Although HIV gp120 envelope protein disrupts the ADA-CD26 interaction [19], possibly contributing to the immunodeficiency [20], ADA is still able to enhance autologous T-cell proliferation against inactivated-HIV presentation by DC in individuals under HAART [21], suggesting a beneficial role for ADA on improving HIV-specific T-cell responses in those individuals [22]. The gene discussed is ADA; the disease is immunodeficiency disease.