Epple et al. [8] compared gastrointestinal mucosal barrier function among 11 untreated, 8 suppressively-treated HIV-infected patients, and 9 HIV-seronegative controls, and found that HIV infection induces intestinal barrier defect by mucosal CD4 T-cell depletion, villous atrophy and alteration of tight-junction protein composition. The gene discussed is CD4; the disease is HIV infectious disease.