G1 and G2 variants of apolipoprotein L1 among Central African population in Trypanosoma brucei gambiense endemic rural area.

Introduction: Apolipoprotein L1 (APOL1) risk variants (G1, G2) are known to enhance the protective ability against human African trypanosomiasis (HAT), in addition to their role in kidney and cardiovascular disease. The effects of these variants on trypanosome infection could differ regionally owing to local adaptations of the host and pathogen. This study explored APOL1 risk variants distribution in HAT-infected and non-infected populations from a rural Trypanosoma brucei gambiense (T. b. gambiense) endemic area in Central Africa.

Methodology: We conducted a cross-sectional study with 124 participants in Masimanimba, a HAT-endemic region in the Democratic Republic of the Congo (DRC). Student's and Pearson`s Chi-square test or Fisher's exact tests were used as appropriate. Statistical significance was set at p < 0.05, based on two-tailed test.

Results: 71 participants (57%) were infected by Trypanosoma, 65 (52%) of whom were symptomatic and 6 (5%) asymptomatic. The overall frequency of risk alleles was 16.5% for G1 and 8.8% for G2. Neither variant was associated with the susceptibility to T. b. gambiense infection (for G1: 19.7% vs. 26.4 %; OR: 0.68 [95% CI: 0.29-1.62], p = 0.394; for G2: 11.3% vs. 13.2% 0.83 [0.27-2.58], p = 0.786). All of the G2 variants were found in symptomatic patients.

Conclusions: APOL1 variants are common in populations living in T. b. gambiense endemic areas of the DRC. Neither variant was associated with susceptibility to T. b. gambiense. The G2 variant was the only one associated with symptomatic HAT.