Steady-state sVCAM-1 serum levels in adults with sickle cell disease.

Cytokines and adhesion molecules play an important role in the pathophysiology of vaso-occlusion in sickle cell disease (SCD), and their in vivo profiles are potential tools for assessing SCD severity. We compared steady-state soluble vascular cell adhesion molecule-1 (sVCAM-1) serum levels to clinical (painful crisis frequency, occurrence of acute chest syndrome, leg ulcers, and cerebrovascular disease) and related hematological parameters of SCD severity (such as HbF%, hemoglobin levels, and leukocyte counts) in 29 HbSS adults. Serum sVCAM-1 levels were not related to clinical severity, but an inverse correlation was demonstrated between sVCAM-1 and hemoglobin levels (r=-0.71, p<0.001) with a positive correlation to serum lactate dehydrogenase levels (r=0.59, p=0.008). Based upon these results, steady-state serum sVCAM-1 levels do not seem to reflect clinical disease severity. However, as VCAM-1 is involved in hematopoiesis, sVCAM-1 levels might reflect bone marrow activity in SCD. This underlies the pleiotropic nature of adhesion molecules in vivo and the need for further research in this area, especially since therapies targeting (cellular) adhesive interactions involving the endothelium are emerging for SCD.