A method of diagnosing latently infected Mycobacterium tuberculosis (LTBI) subjects, said method comprising: (i) culturing isolated peripheral blood mononuclear cells (PBMC) or a blood sample from a subject with a composition comprising six peptides, in which the amino acid sequences of said peptides are chosen from: - peptide 6 of SEQ ID N°2; - peptide 12 of SEQ ID N°3; - peptide 18 of SEQ ID N°4; - peptide 24 of SEQ ID N°5; - peptide 30 of SEQ ID N°6; - peptide 36 of SEQ ID N°7; - peptide 7 of SEQ ID N°8; - peptide 8 of SEQ ID N°9; - peptide 9 of SEQ ID N°10; - peptide 10 of SEQ ID N°11; - peptide 11 of SEQ ID N°12; - peptide 19 of SEQ ID N°13; - peptide 20 of SEQ ID N°14; - peptide 21 of SEQ ID N°15; - peptide 22 of SEQ ID N°16; - peptide 23 of SEQ ID N°17; - peptide 31 of SEQ ID N°18; - peptide 32 of SEQ ID N°19; - peptide 33 of SEQ ID N°20; - peptide 34 of SEQ ID N°21; - peptide 35 of SEQ ID N°22; - peptide 1 of SEQ ID N°25; - peptide 2 of SEQ ID N°26; - peptide 3 of SEQ ID N°27; - peptide 4 of SEQ ID N°28; - peptide 5 of SEQ ID N°29; - peptide 13 of SEQ ID N°30; - peptide 14 of SEQ ID N°31; - peptide 15 of SEQ ID N°32; - peptide 16 of SEQ ID N°33; - peptide 17 of SEQ ID N°34; - peptide 25 of SEQ ID N°35; - peptide 26 of SEQ ID N°36; - peptide 27 of SEQ ID N°37; - peptide 28 of SEQ ID N°38; and - peptide 29 of SEQ ID N°39; (ii) measuring the level of expression of IFN-gamma of said isolated peripheral blood mononuclear cells (PBMC) or of said blood sample; and (iii) deducing therefrom if the subject has a LTBI. (i) culturing isolated peripheral blood mononuclear cells (PBMC) or a blood sample from a subject with a composition comprising six peptides, in which the amino acid sequences of said peptides are chosen from: - peptide 6 of SEQ ID N°2; - peptide 12 of SEQ ID N°3; - peptide 18 of SEQ ID N°4; - peptide 24 of SEQ ID N°5; - peptide 30 of SEQ ID N°6; - peptide 36 of SEQ ID N°7; - peptide 7 of SEQ ID N°8; - peptide 8 of SEQ ID N°9; - peptide 9 of SEQ ID N°10; - peptide 10 of SEQ ID N°11; - peptide 11 of SEQ ID N°12; - peptide 19 of SEQ ID N°13; - peptide 20 of SEQ ID N°14; - peptide 21 of SEQ ID N°15; - peptide 22 of SEQ ID N°16; - peptide 23 of SEQ ID N°17; - peptide 31 of SEQ ID N°18; - peptide 32 of SEQ ID N°19; - peptide 33 of SEQ ID N°20; - peptide 34 of SEQ ID N°21; - peptide 35 of SEQ ID N°22; - peptide 1 of SEQ ID N°25; - peptide 2 of SEQ ID N°26; - peptide 3 of SEQ ID N°27; - peptide 4 of SEQ ID N°28; - peptide 5 of SEQ ID N°29; - peptide 13 of SEQ ID N°30; - peptide 14 of SEQ ID N°31; - peptide 15 of SEQ ID N°32; - peptide 16 of SEQ ID N°33; - peptide 17 of SEQ ID N°34; - peptide 25 of SEQ ID N°35; - peptide 26 of SEQ ID N°36; - peptide 27 of SEQ ID N°37; - peptide 28 of SEQ ID N°38; and - peptide 29 of SEQ ID N°39; - peptide 6 of SEQ ID N°2; - peptide 12 of SEQ ID N°3; - peptide 18 of SEQ ID N°4; - peptide 24 of SEQ ID N°5; - peptide 30 of SEQ ID N°6; - peptide 36 of SEQ ID N°7; - peptide 7 of SEQ ID N°8; - peptide 8 of SEQ ID N°9; - peptide 9 of SEQ ID N°10; - peptide 10 of SEQ ID N°11; - peptide 11 of SEQ ID N°12; - peptide 19 of SEQ ID N°13; - peptide 20 of SEQ ID N°14; - peptide 21 of SEQ ID N°15; - peptide 22 of SEQ ID N°16; - peptide 23 of SEQ ID N°17; - peptide 31 of SEQ ID N°18; - peptide 32 of SEQ ID N°19; - peptide 33 of SEQ ID N°20; - peptide 34 of SEQ ID N°21; - peptide 35 of SEQ ID N°22; - peptide 1 of SEQ ID N°25; - peptide 2 of SEQ ID N°26; - peptide 3 of SEQ ID N°27; - peptide 4 of SEQ ID N°28; - peptide 5 of SEQ ID N°29; - peptide 13 of SEQ ID N°30; - peptide 14 of SEQ ID N°31; - peptide 15 of SEQ ID N°32; - peptide 16 of SEQ ID N°33; - peptide 17 of SEQ ID N°34; - peptide 25 of SEQ ID N°35; - peptide 26 of SEQ ID N°36; - peptide 27 of SEQ ID N°37; - peptide 28 of SEQ ID N°38; and - peptide 29 of SEQ ID N°39; (ii) measuring the level of expression of IFN-gamma of said isolated peripheral blood mononuclear cells (PBMC) or of said blood sample; and (iii) deducing therefrom if the subject has a LTBI.