Plasma level of von Willebrand factor: an indicator of severity in sickle cell disease

ABSTRACT

Sickle cell anaemia is a congenital hemolytic disorder caused by mutation in the beta-globin gene at position 6 with replacement of glutamic acid by valine. Patients who are homozygous for this mutation suffer from hemolytic anaemia and other serious complications. The underlying pathology of many of these complications is the occurrence of recurrent vasoocclusion due to microthrombi formation resulting in organs ischaemia. In this study we investigated the role of vWF as a determinant of sickle cell disease severity through its contribution to the formation of such microthrombi. The clinical disease severity was determined using two different scoring methods, and vWF antigen level in the plasma was estimated by using ELISA technique. Seventy Sudanese patients were investigated in this study. They were 35 females and 35 males, the mean of their ages +/- standard deviation was 6.8 +/- 4.7 years. Seventeen controls with normal haemoglobin were also included with mean age of 6.5 years. Thirty four patients presented during vasoocclusive crisis and 36 presented in steady state. vWF was high [179.83%] among patients compared to controls [82.4%], p< 0.001 there was positive correlation between severity score and vWF level in the plasma in steady state in the two scoring methods used [r = 0.79, p = 0.008 for method I and r = 0.78, p = 0.009 for method II]. So, severity of sickle cell disease increases with elevation of vWF level in the plasma in the steady state