In populations from Ethiopia and Mali, it was found that mean C3 serum concentration was lower in leprosy patients (0.88 mg/mL in Ethiopic and 0.73 mg/mL in patients from Mali) when compared with nonleprosy subjects (1.1 mg/mL, both populations) being the lowest C3 levels in each population found in BL patients (0.62 mg/mL) and in TT patients (0.81 mg/mL) from Mali and Ethiopic populations, respectively. The gene discussed is C3; the disease is Burkitt lymphoma.