Table 1.

Features of the study design and blood collection

• Collection sites were strategically chosen to cover 3 Ethiopian subpopulations at distinct regions:

∘ Gambella: humid tropical woods, 500 m elevation lowland, malaria-exposed

∘ Afar: dry hot desert, lowland from 400 m to below sea level, little malaria

∘ Amhara: temperate, 2,850 m elevation highland, no malaria.

• Ethics approvals by US and Ethiopian institutions and a legal export permit from Ethiopia were kept current and active throughout the study.

• Participants were informed about the project’s purpose, procedures, benefits to their community, and potential (minimal) risks to them.

• Informed consent was obtained from all participants, emphasizing confidentiality measures and their voluntary participation, before venous blood samples were drawn.

• The availability of essential equipment, supplies, and storage facilities at each collection site was arranged.

• Sample labeling and documentation were performed accurately to ensure traceability and minimize potential errors.

• Proper transportation and logistics planning were implemented to maintain sample integrity during transit from rural Ethiopian areas to NIH in the USA.

• Sample integrity and completeness of documentation were confirmed on arrival at NIH.