The predictive value of white cell count in assessing clinical severity of sickle cell anaemia in Afro - Caribbeans patients

Abstract

The relationship between each of haemoglobin concentration (Hb), red cell count (RCC), white cell count (WBC), platelet count (PLT), mean corpuscular volume (MCV), red cell width difference (RWD), and average number of acute admissions per year (AVEADM), were determined in a cross-sectional study of 128 Afro-Caribbean sickle cell anaemia patients attending the Sickle Cell Disease Clinic of Central Middlesex Hospital in London for a mean of 7.6 patient-years. The diagnosis of sickle cell anaemia was made by both haematological and DNA analyses. The haematological parameters were determined using Coulter S automated counter during the steady state periods while the AVEADM was computed from all admissions for painful crisis, acute anaemia and acute chest syndrome, priapism, and acute stroke. Haemoglobin F level was determined by HPLC. Analysis was done in the paediatric and adult patients separately. There were no significant correlations between any of the parameters and AVEADM in the paediatric group. In adult patients, there was significant positive correlation (P < 0.05) between WBC and AVEADM. WBC has a negative correlation with Hb concentration and HbF level. WBC 10x10 9/L and above is associated with Hb and HbF level below the mean for the group. WBC is lower but not significantly, in patients with single a-gene deletion than in those without deletion (P = 0.06). This study suggests that higher WBC count may suggest possible increased hospital admission, lower Hb concentration, and lower HbF level, in adult patients, and that, as a single parameter it can be of value in the assessment of patients with sickle cell anaemia. Possible mechanisms for these findings are also suggested.