Falciparum malaria in naturally infected human patients: ultrastructural alterations of non-parasitized red blood cells during anaemia.

Several ultrastructural alterations have been displayed by non-parasitized erythroblasts (Eb) and erythrocytes (Ec) in the peripheral blood of 28 Saudi patients who were anaemic and suffering from acute falciparum malaria (AFM). A counting system is incorporated to determine the rate of altered to normal red cells in plastic serial sections. The Eb showed for the first time conspicuous surface knobs which were previously described only for parasitized Ec, and are known to play a role in their adhesion to vascular endothelial cells. The Ec displayed a bizarre contour and ragged appearance produced by the abundance of cytoplasmic processes. Such cells were similar to erythrocytic ropalocytes seen in haematological diseases associated with anaemia. The Ec also possessed autolysosome-like vacuoles containing rosette forms of alpha-glycogen-like particles (GLP) while smaller beta-GLP were dispersed in the cytoplasm. Ultrastructural alterations of these cells were suggested to be due to dyserythropoiesis and ineffective erythropoiesis, which were in turn attributed to an unbalance in metabolism as they were being overproduced in response to infection. Numerous haemoglobin-like particles (Hg) were being liberated through the erythrocytes plasma membranes indicating severe haemolysis which is considered to be one of the major factors in producing anaemia during malarial infection. This study showed tat anaemia is common in patients with AFM which is usually associated with structural alterations of non-parasitized immature and mature red blood cells (RBC). In addition, the rate of abnormal RBC correlates with the degree of parasitaemia. Moreover, old patients showed a lower degree of parasitaemia than young patients, possibly due to a less mature immune system in the later.(ABSTRACT TRUNCATED AT 250 WORDS)