CD4 αβ 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 emphasis on CTLA-4 (CD152). In patients with malaria, CTLA-4 expression by CD4 alphabeta T lymphocytes was highly increased. After initiation of antiplasmodial treatment, it returned to control values within a few days. gammadelta 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 hospital admission was correlated positively with other markers of disease severity-the peak of the parasitemia and the peak of serum neopterin levels. These results show that CTLA-4 is a sensitive and dynamic marker for T lymphocyte activation. Its strong increase in acute malaria argues for the involvement of T cells in the human immune response to plasmodia.