Inverse Correlation of Serum Leptin Levels and Platelet Counts in Patients with Menstruation-Associated Cyclic Thrombocytopenia.

Abstract

The platelet counts of patients with cyclic thrombocytopenia (CT) are occasionally associated with menstruation, yet its mechanism is unknown. Leptin has been shown to stimulate the production of Th1 cytokines (Nature1998;27:897), which dominate in idiopathic thrombocytopenic purpura (ITP) (Blood2004;103:2645), and a recent study showed that the serum levels of leptin, whose secretion is menstruation-related, are high in ITP (Eur J Haemataol2004;72:348). Here we examined the serial serum levels of leptin in 3 patients with CT by radioimmunoassay. Case 1 is a 29-year-old woman with ITP who had repeated spontaneous abortion at an early phase of pregnancy accompanied by transient severe thrombocytopenia. Case 2 is a 37-year-old woman diagnosed as having ITP and autoimmune neutropenia during her second pregnancy, whose platelet counts became cyclic after delivery. Case 3 is a 28-year-old woman, who developed CT after splenectomy performed for refractory ITP two years before. The serum leptin levels were inversely correlated with the platelet counts in case 1 (r = −0.573, P =0.047, n=13) and case 3 ( r = −0.771, P =0.029, n=9), and a similar inverse correlation was observed in case 2, although the correlation was statistically not significant (r = −0.524, P=0.116, n=10). These findings suggest that leptin might play an important role in the pathogenesis of menstruation-associated CT. Further interventional studies to give leptin and its antagonists to the patients with CT, as well as to ITP model mice, will be warranted.