Broadening the differential: pneumomediastinum and COVID-19 infection.

The novel coronavirus (COVID-19) has emerged as a new pathogen responsible for an atypical viral pneumonia, with severe cases progressing to an acute respiratory distress syndrome. In our practice, we have observed patients admitted with COVID-19 pneumonia developing worsening hypoxaemic respiratory failure prompting the need for urgent endotracheal intubation. Here, we present a case of a patient admitted with severe COVID-19 pneumonia who required continuous positive airway pressure support following acute deterioration. However, with the patient requiring an increasing fraction of inspired oxygen (FiO2), a prompt CT pulmonary angiogram scan was performed to exclude an acute pulmonary embolism. Surprisingly, this revealed a pneumomediastinum. Following a brief admission to the intensive care unit, the patient made a full recovery and was discharged 18 days post admission.

UK Patients of Bangladeshi Descent with Crohn's Disease Respond Less Well to TNF Antagonists Than Caucasian Patients.

BACKGROUND: Patients with inflammatory bowel disease are currently managed with the assumption that trial data are applicable to all ethnic groups. Previous studies demonstrate differences in disease severity and phenotype of Asian patients with Crohn's disease (CD), including Bangladeshi Asians within the UK. No study has evaluated the impact of ethnicity on response to anti-TNFs. AIM: Our primary endpoint was a comparison of failure-free survival on first prescribed anti-TNF (anti-tumor necrosis factor) therapy in UK Bangladeshi and Caucasian patients with CD. Our secondary aims were to evaluate disease phenotype, indication for anti-TNF prescription, and duration from diagnosis until first anti-TNF prescribed between groups. METHODS: The records of consecutive outpatient appointments over a 12-month period were used to identify Caucasian and Bangladeshi patients prescribed an anti-TNF for CD. Information on patient demographics, ethnicity, disease phenotype, immunomodulator use, outcome from first biologic, duration of therapy, and reason for cessation was recorded. RESULTS: In total, 224 Caucasian and Bangladeshi patients were prescribed an anti-TNF for CD. Bangladeshi patients started an anti-TNF 4.3 years earlier after diagnosis than Caucasian patients (3.9 years vs. 8.2 years: p < 0.01). Bangladeshi patients experienced shorter failure-free survival than Caucasian patients (1.8 vs. 4.8 years p < 0.01). By 2 years, significantly more Bangladeshi patients had stopped anti-TNF due to loss of response (OR 6.35, p < 0.01). CONCLUSIONS: This is the first study to suggest that Bangladeshi patients resident in the UK with CD respond less well to treatment with TNF antagonists than Caucasian patients.

4-1BB ligand activates bystander dendritic cells to enhance immunization in trans.

Expression of the costimulatory receptor 4-1BB is induced by TCR recognition of Ag, whereas 4-1BB ligand (4-1BBL) is highly expressed on activated APC. 4-1BB signaling is particularly important for survival of activated and memory CD8(+) T cells. We wished to test whether coexpression of Ag and 4-1BBL by dendritic cells (DC) would be an effective vaccine strategy. Therefore, we constructed lentiviral vectors (LV) coexpressing 4-1BBL and influenza nucleoprotein (NP). Following s.c. immunization of mice, which targets DC, we found superior CD8(+) T cell responses against NP and protection from influenza when 4-1BBL was expressed. However, functionally superior CD8(+) T cell responses were obtained when two LV were coinjected: one expressing 4-1BBL and the other expressing NP. This surprising result suggested that 4-1BBL is more effective when expressed in trans, acting on adjacent DC. Therefore, we investigated the effect of LV expression of 4-1BBL in mouse DC cultures and observed induced maturation of bystander, untransduced cells. Maturation was blocked by anti-4-1BBL Ab, required cell-cell contact, and did not require the cytoplasmic signaling domain of 4-1BBL. Greater maturation of untransduced cells could be explained by LV expression of 4-1BBL, causing downregulation of 4-1BB. These data suggest that coexpression of 4-1BBL and Ag by vaccine vectors that target DC may not be an optimal strategy. However, 4-1BBL LV immunization activates significant numbers of bystander DC in the draining lymph nodes. Therefore, transactivation by 4-1BBL/4-1BB interaction following DC-DC contact may play a role in the immune response to infection or vaccination.