Deletion of Complement Factor H–Related Genes CFHR1 and CFHR3 Is Associated with Atypical Hemolytic Uremic Syndrome

Atypical hemolytic uremic syndrome (aHUS) is associated with defective complement regulation. Disease-associated mutations have been described in the genes encoding the complement regulators complement factor H, membrane cofactor protein, factor B, and factor I. In this study, we show in two independent cohorts of aHUS patients that deletion of two closely related genes, complement factor H–related 1 (CFHR1) and complement factor H–related 3 (CFHR3), increases the risk of aHUS. Amplification analysis and sequencing of genomic DNA of three affected individuals revealed a chromosomal deletion of ∼84 kb in the RCA gene cluster, resulting in loss of the genes coding for CFHR1 and CFHR3, but leaving the genomic structure of factor H intact. The CFHR1 and CFHR3 genes are flanked by long homologous repeats with long interspersed nuclear elements (retrotransposons) and we suggest that nonallelic homologous recombination between these repeats results in the loss of the two genes. Impaired protection of erythrocytes from complement activation is observed in the serum of aHUS patients deficient in CFHR1 and CFHR3, thus suggesting a regulatory role for CFHR1 and CFHR3 in complement activation. The identification of CFHR1/CFHR3 deficiency in aHUS patients may lead to the design of new diagnostic approaches, such as enhanced testing for these genes

Liver Allograft Failure After Nivolumab Treatment-A Case Report With Systematic Literature Research

Background Orthotopic liver transplantation (OLT) is a potential curative treatment in patients with hepatocellular carcinoma (HCC); however, treatment options for recurrent HCC after OLT are limited. Immune checkpoint inhibitors, such as nivolumab, an inhibitor of programmed cell death protein 1, have been successfully used for metastatic HCC but data on safety of nivolumab following solid organ transplantation are limited. Methods We report a 53-year-old woman with HCC who was treated with OLT. After 2 years, HCC recurred. Initial treatment with sorafenib was discontinued due to side effects and disease progression. Progressive HCC in the lung and lymph nodes was subsequently treated with nivolumab. One week after the first nivolumab dose, rapid progressive liver dysfunction was noted. Liver biopsy revealed severe cellular graft rejection prompting treatment with intravenous steroids and tacrolimus. Liver function continued to decline, leading to severe coagulopathy. The patient succumbed to intracranial hemorrhage. Results A systematic PubMed search revealed 29 cases treated with a checkpoint inhibitor following solid organ transplantation. Loss of graft was described in 4 (36%) of 11 cases with OLT and in 7 (54%) of 13 cases after kidney transplantation. However, cases with favorable outcome were also described. Eighteen cases with adverse events were identified upon searching the World Health Organization database VigiBase, including 2 cases with fatal outcome in liver transplant recipients due to graft loss. Conclusion Experience with checkpoint inhibitors in solid organ transplant recipients is limited. Published cases so far suggest severe risks for graft loss as high as 36% to 54%

Elevated oxysterol levels in human and mouse livers reflect nonalcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH), a primary cause of liver disease, leads to complications such as fibrosis, cirrhosis, and carcinoma, but the pathophysiology of NASH is incompletely understood. Epstein Barr virus induced G protein coupled receptor 2 (EBI2) and its oxysterol ligand 7α,25-dihydroxycholesterol (7α,25-diHC) are recently discovered immune regulators. Several lines of evidence suggest a role of oxysterols in NASH pathogenesis, but rigorous testing has not been performed. We measured oxysterol levels in livers of NASH patients by liquid chromatography-mass spectrometry and tested the role of the EBI2-7α,25-diHC-system in a murine feeding model of NASH. Free oxysterol profiling in livers from NASH patients revealed a pronounced increase in 24- and 7-hydroxylated oxysterols in NASH compared to controls. Levels of 24- and 7-hydroxylated oxysterols correlated with histological NASH activity. Histological analysis of murine liver samples demonstrated ballooning and liver inflammation. No significant genotype related differences were observed in Ebi2-/- animals and animals with defects in the 7α,25-diHC synthesizing enzymes CH25H and CYP7B1 compared to wildtype littermate controls,arguing against an essential role of these genes in NASH pathogenesis. Elevated 24- and 7-hydroxylated oxysterol levels were confirmed in murine NASH liver samples. Our results suggest increased bile acid synthesis in NASH samples, as judged by enhanced level of 7α- hydroxycholest-4-en-3-one, and impaired 24S-hydroxycholesterol metabolism as characteristic biochemical changes in livers affected by NASH

Rates of Hepatocellular Carcinoma After Start of Treatment for Chronic Hepatitis C Remain High with Direct Acting Antivirals: Analysis from a Swiss Liver Transplant Center.

Background Direct-acting antivirals (DAA) have revolutionized the therapy of chronic hepatitis C (CHC) and have replaced previous PEG-interferon/ribavirin (PEG-IFN/RBV) treatment. Patients with CHC and advanced liver disease are at increased risk for hepatocellular carcinoma (HCC). However, the effects of DAA-based CHC treatment on subsequent HCC incidence remain poorly understood. Patients and Methods This retrospective single-institution cohort study included 243 consecutive patients after PEG-IFN/RBV and 263 patients after DAA treatment. Multivariable cause-specific Cox proportional hazards models were used to compare time to HCC between treatment types, censoring patients who died or had an orthotopic liver transplantation (OLT) at the time of the competing event. Age, gender, BMI, viral load, cirrhosis, fibrosis stage, diabetes, virus genotype and previous PEG-IFN/RBV (before DAA) were used as covariates. In addition, we performed a propensity score-matched analysis. Results Nineteen HCC cases were observed after DAA therapy compared to 18 cases after PEG-IFN/RBV treatment. Patients were followed for a median of 4.1 years (IQR: 3.5-4.7) for DAA and 9.3 years (IQR: 6.6-12.4) for the PEG-IFN/RBV group. In an unadjusted Cox model, a hazard ratio (HR) of 6.40 (CI: 2.20-18.61, p=0.006) for HCC following DAA vs PEG-IFN/RBV was estimated. In multivariable Cox proportional hazard models, age and liver cirrhosis were identified as further HCC risk factors but the HR estimates for DAA vs PEG-IFN/RBV still indicate a considerably increased hazard associated with DAA treatment (HR between 7.23 and 11.52, p≤0.001, depending on covariates). A HR of 6.62 (CI: 2.01-21.84, p=0.002) for DAA vs PEG-IFN/RBV was estimated in the propensity score-matched analysis. The secondary outcomes death and OLT did not differ between treatment groups. Conclusion In a cohort study from a tertiary care hospital rates of HCC after the start of DAA treatment were higher compared to PEG-IFN/RBV treatment. Our data reinforce the recommendation that surveillance should be continued after successful CHC treatment

Orbital Pseudotumor as a Rare Extrahepatic Manifestation of Hepatitis C Infection

Hepatitis C is frequently accompanied by immune-related extrahepatic manifestations affecting the skin, kidneys, central and peripheral nervous system and exocrine glands. We present the case of a 40-year-old man with left-sided ptosis, exophthalmos and headache. MRI demonstrated left-sided orbital pseudotumor with lacrimal and retro-orbital contrast enhancement extending to the cavernous sinus and the vestibulocochlear nerve. Immunological tests of serum and cerebrospinal fluid identified hepatitis C virus (HCV) as a potential causative agent but did not indicate any additional infectious, malignant or immunological disorder. Hepatological evaluation revealed no signs of advanced liver disease. After initial spontaneous improvement, the patient subsequently developed vestibulocochlear failure with gait disorder, tinnitus and transient left-parietal sensory loss. Lacrimal biopsy demonstrated lymphocytic infiltrate, prompting steroid treatment. After initial improvement, steroids could not be tapered below 40 mg daily for several months due to recurrent symptoms. Twelve months after the initial presentation, the patient’s chronic HCV infection was successfully treated with sofosbuvir, simeprevir and ribavirin and he remains now free of symptoms without steroids. In patients with chronic hepatitis C, lymphocytic infiltrate of the salivary and lacrimal glands is a frequent phenomenon. However, the extent of the lymphocytic infiltrate beyond the lacrimal gland to the tip of the orbit, cavernous sinus and vestibulocochlear nerve as in our patient is highly unusual. For all symptomatic extrahepatic manifestations of hepatitis C infection, treatment of HCV as the underlying immune stimulus is recommended, and it helped to control the symptoms in our patient. In addition, long-term follow-up for recurrent lymphocyte infiltrate and development of lymphoma is warranted

In vitro and in vivo stability of the ε2ζ2 protein complex of the broad host−range Streptococcus pyogenes pSM19035 addiction system

Streptococcus pyogenes pSM19035−encoded epsilon (10.7 kDa) and zeta (32.4 kDa) proteins are necessary to secure stable plasmid inheritance in bacteria, with zeta acting as toxin that kills plasmid−deprived cells and epsilon as an antitoxin that neutralises the activity of zeta. The epsilon and zeta proteins co−purify as a stable complex that, according to analytical ultracentrifugation and gel filtration, exists as epsilon2zeta2 heterotetramer in solution. Co−crystals of the epsilon2zeta2 complex contain epsilon and zeta in 1:1 molar ratio. Unfolding studies monitoring circular dichroic and fluorescence changes show that the zeta protein has a significantly lower thermodynamic stability than the epsilon protein both in free state and in the complex. Proteolytic studies indicate that zeta protein is more stable in the epsilon2zeta2 complex than in the free state. In vivo studies reveal a short half−life of the epsilon antitoxin (−18 min) and a long lifetime of the zeta toxin (>60 min). When transcription−translation of a plasmid containing the epsilon and zeta genes was inhibited, cell death was observed after a short lag phase that correlates with the disappearance of the epsilon protein from the backgroun

Stability and DNA-binding properties of the ω regulator protein from the broad-host range Streptococcus pyogenes plasmid pSM19035

AbstractAt the transcriptional level, the pSM19035-encoded ω protein coordinates the expression of proteins required for control of copy number and maintenance of plasmids. Using circular dichroism, fluorescence spectroscopy, ultracentrifugation and an electrophoretic mobility shift assay, the wild-type ω protein and a variant with a C-terminal hexa-histidine tag (ω-H6) were characterized. The ω protein is mainly α-helical (42%), occurs as homodimer in solution, unfolds thermally with half transition temperatures, Tm, between ∼43 and ∼78°C depending on the ionic strength of the buffer, and binds PcopS-DNA with high affinity. The ω-H6 protein has a modified conformation with lower α-helix content (29%), lower thermal stability, and strongly reduced affinity to PcopS-DNA