A NOVEL APPROACH TO THROMBOCYTOSIS

Abstract

Thrombopoietin is the key hormone that regulates the differentiation and proliferation of megakaryocytes, the precursors of platelets, in bone marrow. The cytokines interleukin-6 and interleukin-11 play an accessory role.

Thrombocytosis is a commonly encountered clinical scenario, with a large proportion of cases discovered incidentally. The threshold for clinically significant thrombocytosis is variable from patient to patient, although a platelet count of >450xl 09/L is a generally accepted value. Thrombocytosis is classified according to its cause into hereditary (inherited) and acquired (primary & secondary).

Hereditary thrombocytosis (HT) is an autosomal dominant disorder that may be due to mutations in the thrombopoietin (TPO)gene or to mutation in TPO receptor (c-MPL): S505N a mutation exchanging a serine in position 505 with an asparagine or lysine to asparagine substitution at amino acid 39 (G1238T) in MPL (Mpl Baltimore). Its prevalence is probably underestimated because it is not often sought.