Antibody response patterns in COVID-19 patients with different levels of disease severity—Japan

Abstract

BackgroundWe analyzed antibody response patterns according to level of disease severity in patients with novel coronavirus disease 2019 (COVID-19) in Japan.MethodsWe analyzed 611 serum specimens from 231 patients with COVID-19 (mild, 170; severe, 31; critical, 30). IgM and IgG antibodies against nucleocapsid protein (N) and spike 1 protein (S1) were detected by enzyme-linked immunosorbent assays.FindingsThe peaks of fitting curves for the OD values of IgM and IgG antibodies against N appeared simultaneously, while those against S1 were delayed compared with N. The OD values of IgM against N and IgG against both N and S1 were significantly higher in the severe and critical cases than in the mild cases at 11 days after symptom onset. The seroconversion rates of IgG were higher than those of IgM against both N and S1 during the clinical course based on the optimal cut-off values defined in this study. The seroconversion rates of IgG and IgM against N and S1 were higher in the severe and critical cases than in the mild cases.ConclusionOur findings show that a stronger antibody response occurred in COVID-19 patients with greater disease severity and there were low seroconversion rates of antibodies against N and S1 in the mild cases. The antibody response patterns in our population suggest a second infection pattern, leading us to hypothesize that cross-reactivity occurs between SARS-CoV-2 and past infection with other human coronaviruses.

Evaluation of anti-SARS-CoV-2 antibody testing in asymptomatic or mild COVID-19 patients in outbreak on a cruise ship

“…First, although all COVID-19 patients analyzed in this study were either asymptomatic or mild, we did not know their distribution. Because the positivity rates of ELISA-detected anti-SARS-CoV-2 IgG antibodies against SP and NP were lower than those in mild COVID-19 patients in a previous study[7], it is expected that the percentage of asymptomatic COVID-19 patients was higher than that of mild COVID-19 patients. Second, only one kit each of LFA, ECLIA, and ELISA was used in this study.…”

“…Third, the time-course of the anti-SARS-CoV2 antibody testing was not evaluated in this study. This study focused on the time point that was reported as one of the best times for anti-SARS-CoV2 antibody testing [7,9,10]; however, it is possible that the optimal time for anti-SARS-CoV-2 antibody testing in asymptomatic or mild COVID-19 patients varies. Finally, the neutralizing antibodies were not evaluated.…”

“…The cutoff value determined in a previous study was used to interpret the ELISA results. [7] The cutoff values for anti-SARS-CoV-2 IgM and IgG antibody titers against SP were set at 0.25 and 0.26 and those against NP at 0.4 and 0.7, respectively. [7]…”

Can we predict antibody responses in SARS-CoV-2? A cohort analysis

“…After infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), about two thirds of hospitalized patients show IgG seroconversion within the first two weeks of infection [1] while later it will be up to 90% [2]. In contrast for mild cases, seroconversion might only be observed in 48% [2].…”

“…After infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), about two thirds of hospitalized patients show IgG seroconversion within the first two weeks of infection [1] while later it will be up to 90% [2]. In contrast for mild cases, seroconversion might only be observed in 48% [2]. Previous studies in hospitalized patients with Coronavirus disease 2019 (COVID-19) indicate some correlation between disease severity and strength of the antibody response [3-6].…”