A relative ADAMTS13 deficiency supports the presence of a secondary microangiopathy in COVID 19. Issue 193 (September 2020) - Martinelli, Nicola; Montagnana, Martina; Pizzolo, Francesca; Friso, Simonetta; Salvagno, Gian Luca; Forni, Gian Luca; Gianesin, Barbara; Morandi, Matteo; Lunardi, Claudio; Lippi, Giuseppe; Polati, Enrico; Olivieri, Oliviero; et al.