In THEIR study of 36 patients, Oski et al found the plasma acid phenylphosphatase (PAPP) value to be a reliable parameter for separating destructive from nondestructive thrombocytopenias.1 In six patients with acute idiopathic thrombocytopenic purpura (ITP) and in 13 of 15 cases of chronic ITP, elevation of PAPP was thought to reflect thrombocytolysis with release of the enzyme into the plasma. Conversely, in eight cases of hypoplastic thrombocytopenia the PAPP fell somewhat below the normal mean. With the exception of two patients with chronic ITP, the plasma enzyme values correlated well with platelet life-spans and bone marrow megakaryocyte activity. Thus, it was proposed that the PAPP value be added to the diagnostic tests used to classify the thrombocytopenias.
The present report concerns nine patients with ITP in whom an attempt was made to correlate PAPP levels with platelet counts, radioactive chromium (51Cr) platelet lifespans, and therapeutic response to