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Abstract Background Biliary atresia (BA) is rare liver disease of unknown etiology, and is a major indication for liver transplant (LT). Previous data indicate improved outcomes with early referral for Kasai portoenterostomy (KPE). Objective Evaluate the long‐term outcomes in BA, with particular focus on those transitioned to adult care with native livers. Subjects and Methods Patients with BA treated between1980 and 2012 were identified. Data were collected from the time of referral, transition to adult care, and the most recent clinic notes, from which patient and native liver survival were calculated. Results Four hundred and fifty‐four patients with BA were identified, who were followed up for median of 16.4 years from birth; 74 died (41 of whom had a LT), giving a 20‐year survival rate of 83.6%. Two hundred and seventy‐two patients received an LT, with the median native liver survival being 35 months. Of patients who transitioned to adult care, 54 of 180 (30.0%) retained their native liver. Of these, 72% (39 of 54) had evidence of chronic liver disease at transition, of whom 8 were subsequently lost to follow‐up, 9 were transplanted, and 22 remained stable with compensated liver disease. Of the 15 of 54 patients (28%) with no evidence of chronic disease in their native liver disease at transition, 3 were subsequently lost to follow‐up; none received transplants, although 3 patients developed new‐onset liver disease. All patients transitioned to adult care completed secondary school education (N = 180), with 49% having attended college/university and 87% being in employment or education at the last follow‐up. Of female patients, 34% had at least one pregnancy (27 children in 21 women), while 22% of males had fathered a child. Conclusion Long‐term outcomes in BA are good, with patients surviving into adult life. Progression of chronic liver disease and associated morbidity is common in those who retained their native livers, suggesting that these patients require monitoring of liver disease throughout adult life, and early recognition of the need for LT.

Abstract Background Whole genome sequencing is increasingly being used for the diagnosis of patients with rare diseases. However, the diagnostic yields of many studies, particularly those conducted in a healthcare setting, are often disappointingly low, at 25–30%. This is in part because although entire genomes are sequenced, analysis is often confined to in silico gene panels or coding regions of the genome. Methods We undertook WGS on a cohort of 122 unrelated rare disease patients and their relatives (300 genomes) who had been pre-screened by gene panels or arrays. Patients were recruited from a broad spectrum of clinical specialties. We applied a bioinformatics pipeline that would allow comprehensive analysis of all variant types. We combined established bioinformatics tools for phenotypic and genomic analysis with our novel algorithms (SVRare, ALTSPLICE and GREEN-DB) to detect and annotate structural, splice site and non-coding variants. Results Our diagnostic yield was 43/122 cases (35%), although 47/122 cases (39%) were considered solved when considering novel candidate genes with supporting functional data into account. Structural, splice site and deep intronic variants contributed to 20/47 (43%) of our solved cases. Five genes that are novel, or were novel at the time of discovery, were identified, whilst a further three genes are putative novel disease genes with evidence of causality. We identified variants of uncertain significance in a further fourteen candidate genes. The phenotypic spectrum associated with RMND1 was expanded to include polymicrogyria. Two patients with secondary findings in FBN1 and KCNQ1 were confirmed to have previously unidentified Marfan and long QT syndromes, respectively, and were referred for further clinical interventions. Clinical diagnoses were changed in six patients and treatment adjustments made for eight individuals, which for five patients was considered life-saving. Conclusions Genome sequencing is increasingly being considered as a first-line genetic test in routine clinical settings and can make a substantial contribution to rapidly identifying a causal aetiology for many patients, shortening their diagnostic odyssey. We have demonstrated that structural, splice site and intronic variants make a significant contribution to diagnostic yield and that comprehensive analysis of the entire genome is essential to maximise the value of clinical genome sequencing.

Introduction. Hepatitis C virus (HCV) is not currently included in the United Kingdom routine antenatal screening program, but the latest guidelines from the Centers for Disease Control and Prevention, American Association for the Study of Liver Diseases, and Infectious Diseases Society of America recommend HCV screening for all pregnant women during each pregnancy. The aim of this study was to collect qualitative data on the feasibility and acceptability of antenatal HCV screening in pregnant women at the time of routine antenatal screening at 12 weeks, to estimate patient knowledge about HCV and identify the prevalence of HCV infection in antenatal women. Methods. This was a pilot study targeting a single hospital-based antenatal clinic in Birmingham, initially conducted for eight weeks with a further extension of the study period to enhance recruitment to meet the feasibility target of 500 patients. Data collected included demographic and epidemiological details. Pregnant women attending the antenatal unit were given information regarding HCV and antenatal screening for HCV prior to their initial antenatal visit. During the antenatal visit, research nurses provided further information about the study and HCV infection. Consent was obtained for taking part in the study and testing for HCV using blood samples taken at the same time as other routine antenatal screening blood tests. All women who agreed to participate in the study were asked to complete an acceptability and knowledge questionnaire. All women had HCV antibody testing as the primary screening assay. The test result was communicated in writing to the women and their general practitioner. Confirmatory positive antibody tests were followed up with quantitative HCV PCR and genotype analysis. The outcomes of testing were no evidence of HCV infection and evidence of past HCV infection or current HCV infection. Results. Five hundred and forty-nine women were approached in the antenatal clinic; 30 women refused consent while 29 women were excluded from the study (blood tests not performed after consenting, age less than 18 years, and consent form lost). Four hundred and ninety women were included in the study. The median age of the study population was 29 years (range, 18–46). Knowledge about blood-borne viruses was limited; 75% of women had some understanding about antenatal hepatitis B (HBV) and human immunodeficiency virus (HIV) testing. Previous awareness about hepatitis C was reported by 55%. Ninety-one percent of women found the information they were given about hepatitis C helpful. Ninety-six percent of the women included in this study found the counselling they received about HCV useful and felt that the delivery of this information was carried out in an acceptable manner. Once given information about HCV, 99% felt that universal screening for HCV should be implemented. HCV antibody was negative in 489 women. One patient with a positive HCV antibody (prevalence: 0.2%) had a negative HCV PCR. Conclusion. Routine antenatal screening for HCV is not currently recommended in the UK. Our study suggests that antenatal HCV screening would be both feasible and acceptable to most pregnant women attending antenatal clinics. Though the awareness of HCV was low, with appropriate counselling and communication, 99% of pregnant women were in favor of antenatal screening for HCV. Antenatal screening would identify HCV-positive mothers and allow follow-up of their infants so that any infected mothers and infants could be offered effective curative therapy and prevent the progression of liver disease. The inclusion of HCV antenatal screening would complete the blood-borne virus profile and enhance the WHO target to eliminate HCV in the UK.

Abstract Children with progressive familial intrahepatic cholestasis, including bile salt export pump (BSEP) and familial intrahepatic cholestasis–associated protein 1 (FIC1) deficiencies, suffer debilitating cholestatic pruritus that adversely affects growth and quality of life (QoL). Reliance on surgical interventions, including liver transplantation, highlights the unmet therapeutic need. INDIGO was an open‐label, Phase 2, international, long‐term study to assess the efficacy and safety of maralixibat in children with FIC1 or BSEP deficiencies. Thirty‐three patients, ranging from 12 months to 18 years of age, were enrolled. Eight had FIC1 deficiency and 25 had BSEP deficiency. Of the latter, 6 had biallelic, protein truncating mutations (t)‐BSEP, and 19 had ≥ 1 nontruncating mutation (nt)‐BSEP. Patients received maralixibat 266 μg/kg orally, once daily, from baseline to Week 72, with twice‐daily dosing permitted from Week 72. Long‐term efficacy was determined at Week 240. Serum bile acid (sBA) response (reduction in sBAs of > 75% from baseline or concentrations 5 years. No patients with FIC1 deficiency or t‐BSEP deficiency met the sBA responder criteria during the study. Maralixibat was generally well‐tolerated throughout the study. Conclusion: Response to maralixibat was dependent on progressive familial intrahepatic cholestasis subtype, and 6 of 19 patients with nt‐BSEP experienced rapid and sustained reductions in sBA levels. The 7 responders survived with native liver and experienced clinically significant reductions in pruritus and meaningful improvements in growth and QoL. Maralixibat may represent a well‐tolerated alternative to surgical intervention.

Abstract There is growing interest in, but limited data about, intestinal bile acid transport inhibitors as treatment for cholestatic liver disease. The current analyses combine two similar randomized placebo‐controlled trials with subsequent extension phases investigating the impact of maralixibat in children with severe cholestasis secondary to Alagille Syndrome (n = 57). The primary outcomes were measures of pruritus (ItchRO[Obs]) and clinician scratch scale (CSS), both increasing in severity from 0 to 4) and quality of life (QoL) (Parent PedsQL and Multidimensional Fatigue Scale module [MFS] scaled 0–100 with increased QoL) at week 48 of the extension phase relative to the baseline of the placebo‐controlled trials (week 13). Secondary assessments included other clinical and biochemical parameters assessed in participants at week 72 or end of treatment (after week 48). At week 48, statistically and clinically significant least square mean (95% CI) improvements in pruritus and QoL were observed (ItchRO[Obs] −1.59 [−1.81, −1.36], CSS −1.36 [−1.67, −1.05], PedsQL +10.17 [4.48, 15.86], and multidimension fatigue [MFS] +13.97 [7.85, 20.08]). At week 48, serum bile acids, platelet count, and cholesterol decreased, whereas alanine aminotransferase (ALT) increased and total bilirubin (TB) and albumin were stable. Changes were durable at week 72 and end of treatment. There were no deaths; 2 participants underwent liver transplantation. Study drug was discontinued in 9 participants after treatment‐emergent adverse events, 6 of which were events of increased ALT or TB. Conclusion: Maralixibat administration was associated with marked improvement in pruritus and QoL. Interpretation of these findings is complicated by the complex natural history of severe cholestasis in Alagille syndrome.

Background & Aims: Bile salt export pump (BSEP) deficiency frequently necessitates liver transplantation in childhood. In contrast to two predicted protein truncating mutations (PPTMs), homozygous p.D482G or p.E297G mutations are associated with relatively mild phenotypes, responsive to surgical interruption of the enterohepatic circulation (siEHC). The phenotype of patients with a compound heterozygous genotype of one p.D482G or p.E297G mutation and one PPTM has remained unclear. We aimed to assess their genotype-phenotype relationship. Methods: From the NAPPED database, we selected patients with homozygous p.D482G or p.E297G mutations (BSEP1/1; n = 31), with one p.D482G or p.E297G, and one PPTM (BSEP1/3; n = 30), and with two PPTMs (BSEP3/3; n = 77). We compared clinical presentation, native liver survival (NLS), and the effect of siEHC on NLS. Results: The groups had a similar median age at presentation (0.7-1.3 years). Overall NLS at age 10 years was 21% in BSEP1/3 vs. 75% in BSEP1/1 and 23% in BSEP3/3 (p

Introduction: The addition of durvalumab after chemoradiation therapy (CRT) in unresectable stage III NSCLC significantly improves survival. The benefit of this approach in elderly patients is controversial given the toxicity associated with CRT and, thus, may be underutilized. We sought to investigate the outcomes of elderly patients treated with CRT without or without durvalumab at our center. Methods: We reviewed all stage III patients with NSCLC treated with CRT between 2018 and 2020. Patients were analyzed on the basis of age: less than 70 years and 70 years and older. The end points evaluated were treatment patterns, toxicity, progression-free survival, and overall survival. Results: The baseline characteristics including Eastern Cooperative Oncology Group performance status and comorbidities were similar among the 115 patients (44 elderly, 71 young). Completion rates of CRT (100%, 97%) and chemotherapy dose intensity (97%, 97%) were high in elderly and young patients, respectively. There was a trend toward increased hospitalizations in elderly patients because of infections (27% versus 13%, p = 0.08). Of those who did not have primary progression after CRT, 78% of eldery and 81% of young patients received durvalumab. The incidence of grade 3 or higher immune-related adverse events was 9% in elderly and 6% in young patients (p = 0.67). The median progression-free survival was similar (15.6 versus 10.5 mo, p = 0.10), even after adjusting for comorbidities (hazard ratio = 0.6, p = 0.09). The 12-month overall survival rates were 78% in the elderly and 76% in young patients (p = 0.98). Conclusions: Well-selected elderly patients can be treated safely with CRT followed by durvalumab with similar survival benefits compared with their younger counterparts. We would advocate for the referral of all elderly patients for oncologic assessment to avoid undertreatment.

The devastating impact of the COVID-19 pandemic on global health and economic stability is immeasurable. The situation is dynamic and fast-evolving, with the world facing new variants of concern which may have immune escape potential. With threatened treatment and preventative strategies at stake, and the prospect of reinfection prolonging the pandemic, it is more crucial than ever to understand the pathogenesis of SARS-CoV-2 infection, which intriguingly disproportionately affects adults and the elderly. Children infected with SARS-CoV-2 remain largely asymptomatic or undergo a transient mild illness. Understanding why children have a milder phenotype and a significant survival advantage may help identify modifiable risk factors in adults. Current evidence suggests adults with COVID-19 show variability in innate and adaptive immune responses, which result in uncontrolled proinflammatory cytokine production in some patients, leading to severe disease and mortality. Children with acute COVID-19 infection seldom progress to acute respiratory distress syndrome and are less likely to exhibit the cytokine storm which is so prominent in adults. Even with the Kawasaki-like illness, a hyperinflammation syndrome also known as paediatric multisystem inflammatory syndrome temporally associated with SARS-CoV-2, mortality is low. The key to successfully combating SARS-CoV-2 and future zoonotic pandemics may lie in understanding these critical differences and merits focused consideration and research. The impact of community transmission among asymptomatic children is unknown; sustained global decline in infection rates and control of the COVID-19 pandemic may not be achieved until vaccination of children occurs. In this review, we discuss the fundamental differences in the immune response between children and adults in the fight against SARS-CoV-2.

Background. The aim of this study was to determine the long-term efficacy and safety of tacrolimus (Tac) and cyclosporine immunosuppression in pediatric liver transplantation (LTx). Methods. One hundred fifty-six patients who had taken part in a multicenter, randomized, open, parallel study of Tac and corticosteroids versus cyclosporine A microemulsion (CyA-ME), corticosteroids, and azathioprine. Patients were assessed at regular intervals up to 14 y after LTx. Analysis was conducted descriptively. Results. In a long-term follow-up, there was a similar incidence of acute rejection (Tac versus CyA-ME, 5 versus 8) and graft loss (5 versus 10). There were 11 deaths in the cohort, which were from infectious complications/malignancy in the Tac group (n = 2/5) and from chronic rejection/liver failure in the CyA-ME group (n = 3/6). A similar incidence of Epstein-Barr virus and posttransplant lymphoproliferative disease was observed (8 versus 8, 3 versus 3). However, there was a greater incidence of cosmetic adverse events in the CyA-ME cohort, with higher incidences of hypertrichosis (8 versus 27) and gum hyperplasia (20 versus 6). Growth improved equally in both groups. Overall, 81% of patients randomized to Tac remained on Tac therapy at study end, compared with 31% of patients randomized to CyA-ME. Common reasons for switching from CyA-ME included steroid-resistant/acute rejection (n = 12/8) and cosmetic changes (n = 8). Conclusions. This study is the first prospective, observational follow-up study of pediatric patients randomized to Tac and CyA-ME to evaluate long-term outcomes. Our analysis was limited by the degree of switchover between the cohorts; however, there were fewer deaths from chronic rejection/liver failure and reduced adverse events with Tac. Long-term use of Tac and Tac combination therapy appears to be safe and effective immunosuppression for pediatric LTx recipients.

Hepatocellular carcinoma (HCC) is the most common primary liver cancer affecting adults and the second most common primary liver cancer affecting children. Recent years have seen a significant increase in our understanding of the molecular changes associated with HCC. However, HCC is a complex disease, and its molecular pathogenesis, which likely varies by aetiology, remains to be fully elucidated. Interestingly, some inherited cholestatic disorders that manifest in childhood are associated with early HCC development. This review will thus explore how three genes that are associated with liver disease in childhood (ABCB11, TJP2 and VPS33B) might play a role in the initiation and progression of HCC. Specifically, chronic bile-induced damage (caused by ABCB11 changes), disruption of intercellular junction formation (caused by TJP2 changes) and loss of normal apical–basal cell polarity (caused by VPS33B changes) will be discussed as possible mechanisms for HCC development.

Background: The global pandemic caused by novel Coronavirus SARS-CoV-2 disease (COVID-19) is a major threat to the general population and for patients with pre-existing chronic conditions. We report data concerning SARS-CoV-2 infection in children with chronic liver disease (CLD).Methods: A literature review using the online database PubMed was performed to summarize available findings on the association between pre-existing liver disease and COVID-19 infection in children.Results: Children with COVID-19 have preserved effector and immunosuppressive components resulting in a milder disease compared to adults. The most common hepatic manifestation is an elevation of hepatic transaminases. Liver damage may be directly caused by viral infection of liver cells, by medications or by the chronic hypoxia seen in COVID-19 patients. A multicenter study reported that the majority of children with a CLD remained healthy during the outbreak. Similarly, studies reported that children on immunosuppressive treatment, including patients with autoimmune liver disease (AILD) and liver transplantation (LT), maintained good health during the outbreak without experiencing major complications even if infected with COVID-19.Conclusion: COVID-19-related liver injury presents with a mild elevation of transaminases, although its clinical significance is unclear. Children with CLD, including those with AILD and post-LT, do not have an increased risk for severe disease course of SARS-CoV-2 infection with little or no liver dysfunction. These data highlight the necessity to ensure normal standards of care while adhering to national Covid-19 guidelines, and particularly to maintain immunosuppressive medication to prevent relapse or rejection. Further research is required to evaluate the differences in clinical course between immunosuppressed adults and children and in particular whether asymptomatic infection is a concern.

Purpose Anti-programmed cell death protein 1 (PD1)±anti-cytotoxic T-lymphocyte associated protein 4 (CTLA4) immune checkpoint inhibitors (ICIs) are standard therapeutic options for metastatic melanoma. We assessed whether biologic subtype according to primary tumor type or genomic subtype can function as predictive biomarkers for anti-PD1±anti-CTLA4 ICI in patients with advanced melanoma.Methods We performed a single-center retrospective cohort analysis of patients who received anti-PD1±anti-CTLA4 ICI for advanced melanoma between 2012 and 2019. Primary tumor type, BRAF and NRAS mutation status, and other covariates were abstracted from chart review. Log-rank tests and multivariable Cox regression models were used to assess differences in clinical progression-free (cPFS) and overall survival (OS).Results We identified 230 patients who received 249 lines of anti-PD1±anti-CTLA4 ICI for unresectable or metastatic disease. Of these patients, 74% were cutaneous, 11% mucosal, 8% unknown primary and 7% acral. BRAF and NRAS mutations were identified in 35% and 28% of patients, respectively. In multivariable analyses of the entire cohort, acral or mucosal primary tumor type, >3 metastatic sites, elevated LDH were predictive of shorter cPFS and OS. Combination ICI therapy was associated with longer cPFS (HR 0.57, 95% CI 0.38 to 0.86, p=0.007) and OS (HR 0.42, 95% CI 0.28 to 0.65, p

Background/AimsInfectious and genetic factors are invoked, respectively in isolated biliary atresia (BA), or syndromic BA, with major extrahepatic anomalies. However, isolated BA is also associated with minor extrahepatic gut and cardiovascular anomalies and multiple susceptibility genes, suggesting common origins.MethodsWe investigated novel susceptibility genes with genome-wide association, targeted sequencing and tissue staining in BA requiring liver transplantation, independent of BA subtype. Candidate gene effects on morphogenesis, developmental pathways, and ciliogenesis, which regulates left-right patterning were investigated with zebrafish knockdown and mouse knockout models, mouse airway cell cultures, and liver transcriptome analysis.ResultsSingle nucleotide polymorphisms in Mannosidase-1-α-2 (MAN1A2) were significantly associated with BA and with other polymorphisms known to affect MAN1A2 expression but were not differentially enriched in either BA subtype. In zebrafish embryos, man1a2 knockdown caused poor biliary network formation, ciliary dysgenesis in Kupffer’s vesicle, cardiac and liver heterotaxy, and dysregulated egfra and other developmental genes. Suboptimal man1a2 knockdown synergized with suboptimal EGFR signaling or suboptimal knockdown of the EGFR pathway gene, adenosine-ribosylation-factor-6, which had minimal effects individually, to reproduce biliary defects but not heterotaxy. In cultured mouse airway epithelium, Man1a2 knockdown arrested ciliary development and motility. Man1a2–/– mice, which experience respiratory failure, also demonstrated portal and bile ductular inflammation. Human BA liver and Man1a2–/– liver exhibited reduced Man1a2 expression and dysregulated ciliary genes, known to cause multisystem human laterality defects.ConclusionBA requiring transplantation associates with sequence variants in MAN1A2. man1a2 regulates laterality, in addition to hepatobiliary morphogenesis, by regulating ciliogenesis in zebrafish and mice, providing a novel developmental basis for multisystem defects in BA.

Abstract Background Although trough levels of immunosuppressive drugs are largely used to monitor immunosuppressive therapy after solid organ transplantation, there is still no established tool that allows for a validated assessment of functional degree of immunosuppression or the identification of clinically relevant over- or under-immunosuppression, depending on graft homeostasis. Reliable non-invasive markers to predict biopsy proven acute rejection (BPAR) do not exist. Literature data suggest that longitudinal measurements of immune markers might be predictive of BPAR, but data in children are scarce. We therefore propose an observational prospective cohort study focusing on immune monitoring in children after liver transplantation. We aim to describe immune function in a cohort of children before and during the first year after liver transplantation and plan to investigate how the immune function profile is associated with clinical and laboratory findings. Methods In an international multicenter prospective approach, children with end-stage liver disease who undergo liver transplantation are enrolled to the study and receive extensive immune monitoring before and at 1, 2, 3, 4 weeks and 3, 6, 12 months after transplantation, and whenever a clinically indicated liver biopsy is scheduled. Blood samples are analyzed for immune cell numbers and circulating levels of cytokines, chemokines and factors of angiogenesis reflecting immune cell activation. Statistical analysis will focus on the identification of trajectorial patterns of immune reactivity predictive for systemic non-inflammatory states, infectious complications or BPAR using joint modelling approaches. Discussion The ChilSFree study will help to understand the immune response after pLTx in different states of infection or rejection. It may provide insight into response mechanisms eventually facilitating immune tolerance towards the graft. Our analysis may yield an applicable immune panel for non-invasive early detection of acute cellular rejection, with the prospect of individually tailoring immunosuppressive therapy. The international collaborative set-up of this study allows for an appropriate sample size which is otherwise difficult to achieve in the field of pediatric liver transplantation.

Background: Both, markers of cellular immunity and serum cytokines have been proposed as potential biomarkers for graft rejection after liver transplantation. However, no good prognostic model is available for the prediction of acute cellular rejection. The impact of underlying disease and demographic factors on immune status before pediatric liver transplantation (pLTx) is still poorly understood. We investigated expression of immune markers before pLTx, in order to better understand the pre-transplant immune status. Improved knowledge of the impact of pre-transplant variables may enhance our understanding of immunological changes post pLTx in the future.Methods: This is a cross-sectional analysis of data from the ChilSFree study, a European multicentre cohort study investigating the longitudinal patterns of immune response before and after pLTx. Immune cell counts and soluble immune markers were measured in 155 children 1–30 days before pLTx by TruCount analysis and BioPlex assays. Results were logarithmised due to skewed distributions and then compared according to age, sex, and diagnosis using t-tests, ANOVAs, and Tukey post-hoc tests. The association between immune markers at time of pLTx and patients' age was assessed using a fractional polynomial approach. Multivariable regression models were used to assess the relative contribution of each factor.Results: Sex had no effect on immune status. We found strong evidence for age-specific differences in the immune status. The majority of immune markers decreased in a log-linear way with increasing age. T and B cells showed a sharp increase within the first months of life followed by a log-linear decline in older age groups. Several immune markers were strongly associated with underlying diagnoses. The effects of age and underlying disease remained virtually unchanged when adjusting for each other in multivariable models.Discussion: We show for the first time that age and diagnosis are major independent determinants of cellular and soluble immune marker levels in children with end-stage liver disease. These results need to be considered for future research on predictive immune monitoring after pLTx.

Giant cell tumor of bone (GCTB) is a rare condition with distinct radiological features that aid diagnosis. We present the case of an adult female patient, with locally invasive GCTB and review important radiological and management principles. Specific radiological features include locally aggressive, lytic radiolucent lesions, which can demonstrate cortical thinning and expansile remodeling of bone and typically involve the epiphysis and metaphysis. Management is primarily surgical, and denosumab has a role in the advanced setting.

We present the case of a 60-year-old man who developed subacute neurologic changes, in the setting of stage III non-Hodgkin's follicular lymphoma, and was treated with induction chemotherapy, followed by a year of maintenance rituximab. Magnetic resonance imaging of the brain with gadolinium was pathognomonic for progressive multifocal leukoencephalopathy (PML). He was treated with sequential plasmapheresis and intravenous immunoglobulin with clinical improvement. A literature review of the diagnostic workup of rituximab-induced PML was undertaken. This case and the literature review demonstrate the important role of magnetic resonance imaging of the brain in diagnosis and follow-up of rituximab-induced PML. Specific radiologic features in combination with cerebrospinal fluid can be diagnostic and avoid the morbidity and mortality of a diagnostic brain biopsy. Plasmapheresis and intravenous immunoglobulin have a therapeutic role and demonstrate symptom improvement and disease control. Follow-up imaging in combination with clinical response is important in demonstrating a treatment response.

The microenvironment of lymphoid organs can aid healthy immune function through provision of both structural and molecular support. In mice, fibroblastic reticular cells (FRCs) create an essential T-cell support structure within lymph nodes, while human FRCs are largely unstudied. Here, we show that FRCs create a regulatory checkpoint in human peripheral T-cell activation through 4 mechanisms simultaneously utilised. Human tonsil and lymph node-derived FRCs constrained the proliferation of both naïve and pre-activated T cells, skewing their differentiation away from a central memory T-cell phenotype. FRCs acted unilaterally without requiring T-cell feedback, imposing suppression via indoleamine-2,3-dioxygenase, adenosine 2A Receptor, prostaglandin E2, and transforming growth factor beta receptor (TGFβR). Each mechanistic pathway was druggable, and a cocktail of inhibitors, targeting all 4 mechanisms, entirely reversed the suppressive effect of FRCs. T cells were not permanently anergised by FRCs, and studies using chimeric antigen receptor (CAR) T cells showed that immunotherapeutic T cells retained effector functions in the presence of FRCs. Since mice were not suitable as a proof-of-concept model, we instead developed a novel human tissue-based in situ assay. Human T cells stimulated using standard methods within fresh tonsil slices did not proliferate except in the presence of inhibitors described above. Collectively, we define a 4-part molecular mechanism by which FRCs regulate the T-cell response to strongly activating events in secondary lymphoid organs while permitting activated and CAR T cells to utilise effector functions. Our results define 4 feasible strategies, used alone or in combinations, to boost primary T-cell responses to infection or cancer by pharmacologically targeting FRCs.

Liver transplantation is the definitive treatment of liver failure but donor organ shortage limits its availability. Stem cells are highly expandable and have the potential to differentiate into any specialist cell. Use of patient-derived induced Pluripotent Stem Cells (hiPSCs) has the additional advantage for organ regeneration therapies by removing the need for immunosuppression. We compared hepatocyte differentiation of human embryonic stem cells (hESCs) and hiPSCs in a mouse decellularised liver scaffold (3D) with standard in vitro protocol (2D). Mouse livers were decellularised preserving micro-architecture, blood vessel network and extracellular matrix. hESCs and hiPSCs were primed towards the definitive endoderm. Cells were then seeded either in 3D or 2D cultures and the hepatocyte differentiation was continued. Both hESCs and hiPSCs differentiated more efficiently in 3D than in 2D, with higher and earlier expression of mature hepatocyte marker albumin, lipid and glycogen synthesis associated with a decrease in expression of fetal hepatocyte marker alpha-fetoprotein. Thus we conclude that stem cell hepatocyte differentiation in 3D culture promotes faster cell maturation. This finding suggests that optimised 3D protocols could allow generation of mature liver cells not achieved so far in standard 2D conditions and lead to improvement in cell models of liver disease and regenerative medicine applications.