Increasingly, studies are being published that provide evidence for the tropism of SARS-CoV-2 to tissues outside the respiratory system - i.e., the affinity of SARS-CoV-2 to infect organs besides the lungs (Chu et al., 2020; Xiao, Tang et al., 2020). Of note, a postmortem study of six patients who died of COVID-19 revealed that the novel coronavirus has the potential to infect the secondary lymphoid organs – the spleen and lymph nodes (Chen, Feng et al., 2020). The secondary lymphoid organs are vital to the maintenance of the immune system and initiation of adaptive immune responses: once B …
Cytotoxic T Cells and Natural Killer Cells Express the Exhaustion Marker NKG2A; The SARS-CoV Antibody CR3022 Exhibits Cross-Reactivity to SARS-CoV-2 Spike Protein
I reported previously on observed functional exhaustion of T cells in patients with severe COVID-19 (see 4/13 updates). In that study, Diao et al. noted increased expression of the exhaustion markers PD-1 and Tim-3 on T cells that increased with the severity of the disease and recovered to normal levels in the convalescent period (Diao et al., 2020). A similar study out of China observed significantly increased expression of another functional exhaustion marker NKG2A on CD8+ T cells as well as on natural killer (NK) cells in severe compared to non-severe cases (Zheng et al., 2020). The …
Type-I Interferons Are Implicated in the Host Immune Response; Interleukin 6 is a Major Indicator of Disease Severity in COVID-19
Updates on the intricacies of the host immunological response to SARS-CoV-2 are published daily, giving us new insights into the clinical progression of COVID-19 and potential therapeutic routes to pursue. As we move through the worst of the pandemic, it will become increasingly important to turn our attention to untangling the interactions between the novel coronavirus’ biological response and underlying comorbidities so that we may begin to treat patients more specifically. Understanding the immense overlap in the immunopathology of various pathogenic and disease processes will be critical …