Evaluation of various methods of maternal placental blood collection for immunology studies

Prevalence and factors associated with placental malaria in Lira District, Northern Uganda: a cross-sectional study

BACKGROUND

Malaria has a stable perennial transmission across Uganda. Placental malaria is associated with adverse maternal, fetal, and neonatal outcomes. The factors associated with placental malaria are poorly understood in the study setting. The aim of the study was to assess the prevalence of placental malaria and to determine its associated factors among parturient women in Lira District, Uganda.

METHODS

This was a cross-sectional study among 366 pregnant women who delivered at Lira Regional Referral Hospital. Data were collected from December 2018 to February 2019 using an interviewer-administered questionnaire. The variables were socio-demographic, obstetric characteristics, and malaria preventive practices. Standard Diagnostic Bioline Rapid Diagnostic Tests were used to detect placental malaria present in placental blood. Microscopy was used to quantify the grade of placental malaria parasitaemia. Logistic regression was used to assess factors associated with placental malaria.

RESULTS

The mean age of the participants was 25.34 years (standard deviation [SD] 5.73). The prevalence of placental malaria was [4.4% (16/366) 95% CI (2.5 to 7.0)]. Of these, only 7/16 were positive on microscopy, with 2/7 having moderate parasitemia and 5/7 having mild parasitaemia. Women aged less than 20 years [AOR 3.48, 95% CI (1.13 to 10.72)], and those not taking iron supplements during pregnancy [AOR = 3.55, 95% CI (1.02 to 12.31)] were associated with an increased likelihood of having placental malaria.

CONCLUSION

The prevalence of placental malaria was low in this setting. This may have reflected the low malaria transmission rates following intensive indoor residual spraying. Placental malaria infection was associated with younger age and not taking iron supplements during pregnancy. Public health measures need to scale up and emphasise adherence to malaria preventive measures during pregnancy especially among teenage mothers.

Increased peripartum mortality associated with maternal subclinical malaria in Mozambique

BACKGROUND

Plasmodium falciparum infection in pregnant women in sub-Saharan Africa is often asymptomatic. As these forms of malaria are often submicroscopic and difficult to diagnose by conventional methods (microscopy and/or rapid diagnostic test), diagnosis requires the use of molecular techniques such as polymerase chain reaction (PCR). This study analyses the prevalence of subclinical malaria and its association with adverse maternal and neonatal outcomes, a topic that has been scarcely evaluated in the literature.

METHODS

A cross-sectional study was conducted using semi-nested multiplex PCR to assess the presence of P. falciparum in placental and peripheral blood of 232 parturient pregnant women at the Hospital Provincial de Tete, Mozambique between March 2017 and May 2019. Multivariate regressions were performed to assess the associations of maternal subclinical malaria with several maternal and neonatal outcomes after controlling for the presence of preeclampsia/eclampsia (PE/E) and HIV infection, as well as for other maternal and pregnancy characteristics.

RESULTS

In total, 17.2% (n = 40) of the women studied had positive PCR for P. falciparum (7 in placental blood only, 3 in peripheral blood only). We found a significant association between subclinical malaria and a higher peripartum mortality risk, which persisted after controlling for maternal comorbidity and maternal and pregnancy characteristics (adjusted odds ratio: 3.50 [1.11-10.97]). In addition, PE/E and HIV infections were also significantly associated with several adverse maternal and neonatal outcomes.

CONCLUSION

This study demonstrated the association of subclinical malaria, as well as of PE/E and HIV, in pregnant women with adverse maternal and neonatal outcomes. Therefore, molecular methods may be sensitive tools to identify asymptomatic infections that can reduce the impact on peripartum mortality and their contribution to sustained transmission of the parasite in endemic countries.

Polymorphic Molecular Signatures in Variable Regions of the Plasmodium falciparum var2csa DBL3x Domain Are Associated with Virulence in Placental Malaria

The Plasmodium falciparum protein VAR2CSA allows infected erythrocytes to accumulate within the placenta, inducing pathology and poor birth outcomes. Multiple exposures to placental malaria (PM) induce partial immunity against VAR2CSA, making it a promising vaccine candidate. However, the extent to which VAR2CSA genetic diversity contributes to immune evasion and virulence remains poorly understood. The deep sequencing of the var2csa DBL3X domain in placental blood from forty-nine primigravid and multigravid women living in malaria-endemic western Kenya revealed numerous unique sequences within individuals in association with chronic PM but not gravidity. Additional analysis unveiled four distinct sequence types that were variably present in mixed proportions amongst the study population. An analysis of the abundance of each of these sequence types revealed that one was inversely related to infant gestational age, another was inversely related to placental parasitemia, and a third was associated with chronic PM. The categorization of women according to the type to which their dominant sequence belonged resulted in the segregation of types as a function of gravidity: two types predominated in multigravidae whereas the other two predominated in primigravidae. The univariate logistic regression analysis of sequence type dominance further revealed that gravidity, maternal age, placental parasitemia, and hemozoin burden (within maternal leukocytes), reported a lack of antimalarial drug use, and infant gestational age and birth weight influenced the odds of membership in one or more of these sequence predominance groups. Cumulatively, these results show that unique var2csa sequences differentially appear in women with different PM exposure histories and segregate to types independently associated with maternal factors, infection parameters, and birth outcomes. The association of some var2csa sequence types with indicators of pathogenesis should motivate vaccine efforts to further identify and target VAR2CSA epitopes associated with maternal morbidity and poor birth outcomes.

Myeloperoxidase and Other Markers of Neutrophil Activation Associate With Malaria and Malaria/HIV Coinfection in the Human Placenta

Introduction

Placental malaria (PM) is characterized by accumulation of inflammatory leukocytes in the placenta, leading to poor pregnancy outcomes. Understanding of the underlying mechanisms remains incomplete. Neutrophils respond to malaria parasites by phagocytosis, generation of oxidants, and externalization of Neutrophil Extracellular Traps (NETs). NETs drive inflammation in malaria but evidence of NETosis in PM has not been reported. Neutrophil activity in the placenta has not been directly investigated in the context of PM and PM/HIV-co-infection.

Methods

Using peripheral and placental plasma samples and placental tissue collected from Kenyan women at risk for malaria and HIV infections, we assessed granulocyte levels across all gravidities and markers of neutrophil activation, including NET formation, in primi- and secundigravid women, by ELISA, western blot, immunohistochemistry and immunofluorescence.

Results

Reduced peripheral blood granulocyte numbers are observed with PM and PM/HIV co-infection in association with increasing parasite density and placental leukocyte hemozoin accumulation. In contrast, placental granulocyte levels are unchanged across infection groups, resulting in enhanced placental: peripheral count ratios with PM. Within individuals, PM- women have reduced granulocyte counts in placental relative to peripheral blood; in contrast, PM stabilizes these relative counts, with HIV coinfection tending to elevate placental counts relative to the periphery. In placental blood, indicators of neutrophil activation, myeloperoxidase (MPO) and proteinase 3 (PRTN3), are significantly elevated with PM and, more profoundly, with PM/HIV co-infection, in association with placental parasite density and hemozoin-bearing leukocyte accumulation. Another neutrophil marker, matrix metalloproteinase (MMP9), together with MPO and PRTN3, is elevated with self-reported fever. None of these factors, including the neutrophil chemoattractant, CXCL8, differs in relation to infant birth weight or gestational age. CXCL8 and MPO levels in the peripheral blood do not differ with infection status nor associate with birth outcomes. Indicators of NETosis in the placental plasma do not vary with infection, and while structures consistent with NETs are observed in placental tissue, the results do not support an association with PM.

Conclusions

Granulocyte levels are differentially regulated in the peripheral and placental blood in the presence and absence of PM. PM, both with and without pre-existing HIV infection, enhances neutrophil activation in the placenta. The impact of local neutrophil activation on placental function and maternal and fetal health remains unclear. Additional investigations exploring how neutrophil activation and NETosis participate in the pathogenesis of malaria in pregnant women are needed.

Congenital Malaria in Newborns Presented at Tororo General Hospital in Uganda: A Cross-Sectional Study

Despite recent large-scale investments, malaria remains a major public health concern. Few studies have examined congenital malaria, defined as the presence of malaria parasitemia within the first 7 days of life, in endemic areas. This study aimed to determine the prevalence, to describe the clinical presentation, and to examine factors associated with congenital malaria in newborns aged up to 7 days attending Tororo General Hospital in Uganda. A total of 261 mother/baby pairs were recruited in this cross-sectional study. Giemsa-stained thick blood smears for malaria parasites and rapid malaria diagnostic tests were performed on capillary blood samples from all newborns and mothers, as well as on placental and cord samples from newborns delivered in the hospital. The prevalence of congenital malaria in the newborns was 16/261 (6.1%). No single clinical feature was associated with congenital malaria. However, there were associations between congenital malaria and maternal parasitemia (P < 0.001), gravidity of one (P = 0.03), maternal age < 19 years (P = 0.01), cord blood parasitemia (P = 0.01), and placental malaria (P = 0.02). In conclusion, congenital malaria is not rare in Uganda and there are no obvious clinical features associated with it in the newborn. Based on these findings, we recommend strengthening malaria prevention during pregnancy to reduce the occurrence of congenital malaria in newborns.

A minimally invasive, low-stress method for serial blood collection in aging mice

Hematologic analysis is an efficient and valuable tool for real-time health monitoring and immune analysis in mouse aging studies. However, many frequently used blood sampling techniques in mice are incompatible with continuous monitoring with increasing age, as they may involve anesthesia, cause severe stress, or require a high volume of blood. This technical report describes a convenient relatively noninvasive procedure for counting white blood cells in C57Bl/6 mice by an optimized tail blood collection method followed by Wright-Giemsa and Türk staining. This technique can be performed on unanesthetized mice in less than 1 min with minimal stress using only a few microliters of blood. White blood cell analysis can include but is not limited to total and differential white blood cell count and cell morphology. The low blood volume collected is ideal for aging mice in longer-term experiments requiring regular and continuous monitoring.

Mature naïve B cells are retained in the placental intervillous blood and positively associate with specific chemokines in full-term healthy pregnancy

PROBLEM

Circulating B-cell numbers are lower during pregnancy compared with non-pregnant women, but the underlying reasons for this are unknown. Pregnancy-related hormones could influence B-cell lymphopoiesis in the bone marrow, but B cells may also be recruited to the placenta. To investigate the latter, we examined whether the proportions of total B cells and B cells at different maturational stages in placental intervillous blood (IVB) differ compared with peripheral blood (PB).

METHOD OF STUDY

From 23 paired samples of PB and IVB following full-term healthy pregnancies, total B cells and immature/transitional, mature/naïve, and memory B cells were identified by flow cytometry. Chemokine levels in blood were analyzed using a Luminex assay. Placental explant-derived supernatant was assayed for B-cell chemotactic activity.

RESULTS

The proportions of total B cells and mature/naïve B cells were significantly higher in IVB relative to PB, while the fractions of immature/transitional cells and memory B cells were higher in PB. Multivariate factor analysis demonstrated that a specific chemokine profile in IVB, including CCL20, positively associated with higher proportions of mature/naïve B cells in the intervillous space. All B cells expressed CCR6, the corresponding receptor for CCL20, but the intensity of CCR6 expression was significantly higher in mature/naïve B cells relative to immature/transitional B cells. Migration assays showed that placental explant-derived supernatants attract B cells.

CONCLUSION

These results indicate that B cells, and mature/naïve B cells in particular, are retained in the intervillous blood in response to certain chemokines produced by the placenta during late healthy pregnancy.

Maternal, placental and cord blood cytokines and the risk of adverse birth outcomes among pregnant women infected with Schistosoma japonicum in the Philippines

BACKGROUND

The objectives of this study were to 1) evaluate the influence of treatment with praziquantel on the inflammatory milieu in maternal, placental, and cord blood, 2) assess the extent to which proinflammatory signatures in placental and cord blood impacts birth outcomes, and 3) evaluate the impact of other helminths on the inflammatory micro environment.

METHODS/FINDINGS

This was a secondary analysis of samples from 369 mother-infant pairs participating in a randomized controlled trial of praziquantel given at 12-16 weeks' gestation. We performed regression analysis to address our study objectives. In maternal peripheral blood, the concentrations of CXCL8, and TNF receptor I and II decreased from 12 to 32 weeks' gestation, while IL-13 increased. Praziquantel treatment did not significantly alter the trajectory of the concentration of any of the cytokines examined. Hookworm infection was associated with elevated placental IL-1, CXCL8 and IFN-γ. The risk of small-for-gestational age increased with elevated IL-6, IL-10, and CXCL8 in cord blood. The risk of prematurity was increased when cord blood sTNFRI and placental IL-5 were elevated.

CONCLUSIONS

Our study suggests that fetal cytokines, which may be related to infectious disease exposures, contribute to poor intrauterine growth. Additionally, hookworm infection influences cytokine concentrations at the maternal-fetal interface.

CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE

ClinicalTrials.gov (NCT00486863).

Comparative study of mefloquine and sulphadoxine-pyrimethamine for malaria prevention among pregnant women with HIV in southwest Nigeria

OBJECTIVE

To compare the effectiveness of mefloquine and sulphadoxine-pyrimethamine as intermittent preventive therapy for malaria among pregnant women with HIV.

METHODS

The present randomized, controlled, prospective, open-label study enrolled women with HIV who had reached at least 16 weeks of pregnancy attending prenatal clinics at secondary and tertiary health facilities in South West Nigeria between January 1 and August 31, 2016. Block randomization was used to assign patients to treatment with mefloquine or sulphadoxine-pyrimethamine for malaria prophylaxis. The primary outcome was malaria parasitemia at delivery. Data were compared with the χ² and t tests on a per-protocol basis.

RESULTS

Of 142 women enrolled and randomized equally to each group, 131 (92.3%) completed the study (64 in the mefloquine group and 67 in the sulphadoxine-pyrimethamine group). Blood-sample malaria parasites were isolated from 6 (9%) and 5 (7%) patients in the mefloquine and sulphadoxine-pyrimethamine groups, respectively, at enrolment, and 6 (9%) and 9 (13%) patients in the mefloquine and sulphadoxine-pyrimethamine groups, respectively, at delivery; the differences between the groups was not significant at enrolment (P=0.693) or delivery (P=0.466).

CONCLUSION

Outcomes following prophylactic use of mefloquine for intermittent preventive therapy for malaria among pregnant women with HIV were comparable to sulphadoxine-pyrimethamine treatment; mefloquine is a feasible alternative therapy. ClinicalTrials.gov: NCT02524444.

Effect of IPTp on Plasmodium falciparum antibody levels among pregnant women and their babies in a sub-urban coastal area in Ghana

Background

Women exposed to Plasmodium infection develop antibodies and become semi-immune. This immunity is suppressed during pregnancy making both the pregnant woman and the foetus vulnerable to the adverse effects of malaria, particularly by Plasmodium falciparum. Intermittent preventive treatment of malaria in pregnancy (IPTp) with Sulfadoxine–pyrimethamine (SP) tablets is one of the current interventions to mitigate the effects of malaria on both the pregnant woman and the unborn child. The extent to which IPTp may interfere with the acquisition of protective immunity against pregnancy-associated malaria (PAM) is undefined in Ghana.

Methods

Three-hundred-and-twenty pregnant women were randomly enrolled at the antenatal clinic (ANC) in Madina, Accra. Venous blood samples were obtained at first ANC registration and at 4-week intervals (post-IPTp administration). Placental and cord blood samples were obtained at delivery and the infants were followed monthly for 6 months after birth. Anti-IgG and IgM antibodies against a crude antigen preparation and the glutamate-rich protein (GLURP) of P. falciparum were quantified by the enzyme-linked immunosorbent assay (ELISA).

Results

There was a general decline in the trend of mean concentrations of all the antibodies from enrolment to delivery. The levels of antibodies in cord blood and placenta were well correlated. Children did not show clinical signs of malaria at 6 months after birth.

Conclusions

IgG against both crude antigen and GLURP were present in placenta and cord blood and it is therefore concluded that there is a trend of declining antibody from enrolment to delivery and IPTp-SP may have reduced malaria exposure, however, this does not impact on the transfer of antibodies to the foetus in utero. The levels of maternal and cord blood antibodies at delivery showed no adverse implications on malaria among the children at 6 months. However, the quantum and quality of the antibody transferred needs further investigation to ensure that the infants are protected from severe episodes of malaria.

Maternal group B Streptococcus-related stillbirth: a systematic review

BACKGROUND

Limited epidemiological data on the association between maternal rectovaginal group B Streptococcus (GBS) colonisation and stillbirth makes assessment of antenatal interventions for GBS stillbirth difficult.

OBJECTIVES

To systematically review the existing literature and evaluate the incidence of GBS-related stillbirth by region up to March 2015.

SEARCH STRATEGY

A systematic review of the published literature was completed using PubMed/MEDLINE, EMBASE, LILACS, and Cochrane Library, with Medical Subject Headings (MeSH) and search terms based upon the Centers for Disease Control and Prevention's (CDC) Active Bacterial Core Surveillance (ABCs) GBS-related stillbirth definition and chorioamnionitis.

SELECTION CRITERIA

Studies reporting original data on GBS-related stillbirth occurring ≥20 weeks of gestation, with GBS confirmed by autopsy or by culture from the placenta, amniotic fluid, or other normally sterile site samples from the stillborn.

DATA COLLECTION AND ANALYSIS

Descriptive analyses were performed with the absolute GBS-related stillbirth rates and proportion of stillbirths attributed to GBS calculated per study where possible. Differences in stillbirth definitions did not allow for pooled estimates to be calculated.

MAIN RESULTS

Seventeen studies reported GBS-related stillbirth rates varying from 0.04 to 0.9 per 1000 births, with the proportion of stillbirths associated with GBS ranging from 0 to 12.1%. Most studies reported data from before the year 2000 and from high-income countries.

CONCLUSIONS

The sparsely available epidemiological evidence was not reported consistently, emphasising the importance of standardised stillbirth definitions and diagnostic methods to optimally assess the effectiveness of any future antenatal interventions. Timing of stillbirth, GBS serotype, and global diversity were gaps in the current evidence.

TWEETABLE ABSTRACT

Systematic review finds Group B Streptococcus causes up to 12.1% of stillbirths, but more research is needed.

Placental malaria is rare among Zanzibari pregnant women who did not receive intermittent preventive treatment in pregnancy

Zanzibar has transitioned from malaria control to the pre-elimination phase, and the continued need for intermittent preventive treatment during pregnancy (IPTp) has been questioned. We conducted a prospective observational study to estimate placental malaria positivity rate among women who did not receive IPTp with sulfadoxine-pyrimethamine. A convenience sample of pregnant women was enrolled from six clinics on the day of delivery from August of 2011 to September of 2012. Dried placental blood spot specimens were analyzed by polymerase chain reaction (PCR); 9 of 1,349 specimens (0.7%; precision estimate = 0.2–1.1%) were PCR-positive for Plasmodium falciparum. Placental infection was detected on both Pemba (N = 3) and Unguja (N = 6). Placental malaria positivity in Zanzibar was low, even in the absence of IPTp. It may be reasonable for the Ministry of Health to consider discontinuing IPTp, intensifying surveillance efforts, and promoting insecticide-treated nets and effective case management of malaria in pregnancy.

Elevated cytokine and chemokine levels in the placenta are associated with in-utero HIV-1 mother-to-child transmission

OBJECTIVE

To determine whether there is an association between cytokine and chemokine levels in plasma isolated from the placenta and HIV-1 mother-to-child transmission (MTCT).

DESIGN

We designed a case-control study of HIV-infected, pregnant women enrolled in the Malaria and HIV in Pregnancy cohort. Participants were recruited in Blantyre, Malawi, from 2000 to 2004. Patients were women whose children were HIV-1 DNA-positive at birth (in-utero MTCT) or HIV-1 DNA-negative at birth and HIV-1 DNA-positive at 6 weeks postpartum (intrapartum MTCT); controls were women whose children were HIV-1 DNA-negative both at birth and 6 weeks postpartum.

METHODS

After delivery, blood was isolated from an incision on the basal plate of the placenta. We used a Bio-Plex human cytokine assay (Bio-Rad, Hercules, California USA) to simultaneously quantify 27 cytokines, chemokines and growth factors in placental plasma. HIV-1 RNA copies were quantified with the Roche Amplicor kit.

RESULTS

Levels of interleukin (IL) 4, IL-5, IL-6, IL-7, IL-9, eotaxin, IL-1Ra and interferon gamma-induced protein 10 (IP-10) were significantly elevated in placental plasma isolated from cases of in-utero HIV-1 MTCT. In contrast, only granulocyte colony-stimulating factor was elevated in placental plasma isolated from cases of intrapartum MTCT. After adjusting for maternal age, gestational age and peripheral CD4(+) T-cell count, every log(10) increase in placental IP-10 was associated with a three-fold increase in the prevalence of in-utero HIV-1 MTCT.

CONCLUSION

Elevated cytokine and chemokine levels in placental plasma were associated with in-utero and not intrapartum MTCT. IP-10, which is both a T-cell chemokine and potentiator of HIV-replication, was robustly and independently associated with prevalent, in-utero MTCT.

Sequence polymorphism, segmental recombination and toggling amino acid residues within the DBL3X domain of the VAR2CSA placental malaria antigen

Plasmodium falciparum malaria remains one of the world's foremost health problems, primarily in highly endemic regions such as Sub-Saharan Africa, where it is responsible for substantial morbidity, mortality and economic losses. Malaria is a significant cause of severe disease and death in pregnant women and newborns, with pathogenesis being associated with expression of a unique variant of the multidomain Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) called VAR2CSA. Here, we characterize the polymorphism of the DBL3X domain of VAR2CSA and identify regions under selective pressure among placental parasites from women living in endemic western Kenya. In addition to significant levels of polymorphism, our analysis reveals evidence for diversification through intra-segmental recombination and novel mutations that likely contributed to the high number of unique VAR2CSA sequence types identified in this study. Interestingly, we also identified a number of critical residues that may be implicated in immune evasion through switching (or toggling) to alternative amino acids, including an arginine residue within the predicted binding pocket in subdomain III, which was previously implicated in binding to placental CSA. Overall, these findings are important for understanding parasite diversity in pregnant women and will be useful for identifying epitopes and variants of DBL3X to be included in a vaccine against placental malaria.

Maternal malaria induces a procoagulant and antifibrinolytic state that is embryotoxic but responsive to anticoagulant therapy

Low birth weight and fetal loss are commonly attributed to malaria in endemic areas, but the cellular and molecular mechanisms that underlie these poor birth outcomes are incompletely understood. Increasing evidence suggests that dysregulated hemostasis is important in malaria pathogenesis, but its role in placental malaria (PM), characterized by intervillous sequestration of Plasmodium falciparum, proinflammatory responses, and excessive fibrin deposition is not known. To address this question, markers of coagulation and fibrinolysis were assessed in placentae from malaria-exposed primigravid women. PM was associated with significantly elevated placental monocyte and proinflammatory marker levels, enhanced perivillous fibrin deposition, and increased markers of activated coagulation and suppressed fibrinolysis in placental plasma. Submicroscopic PM was not proinflammatory but tended to be procoagulant and antifibrinolytic. Birth weight trended downward in association with placental parasitemia and high fibrin score. To directly assess the importance of coagulation in malaria-induced compromise of pregnancy, Plasmodium chabaudi AS-infected pregnant C57BL/6 mice were treated with the anticoagulant, low molecular weight heparin. Treatment rescued pregnancy at midgestation, with substantially decreased rates of active abortion and reduced placental and embryonic hemorrhage and necrosis relative to untreated animals. Together, the results suggest that dysregulated hemostasis may represent a novel therapeutic target in malaria-compromised pregnancies.

Different regions of HIV-1 subtype C env are associated with placental localization and in utero mother-to-child transmission

HIV infections are initiated by a limited number of variants that diverge into a diverse quasispecies swarm. During in utero mother-to-child transmission (IU MTCT), transmitted viral variants must pass through multiple unique environments, and our previously published data suggest a nonstochastic model of transmission. As an alternative to a stochastic model of viral transmission, we hypothesize that viral selection in the placental environment influences the character of the viral quasispecies when HIV-1 is transmitted in utero. To test this hypothesis, we used single-template amplification to isolate HIV-1 envelope gene (env) sequences from both peripheral plasma and the placentas of eight nontransmitting (NT) and nine IU-transmitting participants. Statistically significant compartmentalization between peripheral and placental HIV-1 env was detected in one of the eight NT cases and six of the nine IU MTCT cases. In addition, viral sequences isolated from IU MTCT placental tissue showed variation in env V1 loop lengths compared to matched maternal sequences, while NT placental env sequences did not. Finally, comparison of env sequences from NT and IU MTCT participants indicated statistically significant differences in Kyte-Doolittle hydropathy in the signal peptide, C2, V3, and C3 regions. Our working hypothesis is that the hydropathy differences in Env associated with IU MTCT alter viral cellular tropism or affinity, allowing HIV-1 to efficiently infect placentally localized cells.

Maternal Schistosomiasis japonica is associated with maternal, placental, and fetal inflammation

Schistosomes infect ∼40 million women of childbearing age and result in the elaboration of proinflammatory cytokines that have been implicated in fetal growth restriction. In murine models and two observational studies in humans, schistosome infection during pregnancy was associated with reduced birth weight, although a recent treatment trial in Schistosoma mansoni did not detect this association. We conducted an observational study among 99 pregnant women living in an area of Schistosoma japonicum endemicity in the Philippines. We enrolled women at 32 weeks gestation and measured S. japonicum and geohelminth infection intensity. We collected maternal peripheral blood at 32 weeks gestation and placental and cord blood at delivery to assess inflammatory status. At delivery, we collected a placental-tissue sample and measured birth weight. In multivariate models adjusted for geohelminths, maternal schistosomiasis was associated with increased levels of inflammatory cytokines in maternal peripheral (tumor necrosis factor alpha [TNF-α] and interleukin 10 [IL-10]), placental (TNF-α, IL-6, TNF-α receptor II [RII], and IL-1β), and cord (IL-1β and TNF-α RII) blood, as well as acute subchorionitis and increased TNF-α production by syncytiotrophoblasts assessed by immunohistochemistry (all P < 0.05). After adjusting for confounders, placental IL-1β, and TNF-α production by syncytiotrophoblasts was independently associated with decreased birth weight (both P < 0.05). Our data indicate that maternal schistosomiasis results in a proinflammatory signature that is detectable in maternal, placental, and fetal compartments, and a subset of these responses are associated with decreased birth weight. This potential mechanistic link between maternal schistosomiasis and poor birth outcomes will contribute to the debate regarding treatment of maternal schistosome infections.

Placental malaria among HIV-infected and uninfected women receiving anti-folates in a high transmission area of Uganda

Background

HIV infection increases the risk of placental malaria, which is associated with poor maternal and infant outcomes. Recommendations in Uganda are for HIV-infected pregnant women to receive daily trimethoprim-sulphamethoxazole (TS) and HIV-uninfected women to receive intermittent sulphadoxine-pyrimethamine (SP). TS decreases the risk of malaria in HIV-infected adults and children but has not been evaluated among pregnant women.

Methods

This was a cross sectional study comparing the prevalence of placental malaria between HIV-infected women prescribed TS and HIV-uninfected women prescribed intermittent preventive therapy with sulphadoxine-pyrimethamine (IPT-SP) in a high malaria transmission area in Uganda. Placental blood was evaluated for malaria using smear and PCR.

Results

Placentas were obtained from 150 HIV-infected women on TS and 336 HIV-uninfected women on IPT-SP. The proportion of HIV-infected and HIV-uninfected women with placental malaria was 19% vs. 26% for those positive by PCR and 6% vs. 9% for those positive by smear, respectively. Among all infants, smear+ placental malaria was most predictive of low birth weight (LBW). Primigravidae were at higher risk than multigravidae of having placental malaria among HIV-uninfected, but not HIV-infected, women. Adjusting for gravidity, age, and season at the time of delivery, HIV-infected women on TS were not at increased risk for placental malaria compared to HIV-uninfected women on IPT-SP, regardless of the definition used.

Conclusion

Prevalence of placental malaria was similar in HIV-infected women on TS and HIV-uninfected women on IPT-SP. Nonetheless, while nearly all of the women in this study were prescribed anti-folates, the overall risk of placental malaria and LBW was unacceptably high. The population attributable risk of placental malaria on LBW was substantial, suggesting that future interventions that further diminish the risk of placental malaria may have a considerable impact on the burden of LBW in this population.

Human immunodeficiency virus co-infection increases placental parasite density and transplacental malaria transmission in Western Kenya

Plasmodium falciparum malaria and human immunodeficiency virus (HIV)-1 adversely interact in the context of pregnancy, however little is known regarding the influence of co-infection on the risk of congenital malaria. We aimed to determine the prevalence of placental and congenital malaria and impact of HIV co-infection on trans-placental malaria transmission in 157 parturient women and their infants by microscopy and by quantitative real-time polymerase chain reaction (PCR) in western Kenya. The prevalence of placental and cord blood infections were 17.2% and 0% by microscopy, and 33.1% and 10.8% by PCR. HIV co-infection was associated with a significant increase in placental parasite density (P < 0.05). Cord blood malaria prevalence was increased in co-infected women (odds ratio [OR] = 5.42; 95% confidence interval [CI] = 1.90-15.47) and correlated with placental parasite density (OR = 2.57; 95% CI = 1.80-3.67). A 1-log increase in placental monocyte count was associated with increased risk of congenital infection (P = 0.001) (OR = 48.15; 95% CI = 4.59-505.50). The HIV co-infected women have a significantly increased burden of placental malaria that increases the risk of congenital infection.

Elevated gamma interferon-producing NK cells, CD45RO memory-like T cells, and CD4 T cells are associated with protection against malaria infection in pregnancy

Previous studies have shown that gamma interferon (IFN-gamma) production in the placenta is associated with protection against placental malaria. However, it remains unknown which IFN-gamma-producing cell subpopulations are involved in this protection and whether the cellular immune components of protection are the same in the peripheral and the placental blood compartments. We investigated cell subpopulations for CD4, CD8, and CD45RO memory-like T cells and CD56+/CD3- natural killer (NK) cells and for IFN-gamma production by these cells in maternal peripheral and placental intervillous blood in relation to the status of malaria infection in pregnancy. Of 52 human immunodeficiency virus-negative enrolled pregnant women residing in Western Kenya, 20 had placental parasitemia. We found that the percentages of CD45RO memory-like and CD4 T cells were significantly higher in the periphery than in the placenta, while the CD56/CD3- NK-cell percentage was higher in the placenta than in the periphery, suggesting differences in immune cell profiles between the two blood compartments. Furthermore, the percentages of peripheral CD45RO memory-like and CD4 T cells were significantly elevated in aparasitemic women compared to levels in the parasitemic group, with aparasitemic multigravid women having the highest percentages of CD45RO memory-like and CD4 T cells. In contrast, at the placental level, IFN-gamma production by innate NK cells was significantly increased in aparasitemic women compared to parasitemic women, regardless of gravidity. These results suggest that the elevated IFN-gamma-producing NK cells in the placenta and CD45RO memory-like and CD4 T cells in peripheral blood may be involved in protection against malaria infection in pregnancy.

Impact of placental Plasmodium falciparum malaria on pregnancy and perinatal outcome in sub-Saharan Africa: I: introduction to placental malaria

Placental malaria is one of the major features of malaria during pregnancy and has been widely used as a standard indicator to characterize malaria infection in epidemiologic investigations. Although pathogenesis of placental malaria is only partially understood, placental sequestration of Plasmodium falciparum results in the accumulation of parasitized erythrocytes in the intervillous space, infiltration by inflammatory cells, and release of pro-inflammatory mediators, which cause pathologic alterations that could impair materno-fetal exchanges, often resulting in adverse pregnancy outcome. In this report, the impact of placental malaria on pregnancy and perinatal outcome is reviewed using data from studies conducted in sub-Saharan Africa. Generally, placental malaria was associated with increased risk of maternal anemia, HIV infection, and maternal mortality, with younger women and primigravidae more likely to be affected. A variety of adverse perinatal outcomes, including low birth weight, preterm delivery, intrauterine growth retardation, reduced fetal anthropometric parameters, fetal anemia, congenital malaria, increased mother-to-child HIV transmission, and perinatal mortality, were associated with placental malaria. There were, however, conflicting reports on whether the risk of these adverse perinatal outcomes associated with placental malaria were statistically significant. There is a clear need to strengthen the malaria prevention and intervention measures for pregnant women in sub-Saharan Africa.