UP-REGULATION OF ICAM-1, IL-1 AND REACTIVE OXYGEN INTERMEDIATES (ROI)BY EXOGENOUS ANTIGENS FROM PLASMODIUM-FALCIPARUM PARASITES IN-VITRO, AND OF SICAM-1 IN THE ACUTE-PHASE OF MALARIA

After 4 hours of stimulation of human mononuclear leukocytes in the pr esence of 300 ng/ml exogenous Plasmodium falciparum antigens, the ICAM -1 expression increased variably from 15% to 375%. Simultaneously, an increase of IL-1 mRNA production could be observed in Northern blot hy bridizations with a specific cDNA gene probe for human IL-1 alpha labe lled with digoxigenin. Furthermore, the reactive oxygen intermediates (ROI) production was also found to be enhanced in similar conditions. Additionally, when the levels of soluble ICAM-1 (sICAM-1) in plasma of 122 patients with P. falciparum or Plasmodium vivax malaria were anal yzed in an enzyme immunoassay (EIA), significant sICAM-1 increases wer e found, more pronounced in patients with P. falciparum malaria, in co mparison with healthy controls and with the same patients 4 weeks afte r chemotherapy, The presented results indicate that the expression of ICAM-1 may also be upregulated by exogenous Plasmodium antigens beside s cytokines like IL-I during the acute phase of malaria, with subseque ntly elevated sICAM-1 concentrations in blood.