The preoperative recurrence score: Predicting early recurrence in peri-hilar cholangiocarcinoma.

INTRODUCTION: Despite advances in surgical techniques, the rate of early recurrence in perihilar cholangiocarcinoma (PCC) remains high. We sought to develop the Preoperative Recurrence Score (PRS), a model to estimate the risk of early recurrence after resection based on preoperative radiological characteristics. MATERIALS AND METHODS: Data of patients who underwent surgery for PCC were retrospectively collected, and preoperative imaging was reviewed to assess tumor characteristics. A model to assess the risk of early recurrence based on preoperative radiologic characteristics was internally developed and externally validated on two cohorts of patients from two European major hepatobiliary surgery referral centers. RESULTS: A total of 215 patients among three different patient cohorts were included in the study. Tumor size ≥18 mm (HR 2.70, 95 % CI 1.48-4.92, p = 0.001), macroscopic portal vein involvement (HR 2.28, 95%CI 1.19-4.34, p = 0.013), hepatic arteries involvement (HR 2.44, 95%CI 1.26-4.71, p = 0.008), and presence of suspicious lymph nodes (HR 1.98, 95%CI 1.02-3.83, p = 0.043) were significantly associated with recurrence-free survival (RFS). The model showed excellent discrimination both on the internal (AUC 0.83) and external validation cohorts (external 1: AUC 0.84; external 2: AUC 0.70). High PRS was associated with worse RFS among all three cohorts, with a 1-year recurrence probability of 80.1 %, 100.0 %, and 54.2 % in the internal and external validation cohorts 1 and 2, respectively. CONCLUSIONS: The PRS is a simple tool that can accurately assess the risk of early recurrence in patients with PCC. Up-front surgery should be carefully evaluated in patients with high PRS, as it could result in a futile resection.

Lysinuric Protein Intolerance: Not Only a Disorder for Pediatric Nephrologists - Case Report.

INTRODUCTION: Lysinuric protein intolerance (LPI) is a multisystemic inborn error of metabolism with a variable clinical expressivity that usually begins in childhood with growth failure and gastroenterological/neurological problems related to the altered urea cycle and, later, with complications involving the renal, pulmonary, and immunohematological systems. CASE REPORT: We present the case of a 40-year-old woman suffering from chronic kidney disease in the context of a LPI, whose diagnosis was challenging because the signs of the disease were always blurred and the patient never manifested critical episodes typical of this multisystemic disease. In addition to renal disease, splenomegaly, thrombocytopenia, elevated lactate dehydrogenase (LDH), hyperferritinemia, and hypertriglyceridemia were also present. A thorough investigation of the patient's food preferences revealed her spontaneous aversion to protein-containing foods and excessive drowsiness during the occurrence of infectious episodes or on the rare occasions of excessive protein intake, although without ever coming to medical attention. These nuanced signs led us to suspect an impairment of the urea cycle and ultimately allowed us to narrow down the diagnosis to LPI through biochemical and genetic investigations. CONCLUSION: Nephrologists should consider LPI in the differential diagnosis, whenever a patient presents with mixed proteinuria, tubular dysfunction, and/or chronic kidney disease of unknown origin. In these circumstances, we suggest looking for other signs such as growth failure, signs and symptoms ascribed to urea-cycle impairment, pulmonary involvement, hepatosplenomegaly, and laboratory alterations such as pancytopenia, hyperferritinemia, lipid abnormalities, and elevated LDH.

Protective Effect of Minimally Invasive Approach on Postoperative Peak Transaminase Following Liver Resection: A Single-Center Propensity Score-Based Analysis.

BACKGROUND: Postoperative serum ALT levels are one of the most frequently used marker to detect liver tissue damage following liver resection. The aim of this study was to evaluate if minimally invasive liver surgery (MILS) may result in less hepatic injury than open hepatectomy by assessing the differences of postoperative ALT levels. METHODS: Patients who underwent MILS between 2009 and 2019 at our unit were included and compared with open liver resections. Median ALT levels was measured on postoperative day (POD) 1, 3 and 5. Postoperative peak transaminase (PPT) of ALT was determined on POD 1. The stabilized inverse probability treatment weighing (SIPTW) process was used to balance the two groups. A multivariable logistic regression analysis was used to analyze factors associated with high PPT. RESULTS: After SIPTW, 292 MILS were compared with 159 open resections. Median ALT levels on POD 1, 3 and 5 were significantly higher in the open group than in the MILS group (301 vs. 187, p = 0.002; 180 vs. 121, p < 0.0001; 104 vs. 60, p < 0.0001; respectively). At the multivariable logistic regression analysis, MILS showed a protective effect for high PPT. CONCLUSIONS: MILS was associated with significantly lower postoperative ALT levels compared with open liver resections. MILS showed a protective effect for high PPT.

Emerging Prognostic Markers in Patients Undergoing Liver Resection for Hepatocellular Carcinoma: A Narrative Review.

In patients with hepatocellular carcinoma (HCC), liver resection is potentially curative. Nevertheless, post-operative recurrence is common, occurring in up to 70% of patients. Factors traditionally recognized to predict recurrence and survival after liver resection for HCC include pathologic factors (i.e., microvascular and capsular invasion) and an increase in alpha-fetoprotein level. During the past decade, many new markers have been reported to correlate with prognosis after resection of HCC: liquid biopsy markers, gene signatures, inflammation markers, and other biomarkers, including PIVKA-II, immune checkpoint molecules, and proteins in urinary exosomes. However, not all of these new markers are readily available in clinical practice, and their reproducibility is unclear. Liquid biopsy is a powerful and established tool for predicting long-term outcomes after resection of HCC; the main limitation of liquid biopsy is represented by the cost related to its technical implementation. Numerous patterns of genetic expression capable of predicting survival after curative-intent hepatectomy for HCC have been identified, but published findings regarding these markers are heterogenous. Inflammation markers in the form of prognostic nutritional index and different blood cell ratios seem more easily reproducible and more affordable on a large scale than other emerging markers. To select the most effective treatment for patients with HCC, it is crucial that the scientific community validate new predictive markers for recurrence and survival after resection that are reliable and widely reproducible. More reports from Western countries are necessary to corroborate the evidence.

"Eculizumab First" in the Management of Posttransplant Thrombotic Microangiopathy.

Introduction: Posttransplant thrombotic microangiopathy (PT-TMA) is an uncommon event that characterizes approximately 3% to 14% of kidney transplants (KTs), and that is associated with a higher risk of delayed graft function and graft loss. PT-TMA occurs more frequently within the first 3 months after transplant and can be a manifestation of de novo disease or the recurrence of previous atypical hemolytic uremic syndrome (aHUS). Abnormalities in complement regulation genes could explain the increased susceptibility of some patients to PT-TMA. Eculizumab is a humanized monoclonal antibody that inhibits the formation of the membrane attack complex C5b-9. The aim of this study is to evaluate the efficacy of eculizumab as treatment for PT-TMA. Methods: We retrospectively analyzed clinical records of 45 KT patients who received eculizumab immediately after the clinical diagnosis of PT-TMA. Results: Kidney biopsy was performed in 91.1% of patients, and complement genetic study was performed in 64.4%. Of the kidney biopsies, 85.4% showed signs of TMA; genetic analysis revealed 1 pathogenetic variant, 2 variants of uncertain significance, 1 likely benign variant, 8 risk polymorphisms, and 27 risk haplotypes. After 2 weeks from the treatment starting, hemoglobin and platelets significantly increased. A remarkable improvement in kidney function was also observed. After 6 months, 28.8% of patients had a complete renal recovery whereas 44.4% had a partial recovery. Conclusion: This is, to our knowledge, the largest series of KT patients with PT-TMA treated with eculizumab. These data suggest that eculizumab is associated with a normalization of hemolysis indices and an important and progressive improvement of graft function.

Radiomics of Intrahepatic Cholangiocarcinoma and Peritumoral Tissue Predicts Postoperative Survival: Development of a CT-Based Clinical-Radiomic Model.

BACKGROUND: For many tumors, radiomics provided a relevant prognostic contribution. This study tested whether the computed tomography (CT)-based textural features of intrahepatic cholangiocarcinoma (ICC) and peritumoral tissue improve the prediction of survival after resection compared with the standard clinical indices. METHODS: All consecutive patients affected by ICC who underwent hepatectomy at six high-volume centers (2009-2019) were considered for the study. The arterial and portal phases of CT performed fewer than 60 days before surgery were analyzed. A manual segmentation of the tumor was performed (Tumor-VOI). A 5-mm volume expansion then was applied to identify the peritumoral tissue (Margin-VOI). RESULTS: The study enrolled 215 patients. After a median follow-up period of 28 months, the overall survival (OS) rate was 57.0%, and the progression-free survival (PFS) rate was 34.9% at 3 years. The clinical predictive model of OS had a C-index of 0.681. The addition of radiomic features led to a progressive improvement of performances (C-index of 0.71, including the portal Tumor-VOI, C-index of 0.752 including the portal Tumor- and Margin-VOI, C-index of 0.764, including all VOIs of the portal and arterial phases). The latter model combined clinical variables (CA19-9 and tumor pattern), tumor indices (density, homogeneity), margin data (kurtosis, compacity, shape), and GLRLM indices. The model had performance equivalent to that of the postoperative clinical model including the pathology data (C-index of 0.765). The same results were observed for PFS. CONCLUSIONS: The radiomics of ICC and peritumoral tissue extracted from preoperative CT improves the prediction of survival. Both the portal and arterial phases should be considered. Radiomic and clinical data are complementary and achieve a preoperative estimation of prognosis equivalent to that achieved in the postoperative setting.

Radiomic Analysis of Intrahepatic Cholangiocarcinoma: Non-Invasive Prediction of Pathology Data: A Multicenter Study to Develop a Clinical-Radiomic Model.

Standard imaging cannot assess the pathology details of intrahepatic cholangiocarcinoma (ICC). We investigated whether CT-based radiomics may improve the prediction of tumor characteristics. All consecutive patients undergoing liver resection for ICC (2009-2019) in six high-volume centers were evaluated for inclusion. On the preoperative CT, we segmented the ICC (Tumor-VOI, i.e., volume-of-interest) and a 5-mm parenchyma rim around the tumor (Margin-VOI). We considered two types of pathology data: tumor grading (G) and microvascular invasion (MVI). The predictive models were internally validated. Overall, 244 patients were analyzed: 82 (34%) had G3 tumors and 139 (57%) had MVI. For G3 prediction, the clinical model had an AUC = 0.69 and an Accuracy = 0.68 at internal cross-validation. The addition of radiomic features extracted from the portal phase of CT improved the model performance (Clinical data+Tumor-VOI: AUC = 0.73/Accuracy = 0.72; +Tumor-/Margin-VOI: AUC = 0.77/Accuracy = 0.77). Also for MVI prediction, the addition of portal phase radiomics improved the model performance (Clinical data: AUC = 0.75/Accuracy = 0.70; +Tumor-VOI: AUC = 0.82/Accuracy = 0.73; +Tumor-/Margin-VOI: AUC = 0.82/Accuracy = 0.75). The permutation tests confirmed that a combined clinical-radiomic model outperforms a purely clinical one (p < 0.05). The addition of the textural features extracted from the arterial phase had no impact. In conclusion, the radiomic features of the tumor and peritumoral tissue extracted from the portal phase of preoperative CT improve the prediction of ICC grading and MVI.

A GWAS in the pandemic epicenter highlights the severe COVID-19 risk locus introgressed by Neanderthals.

Large GWAS indicated that genetic factors influence the response to SARS-CoV-2. However, sex, age, concomitant diseases, differences in ancestry, and uneven exposure to the virus impacted the interpretation of data. We aimed to perform a GWAS of COVID-19 outcome in a homogeneous population who experienced a high exposure to the virus and with a known infection status. We recruited inhabitants of Bergamo province-that in spring 2020 was the epicenter of the SARS-Cov-2 pandemic in Europe-via an online questionnaire followed by personal interviews. Cases and controls were matched by age, sex and risk factors. We genotyped 1195 individuals and replicated the association at the 3p21.31 locus with severity, but with a stronger effect size that further increased in gravely ill patients. Transcriptome-wide association study highlighted eQTLs for LZTFL1 and CCR9. We also identified 17 loci not previously reported, suggestive for an association with either COVID-19 severity or susceptibility.

Bile duct injury after cholecystectomy: timing of surgical repair should be based on clinical presentation. The experience of a tertiary referral center with Hepp-Couinaud hepatico-jejunostomy.

Impact of timing of repair on outcomes of patients repaired with Hepp-Couinaud hepatico-jejunostomy (HC-HJ) after bile duct injury (BDI) during cholecystectomy remains debated. This is an observational retrospective study at a tertiary referral hepato-biliary center. HC-HJ was always performed in patients without sepsis or bile leak and with dilated bile ducts. Timing of repair was classified as: early (≤ 2 weeks), intermediate (> 2 weeks, ≤ 6 weeks), and delayed (> 6 weeks). 114 patients underwent HC-HJ between 1994 and 2022: 42.1% underwent previous attempts of repair at referring institutions (Group A) and 57.9% were referred without any attempt of repair before referral (Group B). Overall, a delayed HC-HJ was performed in 78% of patients; intermediate and early repair were performed in 17% and 6%, respectively. In Group B, 10.6% of patients underwent an early, 27.3% an intermediate, and 62.1% a delayed repair. Postoperative mortality was nil. Median follow-up was 106.7 months. Overall primary patency (PP) attainment rate was 94.7%, with a 5- and 10-year actuarial primary patency (APP) of 84.6% and 84%, respectively. Post-repair bile leak was associated with PP loss in the entire population (odds ratio [OR] 9.75, 95% confidence interval [CI] 1.64-57.87, p = 0.012); no correlation of PP loss with timing of repair was noted. Treatment of anastomotic stricture (occurred in 15.3% of patients) was performed with percutaneous treatment, achieving absence of biliary symptoms in 93% and 91% of cases at 5 and 10 years, respectively. BDI can be successfully repaired by HC-HJ regardless of timing when surgery is performed in stable patients with dilated bile ducts and without bile leak.

Impact of SARS-CoV-2 Omicron and Delta variants in patients requiring intensive care unit (ICU) admission for COVID-19, Northern Italy, December 2021 to January 2022.

This multicenter observational study included 171 COVID-19 adult patients hospitalized in the ICUs of nine hospitals in Lombardy (Northern Italy) from December, 1st 2021, to February, 9th 2022. During the study period, the Delta/Omicron variant ratio of cases decreased with a delay of two weeks in ICU patients compared to that in the community; a higher proportion of COVID-19 unvaccinated patients was infected by Delta than by Omicron whereas a higher rate of COVID-19 boosted patients was Omicron-infected. A higher number of comorbidities and a higher comorbidity score in ICU critically COVID-19 inpatients was positively associated with the Omicron infection as well in vaccinated individuals. Although people infected by Omicron have a lower risk of severe disease than those infected by Delta variant, the outcome, including the risk of ICU admission and the need for mechanical ventilation due to infection by Omicron versus Delta, remains uncertain. The continuous monitoring of the circulating SARS-CoV-2 variants remains a milestone to counteract this pandemic.

An ex vivo test to investigate genetic factors conferring susceptibility to atypical haemolytic uremic syndrome.

Introduction: Comprehensive genetic analysis is essential to clinical care of patients with atypical haemolytic uremic syndrome (aHUS) to reinforce diagnosis, and to guide treatment. However, the characterization of complement gene variants remains challenging owing to the complexity of functional studies with mutant proteins. This study was designed: 1) To identify a tool for rapid functional determination of complement gene variants; 2) To uncover inherited complement dysregulation in aHUS patients who do not carry identified gene variants. Methods: To address the above goals, we employed an ex-vivo assay of serum-induced C5b-9 formation on ADP-activated endothelial cells in 223 subjects from 60 aHUS pedigrees (66 patients and 157 unaffected relatives). Results: Sera taken from all aHUS patients in remission induced more C5b-9 deposition than control sera, independently from the presence of complement gene abnormalities. To avoid the possible confounding effects of chronic complement dysregulation related to aHUS status, and considering the incomplete penetrance for all aHUS-associated genes, we used serum from unaffected relatives. In control studies, 92.7% of unaffected relatives with known pathogenic variants exhibited positive serum-induced C5b-9 formation test, documenting a high sensitivity of the assay to identify functional variants. The test was also specific, indeed it was negative in all non-carrier relatives and in relatives with variants non-segregating with aHUS. All but one variants in aHUS-associated genes predicted in-silico as likely pathogenic or of uncertain significance (VUS) or likely benign resulted as pathogenic in the C5b-9 assay. At variance, variants in putative candidate genes did not exhibit a functional effect, with the exception of a CFHR5 variant. The C5b-9 assay in relatives was helpful in defining the relative functional effect of rare variants in 6 pedigrees in which the proband carried more than one genetic abnormality. Finally, for 12 patients without identified rare variants, the C5b-9 test in parents unmasked a genetic liability inherited from an unaffected parent. Discussion: In conclusion, the serum-induced C5b-9 formation test in unaffected relatives of aHUS patients may be a tool for rapid functional evaluation of rare complement gene variants. When combined with exome sequencing the assay might be of help in variant selection, to identify new aHUS-associated genetic factors.

Survival by Number and Sites of Resections of Recurrence after First Curative Resection of Colorectal Liver Metastases.

BACKGROUND: Recurrence after curative hepatectomy for colorectal liver metastases (CRLM) is common. We sought to determine if number and sites of resections of recurrence after hepatectomy for CRLM impact survival. METHODS: The study included patients who underwent resection of recurrence following complete curative-intent resection of CRLM during 1998-2016 at two academic medical centers in Houston, USA, and Rome, Italy. The survival impacts of number and sites of resections of recurrence were evaluated. Patients with synchronous extrahepatic disease at curative CRLM resection were excluded. RESULTS: Among 2163 patients who underwent curative hepatectomy, 1456 (67.3%) developed a recurrence. Four hundred seventy-eight patients underwent one (322/478; 67.4%) or two or more (156/478; 32.6%) resections of recurrence. The 5-year overall survival (OS) rate was higher in patients with resected than unresected recurrence (70.2% vs. 24.0%; p < 0.001). In patients who underwent only one resection of recurrence, the 5-year OS rate differed by location (lung, 81.6%; liver, 64.3%; other, 54.1%). In patients who underwent two or more resections of recurrence, the 5-year OS rate was similar for liver-only resection (87.5%) and resection of liver and other sites (66.1%) (p = 0.223) and for liver-only resection and other-sites-only resection (80.7%) (p = 0.258); 5-year OS rate by site of first resection of recurrence did not differ between liver (78.5%) and lung (81.8%) (p = 0.502) but was worse for other sites (61.1%) than for lung (p = 0.045). CONCLUSION: When recurrence after initial CRLM resection is resectable, the ability to undergo resection was associated with improved survival and can be considered as an option regardless of the number of recurrence and resection. Sites of resection of recurrence impact survival and should be considered.

High Arterial Lactate Levels after Hepatic Resection Are Associated with Low Oxygen Delivery and Predict Severe Postoperative Complications.

High End-Surgery Arterial Lactate Concentration (ES-ALC) predicts poor outcome after hepatectomy. The aim of this study was to identify intraoperative hemodynamic parameters predicting high ES-ALC during elective liver resection. Patients who underwent liver resection between 2017 and 2018, under FloTrac/EV1000TM hemodynamic monitoring, were included. The ES-ALC cutoff best predicting severe postoperative complications was identified. Association between high ES-ALC and preoperative and intraoperative variables was assessed. 108 patients were included; 90-day mortality was 0.9% and severe morbidity 14.8%. ES-ALC cutoff best discriminating severe complications was 5.05 mmol/L. Patients with ES-ALC > 5.0 mmol/L had a relative risk of severe complications of 2.8% (p = 0.004). High ES-ALC patients had longer surgery and ischemia duration, larger blood losses and higher requirements of fluids and blood transfusions. During surgery, hemoglobin concentration and oxygen delivery (DO2) decreased more significantly in patients with high ES-ALC, although they had similar values of stroke volume and cardiac output to those of other patients. At multivariate analysis, surgery duration and lowest recorded DO2 value were the strongest predictors of high ES-ALC. ES-ALC > 5.0 mmol/L in elective liver resection predicts postoperative morbidity and is essentially driven by the impaired DO2. Timely correction of blood losses might prevent the ES-ALC increase.

Mycoplasma pneumoniae Infection Associated with Anti-Factor H Autoantibodies in Atypical Hemolytic Uremic Syndrome.

Hemolytic uremic syndrome (HUS) is a rare disease characterized by hemolytic anemia, thrombocytopenia, and renal impairment mostly triggered by strains of Shiga-like toxin-producing Escherichia coli (STEC-HUS). A rarer form of HUS, defined as atypical HUS (aHUS), is associated with genetic or acquired dysregulation of the alternative pathway of the complement system and presents a poorer prognosis than STEC-HUS. Factor H autoantibodies (anti-FHs) have been reported in aHUS in 5-11% of cases and are strongly associated with the homozygous deletion of CFHR3-CFHR1 genes. In the large majority of patients, anti-FH-associated aHUS is commonly preceded by gastrointestinal or respiratory tract infections. Here, we described the clinical case of a 3-year-old boy who was hospitalized for aHUS preceded by Mycoplasma pneumoniae (MP) infection. He resulted positive for anti-FHs and carried the homozygous deletion of CFHR3-CFHR1. Of relevance, he also showed a variant of unknown significance in the C5 gene. The patient was successfully treated with eculizumab and achieved hematological and renal remission. The anti-FH titer decreased, became negative after 6 months of mycophenolate mofetil (MMF) treatment, and remained negative for 21-month follow-up indicating that immunosuppression was effective and could prevent the reappearance of anti-FHs. We hypothesized that MP, likely through an evasion strategy of immunosurveillance based on binding of pathogen to FH, triggers anti-FH antibody generation and aHUS in a subject genetically predisposed. In conclusion, to the best of our knowledge, here, we reported the first case of anti-FH-mediated aHUS after an MP infection who benefited from eculizumab and immunosuppressive therapy based on MMF. Hence, monitoring of anti-FHs in patients with post-MP infection glomerulonephritis could be recommended, especially in those with low C3 plasma levels.

Case Report: Tackling Complement Hyperactivation With Eculizumab in Atypical Hemolytic Uremic Syndrome Triggered by COVID-19.

Hemolytic uremic syndrome (HUS) is a rare life-threatening disease of unrestrained complement system dysregulation, microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure in genetically predisposed individuals. In this report, we describe two cases of SARS-CoV-2-associated HUS treated with eculizumab, a C5-blocking monoclonal antibody reported to be remarkably effective in the treatment of HUS. Detailed biochemical and genetic complement system analysis is reported, and the prompt clinical response after C5 pharmacological blockade is documented. Our report provides the rationale and supports the use of terminal complement pathway inhibition for the treatment of SARS-CoV-2-associated HUS.

CFH and CFHR structural variants in atypical Hemolytic Uremic Syndrome: Prevalence, genomic characterization and impact on outcome.

Introduction: Atypical hemolytic uremic syndrome (aHUS) is a rare disease that manifests with microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure, and is associated with dysregulation of the alternative complement pathway. The chromosomal region including CFH and CFHR1-5 is rich in repeated sequences, favoring genomic rearrangements that have been reported in several patients with aHUS. However, there are limited data on the prevalence of uncommon CFH-CFHR genomic rearrangements in aHUS and their impact on disease onset and outcomes. Methods: In this study, we report the results of CFH-CFHR Copy Number Variation (CNV) analysis and the characterization of resulting structural variants (SVs) in a large cohort of patients, including 258 patients with primary aHUS and 92 with secondary forms. Results: We found uncommon SVs in 8% of patients with primary aHUS: 70% carried rearrangements involving CFH alone or CFH and CFHR (group A; n=14), while 30% exhibited rearrangements including only CFHRs (group B; n=6). In group A, 6 patients presented CFH::CFHR1 hybrid genes, 7 patients carried duplications in the CFH-CFHR region that resulted either in the substitution of the last CFHR1 exon(s) with those of CFH (CFHR1::CFH reverse hybrid gene) or in an internal CFH duplication. In group A, the large majority of aHUS acute episodes not treated with eculizumab (12/13) resulted in chronic ESRD; in contrast, anti-complement therapy induced remission in 4/4 acute episodes. aHUS relapse occurred in 6/7 grafts without eculizumab prophylaxis and in 0/3 grafts with eculizumab prophylaxis. In group B, 5 subjects had the CFHR31-5::CFHR410 hybrid gene and one had 4 copies of CFHR1 and CFHR4. Compared with group A, patients in group B exhibited a higher prevalence of additional complement abnormalities and earlier disease onset. However, 4/6 patients in this group underwent complete remission without eculizumab treatment. In secondary forms we identified uncommon SVs in 2 out of 92 patients: the CFHR31-5::CFHR410 hybrid and a new internal duplication of CFH. Discussion: In conclusion, these data highlight that uncommon CFH-CFHR SVs are frequent in primary aHUS and quite rare in secondary forms. Notably, genomic rearrangements involving the CFH are associated with a poor prognosis but carriers respond to anti-complement therapy.

IgA nephropathy and atypical hemolytic uremic syndrome: a case series and a literature review.

BACKGROUND: IgA nephropathy (IgAN) has been anecdotally reported in association with atypical hemolytic uremic syndrome (aHUS). The association likely portends poor renal outcome, and the possible relationship with complement overactivation has yet to be elucidated. We evaluated a series of IgAN patients with aHUS and reviewed the available literature. METHODS: Adult patients who received a diagnosis of IgAN and developed aHUS between January 2009 and December 2019 were included in this retrospective review. RESULTS: We identified six IgAN-aHUS patients, all of whom developed end-stage kidney disease. At aHUS presentation all patients had decreased serum C3 levels. Predisposing pathogenetic variants and risk haplotypes for aHUS in CFH gene heterozygosity were documented in four out of six patients. Anti-CFH antibodies were found to be negative in the five tested patients. In the literature we identified 21 case reports involving aHUS-IgAN and six retrospective studies evaluating the presence of TMA at the time of renal biopsy. Hypertension, severe proteinuria, reduced sC3 and a worse renal prognosis were the common features of most cases. CONCLUSION: Our case series and literature review show that the onset of either aHUS or renal TMA in the course of IgAN are associated with very poor renal outcome. Activation of the alternative pathway revealed by consumption of serum C3 seems to play a major role. Our hypothesis is that the presence of a predisposing factor (e.g. dysregualtion of complement alternative pathway and/or other intrarenal precipitating factors) might be at the heart of aHUS-IgAN pathophysiology.

Eculizumab in patients with severe coronavirus disease 2019 (COVID-19) requiring continuous positive airway pressure ventilator support: Retrospective cohort study.

BACKGROUND: Complement activation contributes to lung dysfunction in coronavirus disease 2019 (COVID-19). We assessed whether C5 blockade with eculizumab could improve disease outcome. METHODS: In this single-centre, academic, unblinded study two 900 mg eculizumab doses were added-on standard therapy in ten COVID-19 patients admitted from February 2020 to April 2020 and receiving Continuous-Positive-Airway-Pressure (CPAP) ventilator support from ≤24 hours. We compared their outcomes with those of 65 contemporary similar controls. Primary outcome was respiratory rate at one week of ventilator support. Secondary outcomes included the combined endpoint of mortality and discharge with chronic complications. RESULTS: Baseline characteristics of eculizumab-treated patients and controls were similar. At baseline, sC5b-9 levels, ex vivo C5b-9 and thrombi deposition were increased. Ex vivo tests normalised in eculizumab-treated patients, but not in controls. In eculizumab-treated patients respiratory rate decreased from 26.8±7.3 breaths/min at baseline to 20.3±3.8 and 18.0±4.8 breaths/min at one and two weeks, respectively (p<0.05 for both), but did not change in controls. Between-group changes differed significantly at both time-points (p<0.01). Changes in respiratory rate correlated with concomitant changes in ex vivo C5b-9 deposits at one (rs = 0.706, p = 0.010) and two (rs = 0.751, p = 0.032) weeks. Over a median (IQR) period of 47.0 (14.0-121.0) days, four eculizumab-treated patients died or had chronic complications versus 52 controls [HRCrude (95% CI): 0.26 (0.09-0.72), p = 0.010]. Between-group difference was significant even after adjustment for age, sex and baseline serum creatinine [HRAdjusted (95% CI): 0.30 (0.10-0.84), p = 0.023]. Six patients and 13 controls were discharged without complications [HRCrude (95% CI): 2.88 (1.08-7.70), p = 0.035]. Eculizumab was tolerated well. The main study limitations were the relatively small sample size and the non-randomised design. CONCLUSIONS: In patients with severe COVID-19, eculizumab safely improved respiratory dysfunction and decreased the combined endpoint of mortality and discharge with chronic complications. Findings need confirmation in randomised controlled trials.

Unravelling the Role of PAX2 Mutation in Human Focal Segmental Glomerulosclerosis.

No effective treatments are available for familial steroid-resistant Focal Segmental Glomerulosclerosis (FSGS), characterized by proteinuria due to ultrastructural abnormalities in glomerular podocytes. Here, we studied a private PAX2 mutation identified in a patient who developed FSGS in adulthood. By generating adult podocytes using patient-specific induced pluripotent stem cells (iPSC), we developed an in vitro model to dissect the role of this mutation in the onset of FSGS. Despite the PAX2 mutation, patient iPSC properly differentiated into podocytes that exhibited a normal structure and function when compared to control podocytes. However, when exposed to an environmental trigger, patient podocytes were less viable and more susceptible to cell injury. Fixing the mutation improved their phenotype and functionality. Using a branching morphogenesis assay, we documented developmental defects in patient-derived ureteric bud-like tubules that were totally rescued by fixing the mutation. These data strongly support the hypothesis that the PAX2 mutation has a dual effect, first in renal organogenesis, which could account for a suboptimal nephron number at birth, and second in adult podocytes, which are more susceptible to cell death caused by environmental triggers. These abnormalities might translate into the development of proteinuria in vivo, with a progressive decline in renal function, leading to FSGS.

CFH and CFHR Copy Number Variations in C3 Glomerulopathy and Immune Complex-Mediated Membranoproliferative Glomerulonephritis.

C3 Glomerulopathy (C3G) and Immune Complex-Mediated Membranoproliferative glomerulonephritis (IC-MPGN) are rare diseases characterized by glomerular deposition of C3 caused by dysregulation of the alternative pathway (AP) of complement. In approximately 20% of affected patients, dysregulation is driven by pathogenic variants in the two components of the AP C3 convertase, complement C3 (C3) and Factor B (CFB), or in complement Factor H (CFH) and Factor I (CFI), two genes that encode complement regulators. Copy number variations (CNVs) involving the CFH-related genes (CFHRs) that give rise to hybrid FHR proteins also have been described in a few C3G patients but not in IC-MPGN patients. In this study, we used multiplex ligation-dependent probe amplification (MLPA) to study the genomic architecture of the CFH-CFHR region and characterize CNVs in a large cohort of patients with C3G (n = 103) and IC-MPGN (n = 96) compared to healthy controls (n = 100). We identified new/rare CNVs resulting in structural variants (SVs) in 5 C3G and 2 IC-MPGN patients. Using long-read single molecule real-time sequencing (SMRT), we detected the breakpoints of three SVs. The identified SVs included: 1) a deletion of the entire CFH in one patient with IC-MPGN; 2) an increased number of CFHR4 copies in one IC-MPGN and three C3G patients; 3) a deletion from CFHR3-intron 3 to CFHR3-3'UTR (CFHR34 - 6 Δ) that results in a FHR3-FHR1 hybrid protein in a C3G patient; and 4) a CFHR31 - 5-CFHR410 hybrid gene in a C3G patient. This work highlights the contribution of CFH-CFHR CNVs to the pathogenesis of both C3G and IC-MPGN.