The titer of aPL was almost similar regardless of thrombosis complicated during COVID-19 or prior history of thrombotic events, except for aCL IgM (0.9 U/ml versus 3.3 U/ml, p =0.002) and aβ2GPI IgM (0 U/ml versus 1.0 U/ml, p=0.0042) (Figure 2, Supplementary Figure 2). Here, CD40LG is linked to COVID-19.