Predictors of Outcome in Pediatric Immune Thrombocytopenia: Relation to Thrombopoietin Levels

Background: It is not easy to predict the course of immune thrombocytopenia (ITP) at the time of diagnosis.

Aim: This prospective study investigated the possible predictors of ITP outcome in children and adolescents including the diagnostic potential of thrombopoietin (TPO).

Methods: Seventy pediatric patients with ITP were studied; 45 had chronic ITP and 25 were newly diagnosed and were followed-up for 3 months. Complete blood count and TPO levels were assessed.

Results: Chronic ITP patients were older (p<0.001), presented more frequently at age >5 years (p=0.027), had higher initial platelet count (p=0.005) but less likely to have platelet count >100 x 109/L after 4 weeks from diagnosis (p=0.017) and frequently used a third line of treatment (p=0.007). After 3 months follow-up of the 25 newly diagnosed ITP patients, 16 entered in a complete remission and they were younger than 5 years and had lower initial platelet count, higher platelet count after 4 weeks from diagnosis, and less frequently used corticosteroid as a second line of therapy compared with the 9 patients who developed persistent ITP. Increased TPO levels were found among patients with persistent ITP and those who experienced relapse. TPO levels were inversely related to platelets count.

Conclusions: The predictors of progression to persistent ITP and chronicity among our pediatric patients were age of onset > 5 years old, high initial platelet count, low platelets count 4 weeks after diagnosis and higher baseline TPO levels which could be used as a serum biomarker of megakaryopoiesis to predict therapeutic response.