Prevalence Of Fetal Hemoglobin And Antibody Responses To Plasmodium Falciparum Antigens In Sickle Cell Disease Patients In Western Kenya

ABSTRACT

Malaria is a major public health problem worldwide with increasing cases and

deaths in sub-Saharan Africa. Sickle cell disease conditions relate geographically

with malaria endemic areas. Fetal hemoglobin (HbF) moderates the clinical severity

of sickle cell disease (SCD) and also provides protection against malaria.

Consequently, it provides survival advantage but the data is limited. Designing a

study linking HbF with protection against malaria infection has been a challenge

due to potential confounders on the exposure outcome. This study therefore

investigated the prevalence and levels of HbF and the IgG responses to Plasmodium

falciparum antigens in 100 SCD patients aged 5-30 years living in a malariaendemic

area in Western Kenya. A cross-sectional study was conducted to

determine the prevalence and levels of HbF and the IgG responses to a panel of

eleven recombinant P. falciparum antigens in SCD patients. The levels of HbF and

the IgG responses to each of the 11 antigens were determined using the alkali

denaturation (Betke) method and the cytometric bead assay in a Luminexsuspension

array technology respectively. The study reports a prevalence of up to 77

% of the SCD patients with high fetal hemoglobin (>10%) with a mean and range of

19.09% (1.44-56.25%) respectively. Generally the levels of HbF increased with age

(r = 0.17, P < 0.05) indicating that fetal hemoglobin provides survival advantage in

SCD, in males there was an increase in HbF with age (r=0.31; P0.05). The IgG responses to the multiple

P. falciparum antigens were differently expressed in the SCD patients, preerythrocytic

antigens showed a statistical difference when the mean IgG levels were

compared using unpaired T test between the seropositive SCD patients and non-

SCD individuals with the later having high IgG levels (P