Background: Sickle cell disease (SCD) patients experience ischemic events resulting from vaso-occlusion of both macro-and microcirculation. A risk factor associated with increased morbidity and mortality is leukocytosis in the absence of infection. This study investigated the role of leukocytes in the pathogenesis of acute sickle cell crisis.
Procedure: Children were enrolled at two tertiary care centers in three groups: hemoglobin SS (Hb SS) patients admitted to hospital with an acute crisis, non-crisis or steady state SS patients, and sickle cell screen negative, racematched controls. Flow cytometry measured cell surface expression of adhesion molecules.
Results: 28 Hb SS and 10 control patients were enrolled. Elevated white blood and platelet counts were observed for the crisis children (P<0.01) compared to healthy control children. There was a significant increase in the expression of adhesion molecules on neutrophils and monocytes (CD11, CD 18 and CD-62L) in children in steady state (P<0.05) compared to crisis, and healthy children. 71% of crisis children were receiving non-steroidal anti-inflammatory drugs (NSAIDs) or hydroxycarbamide, whereas none of the patients in steady state were receiving these drugs.
Conclusion: Further investigation is needed to explain these findings, but is likely due to the use of NSAIDs and hydroxycarbamide in our crisis patients.