Treatment of cryptosporidiosis in immunocompromised hosts.

The most important species of Cryptosporidium in humans, C. parvum and C. hominis, cause severe and chronic life-threatening gastroenteritis in immunocompromised patients. Despite a certain efficacy shown by passive immunotherapy or by some chemotherapeutic agents (e.g. paromomycin and nitazoxanide), no significant benefit has been demonstrated. The use of highly active antiretroviral therapy (HAART) in persons with the acquired immunodeficiency syndrome drastically reduces the prevalence of Cryptosporidium infection. This result seems to be due to aspartyl protease inhibitors of the human immunodeficiency virus included in HAART, which directly interfere with the life cycle of the parasite. The identification of the C. parvum proteases involved in the host-cell interaction could lead to new therapeutic approaches using specific parasite protease inhibitors in immunocompromised persons.