High Performance Liquid Chromatographic Pattern of Children with Sickle Cell Anaemia in Enugu Nigeria

Aim: To identify the quantity of haemoglobin (Hb) ‘S’(HbS), ‘A2’(HbA2), ‘F’(HbF) and other Hb phenotypes of sickle cell anaemia (SCA) children in Enugu Nigeria using High Performance Liquid Chromatography(HPLC).

Introduction: The inheritance of two abnormal Hb genes one of which must be the Hb ‘S’ gene result in Sickle cell disease (SCD). Co-inheritance of two Hb S genes results in homozygous SCD/SCA), coinheritance of Hb ‘S’ with Hb ‘C’ gene gives HbSC disease and with β-thalassemia allele gives HbSβ-thalassemia (Hb S/β Th). SCA is the most common and most severe of the SCD. The phenotypic expressions of Hb vary unpredictably in the same individual and contribute to the varied clinical severity of SCA among other variables. It is therefore imperative to characterize the Hb variants in children with SCA for proper risk stratification necessary for best outcome management. HPLC is the most validated method for screening, detection and quantification of various Hb subtypes.

Methodology: A cross-sectional, descriptive study involving 75 SCA children aged 6 months to 17years, on follow-up at the clinic. Patients on hydroxyurea or who received blood transfusion within the previous four months were excluded. Following due ethical protocols, the D-10 HPLC machine (BIO-RAD D-10) was used to identfy the Hb phenotype in venous blood samples based on their ionic gradients and quantify them by the principle of variable absorbance. The participants’ sociodemographic data were recorded. Participants were grouped into 3 socioeconomic classes (SECs) as proposed by Oyedeji.

Results: There were 48 females (62.7%) and 27 males (37.3%) in age range 6 months – 17 years in lower (16.0%), middle (57.3%) and upper (26.7%) SECs. Majority had HbF below 10% (46.7%), HbS above 80% (43%) and HbA2 of 4% and below (84%). No other Hb variant was identified. The proportion with HbS/HbA2/HbF levels suggestive of beta thalassemia was 16%, 25% males compared to 10.6% females. Females had higher HbF levels while males had higher HbS and HbA2 levels. However the gender differences in HbF, HbS, HbA2 and SECs did not attain statistical significance. A significant negative relationship was found between age and HbF (r = -.424, p < .001) while a significant positive relationship between age and HbS (r = .287, p = .013) and between age and HbA2 (r = .265, p = .022).

Conclusion: Irrespective of gender, high HbS and low HbF levels at direct variance (HbS) and indirect variance (HbF) with age may be found in children with SCA. Observed Hb phenotypes suggest co-existent β- thalassaemia in this subset of southeast Nigerian SCA children.