CD4 alpha beta T lymphocytes express high levels of the T lymphocyte antigen CTLA-4 (CD152) in acute malaria

The role of T lymphocytes in human acute malaria remains under debate. The kinetics of T cell activation in acute malaria were investigated, with emph asis on CTLA-4 (CD152). In patients with malaria, CTLA-4 expression by CD4 alpha beta T lymphocytes was highly increased. After initiation of antiylas modial treatment, it returned to control values within a few days. gamma de lta T cells, which also are implicated in the pathogenesis of human malaria , did not express CTLA-4, The level of CTLA-4 expression at the time of hos pital admission was correlated positively with other markers of disease sev erity-the peak of the parasitemia and the peak of serum neopterin levels, T hese results show that CTLA-4 is a sensitive and dynamic marker for T lymph ocyte activation. Its strong increase in acute malaria argues for the invol vement of T cells in the human immune response to plasmodia.