In HVTN 503, higher pre-HIV IL-17+ CD4+ T cell frequencies were inversely correlated with CD4/CD8 ratio measured both within 180 days (Spearman rank rs = -0.42, p = 0.012) and ≥180 days (rs = -0.55, p = 0.001) after HIV infection, and were associated with faster CD4+ T cells decline (adjusted hazard ratio [aHR] = 3.5, 95% CI: 1.2 - 9.9, p = 0.020). This evidence concerns the gene IL17A and HIV infectious disease.