Among the HVTN 503 laboratory measures assessed at enrolment (Table 2), participants with BEN had significantly lower median CD4 (663 vs. 771 cells/mm3; p = 0.0044), leucocyte (3.4 vs. 5.7x109 cells/L; p<0.001), platelet (252 vs. 281x109 cells/L; p = 0.0058), monocyte (0.25 vs. 0.35x109 cells/L; p<0.001) and basophil (0.02 vs. 0.03x109 cells/L; p = 0.0236) counts compared to those without BEN. This evidence concerns the gene CD4 and Balkan nephropathy.