Clinics (Sao Paulo). 2021;76:e2818.
Antibody indexes in COVID-19 convalescent plasma donors: Unanswered questions
Tatiana Carvalho de Souza Bonetti
, Flavia Roche Moreira Latini
, Adriana Lukow Invitti
, Marcelo Cunio Machado Fonseca
, Fulvio Alexandre Scorza
, Maira Garcia Saldanha
, Fernanda T. Bellucco
, Natalia B.S. Bacarov
, Michel M. Soane
, Manoel João Batista Castelo Girão
DOI: 10.6061/clinics/2021/e2818
OBJECTIVE:
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is characterized by high contagiousness, as well as variable clinical manifestations and immune responses. The antibody response to SARS-CoV-2 is directly related to viral clearance and the antibodies’ ability to neutralize the virus and confer long-term immunity. Nevertheless, the response can also be associated with disease severity and evolution. This study correlated the clinical characteristics of convalescent COVID-19 patients with immunoglobulin A (IgA) and IgG anti-SARS-CoV-2 antibodies.
METHODS:
This study included 51 COVID-19 health care professionals who were candidates for convalescent plasma donation from April to June 2020. The subjects had symptomatic COVID-19 with a polymerase chain reaction-confirmed diagnosis. We measured anti-SARS-CoV-2 IgA and IgG antibodies after symptom recovery, and the subjects were classified as having mild, moderate, or severe symptoms.
RESULTS:
Anti-SARS-CoV-2 antibodies were positive in most patients (90.2%). The antibody indexes for IgA and IgG did not differ significantly between patients presenting with mild or moderate symptoms. However, they were significantly higher in patients with severe symptoms.
CONCLUSIONS:
Our study showed an association between higher antibody indexes and severe COVID-19 cases, and several hypotheses regarding the association of the antibody dynamics and severity of the disease in SARS-CoV-2 infection have been raised, although many questions remain unanswered.
Keywords: Antibodies; COVID-19; Disease Severity; SARS-CoV-2
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