In addition, the design of the study was very systematic in terms of: groups analyzed (HIV-TB vs TB and HIV-LTBI vs LTBI), experimental tools used (Mtb specific and unrelated recall antigens employed), integrity and reproducibility of the results obtained (cytometry data were analyzed by two independent laboratory operators), evaluation of the cytokine profile and memory status in both CD4+ and CD8+ T-cell subsets. The gene discussed is CD4; the disease is tuberculosis.