Using CRISPR to enhance T cell effector function for therapeutic applications

T cells are critical to fight pathogenic microbes and combat malignantly transformed cells in the fight against cancer. To exert their effector function, T cells produce effector molecules, such as the pro-inflammatory cytokines IFN-γ, TNF-α and IL-2. Tumors possess many inhibitory mechanisms that dampen T cell effector function, limiting the secretion of cytotoxic molecules. As a result, the control and elimination of tumors is impaired. Through recent advances in genomic editing, T cells can now be successfully modified via CRISPR/Cas9 technology. For instance, engaging (post-)transcriptional mechanisms to enhance T cell cytokine production, the retargeting of T cell antigen specificity or rendering T cells refractive to inhibitory receptor signaling can augment T cell effector function. Therefore, CRISPR/Cas9-mediated genome editing might provide novel strategies for cancer immunotherapy. Recently, the first-in-patient clinical trial was successfully performed with CRISPR/Cas9-modified human T cell therapy. In this review, a brief overview of currently available techniques is provided, and recent advances in T cell genomic engineering for the enhancement of T cell effector function for therapeutic purposes are discussed.

Cytomegalovirus pancreatitis in an immunocompetent patient

Cytomegalovirus (CMV) is a double-stranded DNA virus, which infects a large portion of the adult population. In immunocompetent patients, it typically is asymptomatic or manifests as mild and self-limiting flu-like illness symptoms, whereas in immunocompromised patients, CMV can cause significant disease. Herein we report an unusual case of CMV pancreatitis in an immunocompetent 75-year-old female. Patient developed severe significant pancreatic necrosis that failed non-operative management, and ultimately underwent pancreatic necrosectomy. Later on, she developed three spontaneous gastric perforations. The first two perforations were managed operatively, but after the third perforation family decided not to undergo another operation. The CMV pancreatitis diagnosis was based on pancreatic histopathology and confirms by a prompt response to ganciclovir. Patient was promptly started on intravenous (IV) ganciclovir which resulted in clinical recovery and she remained asymptomatic more than one-year post op. This is a rare case of CMV pancreatitis with gastric perforations in an immunocompetent patient. High degree of suspicion and appropriate treatment are important for such clinical scenarios.

Acute Acalculous Cholecystitis due to primary acute Epstein-Barr virus infection treated with laparoscopic cholecystectomy; a case report

Introduction

Epstein Barr virus (EBV) is a human herpes virus 4, transmitted through intimate contact between susceptible persons and asymptomatic EBV shedders. It usually presents with fever, pharyngitis and lymphadenopathy. Majority of individuals with primary EBV infection recover uneventfully. Acute Acalculous Cholecystitis (AAC) is usually seen in hospitalized and critically ill patients with major trauma, shock, severe sepsis, total parenteral nutrition and mechanical ventilation.

Case presentation

We report a 25-year- old woman presented with acute Epstein-Barr Virus (EBV)infection and hepatobiliary iminodiacetic acid (HIDA) scan confirmed presence of Acute Acalculous Cholecystitis (AAC). Conservative management was advised initially, but she had a laparoscopic cholecystectomy due to intolerable abdominal pain.

Conclusion

AAC is a rare complication of acute EBV infection and it is usually managed conservatively, although our patient had laparoscopic cholecystectomy due to intolerable abdominal pain.

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Acute Acalculous Cholecystitis (AAC) is a rare complication of acute EBV infection.

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AAC should be suspected in patient with acute EBV infection, presenting with abdominal pain.

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Management is usually conservative without surgical intervention.

Hemophagocytic Lymphohistiocytosis Masquerading as Acute Liver Failure: A Single Center Experience

BACKGROUND/AIM

Hemophagocytic lymphohistiocytosis (HLH) is a potentially life-threatening disorder of extreme inflammation and unregulated immune response which require prompt recognition and early introduction of definitive therapy. HLH can present with wide range of hepatic dysfunction ranging from mild elevation of transaminases to liver failure. This study is carried out to describe the clinical and laboratory presentation of HLH.

METHODS

Patients who were diagnosed with HLH between January 2013 and December 2015 were retrospectively included in this study.

RESULTS

Six patients were diagnosed as secondary HLH with median age of 28.5 years at diagnosis. All patients were presented with history of deep jaundice and high grade fever with pancytopenia and splenomegaly. Underlying diagnosis was viral infections in 4 and probable viral infection in remaining two. Bone marrow hemophagocytosis was present in 3 cases. Three patients were treated with corticosteroids only and one each with corticosteroids with cyclosporine or intravenous immunoglobulin (IVIG) and HLH treatment protocol. One patient died due to acute respiratory distress syndrome (ARDS); another patient died in follow-up due to respiratory failure due to pneumonia.

CONCLUSIONS

HLH is rare and potentially life-threatening cause of prolonged fever, jaundice and pancytopenia. Early diagnosis and initiation of specific therapy can improve clinical outcome.

Macroautophagy Proteins Assist Epstein Barr Virus Production and Get Incorporated Into the Virus Particles

Epstein Barr virus (EBV) persists as a latent herpes virus infection in the majority of the adult human population. The virus can reactivate from this latent infection into lytic replication for virus particle production. Here, we report that autophagic membranes, which engulf cytoplasmic constituents during macroautophagy and transport them to lysosomal degradation, are stabilized by lytic EBV replication in infected epithelial and B cells. Inhibition of autophagic membrane formation compromises infectious particle production and leads to the accumulation of viral DNA in the cytosol. Vice versa, pharmacological stimulation of autophagic membrane formation enhances infectious virus production. Atg8/LC3, an essential macroautophagy protein and substrate anchor on autophagic membranes, was found in virus preparations, suggesting that EBV recruits Atg8/LC3 coupled membranes to its envelope in the cytosol. Our data indicate that EBV subverts macroautophagy and uses autophagic membranes for efficient envelope acquisition during lytic infection.

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Macroautophagic membranes are stabilized during lytic EBV replication.

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Inhibition of macroautophagic membrane formation reduces EBV production.

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Stimulation of macroautophagic membrane formation boosts EBV production.

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Without macroautophagic membranes EBV DNA accumulates in the cytosol.

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Macroautophagic membranes get incorporated into EBV particles.

Hemophagocytic Lymphohistiocytosis (HLH) in Children Presenting as Liver Disease

Hemophagocytic lymphohistiocytosis (HLH) is a rare acute hyperinflammatory condition presenting with high fever, pancytopenia, splenomegaly with the pathologic finding of hemophagocytic lymphohistiocytosis in bone marrow and other tissues. Predominant hepatic manifestations at presentation are rare. We report a series of three cases which showcase the spectrum of liver disease as presentation in hemophagocytic lymphohistiocytosis.