Platelet counts and anti-TPO antibody concentration.

The platelet count (closed circles) is inversely related to anti-TPO antibody concentration (open circles) in thrombocytopenic subjects no. 1 (A), 2 (B), and 3 (C). PEG-rHuMGDF treatment is indicated by vertical lines and chemotherapy by the arrows. Horizontal line denotes normal cutoff of assay for anti-TPO IgG. In panel B, the solid bar indicates cyclosporine administration and solid triangles denote negative anti-TPO antibody screening tests. The anti-TPO antibody titer on day 56 for subject no. 1 (A) is slightly above the cutoff value.