Amplified parallel antigen rapid test for point-of-care salivary detection of SARS-CoV-2 with improved sensitivity.

In the ongoing COVID-19 pandemic, simple, rapid, point-of-care tests not requiring trained personnel for primary care testing are essential. Saliva-based antigen rapid tests (ARTs) can fulfil this need, but these tests require overnight-fasted samples; without which independent studies have demonstrated sensitivities of only 11.7 to 23.1%. Herein, we report an Amplified Parallel ART (AP-ART) with sensitivity above 90%, even with non-fasted samples. The virus was captured multimodally, using both anti-spike protein antibodies and Angiotensin Converting Enzyme 2 (ACE2) protein. It also featured two parallel flow channels. The first contained spike protein binding gold nanoparticles which produced a visible red line upon encountering the virus. The second contained signal amplifying nanoparticles that complex with the former and amplify the signal without any linker. Compared to existing dual gold amplification techniques, a limit of detection of one order of magnitude lower was achieved (0.0064 ng·mL-1). AP-ART performance in detecting SARS-CoV-2 in saliva of COVID-19 patients was investigated using a case-control study (139 participants enrolled and 162 saliva samples tested). Unlike commercially available ARTs, the sensitivity of AP-ART was maintained even when non-fasting saliva was used. Compared to the gold standard reverse transcription-polymerase chain reaction testing on nasopharyngeal samples, non-fasting saliva tested on AP-ART showed a sensitivity of 97.0% (95% CI: 84.7-99.8); without amplification, the sensitivity was 72.7% (95% CI: 83.7-94.8). Thus, AP-ART has the potential to be developed for point-of-care testing, which may be particularly important in resource-limited settings, and for early diagnosis to initiate newly approved therapies to reduce COVID-19 severity.

Boosted abscopal effect from radiotherapy and pembrolizumab in anaplastic thyroid cancer: a mini-review and case report.

BACKGROUND: The abscopal effect, in which radiation induces a systemic anti-tumour immune response, has been demonstrated with radiotherapy. Immunotherapy boosts the abscopal effect by facilitating the immune response to radiation. Radiotherapy and programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) blockade has resulted in the boosted abscopal effect in solid cancers, but its role in anaplastic thyroid cancer (ATC) is unknown. In this mini-review, we describe the abscopal effect and summarise its proposed underlying mechanisms. We then present a potential case of boosted abscopal effect in ATC. CASE DESCRIPTION: In our case presentation, we describe a 51-year-old female who presented with 3 weeks of rapidly enlarging thyroid mass. Examination revealed a 3-cm thyroid nodule which was Bethesda V on fine needle aspiration cytology (FNAC). Intraoperatively, there was a gross extrathyroidal extension into the cricoid cartilage. After total thyroidectomy, post-operative histopathology showed widely invasive follicular thyroid cancer with anaplastic transformation (>50%). Immunohistochemistry showed high PD-L1 expression [combined positive score (CPS) >70%]. Due to residual cricoid cartilage disease and several peri-hilar and lung metastases on positron emission tomography-computed tomography (PET-CT) scan, she underwent post-operative palliative radiotherapy and pembrolizumab. After two cycles of pembrolizumab, repeat PET-CT scan showed complete response (CR) of local and distant disease. She remained well for 32 months, before recent discovery of a right mandible bony metastasis planned for radiotherapy. CONCLUSIONS: This case demonstrates exceptional response to radiotherapy and anti-PD-1 immunotherapy in ATC, potentially illustrating the first known abscopal effect in ATC with this treatment.