Decreased lipid fluidity of the erythrocyte membrane in dogs with leishmaniasis-associated anaemia

In both man and the dog, anaemia resulting from natural leishmaniasis is of ten severe and mainly associated with a shortened life span of erythrocytes . Lipid fluidity of erythrocyte membranes from 17 dogs with anaemia caused by visceral leishmaniasis was investigated by means of fluorescence polariz ation. Results were compared with those from three groups of control animal s (10 healthy dogs, seven dogs with visceral leishmaniasis but no anaemia, and 10 dogs with anaemia unrelated to leishmaniasis). Fluorescence polariza tion values recorded for animals with leishmaniasis-associated anaemia were elevated-indicating reduced erythrocyte membrane fluidity-and significantl y higher than in the control groups. Mechanical sequestration by the spleen due to increased cell rigidity, or alterations in receptor/ligand erythroc yte cytoadherence mechanisms, or both, may result fi-om decreased membrane fluidity and hence contribute to the anaemia of Leishmania-infected dogs. ( C) 2000 Harcourt Publishers Ltd.