MO1016: Features of the Formation of Post-Infectious and Post-Vaccinal Humoral Immune Response to SARS-COV-2 in Kidney Recipients
Authors: Amvrosieva Tamara , Belskaya Ina , Bohush Zoya , Paklonskaya Natallia , Yudziankova Tatsiana , Yuliya Koltunova , Kazinets Olga , Kalachyk Aleh , Chebotareva Tatsiana 
Published: May 2022

Abstract

BACKGROUND
This paper presents the results of studying the characteristics of the antibody response in kidney recipients who are at high risk of severe COVID-19.

METHOD
The study of features of the formation of post-infectious anti-SARS-CoV-2 IgG was carried out in the group of kidney recipients (n = 171) with PCR confirmed diagnosis of COVID-19. Studies of the characteristics of post-vaccination immunity were carried out in a group of vaccinated recipients (n = 49) with Sputnik V (Russia) or Vero Cell (China).
ELISA was used to detect IgG to S and N proteins of the SARS-CoV-2.
Comparative studies used a simple randomized selection of immunocompetent COVID-19 patients (n = 163).
Statistical data processing was carried out using the χ2 and Wald's methods.

RESULTS
It was found that 30 days after the onset of clinical symptoms of COVID-19 in kidney recipients, IgG to S and/or N proteins of SARS-CoV-2 were detected in 89.5% (83.9%–93.3%) of them. The detection rate of IgG to the S protein was higher than that to the N protein [87.7% (81.9%–91.9%) and 62.0% (54.5%–68.9%), respectively). At the same time, the seroprevalence to the pathogen varied by age: in the 18–34-year-old group it was 77.7% (59.9%–88.9%), in the 50–64-year-old group it was 96.7% (88.2%–99.8%) and in the group &gt;64 years old it was 80.0% (66.8%–89.0%). This trend of antibody production in older recipients correlated with the highest frequency of registration in them of moderate and severe forms [66.7% (56.4%–75.6%)]. Differences due to the severity of the disease were noted both in the frequency of detectable antibodies [80.3% (69.5%–88.0%) in recipients with a mild form of COVID-19 and 96.0% in recipients with a severe form of infection (P &lt; .001)] and in the intensity of the formed anti-SARS-CoV-2 immunity. Thus, high values of PC (positivity coefficient) (&gt;12) to S protein were recorded in 52.7% (39.8%–65.3%) and 63.2% (53.1%–72.2%) patients with mild and severe forms of COVID-19, respectively, which indicated a direct dependence of the production of antiviral antibodies on the severity of the infection. It was found that in 62.6% (55.1%–69.5%) of recovered recipients anti-SARS-CoV-2 IgG persisted for a period of 3 months from the onset of infection. In a significant proportion of recipients [42.8% (35.5%–50.2%)], antibodies were detected for up to 15 months. In general, the post-infectious antibody response in kidney recipients and immunocompetent patients had similar patterns of development. Despite the general mechanism of antibody production, in immunocompetent patients, the frequency of detection of antiviral antibodies (to N protein: 82.9% and to S protein: 91.2%), tension indicators (high values of PC to N protein: 51.0% and to S protein: 75.5%) and the duration of retention (in 50.3% at 15 months of monitoring) were slightly higher than the same parameters in recipients with COVID-19.
In kidney recipients after immunization with Sputnik V and Vero Cell (n = 34), a rather low detection rate of antiviral IgG [52.9% (36.7%–68.6%) compared with a similar parameter (P &lt; .001) in vaccinated immunocompetent individuals [96.8% (94.8%–98.1%)] was found. The seroprevalence in the group of recipients with hybrid immunity (after illness and vaccination, n = 15) was 86.7% (60.9%–97.5%). In a comparative analysis of the intensity of post-vaccination immunity, high values of PC to S protein (&gt;12) were recorded in 44.0% (26.7%–62.9%) of recipients vaccinated with Sputnik V and 50.0% (31.4%–68.6%) of recipients vaccinated with Vero Cell. The inverse relationship was observed in immunocompetent individuals: 64.7% (58.1%–70.7%) for Sputnik V and 44.2% (36.8%–51.8%] for Vero Cell.

CONCLUSION
The patterns of antibody response to the causative agent in recipients with COVID-19 are comparable to those in immunocompetent patients, while for vaccinated recipients, a low frequency of detection of antiviral antibodies was shown, which indicates the need to continue research on the humoral immunity in people with vulnerable immunity in order to select the best tactics for COVID-19 immunization.