Dysregulated Immune Responses in SARS-CoV-2-Infected Patients: A Comprehensive Overview

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first detected in humans more than two years ago and caused an unprecedented socio-economic burden on all countries around the world. Since then, numerous studies have attempted to identify various mechanisms involved in the alterations of innate and adaptive immunity in COVID-19 patients, with the ultimate goal of finding ways to correct pathological changes and improve disease outcomes. State-of-the-art research methods made it possible to establish precise molecular mechanisms which the new virus uses to trigger multisystem inflammatory syndrome and evade host antiviral immune responses. In this review, we present a comprehensive analysis of published data that provide insight into pathological changes in T and B cell subsets and their phenotypes, accompanying the acute phase of the SARS-CoV-2 infection. This knowledge might help reveal new biomarkers that can be utilized to recognize case severity early as well as to provide additional objective information on the effective formation of SARS-CoV-2-specific immunity and predict long-term complications of COVID-19, including a large variety of symptoms termed the ‘post-COVID-19 syndrome’.

Effect of Cholecalciferol Supplementation on the Clinical Features and Inflammatory Markers in Hospitalized COVID-19 Patients: A Randomized, Open-Label, Single-Center Study

“…Furthermore, it was noted that key alterations in peripheral blood circulating B cell populations during the acute phase of SARS-CoV-2 infection were linked to the decreased levels of the relative and absolute number of B cells, increased frequencies of plasma cell precursors, atypical CD21-negative and activated B cells etc. [49,51,52]. Currently, we have shown that vitamin D supplementation could effectively decrease the relative numbers of activated CD38++CD27 transitional B cells and 'naïve' B cells in patients with acute COVID-19.…”

Immune Cells Profiles In The Peripheral Blood Of Patients With Moderate To Severe COVID-19 And Healthy Subjects With and Without Vaccination With The Pfizer-BioNTech mRNA Vaccine

“…Various studies have been carried out recently to study the level of monocyte subsets in response to COVID-19 infection. A higher percentage of CD14+CD16+ inflammatory monocytes was demonstrated in patients with mild to severe COVID-19 ( 20 , 31 ). They also showed that there is a significant expansion of CD14+CD16+monocytes producing IL-6 in the peripheral blood of ICU COVID-19 patients than those who did not require ICU hospitalization.…”

“…The detection of immune cells in the peripheral blood at low counts in response to viral infections is attributed to the migration of immune cells to the site of infection or due to the virus-mediated destruction of T cells ( 2 ). In addition, few studies of SARS-CoV-2 infection found that T cells specifically correlate with protection and decreased total lymphocytes, T lymphocyte, and B lymphocyte were associated with severe illness ( 7 , 18 , 19 ) and this decrease is probably caused by a defect in the induction of acquired immunity ( 20 ). In a recent study, the frequency of SARS-CoV-2 specific T cells was equal in vaccinated subjects and patients recovered from COVID-19 ( 13 ).…”

“…CD19+CD38+CD27+ antibody secreting cells were shown, in the present study, to be similar in the COVID 19 patients, HS and VS groups tested ( Figure 2C ). Hyper activation of B cells and an increase in peripheral plasma cells expressing high CD27+ CD38+ was shown to be a sign of poor prognosis ( 20 ). In another previous study, ASCs were detected at a higher level in the blood of a single patient with mild to moderate disease at the time of viral clearance, than in healthy controls ( 10 ).…”

“…The infected patients also produced higher level of CD14+CD16+ cell subset than VS (p= 0.006, Figure 2C ). In normal physiological conditions, 85% of the monocytes in the peripheral blood express CD14++ CD16 low HLA-DR++ phenotype and these cells leave the circulation and infiltrate to the inflammatory site following infection ( 20 ). Various studies have been carried out recently to study the level of monocyte subsets in response to COVID-19 infection.…”