IntrOduction
Historically, the first case of sickle cell disease
(SCD) was reported in 1910 by a Dental Surgeon
who made blood films of one of his patients and
demonstrated red blood cells having a "slender
sickle shape' ,.1 The history of sickle cell anaemia is
a very good reminder of the importance of
supportive role of the laboratory to clinical diagnosis
and research'". The observation that sickle cell trait
may have a survival advantage against malaria was
based on the fact that blood from persons with sickle
cell trait contained less malaria parasites and that the
sickle trait conferred some protection against
malaria in early childhood', The mechanism of such
protection has been the matter of much debate.
Plausible mechanisms include selective sickling of
parasitised red blood cells resulting in more
effective removal by the monocyte-macrophage
system, an inhibitory effect on parasite growth by
increased red cell potassium loss, decreased red cell
PH and increased endothelial adherence of
parasitised sickle red blood cells'. Thus, the
prevalence of sickle cell anaemia closely mirrors the
world-wide distribution of falciparum malaria.
However, due to migration of people to the
industrialised western countries sickle cell disease
has become prevalent in areas where malaria is not
endemic.