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

Clinical characteristics and pregnancy outcomes in pregnant women with TB: a retrospective cohort study

PURPOSE

The influence of pregnancy on tuberculosis (TB) has not been well studied. This study aimed to investigate the demographics, clinical characteristics and outcomes of pregnant-related TB compared with the general population with TB.

METHODS

We retrospectively analysed medical records of women during pregnancy or within six months postpartum with active TB who were admitted to the West China Hospital between 2011 and 2022. According to age, gender and admission time, the general population with active TB was matched at a ratio of 1:2, and the demographics, clinical characteristics and outcomes were compared.

RESULTS

All the participants in both the pregnant and non-pregnant groups were females, averaging 26 years old, with a majority of Han nationality (72.4% vs. 69.5%, respectively). The two groups were comparable (p < .05). Pregnant TB cases showed higher rates of fever (61% vs. 35%), dyspnoea (39.9% vs. 18.7%), neurological symptoms (34.4% vs. 11.0%) and miliary TB (24.5% vs. 10.9%) compared to non-pregnant cases (p < .05). Additionally, the pregnant group exhibited lower red blood cell counts (3.62 × 109/L vs. 4.37 × 109/L), lower albumin levels (31.20 g/L vs. 40.40 g/L) and elevated inflammatory markers (p < .05). Pregnant women with TB had severe outcomes, with 16.3% requiring intensive care unit (ICU) care and a 3.3% TB-related mortality rate - higher than local averages. In contrast, the non-pregnant group had lower rates (0.8% for ICU admission, and no TB-related deaths). Moreover, active TB during pregnancies led to a high rate of spontaneous abortion (34.1%), with military pulmonary TB identified as the sole risk factor for severe TB in pregnancies (OR: 3.6; 95% CI: 1.15, 11.34).

CONCLUSIONS

Manifestations of TB in pregnant women differ from those in the general population with TB. Pregnancy complicated with active TB greatly harms the mother and foetus and requires special attention in the future.

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.

HIV/Tuberculosis Coinfection in Pregnancy and the Postpartum Period

The convergence of Human Immunodeficiency Virus (HIV) and tuberculosis (TB) represents a considerable global public health challenge. The concurrent infection of HIV and TB in pregnant women not only intensifies the transmission of HIV from mother to fetus but also engenders adverse outcomes for maternal health, pregnancy, and infant well-being, necessitating the implementation of integrated strategies to effectively address and manage both diseases. In this article, we review the pathophysiology, clinical presentation, treatment, and management of HIV/TB coinfection during pregnancy, the postpartum period, and lactation and highlight the differences compared to the general population.

Determinants of QuantiFERON Plus-diagnosed tuberculosis infection in adult Ugandan TB contacts: A cross-sectional study

BACKGROUND

The tuberculin skin test is commonly used to diagnose latent tuberculosis infection (LTBI) in resource-limited settings, but its specificity is limited by factors including cross-reactivity with BCG vaccine and environmental mycobacteria. Interferon-gamma release assays (IGRA) overcome this problem by detecting M. tuberculosis complex-specific responses, but studies to determine risk factors for IGRA-positivity in high TB burden settings are lacking.

METHODS

We conducted a cross-sectional study to determine factors associated with a positive IGRA by employing the QuantiFERON-TB® Gold-plus (QFT Plus) assay in a cohort of asymptomatic adult TB contacts in Kampala, Uganda. Multivariate logistic regression analysis with forward stepwise logit function was employed to identify independent correlates of QFT Plus-positivity.

RESULTS

Of the 202 participants enrolled, 129/202 (64%) were female, 173/202 (86%) had a BCG scar, and 67/202 (33%) were HIV-infected. Overall, 105/192 (54%, 95% CI 0.48-0.62) participants had a positive QFT Plus result. Increased risk of QFT-Plus positivity was independently associated with casual employment/unemployment vs. non-casual employment (adjusted odds ratio (aOR) 2.18, 95% CI 1.01-4.72), a family vs. non-family relation to the index patient (aOR 2.87, 95% CI 1.33-6.18), living in the same vs. a different house as the index (aOR 3.05, 95% CI 1.28-7.29), a higher body mass index (BMI) (aOR per additional kg/m2 1.09, 95% CI 1.00-1.18) and tobacco smoking vs. not (aOR 2.94, 95% CI 1.00-8.60). HIV infection was not associated with QFT-Plus positivity (aOR 0.91, 95% CI 0.42-1.96).

CONCLUSION

Interferon Gamma Release Assay positivity in this study population was lower than previously estimated. Tobacco smoking and BMI were determinants of IGRA positivity that were previously unappreciated.

Diagnostic biomarkers for active tuberculosis: progress and challenges

Tuberculosis (TB) is a leading cause of morbidity and mortality from a single infectious agent, despite being preventable and curable. Early and accurate diagnosis of active TB is critical to both enhance patient care, improve patient outcomes, and break Mycobacterium tuberculosis (Mtb) transmission cycles. In 2020 an estimated 9.9 million people fell ill from Mtb, but only a little over half (5.8 million) received an active TB diagnosis and treatment. The World Health Organization has proposed target product profiles for biomarker- or biosignature-based diagnostics using point-of-care tests from easily accessible specimens such as urine or blood. Here we review and summarize progress made in the development of pathogen- and host-based biomarkers for active TB diagnosis. We describe several unique patient populations that have posed challenges to development of a universal diagnostic TB biomarker, such as people living with HIV, extrapulmonary TB, and children. We also review additional limitations to widespread validation and utilization of published biomarkers. We conclude with proposed solutions to enhance TB diagnostic biomarker validation and uptake.

Dynamics of Mycobacterium tuberculosis-Specific and Nonspecific Immune Responses in Women with Tuberculosis Infection during Pregnancy

The immune control of tuberculosis (TB) infection could be influenced by pregnancy. To elucidate this, we longitudinally characterized Mycobacterium tuberculosis (Mtb)-specific and nonspecific immune responses in women during pregnancy and postpartum. HIV-uninfected women without past or current active TB, and with blood samples available from the 1st/2nd trimester, 3rd trimester, and 9 months postpartum, were identified at Ethiopian antenatal care clinics. Twenty-two TB+ women and 10 TB- women, defined according to Mtb-stimulated interferon-γ levels (≥0.35 and <0.20 IU/mL, respectively, in the Quantiferon-TB Gold-Plus assay), were included in the study. Longitudinal dynamics of six cytokines (IL-1ra, IL-2, IP-10, MCP-2, MCP-3, and TGF-β1) were analyzed in supernatants from Mtb-stimulated and unstimulated whole blood. In TB+ women, Mtb-specific expression of IL-2 and IP-10 was higher at 3rd compared to 1st/2nd trimester (median 139 pg/mL versus 62 pg/mL, P = 0.006; 4,999 pg/mL versus 2,310 pg/mL, P = 0.031, respectively), whereas level of Mtb-triggered TGF-β1 was lower at 3rd compared to 1st/2nd trimester (-6.8 ng/mL versus 2.3 ng/mL, P = 0.020). Unstimulated IL-2, IP-10, and MCP-2 levels were increased postpartum, compared with those noted during pregnancy, in TB+ women. Additionally, postpartum levels of proinflammatory cytokines in unstimulated blood were higher in TB+ women, than in TB- women. None of the women developed active TB during follow-up. Taken together, dynamic changes of Mtb-specific cytokine expression revealed during the 3rd trimester in TB+ women indicate increased Mtb-antigen stimulation at later stages of pregnancy. This could reflect elevated bacterial activity, albeit without transition to active TB, during pregnancy. IMPORTANCE Tuberculosis (TB) is globally one of the most common causes of death, and a quarter of the world's population is estimated to have TB infection. The risk of active TB is increased in connection to pregnancy, a phenomenon that could be due to physiological immune changes. Here, we studied the effect of pregnancy on immune responses triggered in HIV-uninfected women with TB infection, by analyzing blood samples obtained longitudinally during pregnancy and after childbirth. We found that the dynamics of Mtb-specific and nonspecific immune responses changed during pregnancy, especially in later stages of pregnancy, although none of the women followed in this study developed active TB. This suggests that incipient TB, with elevated bacterial activity, occurs during pregnancy, but progression of infection appears to be counteracted by Mtb-specific immune responses. Thus, this study sheds light on immune control of TB during pregnancy, which could be of importance for future intervention strategies.

Tuberculin test versus interferon gamma release assay in pregnant women with household contacts of tuberculosis patients

Background

Pregnant women who live in tuberculosis (TB)-affected households are more likely to develop latent TB infection (LTBI), which often escapes treatment. This study aims to determine if Interferon-gamma release (IGRA) is reliable in screening for LTBI in pregnant women, compare to the tuberculin skin test (TST).

Methods

It was a cross-sectional study that involved 60 pregnant women with TB contact history as a proxy for LTBI and 30 pregnant women without contact history. Latent TB was detected using the TST 5 tuberculin units and IGRA using the QuantiFERON Gold Plus TB Test kit (QFT-Plus). The sensitivity and specificity of the two diagnostic methods and the agreement between them were estimated using SPSS version 20.0.

Results

The sensitivity 95% (95% confidence interval [CI]: 86.08%-98.96%) and specificity 26.7% (95% CI: 12.28%-45.89%) of TST were compared to that of the IGRA with 60% (95% CI: 46.54%-72.44%) and 73.3% (95% CI: 54.11%-87.72%) sensitivity and specificity, respectively in detecting LTBI in pregnancy. Although there was a significant difference (P < 0.05) between TST and IGRA, the agreement was fair (kappa 0.39; 95% CI: 0.24-0.45).

Conclusion

TST assay is more sensitive than IGRA; however, the specificity of IGRA was superior to the TST method. In this study, a fair agreement of TST and IGRA was observed for detecting latent TB infection in pregnant women with household contact with TB patients.

Exploring alternative cytokines as potential biomarkers for latent tuberculosis infection in pregnant women

Background

Interferon gamma release assays (IGRAs) are widely used to determine latent tuberculosis infection status. However, its pregnancy-affected performance and cost-expensive nature warrants for different alternatives for pregnant women. This study aims to evaluate the diagnostic performance of several alternative cytokines, including interleukin 2 (IL-2), interleukin 10 (IL-10), and interferon gamma-induced protein 10 (IP-10) to identify latent tuberculosis status in pregnant women.

Materials and methods

123 pregnant womens were recruited for this study. The IGRA status was determined by using QuantiFERON Gold In-Tube. Meanwhile, we measured the level IL-2, IL-10, and IP-10 by using sandwich-microELISA method. We performed normality and comparison test by SPSS. In addition, receiver-operator characteristic (ROC) analyses and the optimal cutoff scores were identified using the EasyROC webtool.

Results

We showed that IL-2, IL-10, and IP-10 were able to discriminate between IGRA-negative and IGRA-positive pregnant women. Moreover, IP-10 showed the highest discriminatory and diagnostic performance when compared to IL-2 and IL-10 with area under the curve (AUC) of 0.96 and cutoff point of 649.65 pg/mL.

Conclusions

Our study showed that IP-10 can be considered as a promising alternative biomarker for IGRAs to diagnose LTBI in pregnant women.

Diagnostic accuracy of the interferon-gamma release assay in acquired immunodeficiency syndrome patients with suspected tuberculosis infection: a meta-analysis

Purpose

The diagnostic accuracy of the interferon-gamma release assay (IGRA) in immunosuppressed patients remains unclear.

Methods

A systematic review and meta-analysis were performed for diagnostic test accuracy of IGRA in tuberculosis (TB) infection among people living with HIV (PLWHIV). Summary estimates of sensitivity and specificity were calculated using both univariate and bivariate models.

Results

The meta-analysis included 45 of the 1,242 first-screened articles. The total number of PLWHIV was 6,525; 3,467 had TB disease, including 806 cases of LTBI and 2,661 cases of active TB. The overall diagnostic odds ratio (DOR) of IGRA in the diagnosis of TB disease was 10.0 (95% confidence interval (CI) 5.59, 25.07), with an area under the curve (AUC) of 0.729. The DOR was better for QFT (14.2 (95%CI 4.359, 46.463)) than T-SPOT (10.0 (95%CI 3.866 26.033)). The sensitivity and specificity of QFT and T-SPOT were 0.663 (95%CI 0.471, 0.813), 0.867 (95%CI 0.683 0.942), and 0.604 (95%CI 0.481, 0.715), 0.862 (95%CI 0.654, 0.954), respectively, in the bivariate model. The sensitivity of IGRA in the diagnosis of LTBI was 0.64 (95%CI 0.61, 0.66).

Conclusion

IGRA was useful in the diagnostic of TB disease in PLWHIV, and QFT showed a better tendency of DOR than T-SPOT. IGRA showed a limited effect to rule out LTBI in PLWHIV.

Longitudinal Variations of M. tuberculosis-Induced IFN-γ Responses in HIV-Negative Pregnant Women Exposed to Tuberculosis

Introduction

Pregnancy triggers an alteration of the immune functions and increases the risk of developing the active tuberculosis (TB) symptoms in exposed women. The effect of pregnancy on the Mycobacterium tuberculosis-specific immune responses used for most of the TB immunodiagnostic assays is not well documented. Here we investigated the changes in the M. tuberculosis-specific IFN-γ production in age-matched pregnant and non-pregnant women according to their TB exposition status.

Methods

We conducted a prospective cohort study on HIV-seronegative pregnant and non-pregnant women with compatible pulmonary TB symptoms addressed to TB healthcare facilities in Antananarivo, Madagascar. Active pulmonary TB was bacteriologically assessed with culture from sputum samples. Clinical data and blood samples were collected at inclusion and after 6 months of follow-up for each individual included. Whole blood samples were stimulated with QuantiFERON TB-Gold Plus (QFT-P) assay antigens. Plasma IFN-γ concentrations were then assessed by ELISA.

Results

A total of 284 women were investigated for the study including 209 pregnant women without confirmed TB (pNTB), 24 pregnant women with bacteriologically confirmed active TB (pATB), 16 non-pregnant women with active TB (ATB), and 35 non-pregnant healthy donors (HC). At inclusion, IFN-γ responses are lower in the pregnant women compared to their age-matched non-pregnant counterparts and independently of their TB status. Among the pregnant women, higher concentrations of M. tuberculosis-specific IFN-γ were observed in those exposed to TB, but with a lower magnitude in the active TB compared to the latently infected pregnant women (p < 0.05 with TB1 and p < 0.01 with TB2). After 6 months of follow-up, the M. tuberculosis-specific IFN-γ responses return to their baseline concentrations except for the pregnant women treated for TB for which none of the QFT-P positive reversed to negative (0%, 0/10) at the end of their TB treatment.

Conclusion

These results support the concept of specific immune priorities characterized by a concomitant reduction in inflammatory immunity during pregnancy and corroborate the important role of activating the M. tuberculosis-specific immune responses to control the infection when the pregnant women are exposed to the pathogen.

Diagnostic Value of Interferon-Gamma Release Assays for Tuberculosis in the Immunocompromised Population

Interferon-gamma release assays (IGRAs) are widely used in the diagnosis of Mycobacterium tuberculosis (M. tuberculosis) infection by detecting interferon-γ released by previously sensitized T-cells in-vitro. Currently, there are two assays based on either enzyme-linked immunosorbent assay (ELISA) or enzyme-linked immunospot (ELISPOT) technology, with several generations of products available. The diagnostic value of IGRAs in the immunocompromised population is significantly different from that in the immunocompetent population because their results are strongly affected by the host immune function. Both physiological and pathological factors can lead to an immunocompromised situation. We summarized the diagnostic value and clinical recommendations of IGRAs for different immunocompromised populations, including peoplewith physiological factors (pregnant and puerperal women, children, and older people), as well as people with pathological factors (solid organ transplantation recipients, combination with human immunodeficiency virus infection, diabetes mellitus, end-stage renal disease, end-stage liver disease, and chronic immune-mediated inflammatory diseases). Though the performance of IGRAs is not perfect and often requires a combination with other diagnostic strategies, it still has some value in the immunocompromised population. Hopefully, the newly developed IGRAs could better target this population.

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

BACKGROUND

HIV and pregnancy may affect latent TB infection (LTBI) diagnostics. Tuberculin skin test (TST) and newer generation QuantiFERON-TB Gold Plus (QFT-Plus) evaluations in pregnant women living with HIV (WLHIV) and without HIV are lacking.

METHODS

In this cross-sectional study, pregnant women underwent TST and QFT-Plus testing during antenatal care in Kenya. We estimated LTBI prevalence and TST and QFT-Plus performances. Diagnostic agreement was assessed with kappa statistic, participant characteristics associated with LTBI and HIV were assessed with generalized linear models, and QFT-Plus quantitative responses were assessed with Mann-Whitney U test.

RESULTS

We enrolled 400 pregnant women (200 WLHIV/200 HIV-negative women) at median 28 weeks gestation (interquartile range 24-30). Among WLHIV (all on antiretroviral therapy), the median CD4 count was 464 cells/mm3 (interquartile range 325-654); 62.5% (125) had received isoniazid preventive therapy. LTBI prevalence was 35.8% and similar among WLHIV and HIV-negative women. QFT-Plus testing identified 3-fold more women with LTBI when compared with TST (32% vs. 12%, P < 0.0001). QFT-Plus positivity prevalence was similar regardless of HIV status, although TB-specific antigen responses were lower in WLHIV than in HIV-negative women with LTBI (median QFT-TB1 1.05 vs. 2.65 IU/mL, P = 0.035; QFT-TB2 1.26 vs. 2.56 IU/mL, P = 0.027). TST positivity was more frequent among WLHIV than among HIV-negative women (18.5% vs 4.6%; P < 0.0001).

CONCLUSIONS

QFT-Plus assay had higher diagnostic yield than TST for LTBI in WLHIV and HIV-negative women despite lower TB-specific antigen responses in WLHIV. Higher TST positivity was observed in WLHIV. LTBI diagnostic performance in the context of pregnancy and HIV has implications for clinical use and prevention studies, which rely on these diagnostics for TB infection entry criteria or outcomes.

Mycobacterium tuberculosis-specific T cell responses are impaired during late pregnancy with elevated biomarkers of tuberculosis risk postpartum

BACKGROUND

Pregnancy is a risk factor for progression from latent tuberculosis infection (LTBI) to symptomatic tuberculosis (TB). However, how pregnancy influences T cell responses to M. tuberculosis (Mtb) is unknown.

METHODS

We measured Mtb-specific cytokines, T-cell memory markers, and overall CD4+ and CD8+ T-cell activation by flow cytometry from 49 women (18 with and 31 without HIV) who became pregnant while enrolled in a randomized controlled trial of pre-exposure prophylaxis for HIV prevention. We analyzed these data using COMPASS, an established statistical method for evaluating overall antigen-specific T cell responses.

RESULTS

Pregnant women with latent TB infection demonstrated significantly diminished Mtb-specific CD4+ cytokine responses in the third trimester (COMPASS score (PFS) 0.07) compared before (PFS 0.15), during (PFS 0.13 and 0.16), and after pregnancy (PFS 0.14; p = 0.0084, Kruskal-Wallis test). Paradoxically, Mtb-specific CD8+ cytokines and nonspecifically activated T-cells increased during late pregnancy. Nonspecific T-cell activation, a validated biomarker for progression from LTBI to TB disease, was increased in LTBI+ women postpartum, compared with LTBI- women.

CONCLUSIONS

Pregnancy-related functional T-cell changes were most pronounced during late pregnancy. Mtb-specific T-cell changes during pregnancy and postpartum, increases in immune activation may contribute to increased risk for TB progression in the postpartum period.

Stages of pregnancy and HIV affect diagnosis of tuberculosis infection and Mycobacterium tuberculosis (MTB)-induced immune response: Findings from PRACHITi, a cohort study in Pune, India

BACKGROUND

Accurate tuberculosis infection (TBI) tests are critical for pregnant women, especially those with HIV, who have a high risk of TB disease.

METHODS

We enrolled interferon gamma release assay (IGRA)+ pregnant women with and without HIV in a longitudinal study, followed up at delivery and 6 months postpartum. Tuberculin skin test (TST) and IGRA were compared by HIV status at each timepoint.

RESULTS

Of 165 enrolled IGRA+ pregnant women: 35 (21%) had HIV and were on antiretroviral therapy with median CD4 of 476 (IQR 399-586). Compared to antepartum, significantly fewer women remained IGRA+ at delivery [HIV+ n=21/35 (62%, p=0.009); HIV- n=100/130 (77%, p=0.002)] and postpartum [HIV+ n=30/35 (87%, p=0.03); HIV- n=116/130 (89%, p=0.01)]. IGRA/TST discordance was high in pregnant women (HIV+: 51%; HIV-: 25%). Median IFN-γ was lowest for all women at delivery; significantly lower in women with HIV at all timepoints compared to women without HIV. TB incidence was 50/ 1000 person-years and 18/1000 person-years among women with and without HIV respectively.

CONCLUSIONS

Pregnancy affects TBI test results and reduces IFN-γ response to M. tuberculosis stimulation. Despite adequate CD4 counts, women with HIV express less IFN-γ than women without HIV, which may explain the high TB incidence in postpartum women with HIV.

Tuberculosis Infection in Women of Reproductive Age: A Cross-sectional Study at Antenatal Care Clinics in an Ethiopian City

BACKGROUND

Knowledge on tuberculosis (TB) infection epidemiology in women of reproductive age living in TB-endemic areas is limited. We used a composite definition of TB infection in a cohort of pregnant women recruited in an Ethiopian city as a model for TB exposure patterns, and to identify factors associated with TB infection.

METHODS

Women seeking antenatal care at public health facilities underwent structured interviews, physical examination, and QuantiFERON-TB Gold-Plus (QFT) testing. Women with symptoms compatible with TB disease, and all human immunodeficiency virus (HIV)-positive women, were investigated for active TB by sputum bacteriological testing. TB infection (TB+) was defined as either positive QFT (≥ 0.35 IU/mL), self-reported previous active TB, or current active TB. Associations between TB infection and clinical, demographic, and socioeconomic characteristics were tested in multiple logistic regression analysis.

RESULTS

Among 1834 participants, 679 (37.0%) met criteria for TB+ (80 [4.4%] previous active TB, 5 [0.3%] current active TB, and 594 [32.4%] QFT-positive without previous or current active TB). Age (annual adjusted odds ratio [AOR], 1.069 [95% confidence interval {CI}, 1.045-1.093]) and HIV infection (AOR, 1.43 [95% CI, 1.033-1.988]) were independently associated with TB+. The relationship with increasing age was only observed in HIV-negative women, and translated to an estimated annual risk of TB infection of 2.1% in HIV-negative women.

CONCLUSIONS

TB infection in women of reproductive age in Ethiopia was independently associated with HIV infection and increasing age, suggesting exposure to contagious TB and continuous acquisition of TB infection in this population.

Longitudinal Mycobacterium tuberculosis specific interferon-γ responses in Ethiopian HIV-negative women during pregnancy and post-partum

Pregnancy may influence cellular immune responses to Mycobacterium tuberculosis. We investigated M. tuberculosis-specific interferon-γ responses in women followed longitudinally during pregnancy and postpartum. Interferon-γ levels (stimulated by M. tuberculosis antigens [TB1 and TB2] and mitogen included in the QuantiFERON-TB Gold Plus assay) were measured in blood from pregnant HIV-negative women identified from a prospective cohort at Ethiopian antenatal care clinics. Longitudinal comparisons included women without active tuberculosis (TB) with M. tuberculosis-triggered interferon-γ responses of ≥ 0.20 IU/ml, sampled on two and/or three occasions (1st/2nd trimester, 3rd trimester, and 9 months postpartum). Among 2,093 women in the source cohort, 363 met inclusion criteria for longitudinal comparisons of M. tuberculosis-stimulated interferon-γ responses. Median M. tuberculosis-triggered interferon-γ concentrations were higher at 3rd than those at the 1st/2nd trimester (in 38 women with samples available from these time points; TB1: 2.8 versus 1.6 IU/ml, P = 0.005; TB2: 3.3 versus 2.8 IU/ml, P = 0.03) and postpartum (in 49 women with samples available from these time points; TB1: 3.1 versus 2.2 IU/ml, P = 0.01; TB2: 3.1 versus 2.3 IU/ml, P = 0.03). In contrast, mitogen-stimulated interferon-γ levels were lower at 3rd than those at 1st/2nd trimester (in 32 women with samples available from these time points: 21.0 versus 34.9 IU/ml, P = 0.02). Results were similar in 22 women sampled on all 3 occasions. In HIV-negative women, M. tuberculosis-stimulated interferon-γ responses were higher during the 3rd trimester than those at earlier stages of pregnancy and postpartum, despite decreased mitogen-triggered responses. These findings suggest increased M. tuberculosis-specific cellular responses due to dynamic changes of latent TB infection during pregnancy.

Effect of pregnancy and HIV infection on detection of latent TB infection by Tuberculin Skin Test and QuantiFERON-TB Gold In-Tube assay among women living in a high TB and HIV burden setting

OBJECTIVE

To investigate the effect of pregnancy and Human immunodeficiency virus (HIV) infection on detection performances of tuberculin skin test (TST) and QuantiFERON-TB Gold In-Tube (QFTGIT) for the diagnosis of latent tuberculosis infection (LTBI) among women living in high TB and HIV endemic setting.

METHOD

A cross-sectional study was conducted among women with and without pregnancy and HIV infection. Three-hundred twenty women were enrolled in this study and were diagnosed using TST and QFTGIT for the detection of LTBI.

RESULTS

Overall prevalence of LTBI among the enrolled women was 55.6%, 46.3% and 51.1% as determined by TST, QFTGIT and concordant TST/QFTGIT results, respectively. Our study revealed that pregnancy or HIV infection reduced the rate of detection of LTBI by TST and QFTGIT tests, with the utmost effect observed in HIV-positive pregnant women. Additionally, we observed that the concordance between TST and QFTGIT among women increased with the presence of pregnancy and/or HIV infection. A history of contact with TB patients was significantly associated with positivity of TST and QFTGIT.

CONCLUSION

This study demonstrated that both pregnancy and HIV infection profoundly affected the detection performance of TST and QFTGIT, which may be associated with immunosuppression of anti-mycobacterial immunity in women with pregnancy and/or HIV infection.

Alternative biomarkers for classification of latent tuberculosis infection status in pregnant women with borderline Quantiferon plus results

Borderline interferon-gamma (IFN-γ) results (near the cut-off level 0.35 IU/ml) occur in QuantiFERON (QFT) assays. We investigated the performance of alternative biomarkers for classification of latent tuberculosis infection (LTBI) status in pregnant women with borderline QFT IFN-γ responses. Pregnant women (n = 96) were identified from a cohort study in Ethiopia, based on QFT-Plus IFN-γ results (QFT-low: <0.20 IU/ml, n = 33; QFT-borderline: 0.20-0.70 IU/ml, n = 31; QFT-high: >0.70 IU/ml, n = 32), including 12 HIV-positive individuals in each group and with 20 HIV-negative non-pregnant women from the same cohort with QFT IFN-γ <0.20 IU/ml as controls. Concentrations of 8 markers (IL-1ra, IL-6, IL-8, IP-10, MCP-1, MCP-2, osteopontin and resistin) were measured in whole blood QFT supernatants, stimulated separately with TB1 and TB2 antigens. K-nearest neighbor analysis (KNN) was used to classify participants with regard to likelihood of LTBI. Concentrations of MCP-2, IP-10 and IL-1ra were higher in QFT-borderline compared to QFT-low participants in both antigen stimulations (p < 0.001). KNN classification indicated high likelihood of LTBI in 13/31 (42%) women with QFT-borderline IFN-γ results. MCP-2, IP-10 and IL-1ra expressed in whole blood after TB antigen stimulation may be considered as alternative biomarkers for classification of LTBI status in pregnant women with borderline QFT IFN-γ results.

Screening and treatment of tuberculosis among pregnant women in Stockholm, Sweden, 2016-2017

Swedish National tuberculosis (TB) guidelines recommend screening of active and latent TB (LTBI) among pregnant women (PW) from high-endemic countries or with previous exposure to possibly improve early detection and treatment.We evaluated cascade of care of a newly introduced TB screening programme of pregnant women in Stockholm county in 2016-2017. The algorithm included clinical data and Quantiferon (QFT) at the Maternal Health Care clinics and referral for specialist care upon positive test or TB symptoms.About 29 000 HIV-negative pregnant women were registered yearly, of whom 11% originated from high-endemic countries. In 2016, 72% of these were screened with QFT, of which 22% were QFT positive and 85% were referred for specialist care. In 2017, corresponding figures were 64%, 19% and 96%, respectively. The LTBI treatment rate among all QFT-positive pregnant women increased from 24% to 37% over time. Treatment completion with mainly rifampicin post-partum was 94%. Of the 69 registered HIV-positive pregnant women, 78% originated from high-endemic countries. Of these, 72% where screened with QFT and 15% were positive, but none was treated for LTBI. 9 HIV-negative active pulmonary TB cases were detected (incidence: 215/100 000). None had been screened for TB prior to pregnancy and only one had sought care due to symptoms.Systematic TB screening of pregnant women in Stockholm was feasible with a high yield of unknown LTBI and mostly asymptomatic active TB. Optimised routines improved referrals to specialist care. Treatment completion of LTBI was very high. Our findings justify TB screening of this risk group for early detection and treatment.

Is there a connection between gestational diabetes mellitus, human immunodeficiency virus infection, and tuberculosis?

Pregnancy is associated with insulin resistance similar to that found in type 2 diabetes mellitus (DM). The prevalence of gestational diabetes mellitus (GDM) in key tuberculosis (TB) endemic countries, such as India and China, has been increasing rapidly in the last decade and may be higher in human immunodeficiency virus (HIV) infected women. Pregnancy is also an independent risk factor for developing active TB; however, little is known about the interaction of GDM, HIV and TB. We review the epidemiology and immunology of GDM, and significant research gaps in understanding the interactions between GDM, pregnancy, and TB in women living with and those without HIV.

Performance of QuantiFERON-TB Gold Plus for detection of latent tuberculosis infection in pregnant women living in a tuberculosis- and HIV-endemic setting

We evaluated the performance of QuantiFERON-TB Gold Plus (QFT-Plus), which includes two Mycobacterium tuberculosis antigen formulations (TB1 and TB2), for detection of latent tuberculosis infection during pregnancy. Eight-hundred-twenty-nine Ethiopian pregnant women (5.9% HIV-positive) were tested with QFT-Plus, with bacteriological sputum analysis performed for women with clinically suspected tuberculosis and HIV-positive women irrespective of clinical presentation. QFT-Plus read-out was categorized according to the conventional cut-off (0.35 IU/ml) for both antigen formulations. In addition, we analysed the distribution of QFT-Plus results within a borderline zone (0.20–0.70 IU/ml), and interferon-γ response in relation to HIV infection and gestational age. Two-hundred-seventy-seven women (33%) were QFT-Plus-positive (HIV-positive 16/49 [33%]; HIV-negative 261/780 [33%]). There was a strong agreement between the two antigen formulations (κ = 0.92), with discordant results in 29 cases (3.5%). Whereas discordant QFT-Plus results were rare in pregnancy, several results with both TB1 and TB2 within the borderline range were observed (11/49 [22%] vs. 43/780 [5.5%] in HIV-positive and HIV-negative women, respectively; p<0.0001). HIV-positive women had lower absolute interferon-γ levels (TB1: 0.47 vs. 2.16 IU/ml; p<0.001, TB2: 0.49 vs. 2.24 IU/ml, p<0.001, considering results ≥0.20 IU/ml) compared to HIV-negative women. QFT-Plus-positive women who submitted samples at later stages of pregnancy had lower mitogen- (p<0.001) but higher TB-antigen-specific (p = 0.031 for TB1, p = 0.061 for TB2) interferon-γ response. Considering their lower capacity to produce TB-specific interferon-γ, a lower cut-off level for defining QFT-Plus-positivity may be considered in HIV-positive pregnant women.