Impact of Antimalarial Treatment on Measures of T Cell Suppression/Regulation in Healthy Adults From Doneguebougou, Mali

Overview

Background: Malaria is a disease that affects many people in the country of Mali and other parts of Africa. It is caused by germs that are spread by mosquito bites. Malaria may be mild, but can also be serious or can lead to death if not diagnosed and treated promptly. Children younger than 5 years and pregnant women are at highest risk of malaria. Researchers want to better understand how malaria infection suppresses the immune system. They want to compare a group of adults who receive antimalarial treatment to a group that does not receive it. Objective: To investigate the effect of antimalarial treatment at the beginning of the dry season on the immune system and malaria episodes. Eligibility: Healthy adults ages 18-60 who live in the area of Doneguebougou, Mali. Design: Participants will be screened with a physical exam and health questions. If participants are found to be sick at the screening visit, they will get initial care at the study clinic free of charge. They may get referrals for consultation. Participants will be randomly assigned to a group. One group will get an approved antimalarial drug called Coartem . The other will not receive it. Participants in the Coartem group will take the drug for 3 days. All participants will have blood tests. Al participants will be seen about once a month for about 1 year. At each visit, they will be asked how they are feeling and be examined. Blood will be drawn. If participants become sick at any time, they will come to the clinic to be examined.

Malaria, caused by Plasmodium falciparum, is a devastating disease that causes significant mortality and morbidity both directly and indirectly in endemic regions. Lower all-cause mortality in children under five years of age have resulted from better malaria transmission control measures in endemic regions. It has been seen in multiple studies that malaria infection, including asymptomatic carriage, suppresses or modulates the immune system; how exactly this suppression is achieved is unclear. Currently, efforts to develop long-lasting, effective vaccines to combat malaria have not been successful. One of the impediments of concern is poor immune response to the vaccine candidates. Understanding the immunomodulatory effects of malaria infection to vaccine responses and to subsequent malaria infection is thus key in these efforts. In order to further understand how the presence of parasitemia may modulate the immune system, we propose to study the effects of treating a portion of adult volunteers with a treatment course of artemether/lumefantrine (Coartem ) at the beginning of the dry season (approximately January) in Ouelessebougou, Mali to clear parasitemia carriage during the dry season and following them for the next 10-12 months through an entire dry and wet season. We will enroll 50% blood smear or polymerase chain reaction (PCR) positive volunteers and distribute them equally into two groups at the beginning of the dry season, those who receive or do not receive antimalarial treatment. These subjects will then be followed monthly throughout the dry and rainy seasons to determine the effect of this treatment on T cell markers of suppression/regulation and the incidence of asymptomatic malaria infection and clinical malaria. We hypothesize that markers of T cell suppression/regulation throughout the dry season will be lower in adults who receive a single pre-emptive treatment with Coartem .