@article {KITAGAWA2947, author = {TAKAO KITAGAWA and MASANOBU KOBAYASHI and TOHRU OHTA and MASARU TERASAKI and YOKO TSUKAMOTO and RIE TAKAI and REIKA ISHIZUMI and OSAMU UEHARA and KOJI NAKAGAWA and KOZO AKINO and MASAHIRO ASAKA and YASUHIRO KURAMITSU}, title = {Nine Cases of SARS-CoV-2-PCR-positive Samples Showed No Increase of Antibodies Against SARS-CoV-2}, volume = {35}, number = {5}, pages = {2947--2949}, year = {2021}, doi = {10.21873/invivo.12587}, publisher = {International Institute of Anticancer Research}, abstract = {Background/Aim: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been affecting Hokkaido, Japan since late February 2020 until present. The aim of this study was to report the relationship between anti-SARS-CoV-2 antibody-positive and SARS-CoV-2 PCR-positive cases by analyzing anti-SARS-CoV-2 antibodies (IgG and total-Ig). Patients and Methods: Serum samples were collected from care workers and nurses in two nursing homes and two hospitals which underwent virus outbreak. All people were confirmed to be SARS-CoV-2-positive by RT-qPCR and their sera was analyzed for anti-SARS-CoV-2 antibodies (IgG and total-Ig). Results: Although 34 out of 43 samples (79.1\%) showed enough amount of anti-SARS-CoV-2 antibodies, 9 RT-qPCR -positive samples (20.9\%) showed absence of anti-SARS-CoV-2 antibodies in their sera. Conclusion: The results that 20.9\% of RT-qPCR-positive samples with SARS-CoV-2 showed absence of anti-SARS-CoV-2 antibodies provides a possibility that the innate immune reaction could eliminate the virus without activating adaptive immune reaction.}, issn = {0258-851X}, URL = {https://iv.iiarjournals.org/content/35/5/2947}, eprint = {https://iv.iiarjournals.org/content/35/5/2947.full.pdf}, journal = {In Vivo} }