Panel 1. Immunostaining positive for SARS-CoV-2 spike protein (SP) (arrows) in representative thrombotic material from COVID-19 + patients, retrieved from cerebral (A) and coronary (C) arteries. Immunohistochemistry for nucleocapsid protein (NP) was negative in the same samples (B-D). Panel 2. Representative immunohistochemical staining positive for SP (E) and NP (F) (arrows) in the lung of a patient affected by COVID-19 (positive control). Representative immunostaining negative for SP (G) and NP (H) in a thrombus retrieved from the middle cerebral artery of a patient not affected by COVID-19 (negative control). Original magnification 20X. Panel 3. Double immunofluorescence of thrombotic material retrieved from COVID-19 and non-COVID-19 patients’ cerebral arteries. In the COVID-19 thrombus, platelets are co-stained with anti-CD61 (red-L,P) and anti-SARS-CoV-2 spike protein (SP) antibodies (green-M,Q), emitting yellow signals in the merged panel (N), while in the control (non-COVID thrombus), only the red CD61 signal is observed (R).
*Figure and legend reprinted from De Michele et al. [21]. The legend title has been slightly adapted. Permission to use this figure has been granted in accordance with the open access Creative Common CC BY 4.0 license.