Characteristics and serological patterns of COVID‐19 convalescent plasma donors: optimal donors and timing of donation

Abstract

BACKGROUND The lack of effective treatments against the 2019 coronavirus disease (COVID‐19) has led to the exploratory use of convalescent plasma for treating COVID‐19. Case reports and case series have shown encouraging results. This study investigated SARS‐CoV‐2 antibodies and epidemiological characteristics in convalescent plasma donors, to identify criteria for donor selection. METHODS Recovered COVID‐19 patients, aged 18‐55 years, who had experienced no symptoms for more than 2 weeks, were recruited. Donor characteristics such as disease presentations were collected and SARS‐CoV‐2 N‐specific IgM, IgG, and S‐RBD‐specific IgG levels were measured by enzyme‐linked immunosorbent assay (ELISA). RESULTS Whereas levels of N‐specific IgM antibody declined after recovery, S‐RBD‐specific and N‐specific IgG antibodies increased after 4 weeks from the onset of symptoms, with no significant correlation to age, sex, or ABO blood type. Donors with the disease presentation of fever exceeding 38.5°C or lasting longer than 3 days exhibited higher levels of S‐RBD‐specific IgG antibodies at the time of donation. Of the 49 convalescent plasma donors, 90% had an S‐RBD‐specific IgG titer of ≥1:160 and 78% had a titer of ≥1:640 at the time of plasma donation. Of the 30 convalescent plasma donors, who had donated plasma later than 28 days after the onset of symptoms and had a disease presentation of fever lasting longer than 3 days or a body temperature exceeding 38.5°C, 100% had an S‐RBD‐specific IgG titer of ≥1:160 and 93% had a titer of ≥1:640. CONCLUSION This study indicates that the S‐RBD‐specific IgG antibody reaches higher levels after 4 weeks from the onset of COVID‐19 symptoms. We recommend the following selection criteria for optimal donation of COVID‐19 convalescent plasma: 28 days after the onset of symptoms and with a disease presentation of fever lasting longer than 3 days or a body temperature exceeding 38.5°C. Selection based on these criteria can ensure a high likelihood of achieving sufficiently high S‐RBD‐specific IgG titers.

SARS-CoV-2 serology and virology trends in donors and recipients of convalescent plasma

“…Protective specific antibodies like IgG produced by B cells after infection with the virus, help block the virus from entering the host cells, as well as defend against viral reinfection. SAR-CoV-2 virus is enveloped with four structural proteins which serve as targets for antibodies [11,20,21], and uses its spike glycoprotein, a main target for neutralization antibody, to bind its receptor and mediate membrane fusion and virus entry [21]. The hypothesis is that administration of convalescent plasma containing such antibodies may mediate viral neutralization [22] by inhibiting viral replication and blunting pro-inflammatory endogenous antibody response [23].…”

“…Information on immune response to SARS-CoV-2 and duration is rather limited. Studies suggest thatt IgM expression is concurrent with IgG expression and both antibodies are associated with a high degree of variability in patients who test positive for the virus [11]. Li et al [11] showed that in 49 potential donors, IgG antibodies increased after 4 weeks from the onset of SARS-CoC-2 symptoms, while in another study these antibodies decreased in 2-3 months after the infection [12].…”

“…Passive immunity delivered as anti-coronavirus antibodies from convalescent human plasma has promise of emerging as a therapeutic option in the treatment of SARS-CoV-2 however, the selection of potential donors and the timing of the donations are critical to ensure therapeutic potency [11]. Shen et al first described a case series of 5 critically ill patients with SARS-CoV-2 and Acute Respiratory Distress Syndrome (ARDS) who showed improvement in clinical status after treatment with convalescent plasma containing neutralizing antibodies [13].…”

IgG seroprevalence against SARS-CoV-2 in a cohort of 449 non-hospitalized, high-risk exposure individuals.

“…It could be suggested that this high rate was due to the exposition to con rmed cases, but leaving time enough to develop a robust humoral IgG response 24 . In fact, plasma from COVID-19 convalescent patients to be used as potential treatment against the infection, show signi cantly higher anti-SARS-CoV-2 titers after more than 42 days from symptom onset to plasma donation 25 . For those symptomatic subjects of our cohort, at least 14 days after the end of symptoms were required before performing the test with an average time gap of more than 40 days.…”

Viejos remedios para nuevos males. El caso del plasma de convalecientes

“…[14][15][16] Desde el punto de vista de los bancos de sangre, es posible establecer el perfil del donante idóneo: paciente recuperado de infección por SARS-CoV-2, diagnosticado mediante hisopado nasofaríngeo con técnica de biología molecular (RT-PCR), captado idealmente a los 28 días del inicio de los síntomas, que cuente con una segun-da prueba molecular negativa al momento de la donación, obtener el componente mediante procedimiento de aféresis, y en términos generales debiendo cumplir con los criterios de la legislación nacional. 17 En resumen, aún con lo controversial del procedimiento, mantiene un lugar importante en la terapéutica de agentes infecciosos nuevos, ya que no hay otra alternativa que posibilite la atención específica fuera de las medidas generales de sostén. La inmunoterapia pasiva llegó para quedarse.…”