Risk of Disease After Isoniazid Preventive Therapy for Mycobacterium tuberculosis Exposure in Young HIV-uninfected Children.

Background: The risk of developing tuberculosis (TB) disease in HIV-uninfected children after isoniazid preventive therapy (IPT) for a positive QuantiFERON-TB Gold In-Tube test (QFT-GIT) is unknown. The aim of this study was to evaluate risk of TB disease after IPT in young HIV-uninfected children with a positive QFT-GIT result, or household TB contact.

Methods: HIV-uninfected South African infants aged 4-6 months were screened for enrolment in a TB vaccine trial.

Specific T cell frequency and cytokine expression profile do not correlate with protection against tuberculosis after bacillus Calmette-Guérin vaccination of newborns.

Rationale: Immunogenicity of new tuberculosis (TB) vaccines is commonly assessed by measuring the frequency and cytokine expression profile of T cells.

Objectives: We tested whether this outcome correlates with protection against childhood TB disease after newborn vaccination with bacillus Calmette-Guérin (BCG).

Methods: Whole blood from 10-week-old infants, routinely vaccinated with BCG at birth, was incubated with BCG for 12 hours, followed by cryopreservation for intracellular cytokine analysis.

Neonatal mycobacterial specific cytotoxic T-lymphocyte and cytokine profiles in response to distinct BCG vaccination strategies.

This study evaluated whether different bacillus Calmette-Guérin (BCG) strains, routes of administration, vaccination age and percutaneous tools influenced immune responses to BCG vaccination in infants. Proliferative responses, cytokine production and cell-mediated cytotoxicity obtained in post-vaccinated children were compared to baseline cord bloods and unvaccinated 10-week-old infants. BCG vaccination generally induced strong lymphoproliferative and T helper type 1 (Th1)-type cytokine responses.