CD4 and tuberculosis: A similar IL-17 mRNA expression has been observed in CD4+ blood cells between TB patients and healthy controls [18], and a higher percentage of IL-17+CD4+ lymphocytes at baseline [19] or after M. tuberculosis antigen stimulation has been observed in TB patients [20], whereas a lower percentage of blood IL-17+CD4+ cells has also been reported in TB patients [9, 16], similar with the present study.