Adverse effects of immunosuppression in pediatric solid organ transplantation

Children Are Not Small Adults: Similarities and Differences in Renal Transplantation Between Adults and Pediatrics

Kidney transplantation is the treatment of choice for all patients with end-stage kidney disease, including pediatric patients. Graft survival in pediatrics was lagging behind adults, but now is comparable with the adult cohort. Although many of the protocols have been adopted from adults, there are issues unique to pediatrics that one should be aware of to take care of this population. These issues include recipient size consideration, increased incidence of viral infections, problems related to growth, common occurrence of underlying urological issues, and psychosocial issues. This article addresses the similarities and differences in renal transplantation, from preparing a patient for transplant, the transplant process, to post-transplant complications.

A quality improvement intervention to decrease the decline in renal function in pediatric liver transplant recipients

BACKGROUND

Chronic kidney disease (CKD) impacts long-term morbidity in pediatric liver transplant (LT) recipients. The prevalence of estimated glomerular filtration rate (eGFR) < 90 mL/min/1.73 m² (eGFR < 90) at our institution was 25% at 1 year post-LT; thus, quality improvement (QI) project was initiated, aiming to decrease the prevalence of eGFR < 90 by at least 20% at 1 year-post LT.

METHODS

Children post-LT under 19 years from 2010 to 2018 were included. Three QI interventions were implemented starting 1/2016: documentation of blood pressure percentile (BP%) and eGFR, documentation of a kidney management plan if either was abnormal, and amlodipine initiation prior to hospital discharge after LT. We compared the prevalence of eGFR < 90 at 3, 12, and 24 months after LT in the pre- and post-intervention period.

RESULTS

68 patients in pre- and 42 in post-intervention periods met inclusion criteria. Pre-intervention BP%, eGFR, and kidney management plan were documented at 25%, 10%, and 22%, compared to 71%, 83%, and 71% post-intervention, respectively. 22% of patients were started on amlodipine prior to discharge from LT in the pre- versus 74% in the post-intervention period. Prevalence of eGFR < 90 at 3 m post-LT was 19% in pre- versus 14% in the post-intervention period (p = .31); at 12 months 24% versus 7% (p = .01) and at 24 months 16% versus 6% (p = .13), respectively. Significant non-modifiable risk factors for eGFR < 90 were malignancy (RR = 4.5, p < .0001), metabolic disorder (RR = 2.6, p = .02), and age at transplant (7% increased risk per year of age, p = .007).

CONCLUSION

By improving documentation of BP%, eGFR, and kidney management plan, the prevalence of eGFR < 90 was decreased by a relative 74% and 60% at 12 and 24 months post-LT, respectively.

Tonsillectomy Outcomes in Children After Solid-Organ Transplantation: A 15-Year Single-Center Experience

OBJECTIVE

Solid-organ transplantation (SOT) has become the standard of care for children with terminal organ failure. Long-term immunosuppression has improved survival substantially but is associated with secondary malignancies and impaired wound healing. Our goal was to review the incidence, outcomes, complications, and rate of posttransplant lymphoproliferative disorder on pathologic examination following tonsillectomy/adenotonsillectomy (T/AT) in children after SOT.

STUDY DESIGN

A retrospective cohort study.

SETTING

Tertiary care children's hospital.

METHODS

Data were extracted from charts of children with a history of kidney, heart, or liver transplantation, who underwent T/AT between 2006 and 2021.

RESULTS

A total of 110 patients met the inclusion criteria, including 46 hearts, 41 kidneys, 19 livers, and 4 liver-and-kidney transplants. The mean age at transplantation was 4.2 years, and the mean transplantation-to-T/AT time interval was 28.8 months. The posttransplant lymphoproliferative disorder was diagnosed in 52 (47.3%) patients, and 25% of these had no tonsillar hypertrophy. There was no difference in age at transplantation, organ received, transplantation-to-T/AT time interval, immunosuppressive medications, tonsil size, or tonsillar asymmetry between patients diagnosed with the posttransplant lymphoproliferative disorder and patients with benign tonsillar/adenotonsillar hypertrophy. Posttonsillectomy complications were similar between the groups.

CONCLUSION

The incidence of posttransplant lymphoproliferative disorder undergoing tonsillectomy for any indication was 47.3%. There was no association between preoperative signs and symptoms and the histopathological diagnosis of posttransplant lymphoproliferative disorder. Stratification by organ received and immunosuppressive medications did not identify differences among the groups relative to the incidence of posttransplant lymphoproliferative disorder and other postoperative complications.

A novel role of Tinospora cordifolia in amelioration of cancer-induced systemic deterioration by taming neutrophil infiltration and hyperactivation

BACKGROUND

Cancer has emerged as a systemic disease which targets various organs thus challenging the overall physiology of the host. Recently, we have shown that hyperactive neutrophils infiltrate various organs of tumor bearing host and contribute to gradual systemic deterioration. Therefore, taming neutrophils via potent immunomodulators could be an appropriate therapeutic approach in regulating systemic damage. Tinospora cordifolia (TC), an Ayurvedic panacea, is known for its immense medicinal values in traditional literature and recent reports have also documented its immunomodulatory potential. However, whether TC can regulate neutrophils to exert its therapeutic effectiveness has not been deciphered so far.

METHODS

For the in vivo study, we utilized murine model of Dalton's Lymphoma (DL). T. cordifolia extract (TCE) treatment was scheduled at early, mid and advanced stages of tumor growth at a dose of 400 mg/kg b.w for 30 consecutive days. Effect of TCE on neutrophil infiltration was examined by immunostaining. Neutrophil elastase (NE) level in serum, ascitic fluid and various tissues was monitored by ELISA. Further, qPCR was performed to assess transcripts levels of NE, myeloperoxidase (MPO), metalloproteinases (MMP-8, MMP-9) and cathepsin G (CSTG) in various tissues. ROS level in tissue was assessed by DHE staining and organ function was assessed by histology post TCE treatment.

RESULTS

Our findings showed that TC treatment significantly reduced neutrophil count in peripheral blood and their infiltration in vital organs of tumor-bearing host. Further, it ameliorated neutrophil hyperactivation by down regulating the expression of its key cargoes including NE, MPO, MMP-8, MMP-9 and CSTG at early and mid stage of tumor growth. In addition, TC treatment prevented histopathological alterations and restored the normal serum enzyme levels at different stages of tumor growth. Importantly, TC treatment also showed significant reduction in tumor burden which was accompanied by a remarkable increase in survival of the tumor-bearing mice.

CONCLUSIONS

We conclude that T. cordifolia could limit systemic damage via regulating neutrophil infiltration and hyperactivation which can further lead to cancer control at both prophylactic and therapeutic level.

Immunotherapeutic strategies to induce inflection in the immune response: therapy for cancer and COVID-19

Cancer has agonized the human race for millions of years. The present decade witnesses biological therapeutics to combat cancer effectively. Cancer Immunotherapy involves the use of therapeutics for manipulation of the immune system by immune agents like cytokines, vaccines, and transfection agents. Recently, this therapeutic approach has got vast attention due to the current pandemic COVID-19 and has been very effective. Concerning cancer, immunotherapy is based on the activation of the host's antitumor response by enhancing effector cell number and the production of soluble mediators, thereby reducing the host's suppressor mechanisms by induction of a tumour killing environment and by modulating immune checkpoints. In the present era, immunotherapies have gained traction and momentum as a pedestal of cancer treatment, improving the prognosis of many patients with a wide variety of haematological and solid malignancies. Food supplements, natural immunomodulatory drugs, and phytochemicals, with recent developments, have shown positive trends in cancer treatment by improving the immune system. The current review presents the systematic studies on major immunotherapeutics and their development for the effective treatment of cancers as well as in COVID-19. The focus of the review is to highlight comparative analytics of existing and novel immunotherapies in cancers, concerning immunomodulatory drugs and natural immunosuppressants, including immunotherapy in COVID-19 patients.

Outcomes of skin cancers in pediatric solid organ transplant patients: A systematic review

BACKGROUND

The most frequently reported malignancies after solid organ transplant are cutaneous, but data on the risk in pediatric populations varies across studies.

OBJECTIVES

To perform a systematic review including reported features and outcomes of skin cancers in pediatric solid organ transplant recipients.

METHODS

EMBASE and MEDLINE were systematically searched (Prospero CRD42020201659).

RESULTS

The review summarizes data from 20 studies on 337 patients, with a median age ranging from 15.0 to 19.5 years as reported in 4 studies, who developed skin malignancies after pediatric solid organ transplantation. Median ages at transplant and skin cancer diagnosis ranged from 1.5 to 17.0 years and 15.3 to 33.5 years, respectively. Squamous cell carcinoma (SCC) was most commonly reported (218 cases), followed by basal cell carcinoma (BCC) (91 cases), melanoma (18 cases), and unspecified keratinocyte carcinomas (2 cases). The median latency period between transplantation and cancer diagnosis ranged from 2.2 to 21.0 years. Overall, 4 studies reported 17 cases of metastasis in total, and recurrence was reported in one case. Six deaths were reported in one study related to SCC and melanoma metastases. The incidence rate of skin cancer after pediatric transplantation per 100 person-years of follow-up was 2.1 based on 5 studies.

CONCLUSION

The most frequent post-transplant malignancy in pediatric organ transplant recipients was SCC.

Survival and Complication of Liver Transplantation in Infants: A Systematic Review and Meta-Analysis

Background: Modern surgical techniques and scientific advancements have made liver transplant (LT) in infants feasible. However, there are only a small number of studies examining the short- as well as long-term outcomes of LT in this vulnerable subset of children. Methods: Comprehensive searches were done systematically through the PubMed, Scopus, and Google scholar databases. Studies that were retrospective record based or adopted a cohort approach and reported either patient survival rates or graft survival rates or complications of LT in infants were included in the meta-analysis. Statistical analysis was done using STATA version 13.0. Results: A total of 22 studies were included in the meta-analysis. The overall pooled patient survival rate at 1 year, >1-5 years, and >5 years post-transplantation was 85% (95% CI: 78--92%), 71% (95% CI: 59-83%), and 80% (95% CI: 69-91%), respectively. The overall pooled graft survival rate at 1 year, >1-5 years, and >5 years post-transplantation was 72% (95% CI: 68-76%), 62% (95% CI: 46-78%), and 71% (95% CI: 56-86%), respectively. The overall pooled rate for vascular complications, need for re-transplantation, biliary complications, and infection/sepsis was 12% (95% CI: 10-15%), 16% (95% CI: 12-20%), 15% (95% CI: 9-21%), and 50% (95% CI: 38-61%), respectively. Conclusion: The current meta-analysis showed modest patient and graft survival rates for infant liver transplantation. However, the complication rates related to infection/sepsis were high. More comprehensive evidence is required from studies with larger sample sizes and a longer duration of follow-up.

Pediatric Liver Transplantation: Then and Now

This paper reviews the past 50 years of liver transplantation in children from the perspective of patient demographics, perioperative patient management, surgical techniques, immunosuppression and patient outcomes.

Pediatric vascularized composite allotransplantation: What is the landscape for obtaining appropriate donors in the United States?

Listing the world's first pediatric bilateral hand transplant patient for a donor posed many challenges including matching the appropriate donor age, bone size, skin tone, and growth potential in an already limited donor population. This study describes the prevalence and distribution of potential pediatric VCA donors in the United States. We assessed the UNOS database from 2008 to 2015 to identify the prevalence of potential pediatric VCA donors. Standard VCA inclusion and exclusion criteria were applied to the dataset for all pediatric solid organ donors. Frequency analyses were performed of characteristics important for VCA matching. The dataset began with 57 300 brain-dead donors and after applying the inclusion and exclusion criteria including age <18, decreased to 4663 (8.1%). The number of pediatric potential VCA donors per UNOS region ranged from 11 to 112/year. The majority of pediatric potential VCA donors were blood type O Whites, with the least common profile being blood type AB of "other" ethnicity. The present study confirmed that pediatric VCA donors are rare and may require longer travel times for procurement and listing at multiple centers in order to find a suitable donor. This will be a limiting factor for the expansion of pediatric VCA.

Association Between Thiopurine S-Methyltransferase (TPMT) Genetic Variants and Infection in Pediatric Heart Transplant Recipients Treated With Azathioprine: A Multi-Institutional Analysis

OBJECTIVES

Bone marrow suppression is a common adverse effect of the immunosuppressive drug azathioprine. Polymorphisms in the gene encoding thiopurine S-methyltransferase (TPMT) can alter the metabolism of azathioprine, resulting in marrow toxicity and life-threatening infection. In a multicenter cohort of pediatric heart transplant (HT) recipients, we determined the frequency of TPMT genetic variation and assessed whether azathioprine-treated recipients with TPMT variants were at increased risk of infection.

METHODS

We genotyped TPMT in 264 pediatric HT recipients for the presence of the TPMT*2, TPMT*3A, and TPMT*3C variant alleles. Data on infection episodes and azathioprine use were collected as part of each patient's participation in the Pediatric Heart Transplant Study. We performed unadjusted Kaplan-Meier analyses comparing infection outcomes between groups.

RESULTS

TPMT variants were identified in 26 pediatric HT recipients (10%): *3A (n = 17), *3C (n = 8), and *2 (n = 1). Among those with a variant allele, *3C was most prevalent in black patients (4 of 5) and *3A most prevalent among white and Hispanic patients (16 of 20). Among 175 recipients (66%) who received azathioprine as part of the initial immunosuppressive regimen, we found no difference in the number of infections at 1 year after HT (0.7 ± 1.3; range, 0-6 versus 0.5 ± 0.9; range, 0-3; p = 0.60) or in freedom from infection and bacterial infection between non-variant and variant carriers. There was 1 infection-related death in each group.

CONCLUSIONS

In this multicenter cohort of pediatric HT recipients, the prevalence of TPMT variants was similar across racial/ethnic groups to what has been previously reported in non-pediatric HT populations. We found no association between variant alleles and infection in the first year after HT. Because clinically detected cytopenia could have prompted dose adjustment or cessation, we recommend future studies assess the relationship of genotype to leukopenia/neutropenia in the pediatric transplantation population.

Mass cytometry reveals a distinct immunoprofile of operational tolerance in pediatric liver transplantation

Long-term IS in transplant patients has significant morbidity, poorer quality of life, and substantial economic costs. TOL, defined as graft acceptance without functional impairment in the absence of IS, has been achieved in some pediatric LT recipients. Using mass cytometry, peripheral blood immunotyping was performed to characterize differences between tolerant patients and patients who are stable on single-agent IS. Single-cell mass cytometry was performed using blood samples from a single-center pediatric LT population of operationally tolerant patients to comprehensively characterize the immune cell populations in the tolerant state compared with patients on chronic low-dose IS. Specific T-cell populations of interest were confirmed by flow cytometry. This high-dimensional phenotypic analysis revealed distinct immunoprofiles between transplant populations as well as a CD4⁺ TOT (CD4⁺ CD5⁺ CD25⁺ CD38^-/lo CD45RA) that correlates with tolerance in pediatric LT recipients. In TOL patients, the TOT was significantly increased as compared to patients stable on low levels of IS. This TOT cell was confirmed by flow cytometry and is distinct from classic Treg cells. These results demonstrate the power of mass cytometry to discover significant immune cell signatures that have diagnostic potential.

Correlation between viral load of cytomegalovirus and tacrolimus and sirolimus levels in transplanted pediatric patients

INTRODUCTION

Survival of transplant patients and grafts depends largely on the use of immunosuppressive drugs. However, a balance remains to be established among immunosuppression, transplant rejection and cytomegalovirus (CMV) infection, which results in a high rate of morbidity and mortality. The aim of this study was to define a better strategy for monitoring transplanted patients based on the analysis of the blood concentration of sirolimus and tacrolimus and the burden of CMV.

METHODS

Fifty five post-transplant (kidney and liver) pediatric patients, nine treated with sirolimus and 46 treated with tacrolimus, were included. A total of 541 measurements were obtained. In each measurement the concentration of immunosuppressant in whole blood and CMV viral load in plasma and whole blood was quantified by real-time PCR. Pearson correlation coefficient (r) was estimated.

RESULTS

Values of r ≤0.0747 were found for the relationship between dose and concentration of immunosuppressant; r = 0.9406 for the relationship between viral load in whole blood and plasma, and r ≤0.4616 for the relationship between concentration of immunosuppressant and viral load.

CONCLUSIONS

These data support that the doses of immunosuppressive drugs do not correlate with the levels of the same in whole blood. Therefore, systemic levels of immunosuppressant should be constantly monitored together with CMV load. Meanwhile, a high correlation between viral load measured in whole blood and plasma was found.

Immunomodulatory drugs: oral and systemic adverse effects

OBJECTIVE

The main objectives are to present the different adverse effects of the immunomodulatory drugs that can impair the quality of life of the immunosuppressed patients and study the impact of immunomodulation on oral diseases. Immunomodulatory drugs have changed the treatment protocols of many diseases where immune functions play a central role, such as rheumatic diseases. Their effect on oral health has not been systematically investigated, however.

STUDY DESIGN

We review current data on the new immunomodulatory drugs from the oral health perspective based on open literature search of the topic.

RESULTS

These target specific drugs appear to have less drug interactions than earlier immunomodulating medicines but have nevertheless potential side effects such as activating latent infections. There are some data showing that the new immunomodulatory drugs may also have a role in the treatment of certain oral diseases such as lichen planus or ameliorating symptoms in Sjögren's syndrome, but the results have not been overly promising.

CONCLUSION

In general, data are sparse of the effect of these new drugs vs. oral diseases and there are no properly powered randomized controlled trials published on this topic.

More benign lymphoproliferative disease after liver transplant in infants

CONTEXT-Despite the high frequency of liver transplants in infants, few data are available on the characteristics of posttransplant lymphoproliferative disorders in liver transplant patients (PTLD). OBJECTIVE-To analyze special features and behavior of PTLD arising after liver transplant in infants. METHODS-A comprehensive search of the literature was conducted for the available data on PTLD in infant liver transplant recipients through PubMed and Google scholar. An infant was defined as a liver recipient who was less than 2 years old at the time of transplant. Overall, 205 cases of PTLD were found in 24 reports, and the 100 infants with PTLD were compared with children and adults with PTLD. RESULTS-PTLD lesions in infants were more likely to be polymorphic whereas monomorphic lesions were more prevalent among older patients (P= .05). Remission rates, metastasis frequency, and organ involvement did not differ significantly between the groups. Survival analysis showed that the infants had a significantly better outcome than did older patients (P= .05). CONCLUSION-PTLD is more benign and may have a better outcome in infant liver transplant recipients than in older recipients. A prospective multicenter approach is needed for future research studies.

Pediatric transplantation: opportunities for pharmacogenomics and genomics

Heterogeneity is the rule among pediatric heart transplant recipients. Patients vary in age, size, organ maturity, immune system maturity and underlying disease etiology, which can all influence post-transplant outcomes. Overall, the survival of pediatric transplant recipients continues to improve and the goal remains long-term survival of the primary graft and mitigation of long-term complications and adverse events. The evolving fields of pharmacogenomics and genomics have the potential to revolutionize and personalize the care of pediatric transplant recipients, and although clinical validation in a pediatric cohort is lacking, many of these technologies are becoming more readily available. We discuss genotype-guided dosing of immunosuppressant medications and other commonly used medications after transplantation, the influence of donor and recipient genotype on risk of post-transplant complications, genotype-guided selection of therapies to treat complications, and the use of next-generation sequencing for noninvasive detection of graft rejection.

Challenges to the clinical application of pluripotent stem cells: towards genomic and functional stability

Human embryonic stem cells (hESCs) can undergo unlimited self-renewal and are pluripotent, retaining the ability to differentiate into all cell types in the body. As a renewable source of various types of human cells, hESCs hold great therapeutic potential. Although significant advances have been achieved in defining the conditions needed to differentiate hESCs into various types of biologically active cells, many challenges remain in the clinical development of hESC-based cell therapy, such as the immune rejection of allogeneic hESC-derived cells by recipients. Breakthroughs in the generation of induced pluripotent stem cells (iPSCs), which are reprogrammed from somatic cells with defined factors, raise the hope that autologous cells derived from patient-specific iPSCs can be transplanted without immune rejection. However, recent genomic studies have revealed epigenetic and genetic abnormalities associated with induced pluripotency, a risk of teratomas, and immunogenicity of some iPSC derivatives. These findings have raised safety concerns for iPSC-based therapy. Here, we review recent advances in understanding the genomic and functional stability of human pluripotent stem cells, current challenges to their clinical application and the progress that has been made to overcome these challenges.

A simplified immune suppression scheme leads to persistent micro-dystrophin expression in Duchenne muscular dystrophy dogs

Highly abbreviated micro-dystrophin genes have been intensively studied for Duchenne muscular dystrophy (DMD) gene therapy. Following adeno-associated virus (AAV) gene transfer, robust microgene expression is achieved in murine DMD models in the absence of immune suppression. Interestingly, a recent study suggests that AAV gene transfer in dystrophic dogs may require up to 18 weeks' immune suppression using a combination of three different immune-suppressive drugs (cyclosporine, mycophenolate mofetil, and anti-dog thymocyte globulin). Continued immune suppression is not only costly but also may cause untoward reactions. Further, some of the drugs (such as anti-dog thymocyte globulin) are not readily available. To overcome these limitations, we developed a novel 5-week immune suppression scheme using only cyclosporine and mycophenolate mofetil. AAV vectors (either AV.RSV.AP that expresses the heat-resistant human alkaline phosphatase gene, or AV.CMV.μDys that expresses the canine R16-17/H3/ΔC microgene) at 2.85×10(12) vg particles were injected into adult dystrophic dog limb muscles under the new immune suppression protocol. Sustained transduction was observed for nearly half year (the end of the study). The simplified immune suppression strategy described here may facilitate preclinical studies in the dog model.

Prolonged survival of allografts induced by mycobacterial Hsp70 is dependent on CD4+CD25+ regulatory T cells

Background

Heat shock proteins (Hsps) are stress induced proteins with immunomodulatory properties. The Hsp70 of Mycobacterium tuberculosis (TBHsp70) has been shown to have an anti-inflammatory role on rodent autoimmune arthritis models, and the protective effects were demonstrated to be dependent on interleukin-10 (IL-10). We have previously observed that TBHsp70 inhibited maturation of dendritic cells (DCs) and induced IL-10 production by these cells, as well as in synovial fluid cells.

Methodology/Principal Findings

We investigated if TBHsp70 could inhibit allograft rejection in two murine allograft systems, a transplanted allogeneic melanoma and a regular skin allograft. In both systems, treatment with TBHsp70 significantly inhibited rejection of the graft, and correlated with regulatory T cells (Tregs) recruitment. This effect was not tumor mediated because injection of TBHsp70 in tumor-free mice induced an increase of Tregs in the draining lymph nodes as well as inhibition of proliferation of lymph node T cells and an increase in IL-10 production. Finally, TBHsp70 inhibited skin allograft acute rejection, and depletion of Tregs using a monoclonal antibody completely abolished this effect.

Conclusions/Significance

We present the first evidence for an immunosuppressive role for this protein in a graft rejection system, using an innovative approach – immersion of the graft tissue in TBHsp70 solution instead of protein injection. Also, this is the first study that demonstrates dependence on Treg cells for the immunosuppressive role of TBHsp70. This finding is relevant for the elucidation of the immunomodulatory mechanism of TBHsp70. We propose that this protein can be used not only for chronic inflammatory diseases, but is also useful for organ transplantation management.