MOLECULAR AND IMMUNOLOGICAL ASPECTS OF ANEMIA IN MALARIA
ABSTRACTS: Anemia is an
inevitable consequence of malaria
especially in children and severe anemia
becomes one of the complications in falciparum malaria. Anemia and malaria,
both become serious problems in developing countries. For this reason a
literature study was done to know the mechanisms and pathogenesis of anemia in
malaria. Plasmodia live in red blood cells, consume and use hemoglobin for
their growth and replication and at the end schizonts rupture and destroy their
erythrocyte host cells. Those mechanisms bring us to the assumption that high
parasitemia will cause higher degree of anemia. But severe anemia can be found
also in children with low parasitemia and anemia can persist for weeks after
parasite clearance by anti-malaria treatment. Literature study revealed that
many other factors also play role in the development of anemia in malaria. First, infected erythrocytes with
changes in surface property and lost deformability will be easily recognized
and cleared up in the spleen. The presence of antibody and immune complex on
the surface of erythrocytes makes them good targets for ADCC,
complement-mediated lysis and erythrophagocytosis. This could involve
non-infected erythrocytes, too. Macrophages and cytokines, especially TNF-α, IFN-γ
and IL-1 have important role in malaria anemia. These cytokines enhance
erythrocyte destruction, increase splenic clearance capacity, enhance
erythrophagocytosis and depress bone marrow capacity for erythropoiesis. Cytokines
also contribute in the increased uptake and intracellular storage of iron by
macrophages, where iron is used for production and functioning of ROI and NO.
Iron uptake and use in macrophages causes iron decrease in the circulation, and
this causes decrease of parasite growth but also impairs erythrocyte production
in bone marrow. Other cytokines, IL-10 and TGF-β represent counter response
against the effects of TNF-α and IFN-γ. IL-10 was proved to stimulate bone
marrow function in vitro. IL-10 concentration is higher in malaria-resistant mice
and TGF-β is found in resolving malaria infection. The reviewed reports
could explain the mechanisms of anemia
in malaria, but no conclusive reports of prevention and treatment suggested
against the anemia related to the mechanisms mentioned. There were some reports
about the effects of anti-malaria drugs on TNF, RNI and ROI production
capacity, but still no practical use suggested.
Author: Sri-Hidajati BS
Journal Code: jpkedokterangg050027
