BP180-specific IgG is associated with skin adverse events, therapy response, and overall survival in non-small cell lung cancer patients treated with checkpoint inhibitors.

BACKGROUND: Anti-programmed cell death protein 1 (PD1)/programmed death-ligand 1(PD-L1) therapy frequently entails immune-related adverse events (irAEs), and biomarkers to predict irAEs are lacking. Although checkpoint inhibitors have been found to reinvigorate T cells, the relevance of autoantibodies remains elusive. OBJECTIVE: Our aim was to explore whether IgG autoantibodies directed against coexpressed antigens by tumor tissue and healthy skin correlate with skin irAEs and therapy outcome. METHODS: We measured skin-specific IgG via enzyme-linked immunosorbent assay in patients with non-small cell lung cancer (NSCLC) who received anti-PD1/PD-L1 treatment between July 2015 and September 2017 at the Kantonsspital St. Gallen. Sera were sampled at baseline and during therapy after 8 weeks. RESULTS: Analysis of publicly available tumor expression data revealed that NSCLC and skin coexpress BP180, BP230, and type VII collagen. A skin irAE developed in 16 of 40 recruited patients (40%). Only elevated anti-BP180 IgG at baseline significantly correlated with the development of skin irAEs (P = .04), therapy response (P = .01), and overall survival (P = .04). LIMITATIONS: The patients were recruited in a single tertiary care center. CONCLUSIONS: Our data suggest that the level of anti-BP180 IgG of NSCLC patients at baseline is associated with better therapy response and overall survival and with a higher probability to develop skin irAEs during anti-PD1/PD-L1 treatment.

Tularemia: an experience of 13 cases including a rare myocarditis in a referral center in Eastern Switzerland (Central Europe) and a review of the literature.

BACKGROUND: Tularemia, a zoonotic disease caused by Francisella tularensis, can cause a broad spectrum of disease in humans including six major clinical presentations: the ulceroglandular, glandular, oculoglandular, oropharyngeal, typhoidal and pneumonic form. The epidemiology and ecology and thus transmission of tularemia are complex, depending on conditions unique to specific locations. CASE SERIES AND METHODS: Thirteen cases with different forms of the disease and one very rare case of a myocarditis are reported, discussed, and reviewed within the scope of current literature. CONCLUSION: Tularemia is a rare, but emerging disease in Central Europe with glandular and ulceroglandular disease as its predominant forms. Transmission is mainly caused by contact with lagomorphs, rodents and tick bites. However, domestic cats may play an important role in transmission too. Myocarditis is probably a worldwide, but very rare manifestation of tularemia.

Acute Hepatitis E Virus infection with coincident reactivation of Epstein-Barr virus infection in an immunosuppressed patient with rheumatoid arthritis: a case report.

BACKGROUND: Hepatitis E virus (HEV) is the most recently discovered of the hepatotropic viruses, and is considered an emerging pathogen in developed countries with the possibility of fulminant hepatitis in immunocompromised patients. Especially in the latter elevated transaminases should be taken as a clue to consider HEV infection, as it can be treated by discontinuation of immunosuppression and/or ribavirin therapy. To our best knowledge, this is a unique case of autochthonous HEV infection with coincident reactivation of Epstein-Barr virus (EBV) infection in an immunosuppressed patient with rheumatoid arthritis (RA). CASE PRESENTATION: A 68-year-old Swiss woman with RA developed hepatitis initially diagnosed as methotrexate-induced liver injury, but later diagnosed as autochthonous HEV infection accompanied by reactivation of her latent EBV infection. She showed confounding serological results pointing to three hepatotropic viruses (HEV, Hepatitis B virus (HBV) and EBV) that could be resolved by detection of HEV and EBV viraemia. The patient recovered by temporary discontinuation of immunosuppressive therapy. CONCLUSIONS: In immunosuppressed patients with RA and signs of liver injury, HEV infection should be considered, as infection can be treated by discontinuation of immunosuppression. Although anti-HEV-IgM antibody assays can be used as first line virological tools, nucleic acid amplification tests (NAAT) for detection of HEV RNA are recommended--as in our case--if confounding serological results from other hepatotropic viruses are obtained. After discontinuation of immunosuppressive therapy, our patient recovered from both HEV infection and reactivation of latent EBV infection without sequelae.

Molecular mechanism underlying B19 virus inactivation and comparison to other parvoviruses.

BACKGROUND: B19 virus (B19V) is a human pathogen frequently present in blood specimens. Transmission of the virus occurs mainly via the respiratory route, but it has also been shown to occur through the administration of contaminated plasma-derived products. Parvoviridae are highly resistant to physicochemical treatments; however, B19V is more vulnerable than the rest of parvoviruses. The molecular mechanism governing the inactivation of B19V and the reason for its higher vulnerability remain unknown. STUDY DESIGN AND METHODS: After inactivation of B19V by wet heat and low pH, the integrity of the viral capsid was examined by immunoprecipitation with two monoclonal antibodies directed to the N-terminal of VP1 and to a conformational epitope in VP2. The accessibility of the viral DNA was quantitatively analyzed by a hybridization-extension assay and by nuclease treatment. RESULTS: The integrity of the viral particles was maintained during the inactivation procedure; however, the capsids became totally depleted of viral DNA. The DNA-depleted capsids, although not infectious, were able to attach to target cells. Comparison studies with other members of the Parvoviridae family revealed a remarkable instability of B19V DNA in its encapsidated state. CONCLUSION: Inactivation of B19V by heat or low pH is not mediated by capsid disintegration but by the conversion of the infectious virions into DNA-depleted capsids. The high instability of the viral DNA in its encapsidated state is an exclusive feature of B19V, which explains its lower resistance to inactivation treatments.

Low pH-dependent endosomal processing of the incoming parvovirus minute virus of mice virion leads to externalization of the VP1 N-terminal sequence (N-VP1), N-VP2 cleavage, and uncoating of the full-length genome.

Minute virus of mice (MVM) enters the host cell via receptor-mediated endocytosis. Although endosomal processing is required, its role remains uncertain. In particular, the effect of low endosomal pH on capsid configuration and nuclear delivery of the viral genome is unclear. We have followed the progression and structural transitions of DNA full-virus capsids (FC) and empty capsids (EC) containing the VP1 and VP2 structural proteins and of VP2-only virus-like particles (VLP) during the endosomal trafficking. Three capsid rearrangements were detected in FC: externalization of the VP1 N-terminal sequence (N-VP1), cleavage of the exposed VP2 N-terminal sequence (N-VP2), and uncoating of the full-length genome. All three capsid modifications occurred simultaneously, starting as early as 30 min after internalization, and all of them were blocked by raising the endosomal pH. In particles lacking viral single-stranded DNA (EC and VLP), the N-VP2 was not exposed and thus it was not cleaved. However, the EC did externalize N-VP1 with kinetics similar to those of FC. The bulk of all the incoming particles (FC, EC, and VLP) accumulated in lysosomes without signs of lysosomal membrane destabilization. Inside lysosomes, capsid degradation was not detected, although the uncoated DNA of FC was slowly degraded. Interestingly, at any time postinfection, the amount of structural proteins of the incoming virions accumulating in the nuclear fraction was negligible. These results indicate that during the early endosomal trafficking, the MVM particles are structurally modified by low-pH-dependent mechanisms. Regardless of the structural transitions and protein composition, the majority of the entering viral particles and genomes end in lysosomes, limiting the efficiency of MVM nuclear translocation.

Parvovirus uncoating in vitro reveals a mechanism of DNA release without capsid disassembly and striking differences in encapsidated DNA stability.

The uncoating mechanism of parvoviruses is unknown. Their capsid robustness and increasing experimental data would suggest an uncoating mechanism without capsid disassembly. We have developed an in vitro system to detect and quantify viral DNA externalization and applied the assay on two parvoviruses with important differences in capsid structure, human B19 and minute virus of mice (MVM). Upon briefly treating the capsids to increasing temperatures, the viral genome became accessible in its full-length in a growing proportion of virions. Capsid disassembly started at temperatures above 60 degrees C for B19 and 70 degrees C for MVM. For both viruses, the externalization followed an all-or-nothing mechanism, without transitions exposing only a particular genomic region. However, the heat-induced DNA accessibility was remarkably more pronounced in B19 than in MVM. This difference was also evident under conditions mimicking endosomal acidification (pH 6.5 to 5), which triggered the externalization of B19-DNA but not of MVM-DNA. The externalized ssDNA was a suitable template for the full second-strand synthesis. Immunoprecipitation with antibodies against conformational epitopes and quantitative PCR revealed that the DNA externalized by heat was mostly dissociated from its capsid, however, the low pH-induced DNA externalization of B19 was predominantly capsid-associated. These results provide new insights into parvovirus uncoating suggesting a mechanism by which the full-length viral genome is released without capsid disassembly. The remarkable instability of the encapsidated B19 DNA, which is easily released from its capsid, would also explain the faster heat inactivation of B19 when compared to other parvoviruses.

Molecular determinants of heritable vitamin E deficiency.

Tocopherol transfer protein (TTP) is a key regulator of vitamin E homeostasis. TTP is presumed to function by transporting the hydrophobic vitamin between cellular compartments, thus facilitating its secretion to the extracellular space. Indeed, recombinant TTP demonstrates marked ability to facilitate tocopherol transfer between lipid bilayers. We report the biochemical characterization of six missense mutations TTP(1) that are found in human AVED patients. We expressed the H101Q, A120T, R192H, R59W, E141K, and R221W TTP mutants in Escherichia coli, and purified the proteins to homogeneity. We then characterized TTP and its mutant counterparts with respect to their affinity for RRR-alpha-tocopherol and to their ability to catalyze tocopherol transfer between membranes. We observe the R59W, E141K, and R221W mutations, associated with the severe, early-onset version of AVED, are impaired in tocopherol binding and transfer activity. Surprisingly, despite the profound clinical effect of the R59W, E141K, and R221W mutations in vivo, their impact on TTP activity in vitro is quite benign (2-3-fold reduction in transfer kinetics). Furthermore, mutations associated with milder forms of the AVED disease, while causing pronounced perturbations in tocopherol homeostasis in vivo, are remarkably similar to the wild-type protein in the tocopherol transfer assays in vitro. Our data indicate that tocopherol transfer activity in vitro does not properly recapitulate the physiological functions of TTP. These findings suggest the possibility that the AVED syndrome may not arise from an inability of TTP to bind or to transfer alpha tocopherol, but rather from defects in other activities of the protein.