The Effect of Jobelyn ( Extract of Sorghum Bicolor) on the Haematological Parameters of Patients With Sickle Cell Anaemia Disease.

Sickle cell anaemia is an inherited haemoglobinopathy caused by a point missense mutation (GAG to GTG) in the beta globin gene that resulted in the substitution of an acidic amino acid ( glutamic acid) with a neutral and hydrophobic amino acid (valine) in the codon 6 of the beta globin chain. This genetic defect has a prevalence of 20% to 40% in Sub Saharan Africa, 7.8% in African Americans and to a lesser extent in the Middle East, Mediterranean and India.

The higher frequency in the sub Saharan Africa is thought to be due to the selective advantage the gene confers on the traits (heterozygotes state) in malaria zone. Nigeria is the most populous country in this region with about 24% frequency of the mutant gene. The prevalence of sickle cell anaemia in Nigeria is about 20 per 1000 life births. This implies that Nigeria may have the highest burden of the disease in the world.

The severity of sickle cell disease varies. The disease is more severe in patients with haemoglobin SS or haemoglobin S beta thalassaemia than in those with haemoglobin S beta+ thalassaemia or haemoglobin SC disease. The Arab - Indian haplotype produces a less severe disease than the African haplotype. Similarly, the coinheritance of one or two, alpha globin chain deletions or high fetal haemoglobin level in hereditary persistence of fetal haemoglobin are associated with mild disease, The severity is therefore higher in the Sub Saharan African sub region. However, the severity of the disease varies widely for unexplained reasons among patients with haemoglobin SS in this region.

The beta S globin chain binds at the valine site with complementary hydrophobic effects on other beta globin chain. This triggers the formation of polymers of haemoglobin. The rate of polymerization is increased with increase in intracellular deoxy-haemoglobin. Factors that promote polymerisation are dehydration, acidosis, increase in the level of 2,3 diphosphoglycerate which may occur in infections. On the other hand, the association of haemoglobin 5 with other haemoglobin that have higher oxygen affinity-like haemoglobin F or haemoglobin A reduce the rate of polymerisation.

The haemoglobin polymer forms a firm gel that damages the cellular membrane. The damaged membrane causes movement of potassium and water out of the cell thus leading to dehydration and more polymer formation. This damage also causes the negatively charged phosphatidylserine to move to the membrane surface and the red cell becomes deformed in shape, more rigid and more adherent to the vascular endothelium. The result of these are easy fragmentation of the membrane and extra vascular haemolysis, complement mediated lysis of the cell and intravascular haemolysis, shortened red cell survival to 4 to 25 days, trapping of rigid irreversible sickle cells in the post capillary venules which is promoted by leukocytosis, platelet activation and inflammatory cytokines.