Effect of Duffy Antigen Receptor for Chemokines on Severity in Sickle Cell Disease

Abstract

Sickle-cell disease is among the commonest severe monogenic global disorders. At the centre of sickle cell disease physiopathology is the polymerisation haemoglobin, resulting in erythrocytes become rigid and vascular occlusion. It has been hypothesized that the Duffy glycoprotein (Fy) on erythrocytes may enhance clearance of inflammatory cytokines. This may have an impact on the initiation and development of vascular occlusion in Sickle cell disease. The aim of this study was to determine whether or not the Duffy genotype is in any way linked with the severity of clinical disease in Sickle cell disease patients. Those who were hospitalized >4 times in the previous year because of Vaso-occlusive crisis were classified as having a severe phenotype. Duffy genotypes were determined by polymerase chain reaction (PCR), then Sty1 restriction endonuclease enzyme analysis. A total of 193 participants (133 cases and 60 controls) were recruited for the study. Vaso-occlusive crises were absent in more than half (58.5%) of the cases. Vaso-occlusive crisis per year occurred three times and four times at 5.2% and 1.65%, respectively. The number of vascular occlusions per year was highest in the 18-28 years and 29-39 years age groups. All the participants were genotyped as homozygotes for Duffy null genotype (FY*B-33/FY*B-33) and categorised as Fy(a-b-). No associations between Duffy genotype and number of VOCs per year was obtained. All the samples analysed were genotyped as Duffy negative homozygous [Fy(a-b-)]. No association between Duffy genotype and number of was vascular occlusion found.