Effect of pregnancy on interferon gamma release-assay and tuberculin skin test detection of latent TB infection among HIV-infected women in a high burden setting

BACKGROUND:Peripartum immunologic changes may affect latent TB infection (LTBI) diagnostic performance among HIV-infected women. METHODS:HIV-infected women were serially-tested with tuberculin skin test (TST) and interferon gamma release assay (IGRA) (QuantiFERON® TB Gold In-tube [QFT]) in pregnancy and weeks postpartum in Kenya. Prevalence, sensitivity and agreement, and correlates of QFT/TST positivity were assessed. Quantitative QFT mitogen and M. tuberculosis antigen (Mtb-Ag) responses were compared by peripartum stage. Incidence of test conversion at 6 weeks postpartum was evaluated in baseline TST-/QFT- women. RESULTS:Among 100 HIV-infected women, median age was 26 years, median CD4 was 555 cells/mm3, and 88% were on antiretrovirals. More women were QFT+ than TST+ in pregnancy (35.4% vs. 13.5%, p=0.001), and postpartum (29.6% vs. 14.8%, p