Anti-thrombopoietin antibodies suppress megakaryocytic colony formation in vitro in patients with systemic lupus erythaematosus

Autoantibodies against thrombopoietin (TPO) have been implicated in systemic lupus erythaematosus (SLE) thrombocytopoenia.1 2 To investigate their pathophysiological significance, we have evaluated the effect of SLE sera on megakaryocytic colony formation in vitro. A total of 35 randomly selected SLE sera were initially screened for the presence of antiplatelet antibodies (APAs), using a commercially available assay (PAK12, GTI Diagnostics, Wauksesha, Wisconsin, USA). In all, 16 sera tested positive and were excluded from the analysis. Only sera negative for APAs have been evaluated in the current study, since APAs have been reported to inhibit megakaryopoiesis in vitro.3 Of the remaining 19 samples, 7 tested positive for anti-TPO antibodies and 12 were negative. TPO concentration was then measured by a …