Cutaneous delayed-type hypersensitivity responsiveness in patients during and after Plasmodium falciparum and Plasmodium vivax infections.

To assess cellular immune function in malaria, 61 patients admitted to the Bangkok Hospital for Tropical Diseases with Plasmodium falciparum (PF) or Plasmodium vivax malaria were examined with the MULTITEST CMI system (Merieux Institute, Florida) to evaluate delayed-type hypersensitivity (DTH) during and after acute disease over 4 weeks. All patients demonstrated significantly decreased responsiveness to seven commonly encountered recall antigens. This deficit was most severe immediately upon admission (prior to therapy). Uncomplicated Pf cases demonstrated significant hyporesponsiveness only during Week 1. Responses in moderate/severe falciparum and all vivax patients gradually increased in Weeks 2 and 3 but remained significantly below control values. This study confirms functional cell-mediated immune deficits in falciparum malaria and, for the first time, shows hyporesponsiveness in vivax malaria. We conclude that malaria causes a pronounced CMI deficit that is still detectable in some individuals for 3-4 weeks after treatment of acute infection. These changes in DTH should be a consideration in future vaccine development and in evaluation of immune status in endemic areas.