PD-L1 promotes oncolytic virus infection via a metabolic shift that inhibits the type I IFN pathway.

While conventional wisdom initially postulated that PD-L1 serves as the inert ligand for PD-1, an emerging body of literature suggests that PD-L1 has cell-intrinsic functions in immune and cancer cells. In line with these studies, here we show that engagement of PD-L1 via cellular ligands or agonistic antibodies, including those used in the clinic, potently inhibits the type I interferon pathway in cancer cells. Hampered type I interferon responses in PD-L1-expressing cancer cells resulted in enhanced efficacy of oncolytic viruses in vitro and in vivo. Consistently, PD-L1 expression marked tumor explants from cancer patients that were best infected by oncolytic viruses. Mechanistically, PD-L1 promoted a metabolic shift characterized by enhanced glycolysis rate that resulted in increased lactate production. In turn, lactate inhibited type I IFN responses. In addition to adding mechanistic insight into PD-L1 intrinsic function, our results will also help guide the numerous ongoing efforts to combine PD-L1 antibodies with oncolytic virotherapy in clinical trials.

Benign Metastasizing Leiomyoma in the Lung Presenting in a Phyllodes-Like Pattern Mimicking a Biphasic Tumor: A Case Report.

Primary biphasic tumors of the lung are rare. Lung lesions with a biphasic pattern are far more commonly primary or metastatic soft tissue tumors with entrapped native respiratory epithelium, giving the false impression of a biphasic tumor. We report a case of bilateral benign metastasizing leiomyomas in a 69-year-old female where the tumor cells diffusely entrapped native respiratory glands in a phyllodes-like pattern. The radiographic characteristics and histologic appearance were not immediately diagnostic and covered a wide differential. Reaching the final diagnosis required the use of immunohistochemical studies as well as correlation with the patient's history and radiographic findings. To the best of our knowledge, this is the first report of pulmonary benign metastasizing leiomyoma presenting in a phyllodes-like pattern. This case illustrates the importance of considering entrapment of native lung epithelium in the differential diagnosis of biphasic-appearing lung tumors.

The Postmortem Interpretation of Cardiac Genetic Variants of Unknown Significance in Sudden Death in the Young: A Case Report and Review of the Literature.

Sudden cardiac death (SCD) in adolescents and young adults is a major traumatic event for families and communities. In these cases, it is not uncommon to have a negative autopsy with structurally and histologically normal heart. Such SCD cases are generally attributed to channelopathies, which include long QT syndrome, short QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia. Our understanding of the causes for SCDs has changed significantly with the advancements in molecular and genetic studies, where many mutations are now known to be associated with certain channelopathies. Postmortem analysis provides great value in informing decision-making with regard to screening tests and prophylactic measures that should be taken to prevent sudden death in first degree relatives of the decedent. As this is a rapidly advancing field, our ability to identify genetic mutations has surpassed our ability to interpret them. This led to a unique challenge in genetic testing called variants of unknown significance (VUS). VUSs present a diagnostic dilemma and uncertainty for clinicians and patients with regard to next steps. Caution should be exercised when interpreting VUSs since misinterpretation can result in mismanagement of patients and their families. A case of a young adult man with drowning as his proximate cause of death is presented in circumstances where cardiac genetic testing was indicated and undertaken. Eight VUSs in genes implicated in inheritable cardiac dysfunction were identified and the interpretation of VUSs in this scenario is discussed.

Pharmacologic HIV-1 Nef blockade promotes CD8 T cell-mediated elimination of latently HIV-1-infected cells in vitro.

Eradication of the HIV-1 latent reservoir represents the current paradigm to developing a cure for AIDS. HIV-1 has evolved multiple mechanisms to evade CD8 T cell responses, including HIV-1 Nef-mediated downregulation of MHC-I from the surface of infected cells. Nef transcripts and protein are detectable in samples from aviremic donors, suggesting that Nef expression in latently HIV-1-infected CD4 T cells protects them from immune-mediated clearance. Here, we tested 4 small molecule inhibitors of HIV-1 Nef in an in vitro primary CD4 T cell latency model and measured the ability of autologous ex vivo or HIV-1 peptide-expanded CD8 T cells to recognize and kill latently infected cells as a function of inhibitor treatment. Nef inhibition enhanced cytokine secretion by autologous CD8 T cells against latently HIV-1-infected targets in an IFN-γ release assay. Additionally, CD8 T cell-mediated elimination of latently HIV-1-infected cells was significantly enhanced following Nef blockade, measured as a reduction in the frequency of infected cells and Gag protein in cultures following viral outgrowth assays. We demonstrate for the first time to our knowledge that Nef blockade, in combination with HIV-specific CD8 T cell expansion, might be a feasible strategy to target the HIV-1 latent reservoir that should be tested further in vivo.

Type I interferon responses are impaired in latently HIV infected cells.

BACKGROUND: The latent HIV-1 reservoir represents the primary barrier to the eradication of HIV-1 infection. The design of novel reservoir-clearance strategies, however, is impeded in part by the inability to distinguish latently HIV-infected cells from uninfected cells. Significant impairment of the type I interferon (IFN-I) response is observed during productive HIV-1 infection. Although this remains poorly described in the context of latent HIV-1 infection, presence of potential defects may serve as a novel therapeutic target. Therefore, IFN-I pathways were characterized using two latently HIV-1-infected cell lines, U1 and OM10.1, in comparison to their respective uninfected parental U937 and HL60 cell lines. FINDINGS: Constitutive expression and induction of important mediators of IFN-I signaling including IFNα/ß cytokines, IFNAR1, MHC-I, ISG15, and PKR were evaluated following exogenous IFNα or poly(I:C) treatment. Differences in basal expression of IFNAR1, MHC-I, and PKR were observed between the latently HIV-1 infected and uninfected cell lines. In parallel, significant impairments in the induction of MHC-I, ISG15 and PKR, as well as secretion of IFNα/ß cytokines were observed in response to appropriate exogenous stimulation within the two latently HIV-infected U1 and OM10.1 cells, relative to their HIV-uninfected parental cells. CONCLUSIONS: In comparison to the HIV-uninfected U937 and HL60 cell lines, widespread defects in IFN-I responsiveness were observed within the latently HIV-infected U1 and OM10.1 cells. These impairments represent novel therapeutic targets, which may be amenable to strategies currently employed in cancer therapy.

Mechanism of hard-nanomaterial clearance by the liver.

The liver and spleen are major biological barriers to translating nanomedicines because they sequester the majority of administered nanomaterials and prevent delivery to diseased tissue. Here we examined the blood clearance mechanism of administered hard nanomaterials in relation to blood flow dynamics, organ microarchitecture and cellular phenotype. We found that nanomaterial velocity reduces 1,000-fold as they enter and traverse the liver, leading to 7.5 times more nanomaterial interaction with hepatic cells relative to peripheral cells. In the liver, Kupffer cells (84.8 ± 6.4%), hepatic B cells (81.5 ± 9.3%) and liver sinusoidal endothelial cells (64.6 ± 13.7%) interacted with administered PEGylated quantum dots, but splenic macrophages took up less material (25.4 ± 10.1%) due to differences in phenotype. The uptake patterns were similar for two other nanomaterial types and five different surface chemistries. Potential new strategies to overcome off-target nanomaterial accumulation may involve manipulating intra-organ flow dynamics and modulating the cellular phenotype to alter hepatic cell interactions.

HCV Specific IL-21 Producing T Cells but Not IL-17A Producing T Cells Are Associated with HCV Viral Control in HIV/HCV Coinfection.

BACKGROUND: Decreased hepatitis C virus (HCV) clearance, faster cirrhosis progression and higher HCV RNA levels are associated with Human Immunodeficiency virus (HIV) coinfection. The CD4+ T helper cytokines interleukin (IL)-21 and IL-17A are associated with virus control and inflammation, respectively, both important in HCV and HIV disease progression. Here, we examined how antigen-specific production of these cytokines during HCV mono and HIV/HCV coinfection was associated with HCV virus control. METHODS: We measured HCV-specific IL-21 and IL-17A production by transwell cytokine secretion assay in PBMCs from monoinfected and coinfected individuals. Viral control was determined by plasma HCV RNA levels. RESULTS: In acutely infected individuals, those able to establish transient/complete HCV viral control tended to have stronger HCV-specific IL-21-production than non-controllers. HCV-specific IL-21 production also correlated with HCV viral decline in acute infection. Significantly stronger HCV-specific IL-21 production was detected in HAART-treated coinfected individuals. HCV-specific IL-17A production was not associated with lower plasma HCV RNA levels in acute or chronic HCV infection and responses were stronger in HIV coinfection. HCV-specific IL-21/ IL-17A responses did not correlate with microbial translocation or fibrosis. Exogenous IL-21 treatment of HCV-specific CD8+ T cells from monoinfected individuals enhanced their function although CD8+ T cells from coinfected individuals were somewhat refractory to the effects of IL-21. CONCLUSIONS: These data show that HCV-specific IL-21 and IL-17A-producing T cells are induced in HIV/HCV coinfection. In early HIV/HCV coinfection, IL-21 may contribute to viral control, and may represent a novel tool to enhance acute HCV clearance in HIV/HCV coinfected individuals.

Infantile cholestasis in the Central-Eastern Province Saudi Arabia.

In the King Khalid University Hospital (Central Province) and King Fahad Hospital of the University (Eastern Province) Saudi Arabia, we identified 64 infants with cholestasis. The causes of cholestasis were idiopathic neonatal hepatitis in 29; extrahepatic biliary atresia in 17; neonatal hepatitis secondary to Rubella and Cytomegalovirus in six and four infants, respectively; paucity of intrahepatic bile ducts in six and galactosaemia in two. The diagnosis was confirmed by liver biopsy and or operative cholangiography, in all infants.

First case of human infection caused by Pasteurella gallinarum causing infective endocarditis in an adolescent 10 years after surgical correction for truncus arteriosus.

OBJECTIVE: To report the first case of human infection (infective endocarditis [IE]) caused by Pasteurella gallinarum and to review the literature regarding IE caused by the genus Pasteurella. SETTING: University hospital based. PATIENT: An adolescent boy who underwent successful correction for truncus arteriosus 10 years before the present illness. RESULTS: Persistent fever, pallor, and a palpable spleen suggested IE clinically. Echocardiography documented vegetation in the conduit that was used for surgical correction. Blood cultures grew P. gallinarum and confirmed its role as the causative organism for IE in the patient. CONCLUSION: This case illustrates that IE may develop in a child with congenital heart disease several years after surgical intervention using material that is foreign to the body (conduit), and that such a complication may involve unusual pathogens. These observations emphasize the need for careful long-term follow-up of children with congenital heart disease even after successful surgical correction.

Percentage glycosylated haemoglobin in normal, G6PD deficient and HbSS Saudi Arabs.

Reference values have been established for erythrocyte glycosylated haemoglobin levels in a normal Saudi population and in subjects with various haematological disorders. The mean glycosylated haemoglobin levels (SE) were 7.28% (0.039) for normal, 6.04% (0.057) for G6PD deficient, 4.40% (0.081) for homozygous sickle cell, and 6.44% (0.109) for heterozygous sickle cell subjects. Values of 6.26% (0.103) and 4.75% (0.127) for glycosylated haemoglobin were determined for heterozygous and homozygous sickle cell subjects with G6PD deficiency, respectively. Statistical analysis of the data shows significant differences in the extent of glycosylation between G6PD deficient, HbSS and normal controls. Where possible the results are compared to values reported for other populations.

Myelofibrosis and pancytopenia in systemic lupus erythematosus.

A 13-year-old Saudi girl presented with severe clinical features of systemic lupus erythematosus of 3 months' duration. In addition to laboratory evidence of the disease, the patient was found to have pancytopenia and myelofibrosis. While pancytopenia was considerably improved by steroids, myelofibrosis was not reversed. The coexistence of myelofibrosis and pancytopenia in patients with systemic lupus erythematosus has been reported, but their possible causal relationship remains unresolved.

Clinical presentation of systemic lupus erythematosus in Saudi patients.

A study conducted to assess the incidence and clinical expression of systemic lupus erythematosus in the Eastern Province of Saudi Arabia revealed that the disease is uncommon in this region, only 32 cases being recorded in five years. However, the clinical manifestations of the disease are similar to those observed elsewhere.