Association of plasma CD40L with acute chest syndrome in sickle cell anemia.

Platelet activation and platelet-derived cytokines contribute to the vascular inflammation and increased thrombotic activity known to occur in patients with sickle cell anemia (SCA). CD40 ligand (CD40L), a platelet-associated pro-inflammatory molecule that promotes endothelial cell activation, is elevated in the circulation of SCA patients. We sought to evaluate the association of CD40L and inflammation with sickle-related clinical complications and laboratory variables in SCA patients.

Negative Epistasis between Sickle and Foetal Haemoglobin Suggests a Reduction in Protection against Malaria.

Background: Haemoglobin variants, Sickle (HbS) and foetal (HbF) have been associated with malaria protection. This study explores epistatic interactions between HbS and HbF on malaria infection.

Methods: The study was conducted between March 2004 and December 2013 within the sickle cell disease (SCD) programme at Muhimbili National Hospital, Tanzania.

Genetic association of fetal-hemoglobin levels in individuals with sickle cell disease in Tanzania maps to conserved regulatory elements within the MYB core enhancer.

Background: Common genetic variants residing near upstream regulatory elements for MYB, the gene encoding transcription factor cMYB, promote the persistence of fetal hemoglobin (HbF) into adulthood. While they have no consequences in healthy individuals, high HbF levels have major clinical benefits in patients with sickle cell disease (SCD) or β thalassemia. Here, we present our detailed investigation of HBS1L-MYB intergenic polymorphism block 2 (HMIP-2), the central component of the complex quantitative-trait locus upstream of MYB, in 1,022 individuals with SCD in Tanzania.

Genome wide association study of fetal hemoglobin in sickle cell anemia in Tanzania.

Background: Fetal hemoglobin (HbF) is an important modulator of sickle cell disease (SCD). HbF has previously been shown to be affected by variants at three loci on chromosomes 2, 6 and 11, but it is likely that additional loci remain to be discovered.

Methods And Findings: We conducted a genome-wide association study (GWAS) in 1,213 SCA (HbSS/HbSβ0) patients in Tanzania.

Genetic variants at HbF-modifier loci moderate anemia and leukocytosis in sickle cell disease in Tanzania.

Fetal hemoglobin (HbF) is a recognized modulator of sickle cell disease (SCD) severity. HbF levels are strongly influenced by genetic variants at three major genetic loci, Xmn1-HBG2, HMIP-2, and BCL11A, but the effect of these loci on the hematological phenotype in SCD, has so far not been investigated. In a cohort of individuals with SCD in Tanzania (HbSS and HbS/β° thalassemia, n = 726, aged 5 or older), HbF levels were positively correlated with hemoglobin, red blood cell (RBC) indices, mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH), and negatively with white blood cell (WBC) and platelet counts (all P < 0.

Global genetic architecture of an erythroid quantitative trait locus, HMIP-2.

HMIP-2 is a human quantitative trait locus affecting peripheral numbers, size and hemoglobin composition of red blood cells, with a marked effect on the persistence of the fetal form of hemoglobin, HbF, in adults. The locus consists of multiple common variants in an enhancer region for MYB (chr 6q23.3), which encodes the hematopoietic transcription factor cMYB.