Anti-GPIbα antibodies block platelet-mediated hepatocyte TPO generation. (A-B) Platelets from BALB/c WT mice were incubated with FL83B cells for 24 hours, after which FL83B cellular TPO mRNA expression was measured by RT-qPCR. In some instances, as indicated, platelets were desialylated with neuraminidase. Purified anti-GPIbα (2 µg/mL) or control anti-αIIb polyclonal IgG (2 µg/mL) (A) or monoclonal anti-GPIbα antibody NIT G (1 µg/mL) (B) was added as indicated, n = 3 (in duplicate). *P < .05, ***P < .001, ****P < .0001. NS, not significant.