopportunistic organisms typically found in otherwise healthy children. A history of respiratory illness before transplant was significantly associated with risk of posttransplant respiratory complications. Eight percentage8% were diagnosed with bronchiectasis, which was more common in recipients of heart and kidney transplant. Bronchiectasis was associated with recurrent hospital admissions with lower respiratory tract infections, treatment of acute rejection episodes, and treatment with sirolimus.

INTERPRETATION

Respiratory morbidity is common after pediatric SOT, and bronchiectasis rates were disproportionately high in this patient group. We hypothesize that this relates to recurrent infections resulting from iatrogenic immunosuppression. Direct pulmonary toxicity from immunosuppression drugs may also be contributory. A high index of suspicion for respiratory complications is needed following childhood SOT, particularly in those with a history of respiratory disease before transplant, experiencing recurrent or severe respiratory tract infections, or exposed to intensified immunosuppression.

Development of a Bak gene based standard curve for absolute quantification of BK virus in real time quantitative PCR assay and noninvasive diagnosis of BK virus nephropathy in kidney allograft recipients

BACKGROUND

BK virus nephropathy (BKVN) is a frequent and serious post-transplant complication and undermines realization of the full benefits of kidney transplantation. We developed a Bak amplicon-based standard curve for absolute quantification of BKV VP1 mRNA copy number in the real time quantitative PCR (RT-qPCR) assay and investigated the performance characteristics of this novel assay.

METHODS

We determined analytical specificity, sensitivity, and precision of our 73 bp mouse Bak amplicon based standard curve for absolute quantification of BKV VP1 mRNA in RT-qPCR assays. The diagnostic accuracy of the Bak standard curve in the RT-qPCR assay for the noninvasive diagnosis of BKVN in human kidney allograft recipients was investigated by quantification of BKV VP1 mRNA copy number in 192 urine samples matched to 192 kidney allograft biopsies from 155 unique kidney allograft recipients. Intraclass correlation coefficients (ICC) were calculated for the threshold cycles (Ct) and BKV VP1 mRNA copy number observed in the RT-qPCR assay with the Bak standard curve or the BKV standard curve.

RESULTS

Performance characteristics of the Bak amplicon-based RT-qPCR assay were exceptional with a slope of -3.291, Y-intercept of 38.60, R² value of 1.00, efficiency of 101% and error of 0.014. Amplification was specific for the Bak amplicon. Intra assay standard deviation (SD) was 0.08 or less and inter assay SD was 0.11 or less for 31 cycles or less of amplification of the Bak amplicon. Receiver operating characteristic (ROC) curve analysis of BKV VP1 mRNA copy number in 192 biopsy matched urines yielded an area under the ROC of 0.982 (95% CI, 0.964 to 0.999, P < 0.0001) for discriminating patients with BKVN biopsies from patients without BKVN biopsies. The striking identity in the measurement of BKV VP1 mRNA copy numbers in the Bak amplicon-based RT-qPCR assay and in the BKV amplicon-based RT-qPCR assay was shown by an ICC of 1.00 when the Cts were compared, and an ICC of 0.99 when the log₁₀ BKV VP1 mRNA copy numbers were compared.

CONCLUSIONS

Bak standard curve for absolute quantification of BKV VP1 mRNA copy number in the RT-qPCR assay demonstrated high efficiency, short and long-term precision and analytical specificity. BKVN was diagnosed with high accuracy. Our new findings, viewed in the light of our earlier demonstration that absolute quantification of a panel of mRNAs encoding immunoregulatory proteins is feasible with the Bak amplicon-based RT-qPCR assays, suggest that the Bak standard curve could serve as a universal calibrator for absolute quantification of transcripts in RT-qPCR assays and help reduce the workload, costs and eliminate contamination of genes of interest by repeated amplification of gene specific standard curves.

A Systematic Review and Meta-Analysis of Serologic Response following Coronavirus Disease 2019 (COVID-19) Vaccination in Solid Organ Transplant Recipients

Solid organ transplant (SOT) recipients are at greater risk of coronavirus disease 2019 (COVID-19) and have attenuated response to vaccinations. In the present meta-analysis, we aimed to evaluate the serologic response to the COVID-19 vaccine in SOT recipients. A search of electronic databases was conducted to identify SOT studies that reported the serologic response to COVID-19 vaccination. We analyzed 44 observational studies including 6158 SOT recipients. Most studies were on mRNA vaccination (mRNA-1273 or BNT162b2). After a single and two doses of vaccine, serologic response rates were 8.6% (95% CI 6.8-11.0) and 34.2% (95% CI 30.1-38.7), respectively. Compared to controls, response rates were lower after a single and two doses of vaccine (OR 0.0049 [95% CI 0.0021-0.012] and 0.0057 [95% CI 0.0030-0.011], respectively). A third dose improved the rate to 65.6% (95% CI 60.4-70.2), but in a subset of patients who had not achieved a response after two doses, it remained low at 35.7% (95% CI 21.2-53.3). In summary, only a small proportion of SOT recipients achieved serologic response to the COVID-19 mRNA vaccine, and that even the third dose had an insufficient response. Alternative strategies for prophylaxis in SOT patients need to be developed. Key Contribution: In this meta-analysis that included 6158 solid organ transplant recipients, the serologic response to the COVID-19 vaccine was extremely low after one (8.6%) and two doses (34.2%). The third dose of the vaccine improved the rate only to 66%, and in the subset of patients who had not achieved a response after two doses, it remained low at 36%. The results of our study suggest that a significant proportion of solid organ transplant recipients are unable to achieve a sufficient serologic response after completing not only the two series of vaccination but also the third booster dose. There is an urgent need to develop strategies for prophylaxis including modified vaccine schedules or the use of monoclonal antibodies in this vulnerable patient population.

Spectrum of Mucormycosis Before and During COVID-19: Epidemiology, Diagnosis, and Current Therapeutic Interventions

Purpose of Review

More than half a billion people have been infected and 6.2 million killed by the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) since the start of the pandemic in 2019. Systemic glucocorticoids are a double-edged sword, on the one hand, life-saving in treating COVID-19 complications while on the other hand, potentially leading to life-and-limb-threatening opportunistic fungal infections. Mucormycosis (MM) is caused by the mucormycetes family. Although rare, it is characterized by high mortality and significant morbidity. The gross similarities observed with other fungal infections which respond to different treatment regimens have made it all the more imperative to quickly and sensitively diagnose and treat MM. This review discusses the epidemiology of MM before and during the COVID-19 pandemic, associated risk factors, COVID-19-associated MM, diagnosis, and current therapeutic interventions.

Recent Findings

There has been a widespread and worrisome trend of rising in cases of MM, worldwide, but more so in the Indian subcontinent, where it is nicknamed the “black fungus.” This upsurge has picked up the pace ever since the start of the COVID-19 pandemic. Necrosis is secondary to the angio-invasive and pro-thrombotic nature of the mold resulting in extensive lesions presenting mostly as rhino-orbital MM (ROM) and rhino-orbito-cerebral MM (ROCM). Infection is mostly observed in subjects with underlying risk factors such as uncontrolled diabetes, those receiving hematopoietic stem cell transplant, and/or on corticosteroid or immunosuppressive therapy, although it is widely suspected that other factors such as iron and zinc may play a role in the pathogenesis of MM. The “One world one guideline” strategy advocates both prophylactic anti-fungal therapy along with aggressive, prompt, and individualized treatment with anti-fungal drugs such as amphotericin B in addition to vigorous surgical intervention. High-risk groups need particularly rapid diagnosis although empirical anti-fungal therapy may not be delayed. Speeding diagnostic turnaround times are essential to institute early therapy, and there is much scope for newer modalities such as PCR, matrix-assisted laser desorption ionization-time of flight mass spectrometry, and whole-genome sequencing in such endeavors. The results of strict monitoring of blood glucose levels along with rational and limited use of steroids and immunomodulatory drugs have proven to be a significant preventive measure.

Summary

The significant rise in cases of MM worldwide has necessitated viewing each case with a strong index of suspicion. Adoption of rapid diagnostics, early antifungal therapy, and prompt surgical interventions are essential, while high-risk groups need particular focused care which may include prophylactic anti-fungal therapy, limited steroid use, and meticulous control of the underlying disease. Developing quicker and more sensitive diagnostic modalities has great potential to improve the detection and management of MM.