Circulating soluble adhesion molecule levels in children with acute lymphoblastic leukaemia

The aim of this study was to evaluate levels of serum soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1) and soluble E-selectin (sE-selectin) as parameters of disease activity and to monitor the response to treatment in children with acute lymphoblastic leukaemia (ALL). The above soluble adhesion molecules were determined in the serum of 35 children with ALL and 30 healthy children (control group) of the same age range. The samples were obtained before treatment, 6 months after the beginning of the treatment (remission of the disease), 6 months after the end of the treatment and during relapse of the disease. The mean levels of sICAM-1, sVCAM-1 and sE-selectin at the onset of the disease were 646.6 +/- 80.9 ng/ml, 1786 +/- 151.8 ng/ml and 140.5 +/- 17.3 ng/ml, respectively. These values were significantly higher (P < 0.001) than those of the control group, which were, 245.8 +/- 25.7 ng/ml, 798.6 +/- 78.9 ng/ml and 44.7 +/- 18.2 ng/ml respectively. During remission, the mean levels did not differ significantly from those of the control group. After the end of the treatment the mean levels again did not show any significant differences compared to the control group. During relapse the soluble adhesion molecule mean levels (923.9 +/- 110.1 ng/ml, 2945.7 +/- 349.9 ng/ml and 258.2 +/- 5.1 ng/ml) were significantly higher (P < 0.001) than those of the control group and also than those obtained during remission and after the end of the treatment (P < 0.001). Pearson's correlation coefficient r was computed in order to detect possible linear correlations between: (1) sICAM-1 and sVCAM-1 (r = 0.632); (2) sICAM-1 and sE-selectin (r = 0.788) and (3) sVCAM-1 and sE-selectin (r = 0.752). All three cases correspond to P < 0.001, thus indicating strong linear correlations.

The levels of soluble circulating adhesion molecule levels can be utilized for monitoring disease activity of ALL and its response to treatment, as well as for early detection of relapse. Strong linear correlations between the three soluble adhesion molecules tested suggest that each of them may be sufficient as an indicator.