Effector T lymphocytes in well-nourished and malnourished infected children

The Tolerance Model of Non-Inflammatory Immune Competence in Acute Pediatric Malnutrition: Origins, Evidence, Test of Fitness and Growth Potential

The tolerance model rests on the thesis of a physiologically regulated, albeit unsustainable, systemic attempt to adapt to the catabolic challenge posed by acute prepubescent malnutrition even in its severe forms. The model centers on the immunological component of the attempt, positing reorientation toward a non-inflammatory form of competence in place of the classic paradigm of immunological attrition and exhaustion. The foundation of the model was laid in 1990, and sixteen years later it was articulated formally on the basis of a body of evidence centered on T cell cytokines and interventions with cytokine and hormonal mediators. The benefit originally suggested was a reduced risk of autoimmune pathologies consequent to the catabolic release of self-antigens, hence the designation highlighting immune tolerance. Herein, the emergence of the tolerance model is traced from its roots in the recognition that acute malnutrition elicits an endocrine-based systemic adaptive attempt. Thereafter, the growth of the evidence base supporting the model is outlined, and its potential to shed new light on existing information is tested by application to the findings of a published clinical study of acutely malnourished children. Finally, some knowledge gaps pertinent to the model are identified and its potential for growth consonant with evolving perceptions of immunobiology is illustrated.

Protein undernutrition reduces the efficacy of praziquantel in a murine model of Schistosoma mansoni infection

Background

Undernutrition and schistosomiasis are public health problems and often occur in low and middle-income countries. Protein undernutrition can alter the host-parasite environment system and aggravate the course of schistosomiasis. This study aimed to assess the impact of a low-protein diet on the efficacy of praziquantel.

Methodology/Principal findings

Thirty-day-old mice were fed with a low-protein diet, and 40 days later, they were individually infected with fifty Schistosoma mansoni cercariae. A 28-day-treatment with praziquantel at 100 mg/kg for five consecutive days followed by distilled water begins on the 36^th day post-infection. Mice were sacrificed on the 64^th day post-infection. We determined the parasitological burden, liver and intestine histomorphometry, liver injury, and immunomodulation parameters. Praziquantel treatment of infected mice fed with a standard diet (IN-PZQ) resulted in a significant reduction of worm and egg burdens and a normalization of iron and calcium levels. The therapy also improved schistosomiasis-induced hepatopathy and oxidative stress. The anti-inflammatory and immunomodulatory activities of praziquantel were also significant in these mice. When infected mice receiving the low-protein diet were treated with praziquantel (ILP-PZQ), the body weight loss and hepatomegaly were not alleviated, and the worm and liver egg burdens were significantly higher than those of IN-PZQ mice (P < 0.001). The treatment did not reduce the increased activities of ALT and γ-GGT, the high malondialdehyde concentration, and the liver granuloma volume. The iron and calcium levels were not ameliorated and differed from those of IN-PZQ mice (P < 0.001 and P < 0.05). Moreover, in these mice, praziquantel treatment did not reverse the high level of IL-5 and the low mRNA expression of CCL3/MIP-1α and CXCL-10/IP-10 induced by S. mansoni infection.

Conclusion/Significance

These results demonstrated that a low-protein diet reduced the schistosomicidal, antioxidant, anti-inflammatory, and immunomodulatory activities of praziquantel.

Almost 90% of people requiring schistosomiasis preventive chemotherapy in 2018 lived in sub-Saharan Africa. Besides, 205.3 million children under five years suffer and die of undernutrition in low- and middle-income countries. The physiopathology of schistosomiasis mansoni involves liver damage, oxidative stress, and perturbation of the immune response. These disturbances are intensified by undernutrition. Praziquantel is used to treat schistosomiasis, but its efficacy on the comorbidity of S. mansoni infection and undernutrition has not been investigated. We conducted this study to assess the effectiveness of praziquantel on S. mansoni infection in mice fed with a low-protein diet. We recorded growth retardation, hepatomegaly, and high worm and egg burdens in mice fed with a low-protein diet and treated with PZQ. Moreover, the treatment did not reverse the liver function injury, oxidative stress, high iron level, and low calcium level. The proinflammatory cytokine IL-5 was still high, and the gene expression of some macrophage-associated chemokines was reduced. Therefore, this study demonstrated that in a murine model of a low-protein diet, the efficacy of praziquantel on S. mansoni infection was reduced. It also underlines the importance of targeting protein deficiency and malnutrition in populations living in schistosomiasis endemic areas for efficient disease control.

Mechanisms of Kwashiorkor-Associated Immune Suppression: Insights From Human, Mouse, and Pig Studies

Malnutrition refers to inadequate energy and/or nutrient intake. Malnutrition exhibits a bidirectional relationship with infections whereby malnutrition increases risk of infections that further aggravates malnutrition. Severe malnutrition (SM) is the main cause of secondary immune deficiency and mortality among children in developing countries. SM can manifest as marasmus (non-edematous), observed most often (68.6% of all malnutrition cases), kwashiorkor (edematous), detected in 23.8% of cases, and marasmic kwashiorkor, identified in ~7.6% of SM cases. Marasmus and kwashiorkor occur due to calorie-energy and protein-calorie deficiency (PCD), respectively. Kwashiorkor and marasmic kwashiorkor present with reduced protein levels, protein catabolism rates, and altered levels of micronutrients leading to uncontrolled oxidative stress, exhaustion of anaerobic commensals, and proliferation of pathobionts. Due to these alterations, kwashiorkor children present with profoundly impaired immune function, compromised intestinal barrier, and secondary micronutrient deficiencies. Kwashiorkor-induced alterations contribute to growth stunting and reduced efficacy of oral vaccines. SM is treated with antibiotics and ready-to-use therapeutic foods with variable efficacy. Kwashiorkor has been extensively investigated in gnotobiotic (Gn) mice and piglet models to understand its multiple immediate and long-term effects on children health. Due to numerous physiological and immunological similarities between pigs and humans, pig represents a highly relevant model to study kwashiorkor pathophysiology and immunology. Here we summarize the impact of kwashiorkor on children's health, immunity, and gut functions and review the relevant findings from human and animal studies. We also discuss the reciprocal interactions between PCD and rotavirus-a highly prevalent enteric childhood pathogen due to which pathogenesis and immunity are affected by childhood SM.

Infection in the Developing Brain: The Role of Unique Systemic Immune Vulnerabilities

Central nervous system (CNS) infections remain a major burden of pediatric disease associated with significant long-term morbidity due to injury to the developing brain. Children are susceptible to various etiologies of CNS infection partly because of vulnerabilities in their peripheral immune system. Young children are known to have reduced numbers and functionality of innate and adaptive immune cells, poorer production of immune mediators, impaired responses to inflammatory stimuli and depressed antibody activity in comparison to adults. This has implications not only for their response to pathogen invasion, but also for the development of appropriate vaccines and vaccination strategies. Further, pediatric immune characteristics evolve across the span of childhood into adolescence as their broader physiological and hormonal landscape develop. In addition to intrinsic vulnerabilities, children are subject to external factors that impact their susceptibility to infections, including maternal immunity and exposure, and nutrition. In this review we summarize the current evidence for immune characteristics across childhood that render children at risk for CNS infection and introduce the link with the CNS through the modulatory role that the brain has on the immune response. This manuscript lays the foundation from which we explore the specifics of infection and inflammation within the CNS and the consequences to the maturing brain in part two of this review series.

How immune-cell fate and function are determined by metabolic pathway choice: The bioenergetics underlying the immune response

Immune cells are highly dynamic in their response to the tissue environment. Most immune cells rapidly change their metabolic profile to obtain sufficient energy to engage in defensive or homeostatic processes. Such "immunometabolism" is governed through intermediate metabolites, and has a vital role in regulating immune-cell function. The underlying metabolic reactions are shaped by the abundance and accessibility of specific nutrients, as well as the overall metabolic status of the host. Here, we discuss how different immune-cell types gain a sufficient energy supply. We then explain how immune cells perform various functions under challenged conditions and expend energy to sustain homeostasis. Finally, we speculate on how the immune-cell metabolic profile might be modulated in health and disease, by manipulating nutrient availability. By such intervention, the recovery of patient with dysregulated immune system responses might be sped up and the fitness of an individual efficiently restored.

Pathogenic signature of invasive non-typhoidal Salmonella in Africa: implications for vaccine development

Invasive non-typhoidal Salmonella (iNTS) infections are a leading cause of bacteremia in Sub-Saharan Africa (sSA), thereby representing a major public health threat. Salmonella Typhimurium clade ST313 and Salmonella Enteriditis lineages associated with Western and Central/Eastern Africa are among the iNTS serovars which are of the greatest concern due to their case-fatality rate, especially in children and in the immunocompromised population. Identification of pathogen-associated features and host susceptibility factors that increase the risk for invasive non-typhoidal salmonellosis would be instrumental for the design of targeted prevention strategies, which are urgently needed given the increasing spread of multidrug-resistant iNTS in Africa. This review summarizes current knowledge of bacterial traits and host immune responses associated with iNTS infections in sSA, then discusses how this knowledge can guide vaccine development while providing a summary of vaccine candidates in preclinical and early clinical development.

Anorexia Nervosa and the Immune System-A Narrative Review

The pathogenesis of an increasing number of chronic diseases is being attributed to effects of the immune system. However, its role in the development and maintenance of anorexia nervosa is seemingly under-appreciated. Yet, in examining the available research on the immune system and genetic studies in anorexia nervosa, one becomes increasingly suspicious of the immune system’s potential role in the pathophysiology of anorexia nervosa. Specifically, research is suggestive of increased levels of various pro-inflammatory cytokines as well as the spontaneous production of tumor necrosis factor in anorexia nervosa; genetic studies further support a dysregulated immune system in this disorder. Potential contributors to this dysregulated immune system are discussed including increased oxidative stress, chronic physiological/psychological stress, changes in the intestinal microbiota, and an abnormal bone marrow microenvironment, all of which are present in anorexia nervosa.

Predictive effects of body mass index on immune reconstitution among HIV-infected HAART users in China

BACKGROUND

Body mass index (BMI) may contribute somewhat to drug metabolism, and thus affecting the efficacy of highly active antiretroviral therapy (HAART). This study aimed to determine the frequencies of underweight, normal and overweight/obesity at pre-HAART in a large cohort of HIV-infected Chinese patients, and investigate the prospective effects of BMI on immune reconstitution after HAART initiation.

METHODS

A longitudinal cohort study was performed to analyze the effects of BMI on immune reconstitution in HIV-infected patients treated with HAART. Multiple linear regression was used to evaluate the relationship between baseline BMI and increased CD4+ T lymphocyte levels at 12 and 30 months after initiating HAART. In addition, Cox proportional hazard model was used to assess the relationship between BMI and time to achieve immunologic reconstitution (CD4+ T lymphocytes>500cells/μL) during the follow-up period.

RESULTS

Among the 1612 enrolled patients, 283 (17.6%) were overweight/obese (BMI ≥ 25 kg/m²), 173 (10.7%) were underweight (BMI < 18.5 kg/m²) and the remaining were normal weight. Prior to HAART initiating, overweight HIV-infected patients were mostly males, older ages, exhibited higher CD4+ T lymphocytes and lower viral loads (p < 0.01 for all). Patients with higher baseline BMI had an independently positive effect on 30-month CD4+ T lymphocyte recovery (p = 0.028), but not 12-month CD4+ T lymphocyte gain (p = 0.104). In addition, a Cox proportional hazard model with baseline BMI as an independent variable indicated that BMI was correlated with an increased likelihood of achieving immunologic reconstitution over time (hazard ratios [HR] 1.03; 95% confidence intervals [CI] 1.01-1.06; p = 0.011), after adjusting for baseline age, gender, CD4+ T lymphocytes, CD4/CD8 ratio, viral load and WHO stage.

CONCLUSIONS

Higher baseline BMI could predict better immune reconstitution in HIV-infected patients after HAART initiating.

Impact of Childhood Malnutrition on Host Defense and Infection

The global impact of childhood malnutrition is staggering. The synergism between malnutrition and infection contributes substantially to childhood morbidity and mortality. Anthropometric indicators of malnutrition are associated with the increased risk and severity of infections caused by many pathogens, including viruses, bacteria, protozoa, and helminths. Since childhood malnutrition commonly involves the inadequate intake of protein and calories, with superimposed micronutrient deficiencies, the causal factors involved in impaired host defense are usually not defined. This review focuses on literature related to impaired host defense and the risk of infection in primary childhood malnutrition. Particular attention is given to longitudinal and prospective cohort human studies and studies of experimental animal models that address causal, mechanistic relationships between malnutrition and host defense. Protein and micronutrient deficiencies impact the hematopoietic and lymphoid organs and compromise both innate and adaptive immune functions. Malnutrition-related changes in intestinal microbiota contribute to growth faltering and dysregulated inflammation and immune function. Although substantial progress has been made in understanding the malnutrition-infection synergism, critical gaps in our understanding remain. We highlight the need for mechanistic studies that can lead to targeted interventions to improve host defense and reduce the morbidity and mortality of infectious diseases in this vulnerable population.

Neurodevelopment: The Impact of Nutrition and Inflammation During Adolescence in Low-Resource Settings

Approximately 1 out of 5 children worldwide suffers from childhood malnutrition or stunting and associated health conditions, including an increased susceptibility to infections and inflammation. Due to improved early interventions, most children even in low-resource settings now survive early childhood malnutrition, yet exhibit continuing evidence of neurodevelopmental deficits, including poor school achievement and behavioral problems. These conditions are compounded in children who continue to be undernourished throughout the adolescent years. At present, these sequelae of malnutrition and infection are of major concern in the adolescent population, given that young people between the ages of 10 and 24 years represent nearly one-quarter of the world's population. Therefore, there is an urgent need to focus on the well-being of this age group and, in particular, on behavioral, cognitive, and brain disorders of adolescents who experienced malnutrition, infection, and inflammation prenatally, in early childhood, and during adolescence itself. Because one-third of all women globally become pregnant during their adolescent years, brain and behavioral disorders during this period can have an intergenerational impact, affecting the health and well-being of the next generation. This article summarizes the current state of knowledge and evidence gaps regarding childhood and adolescent malnutrition and inflammation and their impact on adolescent neurodevelopment, the limited evidence regarding nutrition and psychosocial interventions, and the role of resilience and protective factors in this age group. This overview should help to inform the development of new strategies to improve the neurodevelopmental outcomes of high risk adolescent populations.

Choline is required in the diet of lactating dams to maintain maternal immune function

Choline demands during lactation are high; however, detailed knowledge is lacking regarding the optimal dietary intake during this critical period. The present study was designed to determine the effects of varying intakes of choline on maternal immune function during lactation. Primiparous Sprague–Dawley rats (n42) were randomised 24-48 h before birth and fed the following diets for 21 d: choline-devoid (0 g choline/kg diet; D,n10); 1·0 g choline/kg diet (C1,n11); 2·5 g choline/kg diet (C2·5,n10); 6·2 g choline/kg diet (C6,n11). Splenocytes were isolated and stimulatedex vivowith concanavalin A, lipopolysaccharide (LPS) or CD3/CD28. D and C6 dams had lower final body weight, spleen weight and average pup weight than C1 dams (P< 0·05). There was a linear relationship between free choline concentration in pup stomach contents with maternal dietary choline content (P< 0·001,r20·415). Compared with C1 and C2·5, D spleens had a lower proportion of mature T cells and activated suppressor cells, and this resulted in reduced cytokine production after stimulation (P< 0·05). Feeding 6·2 g choline/kg diet resulted in a higher cytokine production after stimulation with CD3/CD28 (P< 0·05). Except for a higher IL-6 production after LPS stimulation with cells from the C2·5 dams (P< 0·05), there were no differences between the C1 and C2·5 dams. For the first time, we show that feeding lactating mothers a diet free of choline has substantial effects on their immune function and on offspring growth. Additionally, excess dietary choline had adverse effects on maternal and offspring body weight but only minimal effects on maternal immune function.

Outcomes of human immunodeficiency virus-infected children after anti-retroviral therapy in Malaysia

AIMS

To describe outcome and examine factors associated with mortality among human immunodeficiency virus (HIV)-infected children in Malaysia after anti-retroviral therapy (ART).

METHODS

Retrospective and prospective data collected through March 2009 from children in four different states in Malaysia enrolled in TREAT Asia's Pediatric HIV Observational Database were analysed.

RESULTS

Of 347 children in the cohort, only 278 (80.1%) were commenced on ART. The median CD4 count and median age at baseline prior to ART was 272 cells/μL and 4.2 years (interquartile range (IQR): 1.4, 7.4 years), respectively. The median duration of follow-up was 3.7 years (IQR: 1.8, 6.0) with 32 deaths giving a crude mortality rate of 2.86 per 100 child-years. The mortality rate highest in the first 6 months of ART was 10.62 per 100 child-years and declined to 1.83 per 100 child-years thereafter. On univariate analyses, only baseline median CD4 percentage, weight for age z score, height for age z score and anaemia were significantly associated with mortality. Upon including all four of these predictors into a single multivariate model, only weight for age z score remained statistically significantly predictive of mortality.

CONCLUSIONS

Children commenced on ART had high mortality in the first 6 months especially in those with low CD4 percentage, wasting and anaemia. Poor nutritional status is an important independent predictor of mortality in this study. Besides initiating ART therapy, nutritional support and intervention must receive the utmost attention.

Predictors of Mortality in a Clinic Cohort of HIV-1 Infected Children Initiated on Antiretroviral Therapy in Jos, Nigeria

Background:

Mortality among human immunodeficiency virus-1 (HIV-1) infected children initiated on antiretroviral therapy (ART) though on a decline still remains high in resource-limited countries (RLC). Identifying baseline factors that predict mortality could allow their possible modification in order to improve pediatric HIV care and reduce mortality.

Methods:

We conducted a retrospective cohort study analyzing data on 691 children, aged 2 months-15 years, diagnosed with HIV-1 infection and initiated on ART between July 2005 and March 2013 at the pediatric HIV clinic of Jos University Teaching Hospital. Lost to follow-up children were excluded from the analyses. A multivariate Cox proportional hazards model was fitted to identify predictors of mortality.

Results:

Median follow-up time for the 691 children initiated on ART was 4.4 years (interquartile range (IQR), 1.8-5.9) and at the end of 2752 person-years of follow-up, 32 (4.6%) had died and 659 (95.4%) survived. The mortality rate was 1.0 per 100 child-years of follow-up period. The median age of those who died was about two times lower than that of survivors [1.7 years (IQR, 0.6-3.6) versus 3.9 years (IQR, 3.9-10.3), p<0.001]. On unadjusted Cox regression, the risk of dying was about three and half times more in children <5 years of age compared to those >5 years (p=0.02) Multivariate modeling identified age as the main predictor of death with mortality decreasing by 24% for every 1 year increase in age (Adjusted Hazard Ratio (AHR)=0.76 [0.62-0.94], p=0.013.

Conclusion:

The lower mortality rate for our study suggests that even in RLC, mortality rates could be reduced given a good standard of care. Early initiation of ART in younger children with close monitoring during follow-up could further reduce mortality.

The immune system in children with malnutrition--a systematic review

BACKGROUND

Malnourished children have increased risk of dying, with most deaths caused by infectious diseases. One mechanism behind this may be impaired immune function. However, this immune deficiency of malnutrition has not previously been systematically reviewed.

OBJECTIVES

To review the scientific literature about immune function in children with malnutrition.

METHODS

A systematic literature search was done in PubMed, and additional articles identified in reference lists and by correspondence with experts in the field. The inclusion criteria were studies investigating immune parameters in children aged 1-60 months, in relation to malnutrition, defined as wasting, underweight, stunting, or oedematous malnutrition.

RESULTS

The literature search yielded 3402 articles, of which 245 met the inclusion criteria. Most were published between 1970 and 1990, and only 33 after 2003. Malnutrition is associated with impaired gut-barrier function, reduced exocrine secretion of protective substances, and low levels of plasma complement. Lymphatic tissue, particularly the thymus, undergoes atrophy, and delayed-type hypersensitivity responses are reduced. Levels of antibodies produced after vaccination are reduced in severely malnourished children, but intact in moderate malnutrition. Cytokine patterns are skewed towards a Th2-response. Other immune parameters seem intact or elevated: leukocyte and lymphocyte counts are unaffected, and levels of immunoglobulins, particularly immunoglobulin A, are high. The acute phase response appears intact, and sometimes present in the absence of clinical infection. Limitations to the studies include their observational and often cross-sectional design and frequent confounding by infections in the children studied.

CONCLUSION

The immunological alterations associated with malnutrition in children may contribute to increased mortality. However, the underlying mechanisms are still inadequately understood, as well as why different types of malnutrition are associated with different immunological alterations. Better designed prospective studies are needed, based on current understanding of immunology and with state-of-the-art methods.

Impact of protein supplementation and care and support on body composition and CD4 count among HIV-infected women living in rural India: results from a randomized pilot clinical trial

Body composition in HIV-infected individuals is subject to many influences. We conducted a pilot 6-month randomized trial of 68 women living with AIDS (WLA) from rural India. High protein intervention combined with education and supportive care delivered by HIV-trained village women (activated social health activist [Asha] life [AL]) was compared to standard protein with usual care delivered by village community assistants (usual care [UC]). Measurements included CD4 counts, ART adherence, socio-demographics, disease characteristics (questionnaires); and anthropometry (bioimpedance analyzer). Repeated measures analysis of variance modeled associations. AL significantly gained in BMI, muscle mass, fat mass, ART adherence, and CD4 counts compared to UC, with higher weight and muscle mass gains among ART adherent (≥66%) participants who had healthier immunity (CD4 ≥450). BMI of WLA improved through high protein supplementation combined with education and supportive care. Future research is needed to determine which intervention aspect was most responsible.

Prevalence and factors associated with cryptococcal antigenemia among severely immunosuppressed HIV-infected adults in Uganda: a cross-sectional study

Background

Cryptococcal infection is a common opportunistic infection among severely immunosuppressed HIV patients and is associated with high mortality. Positive cryptococcal antigenemia is an independent predictor of cryptococcal meningitis and death in patients with severe immunosuppression. We evaluated the prevalence and factors associated with cryptococcal antigenemia among patients with CD4 counts of 100 cells/mm³ or less in Mulago Hospital, Kampala, Uganda. Screening of a targeted group of HIV patients may enable early detection of cryptococcal infection and intervention before initiating antiretroviral therapy. Factors associated with cryptococcal antigenemia may be used subsequently in resource-limited settings in screening for cryptococcal infection, and this data may also inform policy for HIV care.

Methods

In this cross-sectional study, HIV-infected patients aged 18 years and older with CD4 counts of up to 100 cells/mm³ were enrolled between December 2009 and March 2010. Data on socio-demographics, physical examinations and laboratory tests were collected. Factors associated with cryptococcal antigenemia were analyzed using multiple logistic regression.

Results

We enrolled 367 participants and the median CD4 count was 23 (IQR 9-51) cells/mm³. Sixty-nine (19%) of the 367 participants had cryptococcal antigenemia. Twenty-four patients (6.5%) had cryptococcal meningitis on cerebrospinal fluid analysis and three had isolated cryptococcal antigenemia. Factors associated with cryptococcal antigenemia included: low body mass index of 15.4 kg/m² or less (adjusted odds ratio, AOR = 0.5; 95% CI 0.3-1.0), a CD4+ T cell count of less than 50 cells/mm³ (AOR = 2.7; 95% CI1.2-6.1), neck pain (AOR = 2.3; 95% CI 1.2-4.6), recent diagnosis of HIV infection (AOR = 1.9; 95% CI 1.1-3.6), and meningeal signs (AOR = 7.9; 95% CI 2.9-22.1). However, at sub-analysis of asymptomatic patients, absence of neck pain (AOR = 0.5), photophobia (AOR = 0.5) and meningeal signs (AOR = 0.1) were protective against cryptococcal infection.

Conclusions

Cryptococcal antigenemia is common among severely immunosuppressed HIV patients in Mulago Hospital, Kampala, Uganda. Independent predictors of positive serum cryptococcal antigenemia were CD4⁺ T cell counts of less than 50 cells/mm, low body mass index, neck pain, signs of meningeal irritation, and a recent diagnosis of HIV infection. Routine screening of this category of patients may detect cryptococcosis, and hence provide an opportunity for early intervention. Absence of neck pain, photophobia and meningeal signs were protective against cryptococcal infection compared with symptomatic patients.

An optimal body mass index range associated with improved immune reconstitution among HIV-infected adults initiating antiretroviral therapy

BACKGROUND

Higher body mass index (BMI) was associated with slower human immunodeficiency virus (HIV) disease progression before the availability of effective antiretroviral therapy (ART), but the relationship between pretreatment BMI and CD4(+) lymphocyte recovery on ART is not well described.

METHODS

We conducted an observational cohort study of HIV-infected, ART-naive adults starting treatment at a clinic affiliated with Vanderbilt University in Nashville, Tennessee. We assessed the relationship between pretreatment BMI and CD4(+) lymphocyte count change from baseline to 12 months in all subjects, among those with plasma HIV-1 RNA levels <400 copies/mL for ≥ 6 months and those with <10% change in weight during follow-up. Linear regression models were adjusted for age, sex, race, protease inhibitor usage, year of ART initiation, and baseline CD4(+) lymphocyte count and HIV-1 RNA level.

RESULTS

A total of 915 patients met inclusion criteria; 78% were male, and their median age, BMI, and CD4(+) lymphocyte count were 39 years, 24 kg/m², and 171 cells/μL, respectively. The CD4(+) lymphocyte increase at 12 months was greatest among patients with a pretreatment BMI of ~25-30 kg/m² and diminished above and below this range (P = .03). Similar patterns were observed in the subgroup analyses. Among patients with a pretreatment CD4(+) lymphocyte count < 200 cells/μL, a BMI of ~25 kg/m² was associated with the highest odds of reaching a CD4(+) lymphocyte count > 350 cells/μL at 12 months (P = .05).

CONCLUSIONS

12-month immune reconstitution on ART was highest among patients commonly classified as overweight, suggesting there may be an optimal BMI range for immune recovery on ART.

Thymic function and T cell parameters in a natural human experimental model of seasonal infectious diseases and nutritional burden

BACKGROUND

The study exploits a natural human experimental model of subsistence farmers experiencing chronic and seasonally modified food shortages and infectious burden. Two seasons existed, one of increased deprivation and infections (Jul-Dec), another of abundance and low infections (Jan-Jun); referred to as the hungry/high infection and harvest/low infection seasons respectively. Prior analysis showed a 10-fold excess in infectious disease associated mortality in young adults born in the hungry/high infection versus harvest/low infection season, and reduced thymic output and T cell counts in infancy. Here we report findings on the role of early life stressors as contributors to the onset of T cell immunological defects in later life.

METHODS

We hypothesised that season of birth effects on thymic function and T cell immunity would be detectable in young adults since Kaplan-Meier survival curves indicated this to be the time of greatest mortality divergence. T cell subset analyses by flow-cytometry, sjTRECs, TCRVβ repertoire and telomere length by PCR, were performed on samples from 60 males (18-23 y) selected to represent births in the hungry/high infection and harvest/low infection

RESULTS

Total lymphocyte counts were normal and did not differ by birth season. CD3+ and CD4+ but not CD8+ counts were lower for those born during the hungry/high infection season. CD8+ telomere length also tended to be shorter. Overall, CD8+ TCRVβ repertoire skewing was observed with 'public' expressions and deletions seen in TCRVβ12/22 and TCRVβ24, respectively but no apparent effect of birth season.

CONCLUSIONS

We conclude that, although thymic function was unchanged, the CD4+ and CD3+ counts, and CD8+ telomere length results suggested that aspects of adult T cell immunity were under the influence of early life stressors. The endemicity of CMV and HBV suggested that chronic infections may modulate immunity through T cell repertoire development. The overall implications being that, this population is at an elevated risk of premature immunosenescence possibly driven by a combination of nutritional and infectious burden.

Predictors of mortality in HIV-1 infected children on antiretroviral therapy in Kenya: a prospective cohort

Background

Among children, early mortality following highly active antiretroviral therapy (HAART) remains high. It is important to define correlates of mortality in order to improve outcome.

Methods

HIV-1-infected children aged 18 months-12 years were followed up at Kenyatta National Hospital, Nairobi after initiating NNRTI-based HAART. Cofactors for mortality were determined using multivariate Cox regression models.

Results

Between August 2004 and November 2008, 149 children were initiated on HAART of whom 135 were followed for a total of 238 child-years (median 21 months) after HAART initiation. Baseline median CD4% was 6.8% and median HIV-1-RNA was 5.98-log₁₀ copies/ml. Twenty children (13.4%) died at a median of 35 days post-HAART initiation. Mortality during the entire follow-up period was 8.4 deaths per 100 child-years (46 deaths/100 child-years in first 4 months and 1.0 deaths/100 child-years after 4 months post-HAART initiation). On univariate Cox regression, baseline hemoglobin (Hb) <9 g/dl, weight-for-height z-score (WHZ) < -2, and WHO clinical stage 4 were associated with increased risk of death (Hb <9 g/dl HR 3.00 [95% C.I. 1.21-7.39], p = 0.02, WHZ < -2 HR 3.41 [95% C.I. 1.28-9.08], p = 0.01, and WHO clinical stage 4, HR 3.08 [1.17-8.12], p = 0.02). On multivariate analysis Hb < 9 g/dl remained predictive of mortality after controlling for age, baseline CD4%, WHO clinical stage and weight-for-height z-score (HR 2.95 (95% C.I. 1.04-8.35) p = 0.04).

Conclusion

High early mortality was observed in this cohort of Kenyan children receiving HAART, and low baseline hemoglobin was an independent risk factor for death.

Nutritional aspects of HIV-associated wasting in sub-Saharan Africa

The twin global epidemics of HIV infection and food scarcity disproportionately affect sub-Saharan Africa, and a significant proportion of patients who require antiretroviral therapy (ART) are malnourished because of a combination of HIV-associated wasting and inadequate nutrient intake. Protein-calorie malnutrition, the most common form of adult malnutrition in the region, is associated with significant morbidity and compounds the immunosuppressive effects of HIV. A low body mass index (BMI), a sign of advanced malnutrition, is an independent predictor of early mortality (<6 mo) after ART initiation in several analyses, and recent studies show an association between early weight gain when receiving ART and improved treatment outcomes. The cause of the observed increase in mortality is uncertain, but it is likely due in part to malnutrition-induced immune system dysfunction, a higher burden of opportunistic infections, and metabolic derangements. In this article, we describe the epidemiology of HIV infection and malnutrition in sub-Saharan Africa, potential causes of increased mortality after ART initiation among patients with a low BMI, recent studies on post-ART weight gain and treatment outcome, and trials of macronutrient supplementation from the region. We close by highlighting priority areas for future research.

Macronutrient supplementation for malnourished HIV-infected adults: a review of the evidence in resource-adequate and resource-constrained settings

Access to antiretroviral therapy (ART) for human immunodeficiency virus (HIV) infection has expanded rapidly throughout sub-Saharan Africa, but malnutrition and food insecurity have emerged as major barriers to the success of ART programs. Protein-calorie malnutrition (a common form of malnutrition in the region) hastens HIV disease progression, and food insecurity is a barrier to medication adherence. Analyses of patient outcomes have identified a low body mass index after the start of ART as an independent predictor of early mortality, but the causes of a low body mass index are multifactorial (eg, normal anthropometric variation, chronic inadequate food intake, and/or wasting associated with HIV infection and other infectious diseases). Although there is much information on population-level humanitarian food assistance, few data exist to measure the effectiveness of macronutrient supplementation or to identify individuals most likely to benefit. In this report, we review the current evidence supporting macronutrient supplementation for HIV-infected adults, we report on clinical trials in resource-adequate and resource-constrained settings, and we highlight priority areas for future research.

Expression of cytokine mRNA in lymphocytes of malnourished children

INTRODUCTION

Protein-calorie malnutrition represents a significant worldwide health problem and is associated with an increased risk for infections. The purpose of this study was to evaluate possible changes in type 1/type 2 responses balance in malnourished children.

RESULTS

The data obtained in the present study showed that the expression levels of tumor necrosis factor-alpha, interleukin (IL)-4, and IL-10 were more highly, in contrast IL-2, gamma interferon, and IL-6 genes were expressed less in all groups of malnourished children compared with the well-nourished infected children. It is important to indicate that the data collected in the present work agree with the results obtained by different authors, who showed differences in the production of cytokines in malnourished children.

CONCLUSION

In conclusion, the results suggest that alterations in the balance of type 1/type 2 immune responses exist in malnourished children, and this could be the reason that the immunological system of the malnourished children is incapable of eradicating infections.