Household food insecurity in South Africa from 1999 to 2021: a metrics perspective.

OBJECTIVE: To review and synthesize studies on household food security in South Africa. DESIGN: Systematic mapping review of metrics (methodological review). SETTING: Electronic databases, including EBSCOHost, Scopus and Web of Science, were searched for studies and reports on household food security in South Africa, reporting household food security published between 1999 and 2021. Searching, selecting and reporting were performed according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) statement. PARTICIPANTS: South African households. RESULTS: Forty-eight articles reporting on six national surveys (one repeated annually since 2002) and forty sub-national studies meeting the inclusion criteria were selected. Various metrics, with different recall periods and ways of categorizing food security levels, were identified. Surveys that used similar metrics showed that the percentage of South African households that have experienced food insecurity and hunger has decreased over the review period yet remains concerning. However, the multitude of metrics used to assess the different components and levels of food security limits the comparability of the results to evaluate the scope and scale of the problem. CONCLUSIONS: There is growing support for developing multi-variable approaches for food security research in sub-Saharan Africa. Future research should focus on finding the most appropriate combination of complementary metrics that would allow comparable data while holistically capturing food security and providing insight into the causes and consequences.

Early prediction of clinical response to anti-TNF treatment using multi-omics and machine learning in rheumatoid arthritis.

OBJECTIVES: Advances in immunotherapy by blocking TNF have remarkably improved treatment outcomes for Rheumatoid arthritis (RA) patients. Although treatment specifically targets TNF, the downstream mechanisms of immune suppression are not completely understood. The aim of this study was to detect biomarkers and expression signatures of treatment response to TNF inhibition. METHODS: Peripheral blood mononuclear cells (PBMCs) from 39 female patients were collected before anti-TNF treatment initiation (day 0) and after 3 months. The study cohort included patients previously treated with MTX who failed to respond adequately. Response to treatment was defined based on the EULAR criteria and classified 23 patients as responders and 16 as non-responders. We investigated differences in gene expression in PBMCs, the proportion of cell types and cell phenotypes in peripheral blood using flow cytometry and the level of proteins in plasma. Finally, we used machine learning models to predict non-response to anti-TNF treatment. RESULTS: The gene expression analysis in baseline samples revealed notably higher expression of the gene EPPK1 in future responders. We detected the suppression of genes and proteins following treatment, including suppressed expression of the T cell inhibitor gene CHI3L1 and its protein YKL-40. The gene expression results were replicated in an independent cohort. Finally, machine learning models mainly based on transcriptomic data showed high predictive utility in classifying non-response to anti-TNF treatment in RA. CONCLUSIONS: Our integrative multi-omics analyses identified new biomarkers for the prediction of response, found pathways influenced by treatment and suggested new predictive models of anti-TNF treatment in RA patients.

Alterations of p11 in brain tissue and peripheral blood leukocytes in Parkinson's disease.

Individuals with Parkinson's disease (PD) often suffer from comorbid depression. P11 (S100A10), a member of the S100 family of proteins, is expressed widely throughout the body and is involved in major depressive disorder and antidepressant response. Central p11 levels are reduced in postmortem tissue from depressed individuals; however, p11 has not yet been investigated in PD patients with depression or those without depression. We investigated p11 levels in postmortem PD brains and assessed whether peripheral p11 levels correlate with disease severity. Substantia nigra, putamen, and cortical p11 protein levels were assessed in postmortem brain samples from PD patients and matched controls. In a different set of postmortem brains, p11 mRNA expression was measured in dopaminergic cells from the substantia nigra. Both p11 protein and mRNA levels were decreased in PD patients. Peripheral p11 protein levels were investigated in distinct leukocyte populations from PD patients with depression and those without depression. Monocyte, natural killer (NK) cell, and cytotoxic T-cell p11 levels were positively associated with the severity of PD, and NK cell p11 levels were positively associated with depression scores. Given that inflammation plays a role in both PD and depression, it is intriguing that peripheral p11 levels are altered in immune cells in both conditions. Our data provide insight into the pathological alterations occurring centrally and peripherally in PD. Moreover, if replicated in other cohorts, p11 could be an easily accessible biomarker for monitoring the severity of PD, especially in the context of comorbid depression.

Herpes simplex virus specific T cell response in a cohort with primary genital infection correlates inversely with frequency of subsequent recurrences.

OBJECTIVES: During the last decades, a changing epidemiological pattern of genital herpes simplex virus (HSV) infection has emerged. Primary infection is now caused as often by HSV-1 as by HSV-2. Once established, HSV can be reactivated leading to recurrent mucocutaneous lesions as well as meningitis. Why some otherwise immune-competent individuals experience severe and frequent recurrences is not known, and the immunological mechanism underlying recurrent symptomatic HSV infection is not fully understood. In this study, we investigate and characterise the immune response of patients with first episode of HSV genital infection and its relation to the frequency of symptomatic recurrences. METHODS: In this cohort study, clinical and immunological data were collected from 29 patients who were followed 1 year after presenting with a first episode of genital or meningeal HSV infection. They were classified by PCR and serology as those with primary HSV-1, primary HSV-2 and non-primary HSV-2 infection. RESULTS: HSV-specific interleukin(Il)-4 and Il-10 responses at first visit were higher in primary infected HSV-2 infected patients experiencing lower numbers of recurrences during subsequent year. CONCLUSIONS: The median number of recurrences following primary HSV-2 genital infection may partly be predicted by the strength of an early HSV-specific IL-4 and IL-10 response.

Integration of known DNA, RNA and protein biomarkers provides prediction of anti-TNF response in rheumatoid arthritis: results from the COMBINE study.

OBJECTIVE: In rheumatoid arthritis (RA) several recent efforts have sought to discover means of predicting which patients would benefit from treatment. However, results have been discrepant with few successful replications. Our objective was to build a biobank with DNA, RNA and protein measurements to test the claim that the current state-of-the-art precision medicine will benefit RA patients. METHODS: We collected 451 blood samples from 61 healthy individuals and 185 RA patients initiating treatment, before treatment initiation and at a 3 month follow-up time. All samples were subjected to high-throughput RNA sequencing, DNA genotyping, extensive proteomics and flow cytometry measurements, as well as comprehensive clinical phenotyping. Literature review identified 2 proteins, 52 single-nucleotide polymorphisms (SNPs) and 72 gene-expression biomarkers that had previously been proposed as predictors of TNF inhibitor response (∆DAS28-CRP). RESULTS: From these published TNFi biomarkers we found that 2 protein, 2 SNP and 8 mRNA biomarkers could be replicated in the 59 TNF initiating patients. Combining these replicated biomarkers into a single signature we found that we could explain 51% of the variation in ∆DAS28-CRP. This corresponds to a sensitivity of 0.73 and specificity of 0.78 for the prediction of three month ∆DAS28-CRP better than -1.2. CONCLUSIONS: The COMBINE biobank is currently the largest collection of multi-omics data from RA patients with high potential for discovery and replication. Taking advantage of this we surveyed the current state-of-the-art of drug-response stratification in RA, and identified a small set of previously published biomarkers available in peripheral blood which predicts clinical response to TNF blockade in this independent cohort.

Balance between activating NKG2D, DNAM-1, NKp44 and NKp46 and inhibitory CD94/NKG2A receptors determine natural killer degranulation towards rheumatoid arthritis synovial fibroblasts.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation and synovial hyperplasia leading to progressive joint destruction. Fibroblast-like synoviocytes (FLS) are central components of the aggressive, tumour-like synovial structure termed pannus, which invades the joint space and cartilage. A distinct natural killer (NK) cell subset expressing the inhibitory CD94/NKG2A receptor is present in RA synovial fluid. Little is known about possible cellular interactions between RA-FLS and NK cells. We used cultured RA-FLS and the human NK cell line Nishi, of which the latter expresses an NK receptor repertoire similar to that of NK cells in RA synovial fluid, as an in vitro model system of RA-FLS/NK cell cross-talk. We show that RA-FLS express numerous ligands for both activating and inhibitory NK cell receptors, and stimulate degranulation of Nishi cells. We found that NKG2D, DNAM-1, NKp46 and NKp44 are the key activating receptors involved in Nishi cell degranulation towards RA-FLS. Moreover, blockade of the interaction between CD94/NKG2A and its ligand HLA-E expressed on RA-FLS further enhanced Nishi cell degranulation in co-culture with RA-FLS. Using cultured RA-FLS and the human NK cell line Nishi as an in vitro model system of RA-FLS/NK cell cross-talk, our results suggest that cell-mediated cytotoxicity of RA-FLS may be one mechanism by which NK cells influence local joint inflammation in RA.

A retrospective cohort analysis of factors associated with the development of refeeding syndrome in children 0-59 months diagnosed with severe acute malnutrition in a South African setting.

Background: Refeeding syndrome (RFS) is a life-threatening, underdiagnosed, and under-researched complication in treating children with severe acute malnutrition (SAM). This study aimed to determine the incidence and onset of RFS and identify biochemical abnormalities, clinical signs, and complications associated with RFS development in children, 0-59 months, treated with SAM in a South African public hospital setting. Methods: A retrospective cohort study was performed on hospital medical records of children aged 0-59 months, diagnosed with SAM at Rahima Moosa Mother and Child Hospital, Johannesburg, from 1/10/2014 to 31/12/2018. The onset of RFS among children included in the study was diagnosed based on published criteria for RFS. On admission, children who developed RFS and those who did not were compared concerning biochemistry and clinical signs and symptoms. Results: A total of 148 medical records were retrieved from the hospital archives. The diagnosis of SAM based on the World Health Organization (WHO) definition was confirmed in 126 children who were then included in the study. The median age of the 126 children (63 % male) with confirmed SAM was 11.2 months (P25:7.0 months; P75:17.0 months). The in-hospital mortality rate was 18.2 %, of which 8.7 % were retrospectively diagnosed as having developed RFS during their recorded hospital stay, despite implementing the WHO treatment guidelines for SAM. A significantly higher percentage of the children who developed RFS presented on admission with hypophosphatemia (p = 0.015), hypokalemia (p = 0.001), hyponatremia (p = 0.001), an international normalized ratio (INR) of above 1.7 (p = 0.025), diarrhea (p = 0.042), dehydration (p = 0.029) and urinary tract infection (UTI) (p = 0.041), than those who did not. Children who developed RFS stayed in hospital significantly longer than those who did not (18 vs. 12 days with a p-value of 0.003). Conclusion: In this population of children with SAM treated in a South African public hospital setting, the presence on hospital admission of low levels of electrolytes, elevated INR, dehydration, diarrhea, and UTI was significantly associated with developing RFS. Recognizing these as possible red flags for developing RFS in children admitted with SAM might contribute to improved outcomes and needs further investigation.

Statistical assessment of reliability of anthropometric measurements in the multi-site South African National Dietary Intake Survey 2022.

BACKGROUND: Anthropometric data quality in large multicentre nutrition surveys is seldom adequately assessed. In preparation for the South African National Dietary Intake Survey (NDIS-2022), this study assessed site leads' and fieldworkers' intra- and inter-rater reliability for measuring weight, length/height, mid-upper arm circumference (MUAC), waist circumference (WC) and calf circumference (CC). METHODS: Standardised training materials and measurement protocols were developed, and new anthropometric equipment was procured. Following two training rounds (12 site lead teams, 46 fieldworker teams), measurement reliability was assessed for both groups, using repeated measurements of volunteers similar to the survey target population. Reliability was statistically assessed using the technical error of measurement (TEM), relative TEM (%TEM), intra-class correlation coefficient (ICC) and coefficient of reliability (R). Agreement was visualised with Bland-Altman analysis. RESULTS: By %TEM, the best reliability was achieved for weight (%TEM = 0.260-0.923) and length/height (%TEM = 0.434-0.855), and the poorest for MUAC by fieldworkers (%TEM = 2.592-3.199) and WC (%TEM = 2.353-2.945). Whole-sample ICC and R were excellent ( > 0.90) for all parameters except site leads' CC inter-rater reliability (ICC = 0.896, R = 0.889) and fieldworkers' inter-rater reliability for MUAC in children under two (ICC = 0.851, R = 0.881). Bland-Altman analysis revealed no significant bias except in fieldworkers' intra-rater reliability of length/height measurement in adolescents/adults ( + 0.220 (0.042, 0.400) cm). Reliability was higher for site leads vs. fieldworkers, for intra-rater vs. inter-rater assessment, and for weight and length/height vs. circumference measurements. CONCLUSION: NDIS-2022 site leads and fieldworkers displayed acceptable reliability in performing anthropometric measurements, highlighting the importance of intensive training and standardised measurement protocols. Ongoing reliability assessment during data collection is recommended.

Outcome measures in Angelman syndrome.

BACKGROUND: Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by severe intellectual disability, little to no expressive speech, visual and motor problems, emotional/behavioral challenges, and a tendency towards hyperphagia and weight gain. The characteristics of AS make it difficult to measure these children's functioning with standard clinical tests. Feasible outcome measures are needed to measure current functioning and change over time, in clinical practice and clinical trials. AIM: Our first aim is to assess the feasibility of several functional tests. We target domains of neurocognitive functioning and physical growth using the following measurement methods: eye-tracking, functional Near-Infrared Spectroscopy (fNIRS), indirect calorimetry, bio-impedance analysis (BIA), and BOD POD (air-displacement plethysmography). Our second aim is to explore the results of the above measures, in order to better understand the AS phenotype. METHODS: The study sample consisted of 28 children with AS aged 2-18 years. We defined an outcome measure as feasible when (1) at least 70% of participants successfully finished the measurement and (2) at least 60% of those participants had acceptable data quality. Adaptations to the test procedure and reasons for early termination were noted. Parents rated acceptability and importance and were invited to make recommendations to increase feasibility. The results of the measures were explored. RESULTS: Outcome measures obtained with eye-tracking and BOD POD met the definition of feasibility, while fNIRS, indirect calorimetry, and BIA did not. The most important reasons for early termination of measurements were showing signs of protest, inability to sit still and poor/no calibration (eye-tracking specific). Post-calibration was often applied to obtain valid eye-tracking results. Parents rated the BOD POD als most acceptable and fNIRS as least acceptable for their child. All outcome measures were rated to be important. Exploratory results indicated longer reaction times to high salient visual stimuli (eye-tracking) as well as high body fat percentage (BOD POD). CONCLUSIONS: Eye-tracking and BOD POD are feasible measurement methods for children with AS. Eye-tracking was successfully used to assess visual orienting functions in the current study and (with some practical adaptations) can potentially be used to assess other outcomes as well. BOD POD was successfully used to examine body composition. TRIAL REGISTRATION: Registered d.d. 23-04-2020 under number 'NL8550' in the Dutch Trial Register: https://onderzoekmetmensen.nl/en/trial/23075.

A regulatory polymorphism in PDCD1 is associated with susceptibility to systemic lupus erythematosus in humans.

Systemic lupus erythematosus (SLE, OMIM 152700) is a complex autoimmune disease that affects 0.05% of the Western population, predominantly women. A number of susceptibility loci for SLE have been suggested in different populations, but the nature of the susceptibility genes and mutations is yet to be identified. We previously reported a susceptibility locus (SLEB2) for Nordic multi-case families. Within this locus, the programmed cell death 1 gene (PDCD1, also called PD-1) was considered the strongest candidate for association with the disease. Here, we analyzed 2,510 individuals, including members of five independent sets of families as well as unrelated individuals affected with SLE, for single-nucleotide polymorphisms (SNPs) that we identified in PDCD1. We show that one intronic SNP in PDCD1 is associated with development of SLE in Europeans (found in 12% of affected individuals versus 5% of controls; P = 0.00001, r.r. (relative risk) = 2.6) and Mexicans (found in 7% of affected individuals versus 2% of controls; P = 0.0009, r.r. = 3.5). The associated allele of this SNP alters a binding site for the runt-related transcription factor 1 (RUNX1, also called AML1) located in an intronic enhancer, suggesting a mechanism through which it can contribute to the development of SLE in humans.

Molecular signature of methotrexate response among rheumatoid arthritis patients.

Background: Methotrexate (MTX) is the first line treatment for rheumatoid arthritis (RA), but failure of satisfying treatment response occurs in a significant proportion of patients. Here we present a longitudinal multi-omics study aimed at detecting molecular and cellular processes in peripheral blood associated with a successful methotrexate treatment of rheumatoid arthritis. Methods: Eighty newly diagnosed patients with RA underwent clinical assessment and donated blood before initiation of MTX, and 3 months into treatment. Flow cytometry was used to describe cell types and presence of activation markers in peripheral blood, the expression of 51 proteins was measured in serum or plasma, and RNA sequencing was performed in peripheral blood mononuclear cells (PBMC). Response to treatment after 3 months was determined using the EULAR response criteria. We assessed the changes in biological phenotypes during treatment, and whether these changes differed between responders and non-responders with regression analysis. By using measurements from baseline, we also tried to find biomarkers of future MTX response or, alternatively, to predict MTX response. Results: Among the MTX responders, (Good or Moderate according to EULAR treatment response classification, n = 60, 75%), we observed changes in 29 partly overlapping cell types proportions, levels of 13 proteins and expression of 38 genes during treatment. These changes were in most cases suppressions that were stronger among responders compared to non-responders. Within responders to treatment, we observed a suppression of FOXP3 gene expression, reduction of immunoglobulin gene expression and suppression of genes involved in cell proliferation. The proportion of many HLA-DR expressing T-cell populations were suppressed in all patients irrespective of clinical response, and the proportion of many IL21R+ T-cells were reduced exclusively in non-responders. Using only the baseline measurements we could not detect any biomarkers or prediction models that could predict response to MTX. Conclusion: We conclude that a deep molecular and cellular phenotyping of peripheral blood cells in RA patients treated with methotrexate can reveal previously not recognized differences between responders and non-responders during 3 months of treatment with MTX. This may contribute to the understanding of MTX mode of action and explain non-responsiveness to MTX therapy.

Peripheral blood cellular dynamics of rheumatoid arthritis treatment informs about efficacy of response to disease modifying drugs.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by systemic inflammation and is mediated by multiple immune cell types. In this work, we aimed to determine the relevance of changes in cell proportions in peripheral blood mononuclear cells (PBMCs) during the development of disease and following treatment. Samples from healthy blood donors, newly diagnosed RA patients, and established RA patients that had an inadequate response to MTX and were about to start tumor necrosis factor inhibitors (TNFi) treatment were collected before and after 3 months of treatment. We used in parallel a computational deconvolution approach based on RNA expression and flow cytometry to determine the relative cell-type frequencies. Cell-type frequencies from deconvolution of gene expression indicate that monocytes (both classical and non-classical) and CD4+ cells (Th1 and Th2) were increased in RA patients compared to controls, while NK cells and B cells (naïve and mature) were significantly decreased in RA patients. Treatment with MTX caused a decrease in B cells (memory and plasma cell), and a decrease in CD4 Th cells (Th1 and Th17), while treatment with TNFi resulted in a significant increase in the population of B cells. Characterization of the RNA expression patterns found that most of the differentially expressed genes in RA subjects after treatment can be explained by changes in cell frequencies (98% and 74% respectively for MTX and TNFi).

Predictive value of different body segments to estimate height in a South African adult hospital population.

BACKGROUND AND AIMS: Height measurement is a vital component for assessing nutritional risk, and calculating dietary requirements in a clinical setting where indirect calorimetry is not available. In many patients, height cannot be measured accurately, and equations based on body segments are relied on to predict height. This study aimed to evaluate if specific body segments are better associated with height than others in a South African public hospital setting. METHODS: A descriptive cross-sectional study was conducted in three public hospitals in Bloemfontein, South Africa, on patients, 20-50 years of age, and able to stand upright without assistance to be measured by stadiometer. Spearman correlations were assessed between stadiometer height and arm-span, demi-span, ulna length, knee height, tibia length, fibula length and foot length (measured by standardised techniques). Multiple regression analysis was performed to identify the segment that is most closely associated with stadiometer height in the study population. RESULTS: The sample included 141 participants (61.7% male, median age 38.8 years; IQR: 10.1 years). All measured body segment were statistically significantly correlated with stadiometer height, the strongest association being with knee height in both males (R2:0.77) and females (R2:0.86). Foot length and ulna length had the weakest correlation with stadiometer height in males and females, respectively. Multiple regression analysis identified knee height as having the best predictive value in determining stadiometer height. Overall, measurements of lower leg segments, particularly knee height, predicted measured height better than upper body segments. CONCLUSIONS: When choosing height-prediction equations in clinical settings in populations with a high prevalence of stunting, such as South Africa, the fact that stunting affects the growth of long bones in the lower body more than in the upper body, should be considered.

Musculoskeletal Conditions in Persons Living with HIV/AIDS: A Scoping Review.

OBJECTIVE: Globally 37.9 million people are living with HIV/AIDS, and with mortality rates declining, there is an increasing focus on comorbidities including musculoskeletal (MSK) disorders. Therefore, the aim of this scoping review was to generate and summarize an overview of the existing scientific literature dealing with MSK complaints in people living with HIV/AIDS (PLWHAs). METHODS: This scoping review followed the five-stage methodological framework proposed by Arksey and O'Malley. We searched PubMed, EMBASE, CINAHL, and the Cochrane Library from inception to June 1, 2020. Two reviewers independently reviewed the articles for eligibility. A data extraction form was used to chart information such as author, year of publication, data source, sample size, country of origin, ethnicity, age, gender, antiretroviral therapy, MSK condition prevalence, and anatomical location. RESULTS: The search identified 10 522 articles. Of these, 27 studies were included after full-text screening for data extraction. Studies were conducted in thirteen different countries with diverse data sources such as outpatient clinic files, hospital records, primary care clinic files, and AIDS Service Organization files. PLWHAs have a variety of MSK conditions. Most studies reported spinal pain such as lower back or neck pain, but pain in the extremities and osteoarthritis (OA) were also represented. However, the frequencies of pain at various anatomical sites were highly variable. CONCLUSION: There is a lack of knowledge regarding MSK conditions in PLWHAs. Future studies designed to specifically study MSK complaints and disabilities are needed to gain a better picture of the impact of these conditions in PLWHAs and to inform prevention and treatment strategies globally in this often-underserved population.

Accumulation and activation of natural killer cells in local intraperitoneal HIV-1/MuLV infection results in early control of virus infected cells.

Natural killer (NK) cells are important effectors in resistance to viral infections. The role of NK cells in the acute response to human immunodeficiency virus 1 (HIV-1) infected cells was investigated in a mouse model based on a HIV-1/murine leukemia virus (MuLV) pseudovirus. Splenocytes infected with HIV-1/MuLV were injected intraperitoneally and local immunologic responses and persistence of infected cells were investigated. In vivo depletion with an anti-NK1.1 antibody showed that NK cells are important in resistance to virus infected cells. Moreover, NK cell frequency in the peritoneal cavity increased in response to infected cells and these NK cells had a more mature phenotype, as determined by CD27 and Mac-1 expression. Interestingly, after injection of HIV-1/MuLV infected cells, but not MuLV infected cells, peritoneal NK cells had an increased cytotoxic activity. In conclusion, NK cells play a role in the early control of HIV-1/MuLV infected cells in vivo.

Fetal and adult multipotent mesenchymal stromal cells are killed by different pathways.

BACKGROUND AIMS: Multipotent mesenchymal stromal cells, also known as mesenchymal stem cells (MSC), can be isolated from adult and fetal tissues. Recently, there has been considerable interest in MSC because they have features favorable for transplantation, namely their multipotency and non-immunogenic properties. METHODS: We analyzed how human MSC derived from first-trimester fetal liver and adult bone marrow interact with naive and activated innate natural killer (NK) cells. NK cell function was studied by measuring killing of MSC, as well as degranulation (CD107a) induced by MSC. To assess the importance of NK cell killing, expression of surface epitopes was analyzed by flow cytometry on MSC before and after stimulation with interferon (IFN)γ. RESULTS: Fetal and adult MSC express several ligands to activating NK cell receptors as well as low levels of HLA class I, with large inter-individual variation. Naive peripheral blood NK cells did not lyse fetal or adult MSC, whereas interleukin (IL)2 activated allogeneic as well as autologous NK cells did. Pre-incubation of MSC with IFN-γ increased their levels of HLA class I, protecting them from NK cell recognition. Fetal and adult MSC were preferably killed via the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and Fas ligand (FasL) pathways, respectively. Blocking NKG2D reduced NK cell degranulation in both fetal and adult MSC. CONCLUSIONS: Fetal and adult MSC differ in their interactions with NK cells. Both fetal and adult MSC are susceptible to lysis by activated NK cells, which may have implications for the use of MSC in cell therapy.

Herpesvirus seropositivity in childhood associates with decreased monocyte-induced NK cell IFN-gamma production.

EBV infection is inversely associated with IgE sensitization in children, and this association is further enhanced by CMV coinfection. In mice, herpesvirus latency causes systemic innate activation and protection from bacterial coinfection, implying the importance of herpesviruses in skewing immune responses during latent infection. Early control of viral infections depends on IFN-gamma release by NK cells, which generally requires the presence of accessory cells. We investigated IFN-gamma production by NK cells in PBMCs from children seropositive (SP) for EBV alone, for both EBV and CMV, or seronegative for both viruses. The ability of classical (CD14(++)CD16(-)) and proinflammatory (CD14(+)CD16(+)) monocytes to induce autologous NK cell IFN-gamma was studied by coculture experiments with enriched CD3(-)CD56(+) cells. Transwell experiments were used to evaluate how monocytes interact with NK cells to induce IFN-gamma synthesis. SP children had a significantly reduced proportion of IFN-gamma(+) NK cells and cognate intracellular IFN-gamma levels, which was more pronounced in CMV-coinfected subjects. Also, resting PBMCs of SP children displayed lower proportions of proinflammatory monocytes. IFN-gamma production by NK cells was dependent on interactions with monocytes, with the proinflammatory subset inducing the highest IFN-gamma. Finally, SP children had markedly lower levels of plasma IFN-gamma, concurrent with in vitro findings. Herpesvirus infections could be one contributing factor for maturation toward balanced Th1-Th2 responses. Our data indicate that early infection by herpesviruses may affect NK cell and monocyte interactions and thereby also influence the development of allergies.

The interplay between Leishmania promastigotes and human Natural Killer cells in vitro leads to direct lysis of Leishmania by NK cells and modulation of NK cell activity by Leishmania promastigotes.

NK cells represent one of the first lines of defence in the immune reaction after invasion of Leishmania parasites. Depletion of mouse natural killer (NK) cells dramatically enhances susceptibility of normally resistant mice. In this study we evaluated the fate of NK cells and parasites after contact formation. The hydrophilic fluorescent dye CMFDA (chloro-methylfluorescin diacetate) that allows analysis of cytotoxicity in flow cytometry and microscopy was used. Furthermore, these findings were confirmed with scanning and transmission electron microscopy. Direct contact points were found between Leishmania promastigotes and naïve human NK cells. These contacts were associated with transfer of cytosol by membrane bridges and cytotoxicity of NK cells against Leishmania. However, in contrast to other target cells which allow repeated exocytosis of lytic granules, contact with Leishmania causes immediate destruction of NK cells in a non-apoptotic way. Our results give a reasonable explanation for ex vivo observations of reduced NK cell numbers and impaired NK response in patients with acute cutaneous leishmaniasis. Animal models have clearly shown that NK cells play a key role in the induction and direction of the immune response. Thus inhibition of NK cells at the onset of infection would be advantageous for the survival of the parasite.

Identifying novel B-cell targets for chronic inflammatory autoimmune disease by screening of chemical probes in a patient-derived cell assay.

B-cell secretion of autoantibodies drives autoimmune diseases, including systemic lupus erythematosus and idiopathic inflammatory myositis. Few therapies are presently available for treatment of these patients, often resulting in unsatisfactory effects and helping only some of the patients. We developed a screening assay for evaluation of novel targets suspending B-cell maturation into antibody secreting cells, which could contribute to future drug development. The assay was employed for testing 43 high quality chemical probes and compounds inhibiting under-explored protein targets, using primary cells from patients with autoimmune disease. Probes inhibiting bromodomain family proteins and histone methyl transferases demonstrated abrogation of B-cell functions to a degree comparable to a positive control, the JAK inhibitor tofacitinib. Inhibition of each target rendered a specific functional cell and potential disease modifying effect, indicating specific epigenetic protein targets as potential new intervention points for future drug discovery and development efforts.

NK cell activation by KIR-binding antibody 1-7F9 and response to HIV-infected autologous cells in viremic and controller HIV-infected patients.

Natural killer (NK) cells may be protective in HIV infection and are inhibited by killer cell immunoglobulin-like receptors (KIRs) interacting with MHC class I molecules, including HLA-C. Retention of HLA-C despite downregulation of other MHC class I molecules on HIV infected cells might protect infected cells from NK cell recognition in vitro. To assess the role of inhibitory HLA-C ligands in the capacity of NK cells to recognize autologous infected T cells, we measured NK cell degranulation in vitro in viremic patients, controllers with low viremia, and healthy donors. No difference in NK cell response to uninfected compared to HIV-1(IIIB) infected targets was observed. Activation of NK cells was regulated by KIRs, because NK cell degranulation was increased by 1-7F9, a human antibody that binds KIR2DL1/L2/L3 and KIR2DS1/S2, and this effect was most pronounced in KIR haplotype B individuals.