Fluorescence of Megakaryocytes in Idiopathic Thrombocytopenic Purpura (ITP) Stained with Fluorescent Antiglobulin Serum

1. A technic is described for the direct and indirect visualization of affinity between fluorescein labeled antiglobulin serum and megakaryocytes. 2. Fluorescent megakaryocytes have been found with this technic in the marrow of some patients with chronic ITP, but not in acute ITP. It was possiple to confer fluorescence on normal megakaryocytes by incubating them with sera from patients with chronic ITP, and from a woman who had a child with neonatal thrombocytopenia. 3. Similar reactions were noted in three patients with systemic lupus erythematosus. 4. These findings indicate adherence of a humoral substance (antibody?) for megakaryocytes, which may have etiologic significance in chronic ITP.