P-060: A HIGHER GRANULOCYTE-LYMPHOCYTE RATIO IS ASSOCIATED WITH IMPROVED RED BLOOD CELL INDICES AND AGE IN DUFFY ANTIGEN-NEGATIVE SICKLE CELL DISEASE PATIENTS.

Abstract

Purpose: A higher Neutrophil-Lymphocyte ratio (NLR) has been associated with poor prognosis in many diseases. Most Africans are neutropenic due to the duffy antigen null status. The duffy antigen null status however, has been associated with a higher risk of organ damage in people living with sickle cell disease (SCD). We therefore sought to determine the effect of the proportion of these blood cells to one another on SCD prognosis in Nigeria. Materials and methods: One hundred and thirty (130) sickle cell disease patients in steady state and 117 healthy age- and sex-matched controls were recruited from a tertiary institution in Nigeria. All the participants gave informed consents and blood samples were taken for Full Blood Count and phenotyping by High Performance Liquid Chromatography. Demographic and clinical details were obtained by questionnaire administration. Neutrophils make up over 90% of granulocytes, hence the granulocyte-lymphocyte ratio was determined from the available absolute counts of granulocytes and lymphocytes. A subset of 110 patients who were not on hydroxyurea was used for the analysis. The patients were divided into 3 age groups (< 7years, 8 – 17years and >17years). Data analysis was done using IBM SPSS version 23. Results: The mean absolute lymphocyte counts (ALC) and absolute granulocyte counts (AGC) in SCD patients (5.142 and 5.295 x103/µL respectively) were higher than in controls (2.952 and 2.171 x 103/µL respectively) (p<0.001). ALC and AGC decreased with age (p<0.001, p=0.02 respectively) in the SCD patients. A similar trend in ALC was observed in the control group while there was no significant difference in the AGC of children <7years and adults (>17years) (Fig 1). The mean granulocyte-lymphocyte ratio (GLR) in SCD patients increased from 1.01 in children <8years to 1.40 in adults. For the control group, the GLR decreased from 0.75 in children <8years to 0.66 in children 8–17years old and an increase to 0.95 in adults (Fig 2). In the SCD patients, GLR was positively correlated with RBC (rs=0.351, p<0.001), HGB (rs=0.256, p=0.004), HCT (rs=0.295, p<0.001) and HbA2 (rs=0.293, p<0.001). HbA2 was positively correlated with RBC (rs=0.201, p=0.028) while HbF was negatively correlated with RBC (rs=-0.257, p=0.006) and showed no correlation with the GLR (rs=-0.008, p=0.930). ALC however had a negative correlation with RBC (rs=-0.395, p<0.001), HGB (rs=-0.452, p<0.001) and HCT (rs=-0.395, p<0.001). AGC also had a negative correlation with HGB (rs=-0.245, p=0.006) and HCT (rs=-0.179, p=0.047). These relationships were not observed in the control group except for a positive correlation between HGB and GLR (rs=0.273, p=0.003) and a negative correlation between HGB and ALC (rs=-0.295, p=0.001). GLR was negatively associated with the frequency of painful crisis in the last one year (p<0.001). Conclusion: AGC and ALC decreased with age in our patients with an increase in the GLR. A positive correlation of GLR with RBC, HGB, HCT and HbA2 infers a protective role of a higher GLR/NLR to RBC survival in our patients. A higher GLR may be associated with better clinical outcomes, and neutropenia due to the duffy antigen null status may exacerbate the course of SCD in blacks.Fig 1. The mean absolute counts of granulocyte and lymphocytes in both cases and controls.Figure 1. The percentage of granulocytes and lymphocytes in both cases and controls The authors do not declare any conflict of interest