C-reactive protein as an effector molecule in Covid-19 pathogenesis.

The current pandemic caused by SARS-CoV-2 virus infection is known as Covid-19 (coronavirus disease 2019). This disease can be asymptomatic or can affect multiple organ systems. Damage induced by the virus is related to dysfunctional activity of the immune system, but the activity of molecules such as C-reactive protein (CRP) as a factor capable of inducing an inflammatory status that may be involved in the severe evolution of the disease, has not been extensively evaluated. A systematic review was performed using the NCBI-PubMed database to find articles related to Covid-19 immunity, inflammatory response, and CRP published from December 2019 to December 2020. High levels of CRP were found in patients with severe evolution of Covid-19 in which several organ systems were affected and in patients who died. CRP activates complement, induces the production of pro-inflammatory cytokines and induces apoptosis which, together with the inflammatory status during the disease, can lead to a severe outcome. Several drugs can decrease the level or block the effect of CRP and might be useful in the treatment of Covid-19. From this review it is reasonable to conclude that CRP is a factor that can contribute to severe evolution of Covid-19 and that the use of drugs able to lower CRP levels or block its activity should be evaluated in randomized controlled clinical trials.

Nanoantibodies: small molecules, big possibilities.

Camelids (camels, dromedaries, alpacas, llamas, and vicuñas) contain in their serum conventional heterodimeric antibodies as well as antibodies with no light chains (L) in their structure and composed of only heavy chains (H), called as HcAbs (heavy chain antibodies). Variable fragments derived from these antibodies, called as VHH or nanoantibodies (Nbs), have also been described. Since their discovery, Nbs have been widely used in the fields of research, diagnostics, and pharmacotherapy. Despite being approximately one-tenth the size of a conventional antibody, they retain similar specificity and affinity to conventional antibodies and are much easier to clone and manipulate. Their unique properties such as small size, high stability, strong antigen binding affinity, water solubility, and natural origin make them suitable for the development of biopharmaceuticals and nanoreagents. The present review aims to describe the main structural and biochemical characteristics of these antibodies and to provide an update on their applications in research, biotechnology, and medicine. For this purpose, an exhaustive search of the biomedical literature was performed in the following databases: Medline (PubMed), Google Scholar, and ScienceDirect. Meta-analyses, observational studies, review articles, and clinical guidelines were reviewed. Only original articles were considered to assess the quality of the evidence.

SARS-CoV-2 infection represents a high risk for the elderly: analysis of pathogenesis.

As people get older, age-related alterations occur that lead to increased susceptibility to disease. In the current COVID-19 pandemic, older people are particularly susceptible to a SARS-CoV-2 infection developing into severe disease. The objective of this review was to examine the literature regarding factors that may explain the tendency of this population to develop severe COVID-19. Research articles considered in this review were searched for in EMBASE, PubMed, and Web of Science from December 2019 to December 2020. Citations were screened by two independent reviewers. Studies of the immune system in older individuals found alterations in both the adaptive and innate immune systems. The adaptive system is depressed in its functions, and the innate system is in a pro-inflammatory state that can lead to chronic disease. This pro-inflammatory state may be related to a severe course of disease in COVID-19. This review shows that the level of evidence supporting an association between immune alterations in the elderly and susceptibly to severe progression of SARS-CoV-2 infection is generally consistent. Preventive measures such as early antiviral treatment are of key importance for prevention of severe progression of COVID19.

Inflammation, pyroptosis and its possible relation to the physiopathology of COVID-19

SARS-CoV-2 is the causal agent of the current 2019 coronavirus disease pandemic (COVID-19). Like other respiratory coronaviruses, SARS-CoV-2 is transmitted primarily through respiratory droplets released from an infected person. The pathophysiology of SARS-CoV-2 infection is similar to that of SARS-CoV infection, with aggressive inflammatory responses resulting in severe damage to the respiratory tract. In this review we address the importance of the innate immune response in the physiopathology of COVID-19 with special emphasis on the activation of the inflammasome and the consequent cell death by pyroptosis, two essential elements that could explain the exacerbated inflammatory response observed in some patients.