γδ T cell frequencies are altered in HIV positive pregnant South African women and are associated with preterm birth

Comparative risk of adverse perinatal outcomes associated with classes of antiretroviral therapy in pregnant women living with HIV: systematic review and meta-analysis

Background

Integrase strand transfer inhibitor (INSTI) dolutegravir (DTG)-based antiretroviral therapy (ART) is recommended by World Health Organisation as preferred first-line regimen in pregnant women living with human immunodeficiency virus (HIV) (WLHIV). Non-nucleoside reverse transfer inhibitor (NNRTI)-based ART and protease inhibitor (PI)-based ART are designated as alternative regimens. The impact of different ART regimens on perinatal outcomes is uncertain. We aimed to assess the comparative risk of adverse perinatal outcomes in WLHIV receiving different classes of ART.

Materials and methods

A systematic literature review was conducted by searching PubMed, CINAHL, Global Health, and EMBASE for studies published between Jan 1, 1980, and July 14, 2023. We included studies reporting on the association of pregnant WLHIV receiving different classes of ART with 11 perinatal outcomes: preterm birth (PTB), very PTB, spontaneous PTB, low birthweight (LBW), very LBW, term LBW, preterm LBW, small for gestational age (SGA), very SGA (VSGA), stillbirth, and neonatal death. Pairwise random-effects meta-analyses compared the risk of each adverse perinatal outcome among WLHIV receiving INSTI-ART, NNRTI-ART, PI-ART, and nucleoside reverse transfer inhibitor (NRTI)-based ART, and compared specific "third drugs" from different ART classes. Subgroup and sensitivity analyses were conducted based on country income status and study quality.

Results

Thirty cohort studies published in 2006-2022, including 222,312 pregnant women, met the eligibility criteria. Random-effects meta-analyses found no evidence that INSTI-ART is associated with adverse perinatal outcomes compared to NNRTI-ART and PI-ART. We found that PI-ART is associated with a significantly increased risk of SGA (RR 1.28, 95% confidence interval (95% CI) [1.09, 1.51], p = 0.003) and VSGA (RR 1.41, 95% CI [1.08, 1.83], p = 0.011), compared to NNRTI-ART. Specifically, lopinavir/ritonavir (LPV/r) was associated with an increased risk of SGA (RR 1.40, 95% CI [1.18, 1.65], p = 0.003) and VSGA (RR 1.84, 95% CI [1.37, 2.45], p = 0.002), compared to efavirenz, but not compared to nevirapine. We found no evidence that any class of ART or specific "third drug" was associated with an increased risk of PTB.

Conclusion

Our findings support the recommendation of INSTI-ART as first-line ART regimen for use in pregnant WLHIV. However, the increased risks of SGA and VGSA associated with PI-ART, compared to NNRTI-ART, may impact choice of second- and third-line ART regimens in pregnancy.Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42021248987.

Tissue-resident immunity in the female and male reproductive tract

The conception of how the immune system is organized has been significantly challenged over the last years. It became evident that not all lymphocytes are mobile and recirculate through secondary lymphoid organs. Instead, subsets of immune cells continuously reside in tissues until being reactivated, e.g., by a recurring pathogen or other stimuli. Consequently, the concept of tissue-resident immunity has emerged, and substantial evidence is now available to support its pivotal function in maintaining tissue homeostasis, sensing challenges and providing antimicrobial protection. Surprisingly, insights on tissue-resident immunity in the barrier tissues of the female reproductive tract are sparse and only slowly emerging. The need for protection from vaginal and amniotic infections, the uniqueness of periodic tissue shedding and renewal of the endometrial barrier tissue, and the demand for a tailored decidual immune adaptation during pregnancy highlight that tissue-resident immunity may play a crucial role in distinct compartments of the female reproductive tract. This review accentuates the characteristics of tissue-resident immune cells in the vagina, endometrium, and the decidua during pregnancy and discusses their functional role in modulating the risk for infertility, pregnancy complications, infections, or cancer. We here also review data published to date on tissue-resident immunity in the male reproductive organs, which is still a largely uncharted territory.

Roles of γδT cells in pregnancy and pregnancy-related complications

A successful pregnancy is a complex and unique process comprised of discrete events, including embryo implantation, placentation, and parturition. To maintain the balance between maternal-fetal immune tolerance and resistance to infections, the maternal immune system must have a high degree of stage-dependent plasticity throughout the period of pregnancy. Innate immunity is the frontline force for the establishment of early anti-infection and tolerance mechanisms in mammals. Belonging to the innate immune system, a subset of T cells called γδT cells (based on γδT cell receptors) are the main participants in immune surveillance and immune defense. Unlike traditional αβT cells, γδT cells are regarded as a bridge between innate immunity and acquired immunity. In this review, we summarize current knowledge on the functional plasticity of γδT cells during pregnancy. Furthermore, we discuss the roles of γδT cells in pathological pregnancies.

Maternal HIV infection is associated with distinct systemic cytokine profiles throughout pregnancy in South African women

Maternal HIV infection is associated with adverse pregnancy outcomes, but the mechanisms remain unknown. The course of pregnancy is regulated by immunological processes and HIV infection and antiretroviral therapy (ART) impact key immune mechanisms, which may disrupt the immune programme of pregnancy. We evaluated a broad range of systemic cytokines at each trimester of pregnancy in 56 women living with HIV (WLHIV) and 68 HIV-negative women, who were enrolled in a prospective pregnancy cohort study in Soweto, South Africa. The pro-inflammatory cytokine IP-10 was detected in each trimester in all WLHIV, which was significantly more than in HIV-negative women. The anti-viral cytokine IFNλ1 was detected more frequently in WLHIV, whereas IFNβ and IFNλ2/3 were detected more frequently in HIV-negative women. Th1 cytokines IL-12 and IL-12p70, Th2 cytokine IL-5, and Th17 cytokine IL-17A were detected more frequently in WLHIV throughout pregnancy. Il-6, IL-9, and IL-10 were more commonly detected in WLHIV in the first trimester. Trends of increased detection of Th1 (IL-2, IL-12p70), Th2 (IL-4, Il-5, Il-13) and Th17 (IL-17A, Il-17F, IL-21, IL-22) cytokines were associated with small-for-gestational-age babies. Our findings indicate that maternal HIV/ART is associated with distinct systemic cytokine profiles throughout pregnancy.