Immunophenotypic analysis of HIV-infected children: alterations within the first year of life, changes with disease progression, and longitudinal analyses of lymphocyte subsets

Hospital preparedness and management of pediatric population during COVID-19 outbreak

With the recent pandemic of Coronavirus disease-2019 (COVID-19), there has been a higher number of reported cases in children more than to the prior Corona Virus-related diseases, namely, severe acute respiratory syndrome and the Middle East respiratory syndrome. The rate of COVID-19 in children is lower than adults; however, due to high transmission rate, the number of reported cases in children has been increasing. With the rising numbers among children, it is imperative to develop preparedness plans for the pediatric population at the hospital level, departmental level, and patient care areas. This paper summarizes important considerations for pediatric hospital preparedness at the hospital level that includes workforce, equipment, supply; capacity planning, and infection prevention strategies, it also span over the management of COVID-19 pediatric patients in high-risk areas such as critical care areas, Emergency Department and operative rooms.

Biological Aging and Immune Senescence in Children with Perinatally Acquired HIV

Chronic HIV-infected children suffer from premature aging and aging-related diseases. Viral replication induces an ongoing inflammation process, with the release of pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), the activation of the immune system, and the production of proinflammatory cytokines. Although combined highly active antiretroviral therapy (ART) has significantly modified the natural course of HIV infection, normalization of T and B cell phenotype is not completely achievable; thus, many HIV-infected children display several phenotypical alterations, including higher percentages of activated cells, that favor an accelerated telomere attrition, and higher percentages of exhausted and senescent cells. All these features ultimately lead to the clinical manifestations related to premature aging and comorbidities typically observed in older general population, including non-AIDS-related malignancies. Therefore, even under effective treatment, the premature aging process of HIV-infected children negatively impacts their quality and length of life. This review examines the available data on the impact of HIV and ART on immune and biological senescence of HIV-infected children.

Cytomegalovirus infection is a risk factor for tuberculosis disease in infants

Immune activation is associated with increased risk of tuberculosis (TB) disease in infants. We performed a case-control analysis to identify drivers of immune activation and disease risk. Among 49 infants who developed TB disease over the first 2 years of life, and 129 healthy matched controls, we found the cytomegalovirus-stimulated (CMV-stimulated) IFN-γ response to be associated with CD8+ T cell activation (Spearman's rho, P = 6 × 10-8). A CMV-specific IFN-γ response was also associated with increased risk of developing TB disease (conditional logistic regression; P = 0.043; OR, 2.2; 95% CI, 1.02-4.83) and shorter time to TB diagnosis (Log Rank Mantel-Cox, P = 0.037). CMV+ infants who developed TB disease had lower expression of NK cell-associated gene signatures and a lower frequency of CD3-CD4-CD8- lymphocytes. We identified transcriptional signatures predictive of TB disease risk among CMV ELISpot-positive (area under the receiver operating characteristic [AUROC], 0.98, accuracy, 92.57%) and -negative (AUROC, 0.9; accuracy, 79.3%) infants; the CMV- signature was validated in an independent infant study (AUROC, 0.71; accuracy, 63.9%). A 16-gene signature that previously identified adolescents at risk of developing TB disease did not accurately classify case and control infants in this study. Understanding the microbial drivers of T cell activation, such as CMV, could guide new strategies for prevention of TB disease in infants.

Alteration of T Cell Phenotypes in HIV-Neurotuberculosis Coinfection

BACKGROUND

Neurotuberculosis is one of the commonest HIV associated opportunistic infections of the central nervous system in India. HIV-TB coinfection may lead to altered frequencies of T cells, thereby influencing the course and progression of the disease.

METHODS

We examined the frequencies of T cell subsets in HIV infected individuals with neurotuberculosis (HIV+nTB+) as compared to individuals with HIV associated systemic TB (HIV+sTB+), asymptomatic HIV (HIV+TB-), non-HIV neuro TB (HIV-nTB+), non-HIV systemic TB (HIV-sTB+), and healthy controls (HIV-TB-). Activation and senescence profiles of CD4 and CD8 T cells and memory subsets in peripheral blood mononuclear cells were studied by flow cytometry.

RESULTS

The significant observations among the T cell subsets in HIV+nTB+ were: (1) Naïve T cells: decreased CD4 T cells compared to HIV-sTB+ (P = 0.005); decreased CD8 T cells compared to HIV-nTB+ and HIV-TB- (P ≤ 0.007), (2) Memory T cells: expanded CD4 TEMRA cells compared to HIV-nTB+, HIV-sTB+, and HIV-TB- (P ≤ 0.003); expanded CD8 TEMRA cells compared to HIV-nTB+ and HIV-TB- (P ≤ 0.005), (3) Activated T cells: higher CD4 T cells compared to HIV-nTB+, HIV-sTB+, and HIV-TB- (P ≤ 0.004); higher CD8 T cells compared to HIV + TB-, HIV-nTB+, HIV-sTB+, and HIV-TB- (P ≤ 0.001), and (4) Senescent T cells: increased CD8 T cells compared to HIV-nTB+ and HIV-TB- groups (P = 0.000).

CONCLUSIONS

Increased activation compared to HIV+TB-, HIV-nTB+, HIV-sTB+, and HIV-TB- groups and increased senescence compared to HIV-nTB+ and HIV-TB- groups were observed in CD8 T cells in HIV+nTB+, suggesting that the frequencies of these T cell subsets are altered to a greater extent in these individuals. © 2018 International Clinical Cytometry Society.

Nutritional and Immunological Correlates of Memory and Neurocognitive Development Among HIV-Infected Children Living in Kayunga, Uganda

OBJECTIVE

To identify the nutritional and immunological correlates of memory and neurocognitive development as measured by the Mullen Scales of Early Learning (MSEL) and by the Color Object Association Test (COAT) among children in Uganda.

DESIGN

This analysis uses baseline data collected between 2008 and 2010 from 119 HIV-infected children aged 1-6 years, participating in a randomized controlled trial of an interventional parenting program in Kayunga, Uganda.

METHODS

Peripheral blood draws were performed to determine immunological biomarkers. Unadjusted and adjusted linear regression models were used to relate MSEL and COAT scores to sociodemographic characteristics, weight-for-age Z scores (WAZs), antiretroviral therapy status, and immunological biomarkers.

RESULTS

In the final analysis, 111 children were included. Lower levels of CD4 CD38 T cells (P = 0.04) were associated to higher immediate and total recall scores (P = 0.04). Higher levels of CD8 HLA-DR T cells were associated with higher total recall score (P = 0.04) of the COAT. Higher CD4 CD38 HLA-DR T cells levels were associated with higher gross motor scores of the MSEL (P = 0.02). WAZ was positively correlated to visual reception, fine motor, expressive language, and composite score of the MSEL.

CONCLUSIONS

Overall, WAZ was a stronger predictor of neurocognitive outcomes assessed by the MSEL. CD4 CD38 T cells were more specifically associated with memory-related outcomes. Future research should include immunological markers and standardized neurocognitive tests to further understand this relationship.

Immunological correlates of behavioral problems in school-aged children living with HIV in Kayunga, Uganda

BACKGROUND

HIV can affect the neuropsychological function of children, including their behavior. We aim to identify immunological correlates of behavioral problems among children living with HIV in Uganda.

METHODS

Children participating in a parent randomized control trial in Kayunga, Uganda were assessed with the Behavior Rating Inventory of Executive Function (BRIEF) and the Child Behavior Checklist (CBCL). We constructed simple and multiple linear regression models to identify immunological correlates of behavioral problems.

RESULTS

A total of 144 children living with HIV (50% male) with a mean age of 8.9 years [Standard Deviation (s.d.) = 1.9] were included in the analysis. Eighty-two children were on antiretroviral therapy. Mean CD4 cell count % was 35.1 cells/μl (s.d. = 15.0), mean CD4 cell activation 5.7% (s.d. = 5.1), mean CD8 cell activation was 17.5% (s.d. = 11.2) and 60 children (41.7%) had a viral load of <4000 copies/ml. In the adjusted models for the BRIEF, higher scores were associated with higher viral loads (aβ = 16.7 × 10-6, 95% CI -5.00 × 10-6 to 28.4 × 10-6), specifically on the behavioral regulation index. Higher mean CD8 activation % was associated with higher scores on the Externalizing Problems  and Total Problems  scales of the CBCL (aβ = 0.17, 95% CI 0.04-0.31 and aβ = 0.15, 95% CI 0.00-0.28, respectively).

CONCLUSIONS

Poorer behavioral outcomes were associated with higher viral loads while higher CD8 activation was associated with poorer emotional and behavioral outcomes. Complete immunological assessments for children living with HIV could include commonly used viral and immunological parameters to identify those at higher risk of having negative behavior outcomes and who would benefit the most from behavioral interventions.

Immunologic risk factors for early mortality after starting antiretroviral therapy in HIV-infected Zambian children

To explore immunologic risk factors for death within 90 days of highly active antiretroviral therapy (HAART) initiation, CD4(+) and CD8(+) T cell subsets were measured by flow cytometry and characterized by logistic regression in 149 Zambian children between 9 months and 10 years of age enrolled in a prospective, observational study of the impact of HAART on measles immunity. Of 21 children who died during follow-up, 17 (81%) had known dates of death and 16 (76%) died within 90 days of initiating HAART. Young age and low weight-for-age z-scores were associated with increased risks of mortality within 90 days of starting HAART, whereas CD4(+) T cell percentage was not associated with mortality. After adjusting for these factors, each 10% increase in CD8(+) effector T cells increased the odds of overall mortality [OR=1.43 (95% CI: 1.08, 1.90)] and was marginally associated with early mortality [OR=1.29 (95% CI: 0.97, 1.72)]. Conversely, each 10% increase in CD4(+) central memory T cells decreased the odds of overall [OR=0.06 (95% CI: 0.01, 0.59)] and early mortality [OR=0.09 (95% CI: 0.01, 0.97)]. Logistic regression prediction models demonstrated areas under the receiver-operator characteristic curves of ≥85% for early and overall mortality, with bootstrapped sensitivities of 82-85% upon validation, supporting the predictive accuracy of the models. CD4(+) and CD8(+) T cell subsets may be more accurate predictors of early mortality than CD4(+) T cell percentages and could be used to identify children who would benefit from more frequent clinical monitoring after initiating HAART.

Early immunological predictors of neurodevelopmental outcomes in HIV-infected children

BACKGROUND

A previous analysis of children infected with human immunodeficiency virus (HIV) in the Women and Infants Transmission Study showed a strong correlation between low activated CD8(+) T lymphocytes in the first 2 months of life and good immunological prognosis. We sought to extend these observations to neurodevelopmental prognosis.

METHODS

Ninety-eight HIV-infected children born before 1994 with flow cytometric data from the first 2 months of life and adequate neurodevelopmental testing through age 30 months were studied. Children were divided into those with low (<or=5% CD8(+)HLA-DR(+) cells or <or=25% CD8(+)CD38(+) cells) or high (>5% CD8(+)HLA-DR(+) cells or >25% CD8(+)CD38(+) cells) immune activation at 1 and/or 2 months of age. Analysis was performed using survival analysis, Cox's proportional hazard regression, and longitudinal regression models.

RESULTS

Absence of immune activation, measured as <or=5% CD8(+)HLA-DR(+) cells, was strongly associated with better performance on the psychomotor developmental index of the Bayley scales of infant development through the third year of life. This association persisted after adjustment for CD4 cell count, viral load, and progression to acquired immunodeficiency syndrome (P= .005). An association with the mental development index was also present (P= .048). Significant association between neurodevelopmental outcomes and <or=25% CD8(+)CD38(+) cells was not seen.

CONCLUSIONS

In this prospective cohort study of HIV-infected children, there was a significant favorable association of low immune activation in peripheral T cells at age 1 or 2 months, measured by a low percentage of CD8(+)HLA-DR(+) cells, with subsequent psychomotor and mental development. This association was independent of other indices of severity and progression of HIV infection.

Significantly skewed memory CD8+ T cell subsets in HIV-1 infected infants during the first year of life

HIV-1 infection causes a severe T cell compromise; however, little is known about changes in naive, memory, effector and senescent T cell subsets during the first year of life. T cell subsets were studied over the first year of life in blood from 3 infant cohorts: untreated HIV-infected, HIV-exposed but uninfected, and HIV-unexposed. In HIV-infected infants, the frequency of CCR7(+)CD45RA(+) naive CD8(+) T cells was significantly decreased, while the frequency of CCR7(-)CD45RA(-) effector memory CD8(+) T cells was increased, compared with the control cohorts. A larger population of CD8(+) T cells in HIV-infected infants displayed a phenotype consistent with senescence. Differences in CD4(+) T cell subset frequencies were less pronounced, and no significant differences were observed between exposed and unexposed HIV-uninfected infants. We concluded that the proportion of naive, memory, effector and senescent CD8(+) T cells during the first year of life is significantly altered by HIV-1 infection.

Association of selected phenotypic markers of lymphocyte activation and differentiation with perinatal human immunodeficiency virus transmission and infant infection

This study of a subset of women and infants participating in National Institutes of Health Pediatric AIDS Clinical Trials Group protocol 185 evaluated lymphocyte phenotypic markers of immune activation and differentiation to determine their association with the likelihood of human immunodeficiency virus (HIV) transmission from the women to their infants and the potential for early identification and/or prognosis of infection in the infants. Lymphocytes from 215 human immunodeficiency virus type 1 (HIV)-infected women and 192 of their infants were analyzed by flow cytometry with an extended three-color panel of monoclonal antibodies. Women who did not transmit to their infants tended to have higher CD4+ T cells. Most notably, levels of total CD8+ T cells and CD8+ CD38+ cells made significant independent contributions to predicting the risk of mother-to-child transmission. Adjusting for HIV-1 RNA level at entry, a one percentage-point increase in these marker combinations was associated with a nine percent increase in the likelihood of maternal transmission. Total as well as naive CD4+ T cells were significantly higher in uninfected than infected infants. Total CD8+ cells, as well as CD8+ cells positive for HLA-DR+, CD45 RA+ HLA-DR+, and CD28+ HLA-DR+ were elevated in infected infants. Detailed immunophenotyping may be helpful in predicting which pregnant HIV-infected women are at increased risk of transmitting HIV to their infants. Increasing differences in lymphocyte subsets between infected and uninfected infants became apparent as early as six weeks of age. Detailed immunophenotyping may be useful in supporting the diagnosis of HIV infection in infants with perinatal HIV exposure.

Predictors of immunologic long-term nonprogression in HIV-infected children: implications for initiating therapy

BACKGROUND

Early markers that predict immunologic long-term nonprogression in infants with perinatally acquired HIV infection might assist in subsequent antiretroviral treatment decisions.

OBJECTIVES

We sought to identify early markers of immunologic long-term HIV disease nonprogression.

METHODS

We analyzed immunologic and virologic characteristics at 1 and 2 months of age in HIV-infected children who were enrolled in the Women and Infants Transmission Study and born before 1995, comparing immunologic long-term nonprogressors (ILTNPs; n = 10) with non-ILTNPs (n = 127). ILTNPs were children who survived to 8 years or older with CD4 percentages of 25% or greater and counts of 500 cells/mm 3 or more without receiving highly active antiretroviral therapy. Non-ILTNPs were defined as all other HIV-infected children. Receiver operating characteristic curve analysis was used to assess combined sensitivity and specificity for each of these characteristics and to determine potential threshold values to discriminate between ILTNPs and non-ILTNPs.

RESULTS

Characteristics in the first 2 months of life associated with ILTNP status in univariate analysis included higher CD4 percentages, lower CD8 + percentages, lower CD8 + HLA-DR + percentages, and lower HIV-1 RNA PCR values. In receiver operating characteristic analysis CD8 + HLA-DR + percentage had the best combined sensitivity and specificity for discriminating between ILTNPs and non-ILTNPs. CD8 + HLA-DR + percentages of 5% or less predicted ILTNP status with 80% sensitivity and 80% specificity. In multivariate analysis CD8 + HLA-DR+ percentage of 5% or less remained a significant predictor of ILTNP status after adjusting for CD3 + CD4 + percentage and HIV-1 RNA PCR value (odds ratio, 15.4; 95% CI, 1.9-124.7).

CONCLUSION

CD8 + HLA-DR + T-lymphocyte percentage of less than 5% at 1 to 2 months of age might be predictive for ILTNP status but should not be used at this time to make treatment-deferral decisions. Immune activation in HIV-infected infants might herald more disease progression. Further study of the use of this subpopulation in early infancy to predict ILTNP status is warranted.

Subpoblaciones de células T CD8+ en niños asintomáticos infectados verticalmente por el VIH-1

BACKGROUND AND OBJECTIVE

HIV-infection has distinct patterns of disease progression with heterogeneous manifestations. We analyzed the subsets of CD8+ T cells in a group of long term asymptomatic (LTA) HIV-1-infected children who had stable CD4+ T cell counts (> 600/l).

PATIENTS AND METHODS

Cross-sectional study in HIV-1-vertically infected children older than 7 years who were rated into two groups according to the clinical and immunological classification: a) LTA: 7 asymptomatic HIV-1-infected children in A1, and b) rapid progressor (PR): 14 age-matched C3 HIV-1-infected children. Controls included 17 age-matched uninfected children. Characterization of CD8+ T-cell subsets was done by three-color flow cytometry.

RESULTS

LTA children displayed similar values of memory CD8+ T cells (CD8+CD45RO+, CD8+CD45RA-CD28+, CD8+ CD45RA-CD62L+) as controls but lower than PR children. LTA patients also showed similar values of naïve CD8+ T cells (CD8+CD45RA+CD62L+, CD8+CD45RA+CD28+, CD8+CD45RA+, CD8+CD28+ and CD8+CD62L+) as controls but higher values than PR children. The values of CD8+CD38+ T cells were similar in LTA and controls but lower in PR. However, LTA children had higher values of CD8+HLA-DR+CD38+ and CD8+HLA-DR+ T cells than controls. Additionally, LTA patients had higher values of pre-effector CD8+ T cells than controls yet the values of effector CD8+ T-cells were similar in both LTA and controls. Moreover, the LTA group had lower values of CD8+CD11b+ T cells than controls.

CONCLUSIONS

Asymptomatic HIV-1 infected children have an almost normal CD8+ subset distribution, with the exception of activated and pre-effector CD8+ T cells which were higher.

Discordant expression of perforin and granzyme A in total and HIV-specific CD8 T lymphocytes of HIV infected children and adolescents

OBJECTIVE

Perforin and granzyme are cytotoxic effector molecules that are believed to play essential roles in cytotoxic T cell (CTL) activity. We tested the hypothesis that dysregulation of these effector molecules contributes to defects of CD8 antiviral immune responses in pediatric subjects in chronic stages of perinatal HIV infection.

DESIGN/METHOD

Studies of CD8 T cells were conducted in 33 treatment experienced HIV+ patients (median age, 10.6 years) and in 14 age-matched healthy controls. CD8 T cells specific for HIV Gag and Pol peptides were identified in HLA-A2+ patients by tetramer binding assays. HIV-specific and total CD8 T cells were examined for perforin, granzyme and expression of CD27, a marker that is lost in terminally differentiated cells.

RESULTS

Three populations of CD8 T cells were identified: granzyme+ perforin+; granzyme+ perforin- and cells negative for both perforin and granzyme. In HIV infected patients, granzyme+ cells were increased in total CD8 T cells (39% versus 13% in controls) and were highest in HIV Gag-specific CD8 cells (42%). Perforin+ CD8 T cells were approximately fivefold fewer than granzyme+ CD8 T cells and were enriched in CD27 negative cells. Most HIV-specific CD8 cells were CD27+. Granzyme expression in CD8 T cells correlated negatively with CD4 percentage and positively with virus load.

CONCLUSION

A disproportionate and generalized increase in CD27+, granzyme+, CD8 T cells is a hallmark of established pediatric HIV infection. These findings support the concept of skewed maturation, with failure of CD8 T cells to mature into perforin-enriched, CD27-negative, effector cells.