Premortem skin biopsy assessing microthrombi, IFN I antiviral & regulatory proteins and complement correlates with Covid19 clinical stage, 2022

[SNT Gatchaman]

Premortem Skin Biopsy Assessing Microthrombi, Interferon I Antiviral and Regulatory Proteins, and Complement Deposition Correlates with Coronavirus Disease 2019 Clinical Stage
Jeffrey Laurence, Gerard Nuovo, Sabrina E. Racine-Brzostek, Madhav Seshadri, Sonia Elhadad, A. Neil Crowson, J. Justin Mulvey, Joanna Harp, Jasimuddin Ahamed, Cynthia Magrox

Apart from autopsy, tissue correlates of coronavirus disease 2019 (COVID-19) clinical stage are lacking.

Cutaneous punch biopsy specimens of 15 individuals with severe/critical COVID-19 and six with mild/moderate COVID-19 were examined. Evidence for arterial and venous microthrombi, deposition of C5b-9 and MASP2 (representative of alternative and lectin complement pathways, respectively), and differential expression of interferon type I-driven antiviral protein MxA (myxovirus resistance A) versus SIN3A, a promoter of interferon type I-based proinflammatory signaling, were assessed. Control subjects included nine patients with sepsis-related acute respiratory distress syndrome (ARDS) and/or acute kidney injury (AKI) pre-COVID-19.

Microthrombi were detected in 13 (87%) of 15 severe/critical COVID-19 patients versus zero of six mild/moderate COVID-19 patients (P < 0.001) and none of the nine pre-COVID-19 ARDS/AKI patients (P < 0.001). Cells lining the microvasculature staining for spike protein of severe acute respiratory syndrome coronavirus 2, the etiologic agent of COVID-19, also expressed tissue factor. C5b-9 deposition occurred in 13 (87%) of 15 severe/critical versus zero of six mild/moderate COVID-19 patients (P < 0.001) and none of the nine pre-COVID-19 ARDS/AKI patients (P < 0.001). MASP2 deposition was also restricted to severe/critical COVID-19 cases. MxA expression occurred in all six mild/moderate versus two (15%) of 13 severe/critical cases (P < 0.001) of COVID-19. In contrast, SIN3A was restricted to severe/critical COVID-19 cases and co-localized with severe acute respiratory syndrome coronavirus 2 spike protein. SIN3A was also elevated in plasma of severe/critical COVID-19 patients versus control subjects (P = 0.0128).

In conclusion, we identified premortem tissue correlates of COVID-19 clinical stage using skin. If validated in a longitudinal cohort, this approach could identify individuals at risk for disease progression and enable targeted interventions.

PubMed | PDF

 

[SNT Gatchaman]

Per the title, these index patients were pretty sick. These microthrombi don't sound the same as the putative Pretorius microclots. The paper suggests they are generally platelet aggregates. However, they reference fibrin thrombi in their prior autopsy paper.

Evidence for thrombosis was sought by direct visualization and staining for platelet microthrombi by using an anti-CD61 antibody.

Clinical thrombosis was recognized in six (40%) of 15 severe/critical COVID-19 cases during their hospitalization, three with deep vein thrombosis, two with continuous renal replacement therapy circuit thrombosis, and one with stroke.

there was a striking incidence of microthrombi in normal-appearing skin of the severe/critical cases [87% (13 of 15)], including six (40%) of 15 with arteriolar thrombi versus zero of nine hospitalized control subjects and zero of six in the lesional skin of the mild/moderate cases (P < 0.001).

The microthrombi varied from platelet aggregates highlighted by CD61þ deposits adherent to endothelium to fully formed clots. Both venous and arterial microthrombi were similarly present in the normal-appearing deltoid skin of Case A. There was a clear association between complement C5b-9 and/or MASP2 deposits with the presence of microthrombi in the severe/critical COVID-19 group for 100% (13 of 13) with observed microthrombi. In contrast, only one of the two individuals without microthrombi had such deposits, and none of six individuals with mild/moderate COVID-19, all lacking microthrombi, had complement expression.

the study provides new evidence for both venous and arterial microthrombosis in the normal-appearing skin of patients with severe/critical COVID-19, but not in the skin of SARS-CoV-2 infected individuals with self-limited disease of mild/moderate intensity.

This included 40% of COVID-19 patients with ARDS having arteriolar thrombi versus none of nine critically ill pre-COVID-19 control subjects, four of whom also had sepsis-associated ARDS.

consistent with the autopsy-based observation that arteriolar thrombi are ninefold more prevalent in the lungs of patients with severe/critical COVID-19 versus the lungs of those with other forms of ARDS, and microthrombi are fivefold more prevalent in the hearts of patients dying of COVID-19 versus specimens from control patients, with or without cardiac disease.

numerous microthrombi in both venous and arterial vessels may be a unique characteristic of COVID-19 ARDS versus other forms of ARDS

The demonstration of co-staining of [tissue factor] with SARS-CoV-2 spike protein in the microvasculature in association with microthrombi provides premortem documentation of what had been observed by our group at autopsy in the lungs of patients with critical COVID-19. In the earlier study, TF protein expression was 2.1-fold higher in COVID-19 versus non-COVID-19 ARDS lungs (P < 0.005) and 11-fold (P < 0.001) higher than in control lungs, with fibrin thrombi and thrombi positive for platelet factor 4 found in close proximity to regions expressing TF in COVID-19 ARDS lungs.