Clinical and laboratory factors associated with splenic dysfunction among patients with sickle cell disease in a malaria endemic region

Background: Although loss of splenic function is the expected natural course for individuals with sickle cell disease (SCD), factors such as high HbF and coexistence of alpha thalassemia may ameliorate this process. We evaluated factors associated with two surrogate markers of spleen dysfunction, namely Howell-Jolly bodies (HJBs) and argyrophilic inclusion (AI) red cell counts, among patients with SCD. Methods: Cross-sectional data of 182 patients with SCD (median age 11 y; 1-45 y) and 102 normal controls (median age 12 y; 1-32 y) were evaluated. Blood tests including full blood count, serum chemistry and high-performance liquid chromatography were performed. The HJB and AI red cell counts were performed on peripheral blood smears. Results: The percentages of HJB and AI red cells rose significantly with increasing age in the SCD group. On regression analysis, the frequency of HJB red cells associated positively with mean corpuscular hemoglobin (MCH) (beta=0.289; p=0.001) and negatively with HbF (beta=-0.259; p=0.002). The AI red cell counts also associated positively with MCH (beta= 0.321; P=0.001) and negatively with HbF (beta=-0.242; p=0.020). Conclusions: Data from this study indicate that the negative association of HbF with both markers of splenic dysfunction among our patients with SCD residing in a malaria endemic region is similar to findings elsewhere of its ameliorating effect on splenic dysfunction.