Interferon Gamma Release Assay and Tuberculin Skin Test Performance in Pregnant Women Living With and Without HIV

Maternal breastfeeding and education impact infant growth and development more than in-utero HIV/antiretroviral therapy exposure in context of universal antiretroviral therapy

BACKGROUND

Exposure to HIV and antiretroviral therapy (ART) in utero may influence infant growth and development. Most available evidence predates adoption of universal ART (Option B+ ART regimens). In a recent cohort, we compared growth and development in HIV-exposed uninfected (HEU) to HIV-unexposed (HUU) infants.

DESIGN

Prospective cohort study: data from Impact of Maternal HIV on Mycobacterium Tuberculosis Infection among Peripartum Women and their Infants (MiTIPS) in Western Kenya.

METHODS

Women were enrolled during pregnancy. Mother-infant pairs were followed until 24 months postpartum. We used multivariable linear mixed-effects models to compare growth rates [weight-for-age z score (WAZ) and height-for-age z score (HAZ)] and multivariable linear regression to compare overall development between HEU and HUU children.

RESULTS

About 51.8% (184/355) of the infants were HEU, 3.9% low birthweight (<2.5 kg), and 8.5% preterm (<37 gestational weeks). During pregnancy, all mothers of HEU received ART; 67.9% started ART prepregnancy, and 87.3% received 3TC/FTC, TDF, and EFV. In longitudinal analyses, HEU children did not differ significantly from HUU in growth or development ( P  > 0.05 for all). In the combined HEU/HUU cohort, higher maternal education was associated with significantly better growth and development: WAZ [ β  = 0.18 (95% CI 0.01-0.34)], HAZ [ β  = 0.26 (95% CI 0.04-0.48)], and development [ β  = 0.24 (95% CI 0.02-0.46)]. Breastfeeding was associated with significantly better HAZ [ β =0.42 (95% CI 0.19-0.66)] and development [ β  =0.31 (95% CI 0.08-0.53)].

CONCLUSION

HEU children in the setting of universal maternal ART had a similar growth trajectory and development to HUU children. Breastfeeding and maternal education improved children's weight, height, and overall development irrespective of maternal HIV status.

Maternal HIV Status and Risk of Infant Mycobacterium tuberculosis Infection as Measured by Tuberculin Skin Test

BACKGROUND

The effect of maternal HIV on infant Mycobacterium tuberculosis (Mtb) infection risk is not well-characterized.

METHODS

Pregnant women with/without HIV and their infants were enrolled in a longitudinal cohort in Kenya. Mothers had interferon gamma-release assays (QFT-Plus) and tuberculin skin tests (TST) at enrollment in pregnancy; children underwent TST at 12 and 24 months of age. We estimated the incidence and correlates of infant TST-positivity using Cox proportional hazards regression.

RESULTS

Among 322 infants, 170 (53%) were HIV-exposed and 152 (47%) were HIV-unexposed. Median enrollment age was 6.6 weeks [interquartile range (IQR): 6.1-10.0]; most received Bacillus Calmette-Guerin (320, 99%). Thirty-nine (12%) mothers were TST-positive; 102 (32%) were QFT-Plus-positive. Among HIV-exposed infants, 154 (95%) received antiretrovirals for HIV prevention and 141 (83%) of their mothers ever received isoniazid preventive therapy (IPT). Cumulative 24-month infant Mtb infection incidence was 3.6/100 person-years (PY) [95% confidence interval (CI): 2.4-5.5/100 PY]; 5.4/100 PY in HIV-exposed infants (10%, 17/170) versus 1.7/100 PY in HIV-unexposed infants (3.3%, 5/152) [hazard ratio (HR): 3.1 (95% CI: 1.2-8.5)]. More TST conversions occurred in the first versus second year of life [5.8 vs. 2.0/100 PY; HR: 2.9 (95% CI: 1.0-10.1)]. Infant TST-positivity was associated with maternal TST-positivity [HR: 2.9 (95% CI: 1.1-7.4)], but not QFT-Plus-positivity. Among HIV-exposed children, Mtb infection incidence was similar regardless of maternal IPT.

CONCLUSIONS

Mtb infection incidence (by TST) by 24 months of age was ~3-fold higher among HIV-exposed children, despite high maternal IPT uptake. Overall, more TST conversions occurred in the first 12 months compared to 12-24 months of age, similar in both HIV-exposed and HIV-unexposed children.

Impact of Human Immunodeficiency Virus and Peripartum Period on Mycobacterium tuberculosis Infection Detection

BACKGROUND

Pregnancy and human immunodeficiency virus (HIV) may influence tuberculosis infection detection using interferon (IFN)-γ release assay (QFT-Plus; Qiagen) and tuberculin skin test (TST).

METHODS

Participants in Western Kenya underwent QFT-Plus and TST in pregnancy, 6 weeks postpartum (6wkPP) and 12 months postpartum (12moPP).

RESULTS

400 participants (200 with HIV [WHIV], 200 HIV-negative) enrolled during pregnancy (median 28 weeks' gestation [interquartile range, 24-30]). QFT-Plus positivity prevalence was higher than TST in pregnancy (32.5% vs 11.6%) and through 12moPP (6wkPP, 30.9% for QFT-Plus vs 18.0% for TST; 12moPP, 29.5% vs 17.1%; all P < .001), driven primarily by QFT-Plus-positive/TST-negative discordance among HIV-negative women. Tuberculosis infection test conversion incidence was 28.4/100 person-years (PY) and higher in WHIV than HIV-negative women (35.5 vs 20.9/100 PY; hazard ratio, 1.73 [95% confidence interval, 1.04-2.88]), mostly owing to early postpartum TST conversion among WHIV. Among QFT-Plus-positive participants in pregnancy, Mycobacterium tuberculosis  (Mtb)-specific IFN-γ responses were dynamic through 12moPP and lower among WHIV than HIV-negative women with tuberculosis infection at all time points.

CONCLUSIONS

QFT-Plus had higher diagnostic yield than TST in peripartum women. Peripartum QFT-Plus positivity was stable and less influenced by HIV than TST. Mtb-specific IFN-γ responses were dynamic and lower among WHIV. Tuberculosis infection test conversion incidence was high between pregnancy and early postpartum, potentially owing to postpartum immune recovery.

Prevalence and predictors of tuberculosis infection among people living with HIV in a high tuberculosis burden context

BACKGROUND

Tuberculosis (TB) disease is the leading cause of mortality among people living with HIV (PLHIV). Interferon-gamma release assays (IGRAs) are approved for TB infection ascertainment. However, current IGRA data on the prevalence of TB infection in the context of near-universal access to antiretroviral therapy (ART) and TB preventive therapy (TPT) are lacking. We estimated the prevalence and determinants of TB infection among PLHIV within a high TB and HIV burden context.

METHODS

This cross-sectional study included data from adult PLHIV age ≥18 years in whom QuantiFERON-TB Gold Plus (QFT-Plus) assay, an IGRA, was performed. TB infection was defined as a positive or indeterminate QFT-Plus test. Participants with TB and those who had previously used TPT were excluded. Regression analysis was performed to identify independent predictors of TB infection.

RESULTS

Of 121 PLHIV with QFT-Plus test results, females were 74.4% (90/121), and the mean age was 38.4 (SD 10.8) years. Overall, 47.9% (58/121) were classified as TB infection (QFT-Plus test positive and indeterminate results were 39.7% (48/121) and 8.3% (10/121), respectively). Being obese/overweight (body mass index ≥25 kg/m²; p=0.013, adjusted OR (aOR) 2.90, 95% CI 1.25 to 6.74) and ART usage for >3 years (p=0.013, aOR 3.99, 95% CI 1.55 to 10.28) were independently associated with TB infection.

CONCLUSION

There was a high TB infection prevalence among PLHIV. A longer period of ART and obesity were independently associated with TB infection. The relationship between obesity/overweight and TB infection may be related to ART use and immune reconstitution and requires further investigation. Given the known benefit of test-directed TPT among PLHIV never exposed to TPT, its clinical and cost implications for low and middle-income countries should be explored further.

Tuberculosis Infection in Pregnant People: Current Practices and Research Priorities

Women are significantly more likely to develop tuberculosis (TB) disease within the first 90 days after pregnancy than any other time in their lives. Whether pregnancy increases risk of progression from TB infection (TBI) to TB disease is unknown and is an active area of investigation. In this review, we discuss the epidemiology of TB and TBI in pregnancy, TBI diagnostics, and prevalence in pregnancy. We also review TBI treatment and highlight research priorities, such as short-course TB prevention regimens, drug-resistant TB prevention, and additional considerations for safety, tolerability, and pharmacokinetics that are unique to pregnant and postpartum people.