Merits and Demerits of Sickle Cell Trait Donor Blood in Tropical Transfusion Medicine: Are There Any Indications for Specific Use of Blood Donated by Carriers of Sickle Cell Trait?

Abstract

Haemoglobin-S mutation confers anti-malarial resistance and survival advantage in the tropics. Consequently, a significant and indispensable proportion of tropical blood donors carry sickle cell trait (SCT), which is associated with both merits (advantages) and demerits (disadvantages) in the practice of tropical transfusion medicine. Majority of the literature regarding SCT in blood transfusion highlighted its demerits with little or no reference to its merits, which constitute potentially beneficial qualities and useful applications of SCT blood in tropical transfusion medicine. Hence, the aim of this review is to present an updated, balanced, and comprehensive but concise and critical overview of the literature (using search-terms relevant to SCT in transfusion medicine) for both merits and demerits of SCT donor blood vis-à-vis its potential applications and implications in technical and clinical practice of transfusion medicine in the tropics. The review is presented in a sequential ‘stage-by-stage’ order from pre-donation procedures to blood donation, processing, storage and transfusion. The review explored the potential adverse effects of pre-donation medications on SCT donor, highlighted SCT-associated technical challenges in blood collection, processing and storage, and elucidated the clinical demerits and implications of SCT blood in sickle cell disease, perinatal, and neonatal transfusions. Moreover, the review expounded the merits of SCT blood vis-à-vis the probability of its low risks for transfusion transmitted malaria and HIV infections, and its potential applications in the evolving concept of ‘therapeutically rational transfusion of SCT red cells’ in managing severe and/or drug resistant malaria, and possibly haemophilia. In conclusion, the review underscored the need for tropical transfusionists and clinicians to innovate ways of ameliorating or circumventing the demerits and implications of SCT blood, and at the same time explore the feasibility and safety of its potential merits and applications vis-à-vis the practice of blood transfusion in low resource settings in tropical Africa, and by implication in other regions of the world where SCT is prevalent.