Relationship between foetal haemoglobin and haematological indices in children with sickle cell anaemia from South Western Nigeria.

Background: Foetal haemoglobin (HbF, α2γ2) retards polymerisation of haemoglobin (Hb) in sickle cell anaemia (SCA). In Nigeria, studies on the levels of HbF and its relationship with haematological indices are scanty. This study evaluated HbF concentrations of children with SCA from Southwestern Nigeria and correlated the levels with various haematological indices.
Materials and Methods: HbF levels were quantified by high-performance liquid chromatography and haematological parameters determined with automated haemoanalyser. The relationship between steady-state HbF levels and blood parameters were assessed by statistical analyses.
Results: The mean HbF of the 91 children with SCA (9.6% ± 5.9%) was significantly higher than 0.5 ± 0.7% for the 91 age- and sex-matched controls, P < 0.001. About two-third of children with SCA, sixty (65.9%) had low HbF levels (HbF of < 10%) whereas about one-third, 31 (34.1%) had high HbF level (HbF of ≥ 10%). The mean Hb concentration, haematocrit (Hct) and total red blood cell count were significantly lower amongst children with SCA, whereas the total white blood cell (WBC) counts, neutrophils, monocyte and lymphocyte percent, platelet counts, mean corpuscular Hb (MCH) and MCH concentration were significantly higher. HbF had a positive but weak correlation with Hct (r = 0.24, P = 0.014), Hb concentration (r = 0.21, P = 0.047) and red cell distribution width (r = 0.25, P = 0.015) and an inverse correlation with WBC count (r = -0.23, P = 0.038).
Conclusion: Children with SCA had higher levels of HbF than matched controls. HbF had an inverse correlation with the WBC count and direct relationship with Hct and Hb concentration. It is recommended that routine determination of HbF and its induction are essential to maintain optimal haematological state of patients with SCD.