Defining the Etiology of Renal Allograft Dysfunction Using Banff 2019 Classification: Correlation with Post-Transplant Duration and Creatinine Levels-A Comprehensive Analysis of 200 Renal Biopsies at a Tertiary Care Medical Center Hospital.

OBJECTIVE: Chronic kidney disease is a growing global health issue, contributing significantly to morbidity and mortality. The incidence of end-stage renal disease (ESRD) is approximately 100 per million population. Renal transplantation remains the cornerstone treatment for ESRD, with a projected 20-year survival rate of 60%. We aim to define the etiology of renal allograft dysfunction using the Banff 2019 classification by analyzing 200 renal allograft biopsies in correlation with creatinine levels across post-transplant time frames. METHODOLOGY: 200 renal allograft biopsies are analyzed using the recent Banff 2019 classification with creatinine levels and post-transplant duration correlation. RESULTS: The study included 150 (75%) male patients and 50 (25%) female patients, with the majority 78 (39%) representing the age group of 16-30 years. 36 (18%) biopsies were within 3-month post-transplant, while 92 (46%) were 2-year post-transplant. According to the Banff 2019 classification, 92 (46.0%) transplant rejection biopsies were identified, with most 54 (27%) exhibiting antibody-mediated rejection (Category 2), including 40 (20%) active acute antibody-mediated rejection (ABMR) and 14 (7.0%) chronic active ABMR. T-cell-mediated rejection (TCMR; Category 4) represented 12 (6%) biopsies, including 10 (5%) acute TCMR and 2 (1%) chronic active TCMR. Category 5, the miscellaneous group, represented 100 (50%) biopsies, out of which 32 (16%) exhibited calcineurin inhibitor (CNI) toxicity, 38 (19%) acute tubular necrosis, and 8 (4%) thrombotic microangiopathy. A notable variation in the dysfunction distribution across different post-transplant time frames indicated a temporal evolution in the underlying causes of allograft dysfunction. Specific Banff categories showed a robust association with renal dysfunction, potentially contributing to the elevation of creatinine levels and renal function deterioration. CONCLUSION: Our study highlights the intricate pathophysiology of renal allograft dysfunction. Most biopsies were attributed to ABMR whereas one-third of biopsies exhibited mixed lesions (ABMR and TCMR or ABMR and calcineurin inhibitor toxicity (CNIT)). Additionally, this study suggests that renal allograft rejection remains a significant contributor to graft dysfunction. A complex interplay between histological findings, Banff classification, and renal function is noted. A significant difference in the distribution of dysfunction across post-transplant time frames is noted suggesting a temporal evolution in the etiology of allograft dysfunction. Certain Banff categories demonstrate a stronger association with renal dysfunction that may influence creatinine level increase and renal function deterioration. In correspondence to the recent Banff 2019 guidelines for diagnosing ABMR, we emphasize the role of C4d staining on immunofluorescence or immunohistochemistry in allograft biopsies as imperative for timely diagnosis and immunosuppressant therapy adjustment, ultimately enhancing graft survival. Further research is needed to elucidate the underlying mechanisms driving renal dysfunction in different Banff categories, ultimately informing personalized management strategies for patients with renal allograft dysfunction. In line with the Banff 2019 guidelines for diagnosing ABMR, this study highlights the critical role of C4d staining through immunofluorescence or immunohistochemistry in allograft biopsies for early diagnosis and timely adjustment of immunosuppressive therapy, ultimately improving graft survival.

Calcineurin inhibitors-related posterior reversible encephalopathy syndrome in liver transplant recipients: Three case reports and review of literature.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES), characterized by acute neurological deterioration and extensive white matter lesions on T2-fluid attenuated inversion recovery magnetic resonance imaging (MRI), is increasingly associated with calcineurin inhibitors (CNI)-related neurotoxicity. Prompt diagnosis is crucial, as early intervention, including the modification or discontinuation of CNI therapy, strict blood pressure management, corticosteroid treatment, and supportive care can significantly improve patient outcomes and prognosis. The growing clinical recognition of CNI-related PRES underscores the importance of identifying and managing this condition in patients presenting with acute neurological symptoms. CASE SUMMARY: This report describes three cases of liver transplant recipients who developed PRES. The first case involves a 60-year-old woman who experienced seizures, aphasia, and hemiplegia on postoperative day (POD) 9, with MRI revealing ischemic foci followed by extensive white matter lesions. After replacing tacrolimus, her symptoms improved, and no significant MRI abnormalities were observed after three years of follow-up. The second case concerns a 54-year-old woman with autoimmune hepatitis who developed headaches, seizures, and extensive white matter demyelination on MRI on POD24. Following the switch to rapamycin and the initiation of corticosteroids, her symptoms resolved, and she was discharged on POD95. The third case details a 60-year-old woman with hepatocellular carcinoma who developed PRES, evidenced by brain MRI abnormalities on POD11. Transitioning to rapamycin and corticosteroid therapy led to her full recovery, and she was discharged on POD22. These cases highlight the critical importance of early diagnosis, CNI modification, and stringent management in improving outcomes for liver transplant recipients with CNI-related PRES. CONCLUSION: Clinical manifestations, combined with characteristic MRI findings, are crucial in diagnosing PRES among organ transplant recipients. However, when standard treatments are ineffective or MRI results are atypical, alternative diagnoses should be taken into considered.

Effective calcineurin inhibitor treatment in adult-onset steroid-resistant nephrotic syndrome with a novel splice donor site variant of TRPC6: a case report.

Transient receptor potential canonical 6 (TRPC6) variants, which were initially detected in adult-onset familial focal segmental glomerulosclerosis (FSGS), were also identified in pediatric-onset one. Here, we present a patient with adult-onset steroid-resistant nephrotic syndrome (SRNS) who harbored a likely pathogenic TRPC6 variant and partially responded to calcineurin inhibitors (CNIs). A 44-year-old woman with stable rheumatoid arthritis, systemic lupus erythematosus, and Sjögren's syndrome was presented with nephrotic syndrome. Her renal biopsy results showed minor glomerular abnormalities. Upon admission, she was treated with steroids for around 4 weeks, but it was ineffective. After 1-2 weeks of cyclosporine A (CyA) administration, urine output increased, renal function improved without a decrease in proteinuria, and she was discharged. Her renal function was maintained for 2 months, but after a CyA dose reduction, she was again admitted to the hospital due to relapsing edema, decreased urine output, and worsening renal function. CyA was replaced by tacrolimus (TAC). A second renal biopsy showed nearly the same findings as the first except for tubulointerstitial lesions. After 1-2 weeks of TAC administration, urine output increased, and renal function improved. However, urinary protein levels did not decrease as before. After discharge, a whole exome analysis revealed a heterozygous splice donor site variant NM_004621.6;c.2644 + 1G > A in TRPC6. Genetic testing identified a novel splice donor site variant of TRPC6 in a patient with adult-onset SRNS, which prevented unnecessary steroid continuation. The safety and efficacy of CNI in TRPC6 glomerulopathy must be evaluated in future larger studies with longer follow-up.

Kidney Biopsy Findings After Lung Transplantation.

Introduction: The early diagnosis of histological kidney damage after lung transplantation (LT) is of paramount importance given the negative prognostic implications of kidney disease. Methods: Three pathologists analyzed all kidney biopsies (KBs) (N = 100) performed from 2010 to 2021 on lung transplant patients in 4 Paris transplantation centers. Results: The main indication for biopsy was chronic renal dysfunction (72% of patients). Biopsies were performed at a median of 26.3 months after transplantation and 15 months after a decline in estimated glomerular filtration rate (eGFR) or the onset of proteinuria. Biopsies revealed a wide spectrum of chronic lesions involving the glomerular, vascular, and tubulointerstitial compartments. The 4 most frequent final diagnoses, observed in 18% to 49% of biopsies, were arteriosclerosis, acute calcineurin inhibitor (CNI) toxicity, thrombotic microangiopathy (TMA) and acute tubular necrosis (ATN). TMA was significantly associated with a combination of mTOR inhibitors (mTORi) or CNIs with biological signs present in only 50% of patients. The eGFR was poorly correlated with most lesions, particularly percent glomerulosclerosis, and with the risk of end-stage renal disease (ESRD). Thirty-four patients progressed to ESRD at an average of 20.1 months after biopsy. Three factors were independently associated with the risk of ESRD: postoperative dialysis, proteinuria >3 g/g and percent glomerulosclerosis >4%. Conclusion: Given the great diversity of renal lesions observed in lung transplant recipients, early referral to nephrologists for KB should be considered for these patients when they present with signs of kidney disease.

The use of extended-release tacrolimus twice a day might be beneficial for selected kidney transplant recipients: a case report.

The calcineurin inhibitor tacrolimus, which is available as an immediate- or extended-release formulation, is the standard-of-care immunosuppression after kidney transplantation with low rejection rates, especially in the first year after transplantation. However, its highly variable metabolism rate, narrow therapeutic window, and nephrotoxic side effects require close drug monitoring and individual dosing. Here, we describe first the application of extended-release tacrolimus (ER-Tac) twice daily with beneficial effects in a kidney transplant recipient under extensive therapeutic drug monitoring. A 47-year-old female kidney transplant recipient, who was identified as a fast metabolizer for tacrolimus, presented with declining allograft function and low tacrolimus through levels over time and 8 years after a second kidney transplantation despite the administration of high doses of ER-Tac once daily. Therefore, the area under the concentration-time curve (AUC) showed exceedingly high blood levels of ER-Tac. The latest biopsy of the kidney transplant showed arteriolar hyalinosis with pole vessel stenosis as a sign of chronic transplant vasculopathy and transplant glomerulopathy as a sign of chronic humoral rejection. After the exclusion of other options for immunosuppressive therapy due to the patient's high immunological risk, the patient was switched from ER-Tac once daily to ER-Tac twice daily. After switching to ER-Tac twice daily, the AUC for oral tacrolimus decreased and the transplant function improved despite higher tacrolimus trough levels and a lower total dose administered. This case highlights the importance of careful therapeutic drug monitoring with the performance of an AUC in the follow-up management of kidney transplant recipients.

Transplant-associated thrombotic microangiopathy in pediatrics: incidence, risk factors, therapeutic options, and outcome based on data from a single center.

Background: Transplant-associated thrombotic microangiopathy (TA-TMA) is a critical complication of hematopoietic stem cell transplantation. Awareness about TA-TMA has increased in recent years, resulting in the implementation of TA-TMA screening in most centers. Methods: Retrospective analysis of children who underwent autologous or allogeneic hematopoietic stem cell transplantation at our center between January 2018 and December 2022 was conducted to evaluate the incidence, clinical features, and outcomes of TA-TMA following the administration of different therapeutic options. Results: A total of 45 patients comprised the study cohort, of whom 10 developed TA-TMA with a cumulative incidence of 22% by 100 days after transplantation. Patients with and without TA-TMA in our cohort displayed an overall survival of 80% and 88%, respectively (p = 0.48), and a non-relapse mortality of 0% and 5.7%, respectively (p = 0.12), at 1 year after transplantation. Risk factors for TA-TMA development included allogeneic transplantation and total body irradiation-based conditioning regime. Among the 10 patients with TA-TMA, 7 did not meet the high-risk criteria described by Jodele and colleagues. Of these seven patients, two responded to calcineurin-inhibitor withdrawal without further therapy and five developed multiorgan dysfunction syndrome and were treated with anti-inflammatory steroids (prednisone), and all responded to therapy. The three patients with high-risk TA-TMA were treated with complement blockade or prednisone, and all responded to therapy. Conclusion: TA-TMA is a multifactorial complication with high morbidity rates. Patients with high-risk TA-TMA may benefit from complement blockade using eculizumab. No consensus has been reached regarding therapy for patients who do not meet high-risk criteria. Our analysis showed that these patients may respond to anti-inflammatory treatment with prednisone.

Immunosuppression in adult liver transplant recipients: a 2024 update from the Italian Liver Transplant Working Group.

PURPOSE: Advances in surgical procedures and immunosuppressive therapies have considerably improved the outcomes of patients who have undergone liver transplantation in the past few decades. In 2020, the Italian Liver Transplant Working Group published practice-oriented algorithms for immunosuppressive therapy (IT) in adult liver transplant (LT) recipients. Due to the rapidly evolving LT field, regular updates to the recommendations are required. This review presents a consensus- and evidence-based update of the 2020 recommendations. METHODS: The Italian Liver Transplant Working Group set out to address new IT issues, which were discussed based on supporting literature and the specialists' personal experiences. The panel deliberated on and graded each statement before consensus was reached. RESULTS: A series of consensus statements were formulated and finalized on: (i) oncologic indications for LT; (ii) management of chronic LT rejection; (iii) combined liver-kidney transplantation; (iv) immunosuppression for transplantation with an organ donated after circulatory death; (v) transplantation in the presence of frailty and sarcopenia; and (vi) ABO blood group incompatibility between donor and recipient. Algorithms were updated in the following LT groups: standard patients, critical patients, oncology patients, patients with specific etiology, and patients at high immunologic risk. A steroid-free approach was generally recommended, except for patients with autoimmune liver disease and those at high immunologic risk. CONCLUSION: The updated consensus- and evidence-based 2024 recommendations for immunosuppression regimens in adult patients with ABO-compatible LT address a range of clinical variables that should be considered to optimize the choice of the immunosuppression treatment in clinical practice in Italy.

Long-term follow-up of the randomized, prospective Scandinavian heart transplant everolimus de novo study with early calcineurin inhibitors avoidance (SCHEDULE) trial.

BACKGROUND: Early substitution of calcineurin inhibitor (CNI) with mammalian target of rapamycin inhibitors has been shown to improve kidney function and reduce intimal hyperplasia in heart transplant (HTx) recipients but data on long-term outcome of such a regime are still sparse. METHODS: In the SCHEDULE trial, 115 de novo HTx recipients were randomized to (1) everolimus with reduced exposure of CNI followed by CNI withdrawal at week 7-11 post-transplant or (2) standard-exposure with CNI. Both groups received mycophenolate mofetil and corticosteroids. Herein we report on the 10-12-year long-term follow-up of the study. RESULTS: A total of 78 patients attended the follow-up visit at a median time of 11 years post-transplant. In the everolimus intention to treat (ITT) group 87.5% (35/40 patients) still received everolimus and in the CNI ITT group 86.8% (33/38) still received CNI. Estimated glomerular filtration rate (eGFR) (least square mean (95% CI)) at the 10-12 years visit was 82.7 (74.2-91.1) ml/min/1.73 m2 and 61.0 (52.3-69.7) ml/min/1.73 m2 in the everolimus and CNI group, respectively (p < 0.001). Graft function measured by ejection fraction, ECG, NT-proBNP and drug safety were comparable between groups. During the study period there was a total of 28 deaths, but there was no difference in survival between the everolimus and the CNI group (aHR 0.61 (95% CI 0.29-1.30) p = 0.20). For the composite endpoint of death, re-transplantation, myocardial infarction, PCI, dialysis, kidney transplantation or cancer no between group differences were found (aHR 1.0 (95% CI 0.57-1.77) p = 0.99). CONCLUSIONS: De novo HTx patients randomized to everolimus and low dose CNI followed by CNI free therapy sustained significantly better long-term kidney function than patients randomized to standard therapy. The graft function at 10-12 years was similar in both groups and there was no difference in survival.

Phase I Trial of Brentuximab Vedotin Plus Cyclosporine in Relapsed/Refractory Hodgkin Lymphoma.

INTRODUCTION: BV is an antibody-drug conjugate directed against CD30 and is safe and effective in relapsed/refractory (R/R) Hodgkin lymphoma (HL). Most patients with r/r cHL respond well to BV monotherapy; however, the large of majority of them eventually progress on this drug, and BV-resistant HL remains an unmet need. Preclinical data suggest that BV resistance is mediated at least in part by increased drug efflux associated with increased expression of multidrug resistance pump 1 (MDR1) while CD30 expression appears to be preserved in BV resistant cell lines and patient samples. We conducted a phase 1 study evaluating BV + cyclosporine (CsA) in BV-refractory HL and previous reported results in the dose finding cohort. Here we report the final results from the phase 1 study. METHODS: This was a phase I trial of BV + CsA in patients with r/r HL with dose-finding and dose escalation cohorts. Eligibility criteria included age ≥ 18 years with r/r HL after at least 1 prior line of therapy. Treatment consisted of 1.8 mg/kg BV intravenously on day 1 and CsA 5 to 7.5 mg/kg PO twice daily on days 1 to 5; cycles were 21 days long. Patients in the expansion cohort had to have cHL refractory to BV. The primary objectives were to evaluate safety and tolerability and to determine MTD of BV + CsA; the secondary objective was to determine efficacy of this combination. RESULTS: 29 patients were enrolled onto the study, 14 in the dose finding cohort and 15 in the dose expansion BV refractory cohort. Study accrual was terminated before target accrual due to unacceptable toxicity. 62% of patients were male, and the median age was 36 years (range: 20-69). The median number of prior therapies was 5 (range: 3-12); all patients had prior BV, and 93% had PD-1 directed therapy, and 93% were BV-refractory. Of 22 evaluable patients, CR rate was 27% and ORR 64%; median DOR 4.9 months. Treatment-related deaths occurred in 3 patients, and another patient died during cycle 1 due to cardiac arrest deemed unlikely related to be protocol therapy. All grade GI toxicity was seen in 90% of patients (G3+ in 24%); other common adverse events were nausea (90%), hypertension (90%), nausea (90%), hypertension (90%), anemia (86%), fatigue (76%), neutropenia (76%), leukopenia (76%), hypomagnesemia (76%), anorexia (66%), and hyponatremia (66%). DISCUSSION: BV + CsA demonstrated modest activity in BV-refractory r/r HL; however, toxicity is substantial.

The value of extracorporeal photopheresis as an immunosuppression-modifying approach in solid organ transplantation: a potential solution to an unmet medical need.

Allograft rejection is a critical issue following solid organ transplantation (SOT). Immunosuppressive therapies are crucial in reducing risk of rejection yet are accompanied by several significant side effects, including infection, malignancy, cardiovascular diseases, and nephrotoxicity. There is a current unmet medical need with a lack of effective minimization strategies for these side effects. Extracorporeal photopheresis (ECP) has shown potential as an immunosuppression (IS)-modifying technique in several SOT types, with improvements seen in acute and recurrent rejection, allograft survival, and associated side effects, and could fulfil this unmet need. Through a review of the available literature detailing key areas in which ECP may benefit patients, this review highlights the IS-modifying potential of ECP in the four most common SOT procedures (heart, lung, kidney, and liver transplantation) and highlights existing gaps in data. Current evidence supports the use of ECP for IS modification following SOT, however there is a need for further high-quality research, in particular randomized control trials, in this area.

Calcineurin/NFATc1 pathway represses cellular cytotoxicity by modulating histone H3 expression.

Excess amounts of histones in the cell induce mitotic chromosome loss and genomic instability, and are therefore detrimental to cell survival. In yeast, excess histones are degraded by the proteasome mediated via the DNA damage response factor Rad53. Histone expression, therefore, is tightly regulated at the protein level. Our understanding of the transcriptional regulation of histone genes is far from complete. In this study, we found that calcineurin inhibitor treatment increased histone protein levels, and that the transcription factor NFATc1 (nuclear factor of activated T cells 1) repressed histone transcription and acts downstream of the calcineurin. We further revealed that NFATc1 binds to the promoter regions of many histone genes and that histone transcription is downregulated in a manner dependent on intracellular calcium levels. Indeed, overexpression of histone H3 markedly inhibited cell proliferation. Taken together, these findings suggest that NFATc1 prevents the detrimental effects of histone H3 accumulation by inhibiting expression of histone at the transcriptional level.

Myricetin ameliorates the severity of pancreatitis in mice by regulating cathepsin B activity and inflammatory cytokine production.

Cathepsin B (CTSB) and inflammatory cytokines are critical in initiating and developing pancreatitis. Calcineurin, a central calcium (Ca2+)-responsive signaling molecule, mediates acinar cell death and inflammatory responses leading to pancreatitis. However, the detailed mechanisms for regulating CTSB activity and inflammatory cytokine production are unknown. Myricetin (MC) exhibits various biological activities, including anti-inflammatory effects. Here, we aimed to investigate MC effects on pancreatitis and the underlying mechanisms. Prophylactic and therapeutic MC treatment ameliorated the severity of cerulein-, L-arginine-, and PDL-induced acute pancreatitis (AP). The inhibition of CTSB activity by MC was mediated via decreased calcineurin activity and macrophage infiltration, not neutrophils infiltration, into the pancreas. Additionally, calcineurin activity inhibition by MC prevented the phosphorylation of Ca2+/CaM-dependent protein kinase kinase 2 (CaMKK2) during AP, resulting in the inhibition of CaMKIV phosphorylation and adenosine monophosphate-activated protein kinase (AMPK) dephosphorylation. Furthermore, MC reduced nuclear factor-κB activation by modulating the calcineurin-CaMKIV-IKKα/ß-Iκ-Bα and calcineurin-AMPK-sirtuin1 axes, resulting in reduced production of tumor necrosis factor-α, interleukin (IL)-1ß, and IL-6. Our results showed that MC alleviated AP severity by inhibiting acinar cell death and inflammatory responses, suggesting that MC as a calcineurin and CaMKK2 signaling modulator may be a potential treatment for AP.

Post-infectious pityriasis rubra pilaris in pediatric patients. / Pitiriasis rubra pilaris posinfecciosa en pacientes pediátricos.

Pityriasis rubra pilaris (PRP) is a rare skin condition. The etiology of PRP is unknown; however, it has been associated with infections, autoimmune diseases, and neoplasms. Here we describe the cases of 2 pediatric patients with PRP triggered by a respiratory syncytial virus infection concurrently with obstructive bronchial syndrome. PRP resolved after treatment with topical emollients, topical corticosteroids, and calcineurin inhibitors.

La pitiriasis rubra pilaris (PRP) es una enfermedad dermatológica poco frecuente. Se desconoce su etiología, sin embargo, se ha asociado a infecciones, enfermedades autoinmunes y neoplasias. Se describen los casos de dos pacientes pediátricos que presentaron PRP gatillada por una infección por virus sincicial respiratorio mientras cursaban un síndrome bronquial obstructivo. Los cuadros de PRP remitieron luego del tratamiento tópico con emolientes, corticoesteroides tópicos e inhibidores de la calcineurina.

Successful Treatment with Mycophenolate Mofetil in a Patieint with Anti-MDA 5 Antibody-positive Interstitial Lung Disease and Posterior Reversible Encephalopathy syndrome: A Case Report.

A 59-year-old woman presented with a rash on the top part of her hands and pain in the wrist joint and was diagnosed with dermatomyositis complicated by interstitial pneumonia positive for anti-melanoma differentiation-associated gene 5 (MDA-5) antibody. However, the patient reported a severe headache following treatment with oral prednisolone and tacrolimus. Posterior reversible encephalopathy syndrome (PRES) was diagnosed based on the brain magnetic resonance imaging findings. Tacrolimus was discontinued, and mycophenolate mofetil was instead administered with a favorable outcome. Mycophenolate mofetil should therefore be considered as an alternative treatment for anti-MDA-5-positive interstitial lung disease in cases where calcineurin inhibitors cannot be used.

[Zinc Suppresses Colorectal Cancer Development through Cell-mediated Immunity].

Zinc is one of the essential trace elements, and is involved in various functions in the body. Zinc deficiency is known to cause immune abnormalities, but the mechanism is not fully understood. Therefore, we focused our research on tumor immunity to elucidate the effect of zinc on colorectal cancer and its mechanisms. Mice were treated with azoxymethane (AOM) and dextran sodium sulfate (DSS) to develop colorectal cancer, then the relationship between zinc content in the diet and the number and area of tumors in the colon was observed. The number of tumors in the colon was significantly higher in the no-zinc-added diet group compared to the normal zinc intake group, and about half the number in the high-zinc-intake group compared to the normal-zinc-intake group. In T-cell-deficient mice, the number of tumors in the high-zinc-intake group was similar to that in the normal-zinc-intake group, suggesting that the inhibitory effect of zinc was dependent on T cells. Furthermore, we found that the amount of granzyme B transcript released by cytotoxic T cells upon antigen stimulation was significantly increased by the addition of zinc. We also showed that granzyme B transcriptional activation by zinc addition was dependent on calcineurin activity. Collectively, we have shown that zinc exerts its tumor-suppressive effect by acting on cytotoxic T cells, the center of cellular immunity, and that it increases the transcription of granzyme B, one of the key molecules involved in tumor immunity. In this symposium, we would like to introduce our latest data on the relationship between zinc and tumor immunity.

Calcineurin inhibitor-related hyperkalemia is caused by hyporeninemic hypoaldosteronism and fludrocortisone is an effective treatment: Report of a case series and review of the literature.

INTRODUCTION: Calcineurin inhibitors (CNIs) are widely used in transplantation. Although CNI-related hyperkalemia is common (10%-60.6%), the underlying pathogenetic mechanism is not well-elucidated and may lead to dose adjustment or treatment withdrawal. OBJECTIVE: The aim of this study is to describe CNI-related hyperkalemia due to hyporeninemic hypoaldosteronism in pediatric transplant recipients who were successfully treated with fludrocortisone. METHOD: In a total of 55 hematopoietic stem cell (HSCT) and 35 kidney transplant recipients followed according to institutional immunosuppression protocols, recipients diagnosed with CNI-related hyperkalemia were reviewed. Recipients who were receiving intravenous fluid, potassium, or were diagnosed with hemolysis, acute graft rejection, or had an eGFR < 30 mL/min/1.73m2, were excluded. A detailed analysis of clinical history as well as biochemical studies was carried out to reveal possible pathophysiology. RESULTS: Three pediatric transplant recipients (one HSCT, two kidney transplantation) with findings of hyperkalemia, hyponatremia, and a mild elevation in blood urea nitrogen while on CNIs were recruited. Urinary potassium excretion was diminished while sodium excretion was increased. Plasma aldosterone levels were low, and renin was not increased in response. Primary adrenal insufficiency was ruled out, and hyporeninemic hypoaldosteronism was diagnosed. CNI-related hyperkalemia was detected earlier in case 1, who had HSCT (22 days), than in the second and third cases, who had kidney transplantation (24 and 30 months post-transplantation, respectively). The discrepancy was hypothesized to be explained by higher overall CNI dose due to higher serum target CNI used in HSCT than kidney transplantation. Electrolyte imbalance was reversed upon administration of physiologic dose fludrocortisone (0.05 mg, daily), while fludrocortisone was ceased after CNI withdrawal in case 1, which is additional evidence for the etiological association of CNIs and hyporeninemic hypoaldosteronism. CONCLUSION: Our three cases strengthen the premise that CNI-related hyperkalemia may be due to hyporeninemic hypoaldosteronism, and the timing and severity may be related to CNI dose. Fludrocortisone is a safe and effective treatment in CNI-related hyperkalemia, providing maintenance of CNIs, which are one of the essential therapeutic agents for pediatric transplantation.

Leishmania exploits host cAMP/EPAC/calcineurin signaling to induce an IL-33-mediated anti-inflammatory environment for the establishment of infection.

Host anti-inflammatory responses are critical for the progression of visceral leishmaniasis, and the pleiotropic cytokine interleukin (IL)-33 was found to be upregulated in infection. Here, we documented that IL-33 induction is a consequence of elevated cAMP-mediated exchange protein activated by cAMP (EPAC)/calcineurin-dependent signaling and essential for the sustenance of infection. Leishmania donovani-infected macrophages showed upregulation of IL-33 and its neutralization resulted in decreased parasite survival and increased inflammatory responses. Infection-induced cAMP was involved in IL-33 production and of its downstream effectors PKA and EPAC, only the latter was responsible for elevated IL-33 level. EPAC initiated Rap-dependent phospholipase C activation, which triggered the release of intracellular calcium followed by calcium/calmodulin complex formation. Screening of calmodulin-dependent enzymes affirmed involvement of the phosphatase calcineurin in cAMP/EPAC/calcium/calmodulin signaling-induced IL-33 production and parasite survival. Activated calcineurin ensured nuclear localization of the transcription factors, nuclear factor of activated T cell 1 and hypoxia-inducible factor 1 alpha required for IL-33 transcription, and we further confirmed this by chromatin immunoprecipitation assay. Administering specific inhibitors of nuclear factor of activated T cell 1 and hypoxia-inducible factor 1 alpha in BALB/c mouse model of visceral leishmaniasis decreased liver and spleen parasite burden along with reduction in IL-33 level. Splenocyte supernatants of inhibitor-treated infected mice further documented an increase in tumor necrosis factor alpha and IL-12 level with simultaneous decrease of IL-10, thereby indicating an overall disease-escalating effect of IL-33. Thus, this study demonstrates that cAMP/EPAC/calcineurin signaling is crucial for the activation of IL-33 and in effect creates anti-inflammatory responses, essential for infection.

Tacrolimus Treatment for TAFRO Syndrome.

TAFRO syndrome is an acute systemic inflammatory disorder characterized by thrombocytopenia, anasarca, fever, reticulin myelofibrosis, renal dysfunction, and organomegaly. While its lymph node pathology is similar to that of idiopathic multicentric Castleman disease (iMCD), the clinical features of TAFRO syndrome differ from those of typical iMCD, as they include a more aggressive clinical course and high mortality. However, an optimal treatment strategy for TAFRO syndrome has not yet been established, owing to a poor understanding of its pathogenesis. The limited cases we encountered suggest that tacrolimus treatment in combination with glucocorticoids may potentially be effective and well tolerated as an initial treatment, and hold promise as a glucocorticoid-sparing agent. Herein, we report an additional case and review the sparse literature available regarding TAFRO syndrome treated via tacrolimus.

RyR2 Stabilizer Attenuates Cardiac Hypertrophy by Downregulating TNF-α/NF-κB/NLRP3 Signaling Pathway through Inhibiting Calcineurin.

The effect of Ryanodine receptor2 (RyR2) and its stabilizer on cardiac hypertrophy is not well known. C57/BL6 mice underwent transverse aortic contraction (TAC) or sham surgery were administered dantrolene, the RyR2 stabilizer, or control drug. Dantrolene significantly alleviated TAC-induced cardiac hypertrophy in mice, and RNA sequencing was performed implying calcineurin/NFAT3 and TNF-α/NF-κB/NLRP3 as critical signaling pathways. Further expression analysis and Western blot with heart tissue as well as neonatal rat cardiomyocyte (NRCM) model confirmed dantrolene decreases the activation of calcineurin/NFAT3 signaling pathway and TNF-α/NF-κB/NLRP3 signaling pathway, which was similar to FK506 and might be attenuated by calcineurin overexpression. The present study shows for the first time that RyR2 stabilizer dantrolene attenuates cardiac hypertrophy by inhibiting the calcineurin, therefore downregulating the TNF-α/NF-κB/NLRP3 pathway.

The Ca2+-dependent phosphatase calcineurin dephosphorylates TBK1 to suppress antiviral innate immunity.

Tumor necrosis factor receptor-associated factor family member-associated NF-κB activator-binding kinase 1 (TBK1) plays a key role in the induction of the type 1 interferon (IFN-I) response, which is an important component of innate antiviral defense. Viruses target calcium (Ca2+) signaling networks, which participate in the regulation of the viral life cycle, as well as mediate the host antiviral response. Although many studies have focused on the role of Ca2+ signaling in the regulation of IFN-I, the relationship between Ca2+ and TBK1 in different infection models requires further elucidation. Here, we examined the effects of the Newcastle disease virus (NDV)-induced increase in intracellular Ca2+ levels on the suppression of host antiviral responses. We demonstrated that intracellular Ca2+ increased significantly during NDV infection, leading to impaired IFN-I production and antiviral immunity through the activation of calcineurin (CaN). Depletion of Ca²+ was found to lead to a significant increase in virus-induced IFN-I production resulting in the inhibition of viral replication. Mechanistically, the accumulation of Ca2+ in response to viral infection increases the phosphatase activity of CaN, which in turn dephosphorylates and inactivates TBK1 in a Ca2+-dependent manner. Furthermore, the inhibition of CaN on viral replication was counteracted in TBK1 knockout cells. Together, our data demonstrate that NDV hijacks Ca2+ signaling networks to negatively regulate innate immunity via the CaN-TBK1 signaling axis. Thus, our findings not only identify the mechanism by which viruses exploit Ca2+ signaling to evade the host antiviral response but also, more importantly, highlight the potential role of Ca2+ homeostasis in the viral innate immune response.IMPORTANCEViral infections disrupt intracellular Ca2+ homeostasis, which affects the regulation of various host processes to create conditions that are conducive for their own proliferation, including the host immune response. The mechanism by which viruses trigger TBK1 activation and IFN-I induction through viral pathogen-associated molecular patterns has been well defined. However, the effects of virus-mediated Ca2+ imbalance on the IFN-I pathway requires further elucidation, especially with respect to TBK1 activation. Herein, we report that NDV infection causes an increase in intracellular free Ca2+ that leads to activation of the serine/threonine phosphatase CaN, which subsequently dephosphorylates TBK1 and negatively regulates IFN-I production. Furthermore, depletion of Ca2+ or inhibition of CaN activity exerts antiviral effects by promoting the production of IFN-I and inhibiting viral replication. Thus, our results reveal the potential role of Ca2+ in the innate immune response to viruses and provide a theoretical reference for the treatment of viral infectious diseases.