Effect of Isoniazid Therapy for Latent TB Infection on QuantiFERON-TB Gold In-Tube Responses in Adults With Positive Tuberculin Skin Test Results in a High TB Incidence Area

QuantiFERON-TB Gold In-Tube Test for Tuberculosis Prevention in HIV-Infected Patients

“…The higher reversion rate in our study than in the Norwegian study could be because of our higher rate of compliance to LTBI treatment, lower median IFN-γ baseline level (1.05 IU mL vs. 3.48 IU mL), and a higher proportion of patients completing serial QFT-IT testing (95 vs. 52 ) enabling more accurate assessment of IFN-γ responses. Compared to the studies on non-HIV-infected individuals (11,13,14,(18)(19)(20), the higher reversion rate in this study could be explained by lower median baseline IFN-γ level and longer period between initial and subsequent tests (24 months vs. 4-9 months) after LTBI treatment that allowed detection of delayed reversion. In addition, most of the studies on non-HIV-infected persons did not assess adherence to LTBI treatment, which may have an effect on the IFN-γ response.…”

“…In the present study, the reversion rate of QFT-IT was high (81 ) in patients completing IPT, while reversion were not detected in those without IPT. The reversion rate was higher than those reported in either the HIV-infected persons of the Norwegian study (23 ; 15) or the non-HIV-infected cohort (5-42 ) (11,13,14,(18)(19)(20). The higher reversion rate in our study than in the Norwegian study could be because of our higher rate of compliance to LTBI treatment, lower median IFN-γ baseline level (1.05 IU mL vs. 3.48 IU mL), and a higher proportion of patients completing serial QFT-IT testing (95 vs. 52 ) enabling more accurate assessment of IFN-γ responses.…”

“…Other studies have reported similar responses of IFN-γ after LTBI treatment in both non-HIV-infected (11,13,14,18,19) and HIV-infected individuals (15). However, studies on non-HIV-infected patients have reported that the significant decrease of IFN-γ level occurred regardless of compliance to LTBI treatment (14,20). In a study from South Africa (14), QFT-IT was performed at a median of 9 days after TST.…”

“…The cohort comprised 150 patients with a median age of 40 years (range 18-65 years); of these, 79 (53 ) patients were men, 119 (79 ) had a CD4 count of 200 cells µL, 109 (73 ) had received prior BCG vaccination, 21 (14 ) reported a history of TB exposure, and 113 (75 ) were currently on ART of whom 109 (96 ) reported HIV RNA suppression at the start of the study. There were no indeterminate QFT-IT results.…”

“…Previous studies have reported a positive correlation between IGRAassessed effector T-cell responses and the antigenic and the bacillary burden of Mycobacterium tuberculosis (9,10). Decreased T-cell responses after active TB and LTBI treatment have been demonstrated in non-HIVinfected individuals (9,11), however, to date, reports of changes in interferon-gamma (IFN-γ) levels after LTBI treatment remain controversial (12)(13)(14). Additionally, data regarding the long-term IFN-γ responses after IPT among HIV-infected patients from high-endemic TB settings are limited (15).…”