A 46-year-old man originating from Morocco, with a medical history of end-stage renal disease secondary to type 2 diabetes mellitus presented with chills during haemodialysis (HD) sessions on January 2011. The patient was on HD since 2007, and in 2009, he was included in a prospective study to evaluate the utility of HBHA-IGRA, compared to TST for the detection of LTBI in HD patients (Dessein et al, manuscript in preparation). The QFT-G-IT was highly positive (13.58 IU/ml) as were the PPD- and HBHA-IGRAs with respectively 18,972 pg/ml and 7,287 pg/ml IFN-gamma. These results, especially the high IFN-gamma response to the latency antigen HBHA, indicated that the patient was latently infected with Mtb. During a January 2011 HD session, the patient presented with chills and fever, but no abnormalities were noted upon physical examination, except a weight loss of 4 Kg over the previous weeks. Blood cultures remained negative. A chest radiography revealed no infiltrates, cavities or calcifications. The patient denied prior exposition to Mtb, but the QFT-G-IT was still positive, with values similar to those found two years earlier (14.36 IU/ml), whereas the HBHA-IGRA had become totally negative. However, depletion of the CD4+ regulatory T cells from the PBMC, performed as described previously and based on CD25high T cell depletion by positive immunomagnetic selection, resulted in the re-appearance of a low but positive IFN-gamma response to HBHA stimulation (134 pg/ml). At that time, the IGRA values to rESAT-6 were very high (3,855 pg/ml) so that the HBHA/rESAT-6 ratio was 0.001. Since these results strongly suggested that the patient had progressed from latent Mtb infection to active TB disease, a PET Scan analysis was done demonstrating a strong metabolic captation of cervical and mediastinal lymph nodes. A jugular lymph node was surgically removed and revealed the presence of a granuloma with caseous necrosis. Anti-tuberculosis treatment was immediately initiated (Nicotibine, Rifadine, Tebrazid, Myambutol) and resulted in progressive clinical improvement. Thirty-two days later, the lymph node culture was positive for drug-sensitive Mtb.