Infection in Organ Transplantation

Immune response against bacterial infection in organ transplant recipients

This comprehensive review delves into the intricate dynamics between the immune system and bacterial infections in organ transplant recipients. Its primary objective is to fill existing knowledge gaps while critically assessing the strengths and weaknesses of current research. The paper accentuates the delicate balance that must be struck between preventing graft rejection through immunosuppression and maintaining robust immunity against bacterial threats. In this context, personalized medicine emerges as a transformative concept, offering the potential to revolutionize clinical outcomes by tailoring immunosuppressive regimens and vaccination strategies to the unique profiles of transplant recipients. By emphasizing the pivotal role of continuous monitoring, the review underscores the necessity for vigilant surveillance of transplant recipients to detect bacterial infections and associated immune responses early, thereby reducing the risk of severe infections and ultimately improving patient outcomes. Furthermore, the study highlights the significance of the host microbiome in shaping immune responses, suggesting that interventions targeting the microbiome hold promise for enhancing bacterial immunity in transplant recipients, both in research and clinical practice. In terms of future research directions, the review advocates for large-scale, longitudinal studies encompassing diverse patient cohorts to provide more comprehensive insights into post-transplant immune responses. It also advocates integrating multi-omics approaches, including genomics, transcriptomics, proteomics, and microbiome data, to understand immune responses and their underlying mechanisms. In conclusion, this review significantly enriches our understanding of immune responses in transplant recipients. It paves the way for more effective and personalized approaches to managing infections in this complex setting.

Safety and Immunogenicity of the mRNA-1273 Coronavirus Disease 2019 Vaccine in Solid Organ Transplant Recipients

BACKGROUND

Solid organ transplant recipients (SOTRs) are at high risk for severe COVID-19.

METHODS

This open-label, phase 3b trial evaluated mRNA-1273 in 137 kidney and 77 liver SOTRs and 20 immunocompetent participants. In part A, SOTRs received three 100-µg doses of mRNA-1273; immunocompetent participants received 2 doses. In part B, an additional 100-µg dose was offered ≥4 months after the primary series. Here, we report interim trial results.

RESULTS

mRNA-1273 was well-tolerated in SOTRs. Four serious adverse events were considered vaccine related by the investigator in 3 SOTRs with preexisting comorbidities. No vaccine-related biopsy-proven organ rejection events or deaths were reported. mRNA-1273 elicited modest neutralizing antibody responses after dose 2 and improved responses after dose 3 in SOTRs. Post-dose 3 responses among liver SOTRs were comparable to post-dose 2 responses in immunocompetent participants. Post-additional dose responses were increased in SOTRs, regardless of primary series vaccination. In liver SOTRs, post-additional dose responses were ∼3-fold higher versus post-dose 2 but lower than immunocompetent participant responses. Most kidney SOTRs received multiple immunosuppressants and had reduced antibody responses versus liver SOTRs.

CONCLUSIONS

mRNA-1273 was well-tolerated, and dose 3 and the additional dose improved antibody responses among SOTRs.

CLINICAL TRIALS REGISTRATION

NCT04860297.

Comparison of Dental Findings with Computed Tomographic and Clinical Examination in Patients with End-Stage Heart Failure

Background: This study aimed to evaluate the diagnostic value of pre-existing computed tomography (CT) examinations for the detection of dental pathologies compared with clinical dental examination in patients with end-stage heart failure. Methods: For this purpose, 59 patients with end-stage heart failure and pre-existing non-dental CT images of the craniofacial region were included. Virtual orthopantomograms (vOPG) were reconstructed. Dental pathologies were analyzed in vOPG and source-CT images. Imaging and clinical findings less than 6 months apart were compared (n = 24). Results: The subjective image quality of vOPG was more often rated as insufficient than CT (66%; 20%; p < 0.01). Depending on examination (CT, vOPG or clinic), between 33% and 92% of the patients could require dental intervention such as treatment of caries and periodontitis or tooth extraction. vOPG led to a higher (80%) prevalence of teeth requiring treatment than CT (39%; p < 0.01). The prevalence of teeth requiring treatment was similar in CT (29%) and clinic (29%; p = 1.00) but higher in vOPG (63%; p < 0.01). CT (stage 3 or 4: 42%) and vOPG (38%) underestimated the stage of periodontitis (clinic: 75%; p < 0.01). Conclusions: In conclusion, available CT images including the craniofacial region from patients with end-stage heart failure may contain valuable information regarding oral health status. The assessability of vOPGs might be insufficient and must be interpreted with caution.

The simultaneous presence of active BK, Epstein Barr, and human cytomegalovirus infection and their correlation by host factors in patients suspected of kidney transplant rejection

AIMS

This study aims to evaluate the presence of EBV, HCMV, and BKV genomic sequences in the plasma samples (active infection/viremia) of kidney transplant recipients suspected of rejection and to investigate host and risk factors related to the activation of these viruses in these patients.

METHODS

In this cross-sectional single-center study, plasma samples were collected from 98 suspected kidney transplant rejection patients at Labafinejad Hospital, Tehran, Iran, between December 2022 and June 2023. Quantitative real-time PCR assays for HCMV, EBV, and BK were performed using GeneProof Real-time PCR kits. ROC curve analysis was used to determine the viral load cutoff point for each virus.

FINDINGS

HCMV active viremia was detected in 18 (18.36%) recipients, EBV active viremia in 7 (7.14%), and BKV active viremia in 5 (5.10%). ROC results indicated viral load cutoff points of 778, 661, and 457 points for HCMV, EBV, and BKV, respectively. The duration of time after transplantation significantly differed between active viremia and no viremia groups (120.5 vs. 46 months, P = 0.014). In the BKV active viremia group, the increase in creatinine compared to baseline creatinine was significantly higher than in the no viremia group (2.7 vs. 0.8, P = 0.017). The odds ratio of HCMV active viremia in patients taking tacrolimus was 2.84 times higher, and the odds of HCMV active viremia in patients taking antithymocyte globulin was 3.01 times higher than in patients not taking these drugs.

CONCLUSION

Rapid and timely diagnosis of viral active infections in kidney transplant patients is crucial for effective disease management and implementation of appropriate treatment strategies. Identifying potential risk factors, including host and treatment-related factors that influence transplantation, can facilitate the development of suitable preventive strategies.

Advances in Virus-Specific T Cell Therapy for Polyomavirus Infections: A Comprehensive Review

Polyomaviruses are a group of small, non-enveloped, double-stranded DNA viruses that can infect various hosts, including humans. BKPyV is known to cause conditions such as human polyomavirus-associated nephropathy (HPyVAN), human polyomavirus-associated hemorrhagic cystitis (HPyVHC), and human polyomavirus-associated urothelial cancer (HPyVUC). JCPyV, on the other hand, is responsible for progressive multifocal leukoencephalopathy (PML), a severe demyelinating disease of the central nervous system. PML primarily affects immunocompromised individuals, including those with HIV, recipients of certain immunosuppressive therapies, and transplant patients. The treatment options for HPyV infections have been limited, but recent developments in virus-specific T cell (VST) therapy have shown promise. While VST therapy has shown promise in treating both BKPyV and JCPyV infections, several challenges remain. These include the time-consuming and costly preparation of VSTs, the need for sophisticated production facilities, and uncertainties regarding the optimal cell type and infusion frequency. To the best of our knowledge, 85 patients with hemorrhagic cystitis, 27 patients with BKPyV viremia, 2 patients with BKPyV nephritis, 14 patients with hemorrhagic cystitis and BKPyV viremia, 32 patients with PML were treated with VST in the literature. The overall response was 82, 33, 35, and 10 complete, partial, non-response, and no-outcome-reported (NA), respectively. In conclusion, this review underscores the importance of VST therapy as a promising treatment approach for polyomavirus infections, emphasizing the need for continued research and clinical trials to refine and expand this innovative immunotherapeutic strategy.

Kidney transplantation and perioperative complications: a prospective cohort study

BACKGROUND

Kidney transplant recipients face complex perioperative challenges due to comorbidities from chronic kidney disease. This study aimed to assess perioperative complications in kidney transplant recipients and evaluate the association between the Charlson Comorbidity Index (CCI) and complication severity using the Clavien-Dindo (CD) classification.

METHODS

A prospective cohort study conducted at a tertiary hospital in South Brazil from September 2020 to March 2022, including 230 adult kidney transplant recipients. Data on demographics, comorbidities, and complications were collected. Complications were categorized using the CD scale, and their relationship with CCI was analyzed using univariate and multivariate Cox regression.

RESULTS

Mean age was 49.2 ± 12.7 years, with 58.7% male recipients. The mean CCI score was 3.65±1.5 points. Intraoperative complications occurred in 10.9% of patients, with notable issues including bleeding and airway difficulties. In the immediate postoperative period, 9.1% required urgent dialysis. In the 30-day follow-up, 57.8% had delayed graft function, 21.7% infections, 11.3% had vascular complications, and the mortality was 1.7%. CCI was not a significant predictor of severe complications; however, congestive heart failure was strongly associated with severe complications (HR = 6.6 95% CI 2.6-6.7, p < 0.001).

CONCLUSIONS

Despite a low overall comorbidity profile, kidney transplant recipients faced significant perioperative challenges. The lack of a significant association between the CCI score and severe complications suggests that traditional risk assessment tools may not fully capture the risks specific to the early postoperative period in kidney transplantation, and future research should focus on developing more refined risk assessment models for chronic kidney disease patients.

Donor-derived infections-Insights from Singapore, Japan, and Thailand

BACKGROUND

Solid organ transplantation (SOT) has expanded significantly in Asia over past few decades. Donor-derived infections (DDIs) remain a significant concern as they may adversely impact transplant outcomes. We aim to review the existing regulatory frameworks, screening protocols, and management practices for DDIs in Asia.

METHODS

We reached out to transplant infectious diseases experts in Asia to provide standardized data on annual SOT numbers, incidence of DDIs, regulatory frameworks, donor and recipient screening protocols, and DDI surveillance measures. We present the data from Singapore, Japan, and Thailand.

RESULTS

Donor screening for HIV, hepatitis B, hepatitis C, and syphilis is mandatory in all countries. Additionally, Japan screens for HTLV-1 antibody due to its endemicity. We also reviewed the protocols for screening and prevention of endemic infections in Asia. Singapore is the only country implementing universal screening for all donors for dengue, Zika, and chikungunya via blood and urine RT-PCR. Strongyloidiasis screening is not routinely done, although some transplant centers empirically give ivermectin prophylaxis to organ recipients. Tuberculosis screening with a donor questionnaire and chest radiograph is common for deceased donors, and some centers do Interferon Gamma Release Assay test for living donors. We also found a significant gap in the surveillance and reporting of potential DDIs in Asia and the overall incidence of DDIs in Asia is unknown and likely underreported.

CONCLUSION

The experiences of Singapore, Japan, and Thailand offer valuable insights into current practices and the unmet needs regarding a DDI registry and call for coordinated efforts to address this critical issue in the region.

Nitrofurantoin as an Add-On to Conventional Prophylaxis for the Treatment of Urinary Tract Infections in Kidney Recipients: A Prospective Cohort Study

Urinary tract infections (UTIs) constitute one of the main complications in kidney recipients, increasing both morbidity and mortality. Due to the resurgence of antimicrobial resistance, new prophylactic approaches are being investigated. Nitrofurantoin is an antibiotic from the nitrofuran group that is effective against several Gram-negative and Gram-positive organisms; hence, there has been a resurgence in its prescription for treating MDR pathogens. Objectives: This study aims to assess the effectiveness of nitrofurantoin as an add-on to conventional therapy (amikacin + ceftriaxone or cefotaxime) for the treatment of urinary tract infections in kidney recipients. Methods: In a prospective cohort study, we included patients who received a kidney in a tertiary-care hospital. According to the intensive care specialist, group 1 patients were treated with the conventional prophylactic treatment plus nitrofurantoin as an add-on. Group 2 patients were treated only with the conventional prophylactic treatment. They were followed-up for 3 months, and the incidence of urinary tract infections was reported. Results: The UTI incidence for group 1 at 3 months was 20.6%, and for group 2, it was 20.0%; no statistical difference between treatments was observed (p = 0.9). The most commonly isolated pathogens were E. coli (28.5) and K. pneumonie (28.5%). The factor most associated with developing a UTI was female gender (aHR: 7.0; 95% IC 2.3-20.9, p < 0.001). Conclusions: In our cohort study, nitrofurantoin as an add-on in conventional therapy did not prove to be effective in preventing UTI development; therefore, other treatment options should be considered as a part of prophylactic treatment.

Defining the Landscape of Educational Experiences in Transplant Infectious Diseases: A National Survey of Infectious Diseases Fellows in the United States

Background

Transplant infectious diseases (TID) is a growing area of expertise within infectious diseases (ID), but TID training is not standardized. Previous surveys of fellows identified opportunities to improve TID education resources but did not explore didactic, clinical, and nonclinical experiences comprehensively.

Methods

The American Society of Transplantation ID Community of Practice surveyed adult and pediatric fellows in US-based general ID or dedicated TID training programs to explore their didactic exposure, clinical experiences, and non-direct patient care activities in TID.

Results

A total of 234 fellows initiated the survey, and 195 (83%) (190 general ID and 19 TID fellows, including 125 adult, 76 pediatric, and 8 combined adult-pediatric fellows) completed the entire survey. More than half of the fellows described receiving no formal curricular content on most foundational topics in transplant medicine. Almost all respondents (>90%) had some inpatient TID experience, but for >60% of fellows this was <12 weeks annually. Clinical exposure varied by fellow and patient type-in an average month rotating on an inpatient TID service, more than half of adult fellows had evaluated ≥10 kidney, liver, or hematopoietic stem cell transplant recipients but <10 heart, lung, pancreas, or intestinal recipients; pediatric fellows saw <10 of all patient types. Nearly half (46%) of general ID fellows had not spent any time in the dedicated TID clinic at their program. Few fellows had participated in protocol development, organ selection meetings, or donor evaluations.

Conclusions

This survey highlights important gaps in TID training. Given the increasing need for TID specialists, updated curricula and educational resources are needed.

Posttransplant complications: molecular mechanisms and therapeutic interventions

Posttransplantation complications pose a major challenge to the long-term survival and quality of life of organ transplant recipients. These complications encompass immune-mediated complications, infectious complications, metabolic complications, and malignancies, with each type influenced by various risk factors and pathological mechanisms. The molecular mechanisms underlying posttransplantation complications involve a complex interplay of immunological, metabolic, and oncogenic processes, including innate and adaptive immune activation, immunosuppressant side effects, and viral reactivation. Here, we provide a comprehensive overview of the clinical features, risk factors, and molecular mechanisms of major posttransplantation complications. We systematically summarize the current understanding of the immunological basis of allograft rejection and graft-versus-host disease, the metabolic dysregulation associated with immunosuppressive agents, and the role of oncogenic viruses in posttransplantation malignancies. Furthermore, we discuss potential prevention and intervention strategies based on these mechanistic insights, highlighting the importance of optimizing immunosuppressive regimens, enhancing infection prophylaxis, and implementing targeted therapies. We also emphasize the need for future research to develop individualized complication control strategies under the guidance of precision medicine, ultimately improving the prognosis and quality of life of transplant recipients.

Antibiotic Use in the Surgical Intensive Care Unit

Judicious use of antibiotics in the critically ill starts with the evaluation for suspected infection, including close consideration of the patient's history. If infection is present or strongly suspected, empiric antibiotics should be promptly initiated and selected based on the source of infection, patient factors, and local resistance patterns. If the surgeon decides source control is indicated, they must determine the optimal approach and timing. As soon as culture and sensitivity data are available, de-escalation to narrower spectrum agents is essential to decrease the risks of antibiotic toxicity and resistance. Importantly, surgeons should participate in antibiotic stewardship in their patients.

Epidemiology of Campylobacter Species Infection in Kidney Transplant Recipients: A Retrospective Multicentric Case-Control Study in France

Background

Campylobacteriosis in kidney transplant recipients (KTRs) is the most common identified bacterial cause of diarrhea. Risk factors in KTRs are unknown.

Methods

A 10-year multicentric, retrospective 1:1 case-control study was performed in France between 2010 and 2020. The main aim was to identify factors associated with Campylobacter-related infection in KTRs. The KTRs with a functional graft and campylobacteriosis (positive stool culture and/or blood culture and/or positive nucleic amplification test) and their controls matched on transplantation date within the same center were included.

Results

We identified 326 patients with campylobacteriosis. The estimated incidence rate of campylobacteriosis was 2.3/1000 patient-years. The infection occurred at a median of 2.4 years posttransplantation. The independent risk factors for campylobacteriosis were use of corticosteroids as maintenance regimen (75.8% vs 66%; P < .001), acute rejection (8.9% vs 4%; P = .048), low lymphocyte count (0.96 vs 1.4 giga/liter (G/L); P < .001), and low basal estimated glomerular filtration rate (eGFR) (44.2 vs 57.5 mL/minute/1.73 m2; P < .001). A fluoroquinolone was initiated in 64 (21.4%) patients, with 51.1% of antimicrobial resistance, whereas almost all strains were erythromycin sensitive.

Conclusions

Campylobacteriosis has a higher incidence in the 2 first years of transplantation. The factors independently associated with campylobacteriosis are corticosteroids as maintenance immunosuppressive regimen, low lymphocyte counts, low eGFR, and a history of acute rejection. Due to high antimicrobial resistance with fluoroquinolone, the first line of treatment should be azithromycin.

Microbiome composition recovery after liver transplantation correlates with initial liver disease severity and antibiotics treatment

Liver transplantation (LT) is crucial for end-stage liver disease, but it is linked to infection risks. Pathobionts, microorganisms potentially harmful under specific conditions, can cause complications posttransplant. Monitoring such pathogens in fecal samples can be challenging and therefore remains underexplored post-LT. This study aimed to analyze the gut microbiome before and after LT, tracking pathobionts and correlating clinical data. The study involved 17 liver transplant recipients, 17 healthy relatives (spouses), and 13 donors. Gut samples collected pretranplantation and posttransplantation underwent bacterial and fungal profiling through DNA sequencing. Quantitative polymerase chain reaction was used to assess microbial load. Statistical analyses included alpha and beta diversity measures, differential abundance analysis, and correlation tests between microbiome and clinical parameters. Microbiome analysis revealed dynamic changes in diversity posttransplant. Notably, high-severity patients showed persistent and greater dysbiosis during the first months post-LT compared with low-severity patients, partly due to an antibiotic treatment pre-LT. The analysis identified a higher proportion of pathogens such as Escherichia coli/Shigella flexneri in high-severity cases posttransplant. Furthermore, butyrate producers including Roseburia intestinalis, Anaerostipes hadrus, and Eubacterium coprostanoligenes were positively correlated with levels of albumin. This study offers valuable insights into post-LT microbiome changes, shedding light on the need for tailored prophylactic treatment post-LT.

The impact of cadaveric donor transplant on the development of chronic rhinosinusitis and recalcitrant disease

KEY POINTS

The study found a higher incidence of chronic rhinosinusitis (CRS) and recalcitrant CRS in cadaveric organ transplant recipients compared to those receiving living donor transplants. Recipients of cadaveric transplants were 1.32 times more likely to develop CRS and 1.68 times more likely to develop medically recalcitrant CRS. Living kidney transplants significantly reduced the risk of developing CRS (OR = 0.12) and recalcitrant CRS (OR = 0.11), highlighting a potentially protective effect against these conditions. In contrast, cadaveric liver transplants were associated with an increased risk of CRS and medically recalcitrant CRS. Kaplan-Meier survival analysis indicated a significant difference in time to CRS onset between cadaveric and living donor transplants. Median time to CRS onset was longer for living donor recipients (21.1 months) compared to cadaveric recipients (15.6 months). This study underscores the need for transplant teams and otolaryngologist to consider donor type during transplant follow-up due to differing risks of CRS development.

Causality between herpes virus infections and allograft dysfunction after tissue and organ transplantation: a two-sample bidirectional Mendelian randomization study

Background

Observational studies have suggested that herpes virus infections increase the risk of allograft dysfunction after tissue and organ transplantation, but it is still unclear whether this association is causal. The aim of this study was to assess the causal relationship between four herpes virus infections and allograft dysfunction.

Methods

We used two-sample bidirectional Mendelian randomization (MR) to investigate the causality between four herpes virus infections - cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV) and varicella zoster virus (VZV) - and allograft dysfunction after tissue and organ transplantation. Based on summary data extracted from genome-wide association studies (GWAS), we chose eligible single nucleotide polymorphisms (SNPs) as instrumental variables. The Inverse variance weighted (IVW) method was used as the main analysis method, supplemented by Weighted median and MR-Egger analyses. The MR-PRESSO test, MR-Egger intercept test, heterogeneity test, leave-one-out analysis and funnel plot were used to analyze the sensitivity of MR results.

Results

We found EBV early antigen-D (EA-D) antibody levels and shingles were the only two variables associated with an increased risk of allograft dysfunction. No evidence of allograft dysfunction increasing the risk of the four herpes virus infections was observed. Sensitivity analyses confirmed the robustness of our results.

Conclusions

Our results suggest that EBV and VZV are involved in graft rejection or dysfunction. However, the relationship between CMV and HSV infections and allograft dysfunction remains unclear and requires further clarification.

Intensive care of a patient undergoing combined multi-organ cluster ("larynx-trachea-thyroid-hypopharynx-esophagus") transplantation: A case report

OBJECTIVE

The aim of this study was to summarize the intensive care experience of a patient undergoing combined multi-organ cluster ("larynx-trachea-thyroid-hypopharynx-esophagus") transplantation.

METHODS

The intensive care management plan for this case was developed by a multidisciplinary team, with focus on 6 aspects: (1) stabilizing the circulation and reducing anastomotic tension by position management to improve the survival chances of transplanted organs, (2) adopting goal-directed analgesia and sedation protocols, as well as preventing anastomotic fistula, (3) implementing a bedside ultrasound-guided nutrition plan, (4) employing "body-mind" synchronous rehabilitation to facilitate functional recovery, (5) taking antirejection treatment and protective isolation measures, (6) monitoring and nursing thyroid function.

RESULTS

During the intensive care, the patient's vital signs were stable. The patient was successfully weaned from the ventilator and transferred to the general ward for further treatment at 9 days postoperatively, and discharged upon recovery at 58 days postoperatively. The patient was in good condition during follow-up.

CONCLUSION

This study provides reference for the care of patients who undergo similar transplantation in the future.

Pulmonary Nocardiosis in Renal Transplant Recipients From Pakistan: Risk Factors, Clinical Presentation, and Mortality

OBJECTIVES

Nocardia is an opportunistic infection among renal transplant recipients with an incidence of <1% but high mortality. Data from Pakistan are scarce. Our aim was to find the risk factors, clinical and radiographic findings, antimicrobial sensitivity, and outcomes of Nocardia infection among renal transplant recipients in Pakistan.

MATERIALS AND METHODS

All adult renal transplant recipients diagnosed with nocardiosis between 2013 and 2020 were included. The cases were matched 1:2 with controls based on sex, age (±1 year), and transplant date (±1 year). Risk factors, clinical features, antibiotic sensitivities and outcomes were analyzed.

RESULTS

A total of 48 patients developed nocardiosis. Around 25% of patients presented with disseminated disease. Median time from transplant to disease development was 2.68 years. High-dose methylprednisolone and presence of cytomegalovirus infection within 90 days of disease development were independent risk factors for Nocardia infection. The mortality rate was 20%. Central nervous system disease and cytomegalovirus infection within 90 days were significantly associated with mortality. The most susceptible drugs were co-trimoxazole and linezolid. Imipenem susceptibility was only 20%.

CONCLUSIONS

High-dose methylprednisolone and cytomegalovirus infection were independent risk factors for Nocardia infection. Central nervous system disease was associated with mortality. Nocardia species were highly resistant to ceftriaxone and imipenem in our patient population.

Guidelines for Antibiotics Prescription in Critically Ill Patients

How to cite this article: Khilnani GC, Tiwari P, Mittal S, Kulkarni AP, Chaudhry D, Zirpe KG, et al. Guidelines for Antibiotics Prescription in Critically Ill Patients. Indian J Crit Care Med 2024;28(S2):S104-S216.

Hospitalizations for opportunistic infections following transplantation and associated risk factors: A national cohort study of Medicare beneficiaries

BACKGROUND

Opportunistic infections (OIs) are a significant cause of morbidity and mortality after organ transplantation, though data in the liver transplant (LT) population are limited.

METHODS

We performed a retrospective cohort study of LT recipients between January 1, 2007 and Deceber 31, 2016 using Medicare claims data linked to the Organ Procurement and Transplantation Network database. Multivariable Cox regression models evaluated factors independently associated with hospitalizations for early (≤1 year post transplant) and late (>1 year) OIs, with a particular focus on immunosuppression.

RESULTS

There were 11 320 LT recipients included in the study, of which 13.2% had at least one OI hospitalization during follow-up. Of the 2638 OI hospitalizations, 61.9% were early post-LT. Cytomegalovirus was the most common OI (45.4% overall), although relative frequency decreased after the first year (25.3%). Neither induction or maintenance immunosuppression were associated with early OI hospitalization (all p > .05). The highest risk of early OI was seen with primary sclerosing cholangitis (aHR 1.74; p = .003 overall). Steroid-based and mechanistic target of rapamycin inhibitor-based immunosuppression at 1 year post LT were independently associated with increased late OI (p < .001 overall).

CONCLUSION

This study found OI hospitalizations to be relatively common among LT recipients and frequently occur later than previously reported. Immunosuppression regimen may be an important modifiable risk factor for late OIs.

Clinical approach to donor-derived infection in solid organ transplant recipients

Donor-derived infection is an uncommon but potentially devastating complication of solid organ transplantation (SOT). Accurate and timely identification of unexpected infectious disease transmission events has implications not only for the recipient(s) experiencing infection, but also other recipients of organs or tissues from the same donor who may require additional testing or risk mitigation, as well as the broader organ transplant regulatory framework. This narrative review synthesizes data from published reports of symptomatic unexpected donor-derived infections in SOT recipients to provide clinicians with a systematic approach to the evaluation of undifferentiated illnesses that may be of donor origin. Key reasons to consider donor-derived infection include certain microbiologically proven infections in the recipient, especially early after transplant, characteristics of the donor or their management that suggest potential exposure to or infection with specific pathogens prior to organ procurement, and select clinical syndromes that occur in the post-transplant period. Syndromes for which expedited consideration and evaluation of donor-derived infection may be warranted include central nervous system infection, graft or perigraft complications developing in the absence of typical risk factors, and unexplained critical illness/sepsis syndrome in the early post-transplant period. When embarking on an investigation of a suspected donor-derived infection, clinicians should apply knowledge of the entire continuum of the organ procurement and transplant process to ensure unbiased and comprehensive data collection that will facilitate appropriate adjudication of these uncommon but high-consequence events.

Elucidating the nexus between onco-immunology and kidney transplantation: An insight from precision medicine perspective

The interplay of onco-immunology and kidney transplantation heralds a transformative era in medical science. This integration, while promising, presents significant challenges. Chief among these is the dichotomy of immunosuppression-boosting immunity against malignancies while suppressing it for graft survival. Additionally, limited clinical data on novel therapies, genetic variations influencing responses, economic concerns, and the narrow therapeutic window for post-transplant malignancies necessitate strategic addressal. Conversely, opportunities abound, including personalized immune monitoring, targeted therapies, minimized immunosuppression, and improved patient quality of life. Emphasizing collaborative research and interdisciplinary cooperation, the merging of these fields offers the potential for enhanced graft survival and reduced post-transplant malignancy risks. As we harness modern technology and promote patient-centric care, the vision for the future of kidney transplantation becomes increasingly hopeful, paving the way for more personalized and effective treatments. The article aims to elucidate the critical challenge of balancing immunosuppression to simultaneously combat malignancies and ensure graft survival. It addresses the scarcity of clinical data on novel therapies, the impact of genetic variations on treatment responses, and the economic and therapeutic concerns in managing post-transplant malignancies. Furthermore, it explores the opportunities precision medicine offers, such as personalized immune monitoring, targeted therapies, and reduced immunosuppression, which could significantly improve patient outcomes. Highlighting the importance of collaborative research and interdisciplinary efforts, the article seeks to demonstrate the potential for enhanced graft survival and reduced post-transplant malignancy risks. By leveraging modern technology and prioritizing patient-centric care, it envisions a future where kidney transplantation is more personalized and effective, offering hope for advancements in this field.

Neutrophilic Myocarditis: Insights from a Forensic Centre's Retrospective Study

BACKGROUND

Neutrophilic myocarditis often stems from bacterial or fungal infections, and it is typically detectable through blood cultures or analyses of the primary infection site. However, research specifically addressing the morphological features of acute myocarditis in complex sepsis cases is scarce, with existing studies primarily dating back to the pre-antibiotic era.

METHODS

This study constitutes a retrospective and descriptive analysis encompassing 22 forensic cases. We collected data from forensic reports emphasising clinical details, disease history, gross observations, and histopathological findings.

RESULTS

The results show that using positive-air-pressure ventilation could be related to cardiac inflammation (45.45%, 10/22). Despite large-spectrum antibiotic therapy, the blood samples were positive for Staphylococcus aureus (MRSA strain), Klebsiella pneumoniae (ESBL strain), Acinetobacter baumannii, and Pseudomonas aeruginosa. Colonies developed in the myocardium of 36% of the patients (8/22), where 4 of them had septic emboli. Fungal myocarditis accompanied bacterial infections (2/8) and were unsuspected clinically. Background changes, such as interstitial fibrosis and arteriosclerosis, were associated with a greater degree of inflammation and septic embolism.

CONCLUSION

Neutrophilic myocarditis in patients with emerging sepsis is linked to fatal virulent infections, where bacteria and/or fungi contaminate and impair the myocardium syncytium. Prolonged hospitalisation and positive-air-pressure ventilation may be a risk factor for this condition and needs further research.

The bacterial and fungal profiles of patients hospitalized with non-COVID-19 lower respiratory tract infections in Wuhan, China, 2019-2021

AIMS

A severe lockdown occurred in Wuhan during the COVID-19 pandemic, followed by a remission phase in the pandemic's aftermath. This study analyzed the bacterial and fungal profiles of respiratory pathogens in patients hospitalized with non-COVID-19 lower respiratory tract infections (LRTIs) during this period to determine the pathogen profile distributions in different age groups and hospital departments in Wuhan.

METHODS AND RESULTS

We collected reports of pathogen testing in the medical records of patients hospitalized with non-COVID-19 LRTI between 2019 and 2021. These cases were tested for bacterial and fungal pathogens using 16S and internal transcribed spacer sequencing methods on bronchoalveolar lavage fluid samples. The study included 1368 cases. The bacteria most commonly identified were Streptococcus pneumoniae (12.50%) and Mycoplasma pneumoniae (8.33%). The most commonly identified fungi were Aspergillus fumigatus (2.49%) and Pneumocystis jirovecii (1.75%). Compared to 2019, the S. pneumoniae detection rates increased significantly in 2021, and those of M. pneumoniae decreased. Streptococcus pneumoniae was detected mainly in children. The detection rates of almost all fungi were greater in the respiratory Intensive Care Unit compared to respiratory medicine. Streptococcus pneumoniae and M. pneumoniae were detected more frequently in the pediatric department.

CONCLUSIONS

Before and after the COVID-19 outbreak, a change in the common pathogen spectrum was detected in patients with non-COVID-19 in Wuhan, with the greatest change occurring among children. The major pathogens varied by the patient's age and the hospital department.

Macrophage-Biomimetic Nanoplatform-Based Therapy for Inflammation-Associated Diseases

Inflammation-associated diseases are very common clinically with a high incidence; however, there is still a lack of effective treatments. Cell-biomimetic nanoplatforms have led to many breakthroughs in the field of biomedicine, significantly improving the efficiency of drug delivery and its therapeutic implications especially for inflammation-associated diseases. Macrophages are an important component of immune cells and play a critical role in the occurrence and progression of inflammation-associated diseases while simultaneously maintaining homeostasis and modulating immune responses. Therefore, macrophage-biomimetic nanoplatforms not only inherit the functions of macrophages including the inflammation tropism effect for targeted delivery of drugs and the neutralization effect of pro-inflammatory cytokines and toxins via membrane surface receptors or proteins, but also maintain the functions of the inner nanoparticles. Macrophage-biomimetic nanoplatforms are shown to have remarkable therapeutic efficacy and excellent application potential in inflammation-associated diseases. In this review, inflammation-associated diseases, the physiological functions of macrophages, and the classification and construction of macrophage-biomimetic nanoplatforms are first introduced. Next, the latest applications of different macrophage-biomimetic nanoplatforms for the treatment of inflammation-associated diseases are summarized. Finally, challenges and opportunities for future biomedical applications are discussed. It is hoped that the review will provide new ideas for the further development of macrophage-biomimetic nanoplatforms.

Developing a genetic testing panel for evaluation of morbidities in kidney transplant recipients

Cardiovascular disease, infection, malignancy, and thromboembolism are major causes of morbidity and mortality in kidney transplant recipients (KTR). Prospectively identifying monogenic conditions associated with post-transplant complications may enable personalized management. Therefore, we developed a transplant morbidity panel (355 genes) associated with major post-transplant complications including cardiometabolic disorders, immunodeficiency, malignancy, and thrombophilia. This gene panel was then evaluated using exome sequencing data from 1590 KTR. Additionally, genes associated with monogenic kidney and genitourinary disorders along with American College of Medical Genetics (ACMG) secondary findings v3.2 were annotated. Altogether, diagnostic variants in 37 genes associated with Mendelian kidney and genitourinary disorders were detected in 9.9% (158/1590) of KTR; 25.9% (41/158) had not been clinically diagnosed. Moreover, the transplant morbidity gene panel detected diagnostic variants for 56 monogenic disorders in 9.1% KTRs (144/1590). Cardiovascular disease, malignancy, immunodeficiency, and thrombophilia variants were detected in 5.1% (81), 2.1% (34), 1.8% (29) and 0.2% (3) among 1590 KTRs, respectively. Concordant phenotypes were present in half of these cases. Reviewing implications for transplant care, these genetic findings would have allowed physicians to set specific risk factor targets in 6.3% (9/144), arrange intensive surveillance in 97.2% (140/144), utilize preventive measures in 13.2% (19/144), guide disease-specific therapy in 63.9% (92/144), initiate specialty referral in 90.3% (130/144) and alter immunosuppression in 56.9% (82/144). Thus, beyond diagnostic testing for kidney disorders, sequence annotation identified monogenic disorders associated with common post-transplant complications in 9.1% of KTR, with important clinical implications. Incorporating genetic diagnostics for transplant morbidities would enable personalized management in pre- and post-transplant care.

A Digital Approach to Improve Infection Screening Among Solid Organ Transplant Candidates

BACKGROUND

Pretransplant infection screening (IS) of potential organ recipients is essential to optimal outcome of solid organ transplantation (SOT).

METHODS

A pre-post study was performed during 2020-2023 to investigate the impact of the STREAM (Solid organ TRansplant stEwArdship and Multidisciplinary approach) intervention to improve IS in SOT. The intervention, performed in 2022, included the implementation of IS through educational meetings, local guidelines, and the availability of a digital screening tool. The objective of the study was the assessment of IS completion, including a list of 17 laboratory tests and the investigation of vaccination status. The reduction of unnecessary tests was also analyzed. The test of proportions and a multilevel multivariate Poisson regression model were used to compare IS completion before and after STREAM. infectious diseases (ID) consultation and urgent evaluation were investigated as predictors of IS completion.

RESULTS

A total of 171 patients were enrolled, including liver (44%), heart (32%), and kidney (24%) transplant candidates. Mean age was 56 ± 11 years, and most patients (77%) were males. Ninety-five (56%) patients were included before the intervention and 76 (44%) after STREAM. IS completion increased after STREAM (IRR 1.41, p < 0.001) with significant improvement recorded for seven (39%) IS items. Unnecessary tests decreased by 43% after the intervention. ID consultation (IRR 1.13, p = 0.02) and urgent evaluation (p = 0.68, p < 0.001) were predictors of IS improvement.

CONCLUSIONS

STREAM was successful in improving IS completion. Further research is needed to investigate the impact of this intervention on posttransplant infections.

Fatal Infections Differentially Involve Allograft and Native Lungs in Single Lung Transplant Recipients

CONTEXT.—

Respiratory infections complicate lung transplantation and increase the risk of allograft dysfunction. Allograft lungs may have different susceptibilities to infection than native lungs, potentially leading to different disease severity in lungs of single lung transplant recipients (SLTRs).

OBJECTIVE.—

To study whether infections affect allograft and native lungs differently in SLTRs but similarly in double LTRs (DLTRs).

DESIGN.—

Using an institutional database of LTRs, medical records were searched, chest computed tomography studies were systematically reviewed, and histopathologic features were recorded per lung lobe and graded semiquantitatively. A multilobar-histopathology score (MLHS) including histopathologic data from each lung and a bilateral ratio (MLHSratio) comparing histopathologies between both lungs were calculated in SLTRs and compared to DLTRs.

RESULTS.—

Six SLTRs died of infection involving the lungs. All allografts showed multifocal histopathologic evidence of infection, but at least 1 lobe of the native lung was uninvolved. In 4 of 5 DLTRs, histopathologic evidence of infection was seen in all lung lobes. On computed tomography, multifocal ground-glass and/or nodular opacities were found in a bilateral distribution in all DLTRs but in only 2 of 6 SLTRs. In SLTRs, the MLHSAllograft was higher than MLHSNative (P = .02). The MLHSratio values of SLTR and DLTR were significantly different (P < .001).

CONCLUSIONS.—

Allograft and native lungs appear to harbor different susceptibilities to infections. The results are important for the management of LTRs.

Combined Metagenomic Viral Detection and Donor-Derived Cell-Free DNA Quantification in Plasma From Kidney Transplant Recipients

BACKGROUND

Kidney transplant recipients require potent immunosuppression and are predisposed to opportunistic infections, many of which have a viral etiology. Currently, viral assays detect and quantify single pathogens using PCR or qPCR. An unbiased sequencing method with comparable accuracy would allow simultaneous monitoring of multiple viral pathogens and nonpathogenic Anelloviridae. The quantification of donor-derived cell-free DNA (dd-cfDNA) is an established method for the detection of allograft rejection, and a single workflow combining dd-cfDNA quantification and viral detection represents an opportunity to improve patient monitoring and management.

METHODS

Whole genome sequencing of cell-free DNA was performed using 1,980 plasma samples from 256 subjects enrolled in a multi-center study. Non-human sequences underwent reference-assisted assembly and taxonomic annotation of the viral DNA pathogens.

RESULTS

Of the 1,980 samples tested, 1,453 (73.4%) had ≥1 viral detection(s), either a known viral pathogen or torque teno virus (TTV), with positivity rates generally declining 12-18 months post-transplant. Concordance of metagenomic NGS (mNGS) viral detection with qPCR detection was 97.7% (94.1% sensitivity, 98.2% specificity), and a linear relationship was demonstrated between mNGS viral quantitation and qPCR results. BK virus, cytomegalovirus, and Epstein-Barr virus were detected by sequencing up to 60 days prior to independently established clinical diagnoses.

CONCLUSIONS

Whole-genome sequencing allows simultaneous quantification of dd-cfDNA as well as sensitive and early detection of viral infection through secondary analysis of the same sequencing results. In combination with dd-cfDNA, mNGS viral detection may provide additional pathogen surveillance results and serve as a useful biomarker for both over- and under-immunosuppression.

Screening for tropical and imported infections in migrant kidney transplant candidates from the kidney transplant access consultation

BACKGROUND AND OBJECTIVE

Kidney transplantation (KT) should be postponed in those people with active bacterial, fungal, viral and parasitic processes, since these must be treated and resolved previously. The objective of this study is to present the screening circuit implemented by the Nephrology clinic and describe the prevalence of tropical and imported infections in KT candidates born or coming from endemic areas.

MATERIALS AND METHODS

Descriptive cross-sectional study, carried out in 2021. Sociodemographic and clinical variables, serological data of general infections and specific tests of tropical infectious diseases were collected. A descriptive analysis of the data was carried out.

RESULTS

67 TR candidates from Latin America (32.8%), North Africa (22.4%), Sub-Saharan Africa (14.9%) and Asia (29.9%) were included. 68.7% were men and the mean age was 48.9 ± 13.5 years. After the general and specific studies, 42 (62.7%) patients were referred to the Infectious Diseases Service to complete this study or indicate treatment. 35.8% of the patients had eosinophilia, and in one case parasites were detected in feces at the time of the study. Serology for strongyloidiasis was positive in 18 (26.9%) cases, while positive serology for other tropical infections was hardly detected. 34.3% of patients had latent tuberculosis infection.

CONCLUSIONS

The prevalence of tropical and imported infections in migrant candidates for RT was low, except for strongyloidiasis and latent tuberculosis infection. Its detection and treatment are essential to avoid serious complications in post-TR. To this end, the implementation of an interdisciplinary screening program from the KT access consultation is feasible, necessary and useful.

Infectious Diseases and Clinical Xenotransplantation

Xenotransplantation, transplantation into humans of vascularized organs or viable cells from nonhuman species, is a potential solution to shortages of transplantable human organs. Among challenges to application of clinical xenotransplantation are unknown risks of transmission of animal microbes to immunosuppressed recipients or the community. Experience in allotransplantation and in preclinical models suggests that viral infections are the greatest concern. Worldwide, the distribution of swine pathogens is heterogeneous and cannot be fully controlled by international agricultural regulations. It is possible to screen source animals for potential human pathogens before procuring organs in a manner not possible within the time available for surveillance testing in allotransplantation. Infection control measures require microbiological assays for surveillance of source animals and xenograft recipients and research into zoonotic potential of porcine organisms. Available data suggest that infectious risks of xenotransplantation are manageable and that clinical trials can advance with appropriate protocols for microbiological monitoring of source animals and recipients.

Modulation of allograft immune responses by Porphyromonas gingivalis lipopolysaccharide administration in a rat model of kidney transplantation

Periodontitis is a chronic inflammatory disease that affects the periodontal tissues. Although it is associated with various systemic diseases, the impact of periodontitis on kidney transplantation (KT) outcomes, particularly allograft rejection, remains unclear. This study investigated the effect of periodontitis on transplant immunity, specifically examining Porphyromonas gingivalis-derived lipopolysaccharide (LPS-PG). In vitro experiments revealed that LPS-PG increased regulatory T cells (Tregs) in Lewis rat spleen cells. In a mixed lymphocyte reaction assay, concentrations of interferon-γ, indicative of alloreactivity, were lower than in controls when LPS-PG was added to the culture and when LPS-PG-administered Lewis rat spleen cells were used as responders. In a rat KT model, LPS-PG administration to recipients promoted mild tubulitis and low serum creatinine and blood urea nitrogen levels 5 days post-KT compared with PBS-administered controls. Furthermore, LPS-PG-administered recipients had an elevated Treg proportion in their peripheral blood and spleen cells, and increased infiltrating Tregs in kidney allografts, compared with controls. The elevated Treg proportion in peripheral blood and spleen cells had a significant negative correlation with serum creatinine, suggesting elevated Tregs modulated allograft rejection. These findings suggest that periodontitis might modulate alloimmune reactivity through LPS-PG and Tregs, offering insights to refine immunosuppressive strategies for KT recipients.

Ewingella americana Infections in Humans-A Narrative Review

Ewingella americana is a Gram-negative rod that belongs to the order Enterobacterales and the family Yersiniaceae and was first identified in 1983 from 10 clinical strains in the United States of America. The present study aimed to identify all the published cases of E. americana in the literature, describe the epidemiological, clinical, and microbiological characteristics, and provide data regarding its antimicrobial resistance, treatment, and outcomes. A narrative review was performed based on a PubMed and Scopus databases search. In total, 16 studies provided data on 19 patients with infections by E. americana. The median age of the patients was 55 years, and 47.4% were male. The most common infections were those of the bloodstream, the respiratory tract, and the peritoneal cavity. Antimicrobial resistance to cephalosporins, aminoglycosides, and the combination of trimethoprim with sulfamethoxazole was minimal, and these were the most commonly used antimicrobials for treating these infections. No included study provided information on the genetic or molecular mechanism of this pathogen's antimicrobial resistance. The overall mortality was minimal, with only one patient with bacteremia succumbing to the infection. Further studies are needed to better understand this microorganism, its pathogenic potential in humans, and the genetic and molecular mechanisms underlying its antimicrobial resistance, for which very little evidence exists to date.

Assessing the impact of positive cultures in preservation fluid on renal transplant outcomes: a scoping review

BACKGROUND

Infection following kidney transplantation is a significant risk factor for adverse outcomes. While the donor may be a source of infection, microbiological assessment of the preservation fluid (PF) can mitigate potential recipient contamination and help curb unnecessary antibiotic use. This scoping review aimed to describe the available literature on the association between culture-positive preservation fluid, its clinically relevant outcomes, and management.

METHODS

Following the Joanna Briggs Institute's scoping review recommendations, a comprehensive search in databases (EMBASE, MEDLINE, and gray literature) was conducted, with data independently extracted by two researchers from selected studies.

RESULTS

We analysed 24 articles involving 12,052 samples, predominantly published post-2000, 91% of which retrospective. The prevalence of culture-positive preservation fluid varied from 0.86 to 77.8%. Coagulase-negative staphylococci emerged as the most frequently isolated pathogen in 14 studies. The presence of ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species), observed in two studies involving 1074 donors, was significantly associated with an increased risk of probable donor-derived infections (p-DDI). Of the reviewed articles, 14 reported on probable donor-derived infections, while 19 addressed the topic of preemptive antibiotic therapy.

CONCLUSIONS

Routine culturing of preservation fluid is crucial for the identification of pathogenic organisms, facilitates targeted treatment and prevents probable donor-derived infections. Furthermore, this approach helps avoid the treatment of low-virulence contaminants, thereby reducing unnecessary antimicrobial use and the risk of antibiotic resistance. In cases where ESKAPE or Candida species are detected, preemptive therapy appears to be an important strategy. Given that the current evidence primarily stems from retrospective studies, there is a pressing need for large-scale, prospective trials to corroborate these recommendations. This scoping review currently represents the most thorough compilation of evidence on how contamination of preservation fluids affects kidney transplant management.

D-SPIN constructs gene regulatory network models from multiplexed scRNA-seq data revealing organizing principles of cellular perturbation response

Gene regulatory networks within cells modulate the expression of the genome in response to signals and changing environmental conditions. Reconstructions of gene regulatory networks can reveal the information processing and control principles used by cells to maintain homeostasis and execute cell-state transitions. Here, we introduce a computational framework, D-SPIN, that generates quantitative models of gene regulatory networks from single-cell mRNA-seq datasets collected across thousands of distinct perturbation conditions. D-SPIN models the cell as a collection of interacting gene-expression programs, and constructs a probabilistic model to infer regulatory interactions between gene-expression programs and external perturbations. Using large Perturb-seq and drug-response datasets, we demonstrate that D-SPIN models reveal the organization of cellular pathways, sub-functions of macromolecular complexes, and the logic of cellular regulation of transcription, translation, metabolism, and protein degradation in response to gene knockdown perturbations. D-SPIN can also be applied to dissect drug response mechanisms in heterogeneous cell populations, elucidating how combinations of immunomodulatory drugs can induce novel cell states through additive recruitment of gene expression programs. D-SPIN provides a computational framework for constructing interpretable models of gene-regulatory networks to reveal principles of cellular information processing and physiological control.

Impaired immune responses and prolonged viral replication in lung allograft recipients infected with SARS-CoV-2 in the early phase after transplantation

PURPOSE

Lung transplant recipients are at increased risk of severe disease following infection with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) due to high-dose immunosuppressive drugs and the lung is the main organ affected by Coronavirus disease 2019 (COVID-19). Several studies have confirmed increased SARS-CoV-2-related mortality and morbidity in patients living with lung allografts; however, detailed immunological studies of patients with SARS-CoV-2 infection in the early phase following transplantation remain scarce.

METHODS

We investigated patients who were infected with SARS-CoV-2 in the early phase (18-103 days) after receiving double-lung allografts (n = 4, LuTx) in comparison to immunocompetent patients who had not received solid organ transplants (n = 88, noTx). We analyzed SARS-CoV-2-specific antibody responses against the SARS-CoV-2 spike and nucleocapsid proteins using enzyme-linked immunosorbent assays (ELISA), chemiluminescence immunoassays (CLIA), and immunoblot assays. T cell responses were investigated using Elispot assays.

RESULTS

One LuTx patient suffered from persistent infection with fatal outcome 122 days post-infection despite multiple interventions including remdesivir, convalescent plasma, and the monoclonal antibody bamlanivimab. Two patients experienced clinically mild disease with prolonged viral shedding (47 and 79 days), and one patient remained asymptomatic. Antibody and T cell responses were significantly reduced or undetectable in all LuTx patients compared to noTx patients.

CONCLUSION

Patients in the early phase following lung allograft transplantation are vulnerable to infection with SARS-CoV-2 due to impaired immune responses. This patient population should be vaccinated before LuTx, protected from infection post-LuTx, and in case of infection treated generously with currently available interventions.

The epidemiology of invasive fungal infections in transplant recipients

Transplant patients, including solid-organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients, are exposed to various types of complications, particularly rejection. To prevent these outcomes, transplant recipients commonly receive long-term immunosuppressive regimens that in turn make them more susceptible to a wide array of infectious diseases, notably those caused by opportunistic pathogens. Among these, invasive fungal infections (IFIs) remain a major cause of mortality and morbidity in both SOT and HSCT recipients. Despite the continuing improvement in early diagnostics and treatments of IFIs, the management of these infections in transplant patients is still complicated. Here, we provide an overview concerning the most recent trends in the epidemiology of IFIs in SOT and HSCT recipients by describing the prominent yeast and mold species involved, the timing of post-transplant IFIs and the risk factors associated with their occurrence in these particularly weak populations. We also give special emphasis into basic research advances in the field that recently suggested a role of the global and long-term prophylactic regimen in orchestrating various biological disturbances in the organism and conditioning the emergence of the most adapted fungal strains to the particular physiological profiles of transplant patients.

Assessing vaccine-induced immunity against pneumococcus, hepatitis A and B over a 9-year follow-up in pediatric liver transplant recipients: A nationwide retrospective study

Pediatric liver transplant recipients are particularly at risk of infections. The most cost-effective way to prevent infectious complications is through vaccination, which can potentially prevent infections due to hepatitis B (HBV) virus, hepatitis A virus (HAV), and invasive pneumococcal diseases. Here, we performed a retrospective analysis of HBV, HAV, and pneumococcal immunity in pediatric liver transplant recipients between January 1, 2009, and December 31, 2020, to collect data on immunization and vaccine serology. A total of 94% (58/62) patients had available vaccination records. At transplant, 90% (45/50) were seroprotected against HBV, 63% (19/30) against HAV, and 78% (18/23) had pneumococcal immunity, but immunity against these 3 pathogens remained suboptimal during the 9-year follow-up. A booster vaccine was administered to only 20% to 40% of patients. Children who had received >4 doses of HBV vaccine and > 2 doses of HAV vaccine pretransplant displayed a higher overall seroprotection over time post-solid organ transplant. Our findings suggest that a serology-based approach should be accompanied by a more systematic follow-up of vaccination, with special attention paid to patients with an incomplete vaccination status at time of transplant.

Renal Aspergillosis Complicating Renal Allograft Transplantation: A Case Report

Renal aspergillosis is a rare yet potentially devastating complication following renal allograft transplantation. We present the case of a 45-year-old male with a history of crescentic IgA nephropathy who underwent renal allograft transplantation from his mother. Despite initial favorable progress, he developed post-transplant renal dysfunction attributed to active antibody-mediated rejection. Subsequently, he presented with signs of systemic infection and graft dysfunction, leading to the diagnosis of renal aspergillosis. Despite aggressive management, including antifungal therapy and cessation of immunosuppression, the patient progressed to renal graft cortical necrosis, necessitating nephrectomy. This case underscores the challenges in diagnosing and managing renal aspergillosis in transplant recipients and highlights the importance of early recognition and prompt intervention to improve outcomes in such cases.

Infections After Liver Transplant -Timeline, Management and Prevention

Liver transplantation (LT) is the standard treatment for end- stage liver disease. Patient and graft survival have improved significantly in the last three decades owing to improvement in surgical technique, better perioperative management and better immunosuppressive regimens. However, LT recipients are at increased risk of infections, particularly in the first year after transplantation. The risk of infection is directly proportional to immunosuppressive regimen and graft function. In this review, we will briefly discuss the timeline of infections after liver transplant, preventive strategies and management of infectious complications.

From islet transplantation to beta-cell regeneration: an update on beta-cell-based therapeutic approaches in type 1 diabetes

INTRODUCTION

Type 1 diabetes (T1D) mellitus is an autoimmune disease in which immune cells, predominantly effector T cells, destroy insulin-secreting beta-cells. Beta-cell destruction led to various consequences ranging from retinopathy and nephropathy to neuropathy. Different strategies have been developed to achieve normoglycemia, including exogenous glucose compensation, whole pancreas transplantation, islet transplantation, and beta-cell replacement.

AREAS COVERED

The last two decades of experience have shown that indigenous glucose compensation through beta-cell regeneration and protection is a peerless method for T1D therapy. Tremendous studies have tried to find an unlimited source for beta-cell regeneration, on the one hand, and beta-cell protection against immune attack, on the other hand. Recent advances in stem cell technology, gene editing methods, and immune modulation approaches provide a unique opportunity for both beta-cell regeneration and protection.

EXPERT OPINION

Pluripotent stem cell differentiation into the beta-cell is considered an unlimited source for beta-cell regeneration. Devising engineered pancreas-specific regulatory T cells using Chimeric Antigen Receptor (CAR) technology potentiates an effective immune tolerance induction for beta-cell protection. Beta-cell regeneration using pluripotent stem cells and beta-cell protection using pancreas-specific engineered regulatory T cells promises to develop a curative protocol in T1D.

The Predictors and Risk Factors of 2-Year Rejection in Renal Transplant Patients: A Multicenter Case-Control Study

INTRODUCTION

Kidney transplantation is a definitive treatment for end-stage renal disease. It is associated with improved life expectancy and quality of life. One of the most common complications following kidney transplantation is graft rejection. To our knowledge, no previous study has identified rejection risk factors in kidney transplant recipients in Saudi Arabia. Therefore, this study aimed to determine the specific risk factors of graft rejection.

METHODS

A multicenter case-control study was conducted at four transplant centers in Saudi Arabia. All adult patients who underwent a renal transplant between January 1, 2015 and December 31, 2021 were screened for eligibility. Included patients were categorized into two groups (cases and control) based on the occurrence of biopsy-proven rejection within 2 years. The primary outcome was to determine the risk factors for rejection within the 2 years of transplant. Exact matching was utilized using a 1:4 ratio based on patients' age, gender, and transplant year.

RESULTS

Out of 1,320 screened renal transplant recipients, 816 patients were included. The overall prevalence of 2-year rejection was 13.9%. In bivariate analysis, deceased donor status, the presence of donor-specific antibody (DSA), intraoperative hypotension, Pseudomonas aeruginosa, Candida, and any infection within 2 years were linked with an increased risk of 2-year rejection. However, in the logistic regression analysis, the presence of DSA was identified as a significant risk for 2-year rejection (adjusted OR: 2.68; 95% CI: 1.10, 6.49, p = 0.03). Furthermore, blood infection, infected with Pseudomonas aeruginosa or BK virus within 2 years of transplant, were associated with higher odds of 2-year rejection (adjusted OR: 3.10; 95% CI: 1.48, 6.48, p = 0.003, adjusted OR: 3.23; 95% CI: 0.87, 11.97, p = 0.08 and adjusted OR: 2.76; 95% CI: 0.89, 8.48, p = 0.07, respectively).

CONCLUSION

Our findings emphasize the need for appropriate prevention and management of infections following kidney transplantation to avoid more serious problems, such as rejection, which could significantly raise the likelihood of allograft failure and probably death. Further studies with larger sample sizes are needed to investigate the impact of serum chloride levels prior to transplant and intraoperative hypotension on the risk of graft rejection and failure.

Evidence for Immunity against Tetanus, Diphtheria, and Pertussis through Natural Infection or Vaccination in Adult Solid Organ Transplant Recipients: A Systematic Review

(1) Background: We aim to systematically review the current evidence on immunity against tetanus, diphtheria, and pertussis in adult solid organ transplantation (SOT) recipients, either through natural infection or vaccination. (2) Methods: This systematic review was conducted per PRISMA guidelines. We assessed the risk of bias using the Cochrane RoB 2 and ROBINS-I and summarized the findings narratively due to the heterogeneity of the studies. (3) Results: Of the 315 screened articles, 11 were included. Tetanus immunity varied between 55% and 86%, diphtheria immunity from 23% to 75%, and pertussis immunity was between 46% and 82%. Post-vaccination immunity showed variation across the studies, with some indicating reductions and others no change, with antibody responses influenced by transplanted organs, gender, age, and immunosuppressive regimens. The single randomized study exhibited a low risk of bias, while of the ten non-randomized studies, six showed moderate and four serious risks of bias, necessitating cautious interpretation of results. (4) Conclusions: SOT recipients exhibit considerable immunity against tetanus and diphtheria at transplantation, but this immunity decreases over time. Although vaccination can enhance this immunity, the response may be suboptimal, and the increased antibody levels may not persist, underscoring the need for tailored vaccination strategies in this vulnerable population.

Monocentric, Retrospective Study on Infectious Complications within One Year after Solid-Organ Transplantation at a Belgian University Hospital

The epidemiology, diagnostic methods and management of infectious complications after solid-organ transplantation (SOT) are evolving. The aim of our study is to describe current infectious complications in the year following SOT and risk factors for their development and outcome. We conducted a retrospective study in adult SOT recipients in a Belgian university hospital between 2018 and 2019. We gathered demographic characteristics, comorbidities leading to transplantation, clinical, microbiological, surgery-specific and therapeutic data concerning infectious episodes, and survival status up to one year post-transplantation. Two-hundred-and-thirty-one SOT recipients were included (90 kidneys, 79 livers, 35 lungs, 19 hearts and 8 multiple organs). We observed 381 infections in 143 (62%) patients, due to bacteria (235 (62%)), viruses (67 (18%)), and fungi (32 (8%)). Patients presented a median of two (1-5) infections, and the first infection occurred during the first six months. Nineteen (8%) patients died, eleven (58%) due to infectious causes. Protective factors identified against developing infection were obesity [OR [IC]: 0.41 [0.19-0.89]; p = 0.025] and liver transplantation [OR [IC]: 0.21 [0.07-0.66]; p = 0.007]. Risk factors identified for developing an infection were lung transplantation [OR [IC]: 6.80 [1.17-39.36]; p = 0.032], CMV mismatch [OR [IC]: 3.53 [1.45-8.64]; p = 0.006] and neutropenia [OR [IC]: 2.87 [1.27-6.47]; p = 0.011]. Risk factors identified for death were inadequate cytomegalovirus prophylaxis, infection severity and absence of pneumococcal vaccination. Post-transplant infections were common. Addressing modifiable risk factors is crucial, such as pneumococcal vaccination.

Anti-Donor T-Cell Responses Are Not Necessarily Attenuated During Cytomegalovirus Infection in Kidney Transplant Recipients

BACKGROUND

Cytomegalovirus (CMV), the most common opportunistic infection of kidney transplantation (KT), is preventable by prophylactic and preemptive antiviral drugs in CMV-immunoglobulin (Ig)G-positive donors. Our preemptive therapy optimized immunosuppressive doses based on mixed lymphocyte response (MLR) results, regardless of preoperative CMV-IgG serostatus pairing. This study used the MLR to compare the anti-donor T-cell responses between CMV antigenemia-positive and -negative cases.

METHODS

One hundred patients underwent KT using a cyclosporine (CsA)-based immunosuppressive regimen at Hiroshima University Hospital. CMV antigenemia-positive cells were defined as 4/50,000 CMVpp65-positive cells. T-cell responses to allo-antigens were measured using MLR assays to evaluate patients' anti-donor immune reactivity. After analyzing the proliferation of CD4+ and CD8+ T-cell subsets, the stimulation indices of CD4+ or CD8+ T cells were quantified. The study used no prisoners, and the participants were neither coerced nor paid. The manuscript was created in compliance with the Helsinki Congress and the Declaration of Istanbul.

RESULTS

Forty-three patients tested positive for CMV antigenemia within 3 months after KT. No significant differences were found between the CMV antigenemia-positive and -negative groups in the stimulation indices for CD4+ and CD8+ T-cell responses to anti-donor stimulation. However, T-cell responses to third-party stimuli during the postoperative month 1 were significantly less in the CMV antigenemia-positive than -negative group.

CONCLUSION

Anti-donor T-cell responses are not necessarily attenuated during CMV infection in KT recipients. In CMV-infected KT recipients, caution should be exercised against inadvertent dose reduction of immunosuppressants.

Gram-negative bacterial colonizations before bilateral lung transplant. The impact of 'targeted' versus 'standard' surgical prophylaxis

BACKGROUND

Infections are one of the most common causes of death after lung transplant (LT). However, the benefit of 'targeted' prophylaxis in LT recipients pre-colonized by Gram-negative (GN) bacteria is still unclear.

METHODS

All consecutive bilateral LT recipients admitted to the Intensive Care Unit of the University Hospital of Padua (February 2016-2023) were retrospectively screened. Only patients with pre-existing GN bacterial isolations were enrolled and analyzed according to the antimicrobial surgical prophylaxis ('standard' vs. 'targeted' on the preoperative bacterial isolation).

RESULTS

One hundred eighty-one LT recipients were screened, 46 enrolled. Twenty-two (48%) recipients were exposed to 'targeted' prophylaxis, while 24 (52%) to 'standard' prophylaxis. Overall prevalence of postoperative multi-drug resistant (MDR) GN bacteria isolation was 65%, with no differences between the two surgical prophylaxis (p = 0.364). Eleven (79%) patients treated with 'standard' prophylaxis and twelve (75%) with 'targeted' therapy reconfirmed the preoperative GN pathogen (p = 0.999). The prevalence of postoperative infections due to MDR GN bacteria was 50%. Of these recipients, 4 belonged to the 'standard' and 11 to the 'targeted' prophylaxis (p = 0.027).

CONCLUSIONS

The administration of a 'targeted' prophylaxis in LT pre-colonized recipients seemed not to prevent the occurrence of postoperative MDR GN infections.

Infections in Heart and Lung Transplant Recipients

Infections in heart and lung transplant recipients are complex and heterogeneous. This article reviews the epidemiology, risk factors, specific clinical syndromes, and most frequent opportunistic infections in heart and/or lung transplant recipients that will be encountered in the intensive care unit and will provide a practical approach of empirical management.