t6A and ms2t6A Modified Nucleosides in Serum and Urine as Strong Candidate Biomarkers of COVID-19 Infection and Severity.

SARS-CoV-2 infection alters cellular RNA content. Cellular RNAs are chemically modified and eventually degraded, depositing modified nucleosides into extracellular fluids such as serum and urine. Here we searched for COVID-19-specific changes in modified nucleoside levels contained in serum and urine of 308 COVID-19 patients using liquid chromatography-mass spectrometry (LC-MS). We found that two modified nucleosides, N6-threonylcarbamoyladenosine (t6A) and 2-methylthio-N6-threonylcarbamoyladenosine (ms2t6A), were elevated in serum and urine of COVID-19 patients. Moreover, these levels were associated with symptom severity and decreased upon recovery from COVID-19. In addition, the elevation of similarly modified nucleosides was observed regardless of COVID-19 variants. These findings illuminate specific modified RNA nucleosides in the extracellular fluids as biomarkers for COVID-19 infection and severity.

[Evaluation of the enzyme-linked immunosorbent assay system for sero-diagnosis of summer-type hypersensitivity pneumonitis].

Summer-type hypersensitivity pneumonitis (SHP) is the most prevalent type of hypersensitivity pneumonitis in Japan. Its main causative antigenic organisms are Trichosporon species. Although this disease had been thought to be unique to Japan, more than ten patients were found in Korea, recently. It is expected that patients with SHP will be found elsewhere in the Temperate Zones, the tropics or in the subtropics. It is important in diagnosing SHP to prove specific antibody against causative antigen in patient's serum, for the existence of specific antibody indicates the patient had been exposed to, and sensitized to the antigen. In the present study, we devised Enzyme-linked Immunosorbent Assay system using monoclonal antibody specific to T. asahii, to measure antibodies against T. asahii. We evaluated the usefulness of the system by using sera from patients with SHP, patients with other pulmonary diseases, or healthy volunteers. We found specificity and sensitivity of the system were 92.8% and 92.3%, respectively. This system was proved to be useful in diagnosing SHP.