One possible explanation for the lower frequency of post-treatment increases in ALT in malaria-endemic settings is that there may be a reduced susceptibility to hepatic injury due to previous exposure to malaria,54 with resulting modulation of the host immune response.55 This may also explain why ALT increases post-treatment occur more often in returned travelers,5,47 in whom most malaria episodes will be a primary infection. This evidence concerns the gene GPT and malaria.