Bae S, et al. J Korean Med Sci. 2021 Apr;36(17):e115. https://doi.org/10.3346/jkms.2021.36.e115

The severity of COVID-19 ranges from mild to critical diseases. However, limited data have been published on the detailed kinetics of viral load and host immune response throughout the disease course depending on disease severity. In this study, we comprehensively analyzed viral load, antibody responses to SARS-CoV-2, and cytokines/chemokines during the disease course, and identified the factors related to severity. Nasopharyngeal (NP) and plasma specimens were obtained from 31 patients with COVID-19 during hospitalization. Viral RNA in NP specimens was quantified by reverse transcription–PCR. Anti–SARS-CoV-2 antibodies and cytokines/chemokines in plasma specimens were analyzed by ELISA and cytometric bead array. The viral load in patients with COVID-19 peaked at the early stage of the disease and continuously decreased. Severe and critical cases showed higher viral load and prolonged viral shedding than asymptomatic and mild cases. Whereas plasma IgG was gradually increased and maintained during hospitalization, plasma IgM peaked at 3 weeks after symptom onset and dissipated. The antibody response in severe and critical cases was slightly delayed but stronger than those in others. High levels of interferon (IFN)-α, IFN-γ–induced protein-10, monokine induced by IFN-γ, and interleukin-6 at 5–10 days from symptom onset were associated with the severity of COVID-19. Our data indicate that high viral load in the respiratory tract and excessive production of cytokines and chemokines between 1 and 2 weeks from the symptom onset were significantly associated with the severity of COVID-19.

Lee YW, et al. J Korean Med Sci. 2021 May;36(21):e153. https://doi.org/10.3346/jkms.2021.36.e153

Background. Data on the accuracy of conventional histomorphologic diagnosis are limited, especially in mucormycosis. We therefore investigated the accuracy of histomorphologic diagnosis of mucormycosis and aspergillosis, using immunohistochemistry (IHC) tests for mucormycosis and aspergillosis. Methods. Patients enrolled met the modified criteria for proven and probable mucormycosis (during a 22-year period) or invasive aspergillosis (during a 6-year period) and had formalin-fixed, paraffin-embedded tissues available. We first tested the diagnostic performance of IHC for mucormycosis and aspergillosis in proven cases. Then we determined the accuracy of histomorphologic diagnosis of probable cases, using the IHC tests. Results. In 7 proven cases of mucormycosis, the sensitivity and specificity of mucormycosis IHC were 100% (95% confidence interval, 65%–100%) and 100% (68%–100%), respectively. In 8 proven cases of aspergillosis, and the sensitivity and specificity of aspergillosis IHC staining were 87% (53%–98%) and 100% (65%–100%), respectively. Of 23 probable mucormycosis cases, 20 (87%) were positive with mucormycosis IHC, 2 (9%) were positive with aspergillosis IHC (including 1 positive for both), and 2 were negative with both. Of 16 probable aspergillosis cases, 10 (63%) were positive with aspergillosis IHC, 4 (25%) were positive with mucormycosis IHC, and 2 (13%) were negative with both tests. Conclusions. Aspergillosis and mucormycosis seem not to be correctly diagnosed morphologically, because some of the probable cases showed either test with both antibodies or failure to stain with the homologous antibody. In the absence of fungal culture results, the IHC tests seem helpful in differentiating between aspergillosis and mucormycosis.