Osteopontin is involved in Th1-mediated immunity against Plasmodium falciparum infection in a holoendemic malaria region in Vietnam

We examined the role of osteopontin (OPN) in immunity against Plasmodium falciparum infection. We measured the mRNA levels for OPN and several cytokines in RNA preparations extracted from dried blood on filter paper obtained from falciparum malaria patients in Vietnam. Expression of OPN mRNA was detected in 134 of 161 patients. The expression of both interleukin-12 p40 and interferon-γ mRNAs in the group positive for OPN mRNA was significantly higher than that in the group negative for OPN mRNA. The level of parasitemia in the OPN mRNA-positive group was much lower than that in the negative one. These results suggest that OPN might suppress multiplication of the parasites through T helper 1 cells-mediated immune responses.