Relation of serum levels of thrombopoietin to thrombocytopenia in extrahepatic portal vein obstruction versus cirrhotic children.

INTRODUCTION: In patients with portal hypertension, thrombocytopenia in cirrhotics and noncirrhotics is thought to be caused by sequestration and destruction of platelets within a large spleen, suppression of platelet production in the bone marrow, and decreased activity of the hematopoietic growth factor thrombopoietin (TPO). AIM: Determining the level of TPO in cirrhotic thrombocytopenic patients and correlate it to the degree of disease severity and platelet count. METHODS: A cross-sectional study conducted on 62 children; 25 cases with cirrhosis, 20 patients with extrahepatic portal vein obstruction (EHPVO), and 17 healthy age-matched and sex-matched controls. The severity of liver cirrhosis was graded according to the Child-Pugh classification. TPO was measured using the quantitative human TPO by enzyme-linked immunosorbant assay. RESULTS: Serum TPO levels were significantly lower in the cirrhotic group compared with both EHPVO patients and healthy controls (P=0.01 for each). Both of the Child-Pugh B and C cirrhotic cases had significantly lower TPO levels compared with Child A cases (P=0.003). We found a significant positive correlation between platelet count and serum TPO level (r=0.56, P=0.004) in the cirrhotic group but not in the EHPVO group (r=0.1, P>0.05). CONCLUSIONS: TPO underproduction contributes to thrombocytopenia in children with cirrhosis; whereas in children with EHPVO, TPO production is unaffected and thrombocytopenia is secondary to hypersplenism. TPO receptor agonists may be useful to improve platelet counts in the former group.