The production and clinical implications of SARS-CoV-2 antibodies

Abstract

Funding 1. Chongqing Education Board "new coronavirus infection and prevention" emergency scientific research project (KYYJ202006).2. Chongqing Science and Technology Bureau "new crown pneumonia epidemic emergency science and technology special" the fourth batch of projects. Famous teacher project of Chongqing talent planAll rights reserved. No reuse allowed without permission. AbstractBackground: Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), a novel betacoronavirus, has caused an outburst of pneumonia cases in Wuhan, China. We report the production of specific IgM and IgG antibodies after the infection of SARS-CoV-2 and its implication for the diagnosis, pathology and the course of the disease as well as the recurrence of positive nucleic acid tests after discharge.Methods: Test results for SARS-CoV-2 IgM and IgG antibodies of 221 confirmed COVID-19 patients were retrospectively examined, and their clinical data were collected and analyzed based on various subgroups. SARS-CoV-2 IgM and IgG antibodies were determined with the chemiluminescence method. Findings: The concentration (S/CO) of SARS-CoV-2 IgM and IgG antibodies peaked on day 19-21 after symptom onset, with a median of 17.38 (IQR 4.39-36.4) for IgM and 5.59 (IQR 0.73-13.65) for IgG.Detection rates reached highest on day 16-18 and day 19-21 for IgM and IgG, which were 73.6% and 98.6%, respectively, with significantly higher concentration of IgG in critically ill patients than in those with mild to moderate disease (P=0.027). The concentration of the antibodies on day 16-21 is not correlated with the course or outcome of the disease (Spearman r < 0.20, P > 0.05). Nasopharyngeal swabs revealed positive SARS-CoV-2 RNA in up to 52.7% of recovered patients after discharge, whose IgG proved to be significantly lower than that of those with negative RNA results (P = 0.009). IgG and IgM were tested twice within 14 days after discharge with a 7-day interval, and the second testing of these antibodies displayed a decrease in concentration of 21.2% (IQR, 11.2%，34.48%) for IgG and 23.05% (IQR, -27.96%，46.13%) for IgM, without statistical significance between the patients with redetectable positive RNA results and those with negative RNA results after discharge. However, those with positive results experienced a count decrease in lymphocyte subsets.Interpretation: The concentration of SARS-CoV-2 IgM and IgG antibodies peaked on day 19-21 after symptom onset, and antibody testing on day 16-21 is associated with increased detection rates, but the antibody concentration does not affect the course and outcome of the infection. Recovering patients with re-detectable positive SARS-CoV-2 RNA displayed lower concentration of IgG, but the downward trend of IgG during recovery indicated its limited duration of protection, and the protective effect of IgG remains to be investigated.Funding: Chongqing Education Board, Chongqing Science and Technology Bureau, Famous teacher project of Chongqing talent plan All rights reserved. No reuse allowed without permission.

Antibody response to SARS-CoV-2 infection in humans: a systematic review

“…Older adults • Five studies found no association between antibody response and age, for both antibody positivity 147 or IgM/IgG titre. 21,58,148,167 • One study found that 'older' patients were more likely to seroconvert, 153 and concentration of IgG was related to age.…”

“…40,43,62,63 Virus-specific IgM became undetectable in almost all cases by around six weeks after disease onset in two small but high quality cohort studies. 53,64 Fewer studies describe IgA dynamics compared to IgM or IgG. IgA levels are reported to peak between 16 -22 days post symptom onset, although there is no consensus on trends over time.…”

“…• Ten studies reported that more severe cases have higher IgG titres, 23,34,39,42,75,[146][147][148][149][150] three studies reported no difference between mild and severe cases, 45,53,63 and two studies report severe cases have lower IgG titres. 53,63 • Five studies reported severe cases have higher IgM titres, 23,34,39,45,53 two studies reported no difference in between mild and severe cases, 64,102 and three studies reported severe cases have lower IgM titres. [150][151][152] • Three studies report severe cases have higher IgA titres, 23,140,148 one study reports no difference between mild and severe cases.…”

“…Three studies report an association between co-morbidities and seroconversion or antibody positivity, 64,153 with one finding immunocompromised individuals developed a lower response. 154…”

Microbiological Diagnosis of Covid-19 Disease in Children

“…Ancak, antikor konsantrasyonunun enfeksiyonun seyrini ve sonucunu etkilemediği görülmüştür. Ayrıca iyileşme sırasında saptanabilir düzeyde SARS-CoV-2 RNA pozitifliği olanlarda da IgG konsantrasyonlarının düşük olduğu gösterilmiştir (27) .…”