Observational Study
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Biol Chem. Mar 27, 2023; 14(2): 40-51
Published online Mar 27, 2023. doi: 10.4331/wjbc.v14.i2.40
Temporal pattern of humoral immune response in mild cases of COVID-19
Isadora Maria Pilati Campos, Milena Marques, Gabrielle Caroline Peiter, Ana Paula Carneiro Brandalize, Mauricio Bedim dos Santos, Fabrício Freire de Melo, Kádima Nayara Teixeira
Isadora Maria Pilati Campos, Milena Marques, Ana Paula Carneiro Brandalize, Mauricio Bedim dos Santos, Kádima Nayara Teixeira, Campus Toledo, Universidade Federal do Paraná, Toledo 85.919-899, Paraná, Brazil
Gabrielle Caroline Peiter, Setor Palotina, Universidade Federal do Paraná, Palotina 85.950-000, Paraná, Brazil
Fabrício Freire de Melo, Campus Anísio Teixeira, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Bahia, Brazil
Author contributions: Teixeira KN and Brandalize APC designed, coordinated the study and interpreted the data; Pilati Campos IM and Peiter GC carried out the experiments, acquired and analyzed data; dos Santo MB carried out the statistical analyses; Pilati Campos IM and Marques M reviewed the literature and wrote the manuscript; Teixeira KN and de Melo FF reviewed the manuscript.
Institutional review board statement: The study was approved by the Ethics Committee for research with humans of the Setor de Ciências da Saúde-Universidade Federal do Paraná (UFPR)/Brazil (Protocol no. 35872520.8.0000.0102).
Informed consent statement: All study participants were over 18 years old, and they read and signed the informed consent statement.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: The study participants gave informed consent for data disclosure in an anonymous way, without exposing their identity.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Kádima Nayara Teixeira, PhD, Professor, Campus Toledo, Universidade Federal do Paraná, Biopark-Avenida Max Planck, 3796, Toledo 85.919-899, Paraná, Brazil. kadimateixeira@ufpr.br
Received: August 28, 2022
Peer-review started: August 28, 2022
First decision: November 30, 2022
Revised: December 8, 2022
Accepted: February 2, 2023
Article in press: February 2, 2023
Published online: March 27, 2023
Processing time: 205 Days and 11.2 Hours
ARTICLE HIGHLIGHTS
Research background

The molecular test used in the diagnosis of coronavirus disease 2019 is very specific and sensitive, however, it is not able to detect previous exposure to the virus nor to assess immunological memory. Therefore, serological tests that have this capability are used as tools for understanding the course of the humoral immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Research motivation

The motivation for this study arose from the serological test developed at the Federal University of Paraná, which in the validation process showed better sensitivity than commercial tests. A more sensitive test allows specific antibodies to be detected even at low titers, and thus to effectively assess whether there is still a protective antibody response in individuals who have been infected by the virus.

Research objectives

The aim of this study was to identify if a pattern of SARS-CoV-2 specific immunoglobulin G (IgG) production can be determined according to the time elapsed since diagnosis of the disease/onset of symptoms. The data could indicate, for example, the interval between vaccination doses.

Research methods

This study was initiated after approval by the ethics committee. The participants were tested by real-time reverse transcriptase-polymerase chain reaction, the municipal government provided us with the data. Only positive cases were included in the study. Blood collection was performed by our research team and the method used for specific IgG antibodies was the indirect enzyme-linked immunosorbent assay. Statistical analyses were performed by the statistician of the research group, one of the authors of the manuscript.

Research results

The results of the study showed that there is no time pattern for the production of specific IgG. Less than one month after infection, some participants no longer have detectable IgG in the serum, while others have the antibodies seven months after infection.

Research conclusions

In addition to the impossibility of establishing a temporal pattern of IgG response, the data indicate that SARS-CoV-2 does not appear to induce a long-lasting humoral response.

Research perspectives

The study perspective is to analyze the immunoglobulin M (IgM) response of the same volunteers and determine the titers of both IgG and IgM to better understand seroconversion and the robustness of the anti-SARS-CoV-2 antibody response.