SERPINE1 and epidermolysis bullosa: However, EB patients showed lower levels of PAI-1 (P < 0.01) and lower PAI-1/t-PA ratio (P = 0.014) at 0 hours, with higher levels of D-dimer at 4 hours 1015 (944–1177) ng/mL vs 895 (753–905) ng/mL in the non-EB group (P = 0.18).