Disturbances in the IgG Antibody Profile in HIV-Exposed Uninfected Infants Associated with Maternal Factors

Over the last 20 years, the incidence of vertical HIV transmission has decreased from 25%-42% to less than 1%. Although there are no signs of infection, the health of HIV-exposed uninfected (HEU) infants is notoriously affected during the first months of life, with opportunistic infections being the most common disease. Some studies have reported effects on the vertical transfer of antibodies, but little is known about the subclass distribution of these antibodies. We proposed to evaluate the total IgG concentration and its subclasses in HIV+ mothers and HEU pairs and to determine which maternal factors condition their levels. In this study, plasma from 69 HEU newborns, their mothers, and 71 control pairs was quantified via immunoassays for each IgG isotype. Furthermore, we followed the antibody profile of HEUs throughout the first year of life. We showed that mothers present an antibody profile characterized by high concentrations of IgG1 and IgG3 but reduced IgG2, and HEU infants are born with an IgG subclass profile similar to that of their maternal pair. Interestingly, this passively transferred profile could remain influenced even during their own antibody production in HEU infants, depending on maternal conditions such as CD4+ T-cell counts and maternal antiretroviral treatment. Our findings indicate that HEU infants exhibit an altered IgG subclass profile influenced by maternal factors, potentially contributing to their increased susceptibility to infections.

Viral infections in stillbirth: a contribution underestimated in Mexico?

OBJECTIVES

To analyze the role of viral infections as etiology of stillbirths in Mexico and their epidemiological impact in the context of the global Every Newborn Initiative.

METHODS

A comprehensive literature search was performed in electronic databases related to stillbirth and viral infections published prior to January 19th 2021. Stillbirths records and causes from National Mexican databases, during 2008-2019 period were also computed.

RESULTS

Only two articles with a direct relationship between viral infection and stillbirth were found, and one article with an indirect serological association was identified. During the analyzed period there were 198,076 stillbirths, with a National stillbirth rate (SBR) ranging from 6.9 to 6.5 between 2008 and 2014, with a subsequent increase to reach 7.7 in 2019. Only 19 cases were attributed to viral causes and a specific virus was identified in 11. The main causes of early stillbirth were a fetus with premature rupture of membranes and light for gestational age, and for late stillbirth these were fetus affected by oligohydramnios and slow fetal growth. The percentage classified as unspecified deaths varied from 34.4-41.9%.

CONCLUSIONS

In Mexico, there has been an increase in SBR during last years, but the goals of the Every Newborn Initiative is met. More than 14,500 stillbirths with at least 5,100 unspecified cases have been reported per year, and only 11 cases were attributable to a specific virus, highlighting the serious underestimation of cases and the need of implementation of routine viral diagnosis methods to improve the care of this global health problem.

Embryonic neural stem/progenitor cells as model to characterize dystrophin and dystrophin-associated proteins expression during neuronal or astrocytic differentiation

Neural stem/progenitor cells (NSPC) are multipotent cells that renew themselves and could differentiate into neurons and macro glia (astrocytes and oligodendrocytes) of the nervous system during embryonic development. Duchenne muscular dystrophy is a severe type of muscular dystrophy caused by mutations in the dmd gene, and one-third of patients cursed with neuro-cognitive impairments. In this data article, we take advantage of the differentiation capacity of NSPC as a model to increase our knowledge in the neuronal and/or astrocytic differentiation and to evaluate the expression of dystrophins and dystrophin-associated proteins. We showed the characterization of undifferentiated and neuron and/or astrocyte differentiated NSPC. In addition, we evaluated the expression and subcellular localization of dystrophins and β-dystroglycan in undifferentiated NSPC and differentiated to neurons and astrocytes.•

Primary culture of NSPC was characterized by the expression of multipotent markers nestin and Sox2.

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Neuronal or astrocytic differentiation of NSPC was performed by basic fibroblast growth factor (FGF2) withdrawal, histamine or ciliary neurotrophic factor (CNTF) treatment, and expression of βIII-tubulin or glial fibrillary acidic protein (GFAP) as differentiation markers for neurons or astrocytes was evaluated.

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This study will contribute to the understanding of dystrophins and dystrophin-associated proteins expression and function during neuronal or astrocytic differentiation of NSPC

Impaired T helper cell responses in human immunodeficiency virus-exposed uninfected newborns

Introduction

HIV‐exposed uninfected (HEU) newborns suffer from higher risks of opportunistic infections during the first months of life compared to HIV‐unexposed uninfected (HUU) newborns. Alterations in thymic mass, amounts of T helper (Th) cells, T‐cell receptor diversity, and activation markers have been found in HEU newborns, suggesting alterations in T cell ontogeny and differentiation. However, little is known about the ability of these cells to produce specialized Th responses from CD4⁺ T cells.

Method

To characterize the Th cell profile, we evaluated the frequency of Th₁ (CD183⁺CD194⁻CD196⁻/CXCR3⁺CCR4⁻CCR6⁻), Th₂ (CD183⁻CD194⁺CD196⁻/CXCR3⁻CCR4⁺CCR6⁻), Th₁₇ (CD183⁻CD194⁺CD196⁺/CXCR3⁻CCR4⁺CCR6⁺), and CD4⁺CD25⁺⁺ blood T‐cell phenotypes in 50 HEU and 25 HUU newborns. Early activation markers on CD4⁺ T cells and the Th cytokine profile produced from mononuclear cells under polyclonal T cell stimulation were also studied. Additionally, we probed the ability of CD4⁺ T cells to differentiate into interferon (IFN)‐γ‐producing Th₁ CD4⁺ T cells in vitro.

Results

Lower percentages of differentiated Th₁, Th₂, Th_17, and CD4⁺CD25⁺⁺ T cells were found in blood from HEU newborns than in blood from HUU newborns. However, polyclonally stimulated Th cells showed a similar ability to express CD69 and CD279 but produced less secreted interleukin (IL)‐2 and IL‐4. Interestingly, under Th₁ differentiation conditions, the percentages of CD4⁺IFN‐γ⁺ T cells and soluble IFN‐γ were higher in HEU newborns than in HUU newborns.

Conclusion

HEU neonates are born with reduced proportions of differentiated Th₁/Th₂/Th₁₇ and CD4⁺CD25⁺⁺ T cells, but the intrinsic abilities of CD4⁺ T cells to acquire a Th₁ profile are not affected by the adverse maternal milieu during development.

Congenital Zika Syndrome and Extra-Central Nervous System Detection of Zika Virus in a Pre-term Newborn in Mexico

BACKGROUND

During pregnancy, the Zika virus (ZIKV) replicates in the placenta and central nervous system (CNS) of infected fetuses; nevertheless, the ability of ZIKV to replicate in other fetal tissues has not been extensively characterized.

METHODS

We researched whether dissemination of congenitally-acquired ZIKV outside the CNS exists by searching for the accumulation of the viral envelope protein, ZIKV ribonucleic acid (RNA), and infectious viral particles in different organs of a deceased newborn with Congenital Zika Syndrome. A real-time qualitative polymerase chain reaction (qPCR) was used to detect ZIKV RNA in the brain, thymus, lungs, kidneys, adrenal glands, spleen, liver, and small intestine. The same tissues were analyzed by indirect immunofluorescence and immunoperoxidase assays using the monoclonal antibody 4G2 to detect ZIKV envelope antigens. Isolation of infectious ZIKV in a cell culture was carried out using brain and kidney samples.

RESULTS

A postmortem, virological analysis of multiple organs, such as the kidneys (epithelial cells in the renal tubules), lungs (bronchial epithelia), thymus (epithelial cells inside the Hassall's corpuscles), and brain (neurons, ependymal cells, and macrophages) revealed the presence of ZIKV RNA and envelope antigens. Other tissues of the deceased newborn tested positive by qPCR for Epstein-Barr virus and human herpesvirus 6, including the brain cortex (Epstein-Barr) and the thymus, kidneys, and adrenal glands (human herpesvirus 6). The kidneys were identified as a significant niche for viral replication, given that infectious particles were successfully isolated from renal tissues.

CONCLUSIONS

Our findings demonstrate the ability of congenitally-acquired ZIKV to produce disseminated infections and the viral tropism towards epithelial cells.

Cellular and molecular mechanisms of viral infection in the human placenta

The placenta is a highly specialized organ that is formed during human gestation for conferring protection and generating an optimal microenvironment to maintain the equilibrium between immunological and biochemical factors for fetal development. Diverse pathogens, including viruses, can infect several cellular components of the placenta, such as trophoblasts, syncytiotrophoblasts and other hematopoietic cells. Viral infections during pregnancy have been associated with fetal malformation and pregnancy complications such as preterm labor. In this minireview, we describe the most recent findings regarding virus-host interactions at the placental interface and investigate the mechanisms through which viruses may access trophoblasts and the pathogenic processes involved in viral dissemination at the maternal-fetal interface.