THROMBOPOIETIN, INTERLEUKIN-6, AND P-SELECTIN AT DIAGNOSIS AND DURINGPOST-STEROID RECOVERY PERIOD OF PATIENTS WITH AUTOIMMUNE THROMBOCYTOPENIC PURPURA

Plasma concentrations of the most potent megakaryocytopoietic cytokine s, thrombopoietin (TPO) and interleukin-6 (IL-6), and the platelet act ivation marker P-selectin were evaluated in 24 patients with autoimmun e thrombocytopenic purpura (ATP) who responded to conventional steroid treatment, at diagnosis and after steroid-induced recovery. Baseline TP.O concentration (median [interquartile range] = 0 [17.52] pg/ml) wa s significantly decreased and IL-6 (38 [19.75] pg/ml) and P-selectin ( 485 [393.75] ng/ml) were significantly elevated compared with healthy subjects (100 [68] pg/ml, 8 [7] pg/ml and 166 [69] ng/ml, respectively ). Following steroid treatment, all values approached normal, i.e., TP O (20 [18.75] pg/ml) was increased and IL-6 (19.5 [13] pg/ml) and P-se lectin (248 [172.5] ng/ml) were decreased, significantly. The decrease of TPO in ATP is suggested to occur due to increased megakaryocyte ma ss and, consequently, TPO clearance. The non-lineage-specific cytokine IL-6 may be elevated to compensate for megakaryocytopoiesis/thrombopo iesis. The elevation of P-selectin may reflect compensatory platelet h yperactivation; however, this molecule also might be a marker of plate let destruction.