CD4 and tuberculosis: Although the underlying immunological mechanisms of TB-RIIS are incompletely understood, a few clinical studies have demonstrated that risk factors for the development of TB-IRIS include low pre-ART CD4+ T cell counts, stronger CD4+ T cell increase after ART and short interval between starting antituberculous therapy and ART [7, 8], while the other studies did not find the relationship between these risk factors and developing IRIS [9].