{"id":8173,"date":"2022-03-07T15:06:52","date_gmt":"2022-03-07T06:06:52","guid":{"rendered":"https:\/\/www.emukk.com\/WP\/?p=8173"},"modified":"2022-03-07T15:11:34","modified_gmt":"2022-03-07T06:11:34","slug":"complement-activation-might-be-strongly-involved-in-systemic-worsening-of-sars-cov-2-studies-from-autopsy-lung-and-kidney-samples","status":"publish","type":"post","link":"https:\/\/www.emukk.com\/WP\/en\/complement-activation-might-be-strongly-involved-in-systemic-worsening-of-sars-cov-2-studies-from-autopsy-lung-and-kidney-samples\/","title":{"rendered":"Complement activation might be strongly involved in systemic worsening of COVID-19: studies from autopsy lung and kidney samples"},"content":{"rendered":"

A group from Department of Nephropathology, University Hospital Erlangen, Friedrich-Alexander-University (FAU) Erlangen-N\u00fcrnberg, Erlangen, Germany, etc. has reported that complement activation might be involved in systemic worsening of COVID-19.
\nhttps:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC8884149\/<\/a><\/p>\n

One pathway potentially involved in the SARS-CoV-2 driven inflammatory cytokine overproduction is activation of the complement system. This system, which belongs to the innate immune system, acts as a crucial component in the defense against infection by opsonizing pathogens or damaged cells, attracting and activating leukocytes or directly lysing bacteria or cells through the membrane attack complex. <\/p>\n

Initiation of the complement cascade can be done by three different pathways, the classical pathway<\/strong>, the lectin pathway<\/strong>, and the alternative pathway<\/strong>.
\nThe classical pathway<\/strong> is activated by immune complexes (antigen-IgM and antigen-IgG complexes) and many other self and non-self molecules binding to C1q, leading to a conformational change, and activating serine proteases C1s and C1r.
\nThe lectin pathway<\/strong> is activated by plasma-circulating lectins (collectins like mannan-binding lectin and ficolins) recognize carbohydrate patterns on the surface of microorganisms, called pathogen-associated molecular patterns (PAMPs), and activate MAPS-1 and MAPS-2 which cleave C4 to C4a and C4b.
\nThe alternative pathway<\/strong> is constantly active at a low level and is initiated by spontaneous hydrolysis of C3. Hydrolysed C3 binds to factor B (CFB) which acts as a substrate to serine protease factor D (CFD), resulting in formation of a C3 convertase.
\nIn the end, all 3 complement pathways can lead to C3 convertase activation which cleave C3 to C3a and C3b, followed by the same pathway triggering the formation of the membrane attack complex (MAC).<\/p>\n

In this study, though comparative study of autopsy lung and kidney tissue samples died from COVID-19 with those of died from non-COVID-19, it was found that the lectin pathway was activated in both lungs and kidneys of patients with severe COVID-19. Activation of the lectin pathway was supported by staining for C4d in the same localization as described for MASP-2, suggesting that complement activation might be strongly involved in systemic worsening of COVID-19 inflammatory response. <\/p>\n

< a href=\"\">\"\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

A group from Department of Nephropathology, University Hospital Erlangen, Friedrich-Alexander-University (FAU)<\/p><\/div>\n

\u7d9a\u304d\u3092\u8aad\u3080<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[70],"tags":[],"class_list":["post-8173","post","type-post","status-publish","format-standard","hentry","category-nature-en"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t