ADAMTS13 and vitamin B12 deficiency: Vitamin B12 has antioxidant properties, and the deficiency of vitamin B12 is associated with elevated inflammatory markers, which includes interleukin-6 (IL-6), malondialdehyde, and high sensitivity C-reactive protein.6 It is interesting that IL-6 in-vitro models revealed that it can be a direct catalytic inhibitor of ADAMTS13.7 Therefore, rarely the oxidative stress-induced IL-6 production in severe vitamin B12 deficiency can reduce ADAMTS13 activity, leading to the accumulation of unusually large multimers of von Willebrand factor causing platelet aggregation and thrombi.