In multivariate regression analyses, plasma CDH2 level was significantly associated with plasma level of cytokine IL-7 (β = -0.32, P = 0.0008), HIV infection status (β = -5.35, P = 0.003), and the urine morphine test results (β = -3.24, P = 0.028) (Table 3). This evidence concerns the gene IL7 and HIV infectious disease.