CD4 and tuberculosis: We demonstrated that CD4+ and CD8+ T lymphocyte expansion followed Mtb infection and was accompanied by the preferential expression of certain TCR Vα and Vβ gene families, supporting the previous work that demonstrated clonal expansion of Vβ 2+ CD8+ effector T cells in the peripheral blood of pediatric tuberculosis patients [20] and selection expansion of HLA-DR17, DQ2-restricted Vα 2.3+ CD4+ T cells following stimulation with live Mtb or soluble Mtb extracts [26].