Antigen testing for COVID-19 using image-based assessment of oral specimens

While numerous diagnostic tests for COVID-19 have been developed for clinical and public health use, most of them provide binary or one-dimensional information on SARS-CoV-2 infection in pursuit of speed and ease of use. As their readouts are largely dependent on the specimen collection procedure, reliable diagnosis is still difficult. Here we report the development of a prototypical method for the immunocytochemical diagnosis of SARS-CoV-2 infection using oral specimens and fluorescent nanobodies against the viral spike and nucleocapsid proteins. Our cytological approach for the detection of SARS-CoV-2 infection was validated by our finding that at least half of SARS-CoV-2 RNAs in oral specimens were localized in the cellular fraction. Mapping antigens on sampled cells provided qualitative image data to which appropriate statistical texture analysis could be applied for the quantitative assessment of SARS-CoV-2 infectious status. A comprehensive comparative analysis revealed that oral cavity swabbing by medical workers provides specimens for COVID-19 diagnosis that yield comparable diagnostic accuracy as self-collected saliva specimens. Our diagnostic strategy may enable medical workers to acquire a wealth of information on virus-human cell interactions for multifaceted insight into COVID-19.

SARS-CoV-2 RT-qPCR testing of pooled saliva samples: a case study of 824 asymptomatic individuals and a questionnaire survey in Japan

From the beginning of the COVID-19 pandemic, the demand for diagnostic and screening tests has exceeded supply. Although the proportion of vaccinated people has increased in wealthier countries, breakthrough infections have occurred amid the emergence of new variants. Pooled-sample COVID-19 testing using saliva has been proposed as an efficient, inexpensive, and non-invasive method to allow larger-scale testing, especially in a screening setting. In this study, we aimed to evaluate pooled RT-qPCR saliva testing and to compare the results with individual tests. Employees of Philips Japan, Ltd. were recruited to participate in COVID-19 screening from October to December 2020. Asymptomatic individuals (n=824) submitted self-collected saliva samples. Samples were tested for the presence of SARS-CoV-2 by RT-qPCR in both 10-sample pools and individual tests. We also surveyed participants regarding their thoughts and behaviors after the PCR screening project. Two of the 824 individuals were positive by RT-qPCR. In the pooled testing, one of these two had no measurable Ct value, but showed an amplification trend at the end of the PCR cycle. Both positive individuals developed cold-like symptoms, but neither required hospitalization. Of the 824 participants, 471 responded to our online questionnaire. Overall, while respondents agreed that PCR screening should be performed regularly, the majority were willing to undergo PCR testing only when it was provided for free or at low cost. In conclusion, pooled testing of saliva samples can support frequent large-scale screening that is rapid, efficient, and inexpensive.

TP53 variants in p53 signatures and the clonality of STICs in RRSO samples / 부인종양

Objective@#Precursor lesions may be identified in fallopian tube tissue after risk-reducing salpingo-oophorectomy (RRSO) in patients with pathogenic variants of BRCA1/2. Serous tubal intraepithelial carcinoma (STIC) is considered a precursor of high-grade serous carcinoma, whereas the significance of the p53 signature remains unclear. In this study, we investigated the relationship between the p53 signature and the risk of ovarian cancer. @*Methods@#We analyzed the clinicopathological findings and conducted DNA sequencing for TP53 variants of p53 signatures and STIC lesions isolated using laser capture microdissection in 13 patients with pathogenic variants of BRCA1/2 who underwent RRSO and 17 control patients with the benign gynecologic disease. @*Results@#TP53 pathogenic variants were detected significantly higher in RRSO group than control (p<0.001). No difference in the frequency of p53 signatures were observed between groups (53.8% vs 29.4%; p=0.17). TP53 sequencing and next-generation sequencing analysis in a patient with STIC and occult cancer revealed 2 TP53 mutations causing different p53 staining for STICs and another TP53 mutation shared between STIC and occult cancer. @*Conclusion@#The sequence analysis for TP53 revealed 2 types of p53 signatures, one with a risk of progression to STIC and ovarian cancer with pathological variants in TP53 and the other with a low risk of progression without pathological variants in TP53 as seen in control.