Monocytes In Children Research Articles

Nitric oxide production by monocytes in children with OSA and endothelial dysfunction

OSA (obstructive sleep apnoea) is associated with a higher risk for alterations in post-occlusive hyperaemia, an eNOS (endothelial NO synthase)-dependent endothelial response. However, since not all children manifest endothelial dysfunction, we hypothesized that differences in circulating monocyte subsets and NO production may underlie the vascular phenotype in paediatric OSA. Matched pre-pubertal children with OSA with abnormal endothelial function (OSAab) and with normal endothelial function (OSAn), and controls (CO) were recruited. Peripheral blood mononuclear cells were subtyped into CD14+ and CD16+ cells, and NO production was assessed using flow cytometry. Endothelial dysfunction was defined as Tmax (time to reach maximal reperfusion)>45 s by laser Doppler flowmetry. A total of 11 OSAab, 12 OSAn and 12 CO-matched children completed the study. The OSAab group had increased CD16+ and decreased CD14+ cell numbers. They also had increased CX3CR1 (CX3C chemokine receptor 1) expression in CD16+ monocytes (P<0.01). Furthermore, monocytes from the OSAab group exhibited overall reduced NO production (787±71 compared with 1226±229 and 1089±116 median fluorescence intensity in the OSAn group and CO children respectively; P<0.01). Significant bivariate associations emerged between NO production, monocyte subsets, CX3CR1 in CD16+ monocytes, the CD14+/CD16+ ratio and Tmax. Thus OSA in children is associated with increased numbers of pro-inflammatory monocytes and reduced NO production in circulating monocytes that are closely associated with endothelial function.

Sa1157 Normal Programmed Death-1 Expression in Peripheral Blood T-Cells, but Not Monocytes in Children With New Onset Crohn Disease

The incidence of VEO-IBD ranged from 0.8 to 3.3/100,000/year. The mean rate of increase was 4% per year (p=0.06; CI 0%, 8%). The rate of increase was significant in males (p= 0.04) compared to females (p=0.281). The incidence of UC increased strikingly from 0.6 to 2.3/100,000/year (CI 0.025, 0.164) at an average annual rate of 9%. Pancolonic UC increased 7-fold from 0.3 to 2.3/100,000/year (p=0.005). Using PUCAI scores, severe disease activity at presentation increased significantly from 0% to 36% (p=0.002). The incidence of CD increased at a slower rate of 0.02/100,000/year (CI -0.41, 0.079). Significantly more males (44%) than females (18%) had both upper and lower GI tract involvement (p=0.03). 76% of patients with CD had inflammatory disease behaviour while 24% had stricturing or penetrating disease. A total of 31% of children presented with perianal disease. At one year follow up 64% were in clinical remission, with 56% in steroid-free remission. Fifty two (35%) children commenced immunomodulators within 1 year of diagnosis while 6 (4%) underwent surgery. At maximum follow up (median 60 months), 24 (16%) children had commenced biologics, 76 (48%) immunomodulators and 20 (13%) had undergone surgery (12 UC; 8 CD). This is the first national population-based study describing the epidemiology and outcomes of VEO-IBD phenotypes. Boys hadmore extensive disease than girls. Substantial and sustained increases in the incidence and severity of UC in particular were observed. Prospective longitudinal studies are required to fully elucidate the factors underlying the aetiology and outcome of VEO-IBD.

Hypercholesterolemia and reduced HDL-C promote hematopoietic stem cell proliferation and monocytosis: Studies in mice and FH children

Previous studies have shown that mice with defects in cellular cholesterol efflux show hematopoietic stem cell (HSPC) and myeloid proliferation, contributing to atherogenesis. We hypothesized that the combination of hypercholesterolemia and defective cholesterol efflux would promote HSPC expansion and leukocytosis more prominently than either alone.We crossed Ldlr−/− with Apoa1−/− mice and found that compared to Ldlr−/− mice, Ldlr−/−/Apoa1+/− mice, with similar LDL-cholesterol levels but reduced HDL-cholesterol (HDL-C) levels, had expansion of HSPCs, monocytosis and neutrophilia. Ex vivo studies showed that HSPCs expressed high levels of Ldlr, Scarb1 (Srb1), and Lrp1 and were able to take up both native and oxidized LDL. Native LDL directly stimulated HSPC proliferation, while co-incubation with reconstituted HDL attenuated this effect. We also assessed the impact of HDL-C levels on monocytes in children with familial hypercholesterolemia (FH) (n = 49) and found that subjects with the lowest level of HDL-C, had increased monocyte counts compared to the mid and higher HDL-C levels. Overall, HDL-C was inversely correlated with the monocyte count. These data suggest that in mice, a balance of cholesterol uptake and efflux mechanisms may be one factor in driving HSPC proliferation and monocytosis. Higher monocyte counts in children with FH and low HDL-cholesterol suggest a similar pattern in humans.

CD64 expression on monocytes in children with Adenoid Hypertrophy

Adenoids with obstructive hypertrophy (AH) are considered to be one of the most ancient and common problems in Paediatrics. This study aimed at investigating the expression of CD 64 on monocytes in children who had to undergo adenoidectomy. Therefore, 66 children (24 females, 42 males, mean age 4.9 years), affected by AH and requiring adenoidectomy (54%) or adeno-tonsillectomy (46%) were consecutively enrolled into the study. Moreover, 30 healthy children (11 females, 19 males, mean age 11.2 years) were enrolled in this study as controls. CD64 expression on monocytes was measured. Children with severe AH had higher CD64 values than children with AH size 3 and controls. This preliminary study shows that CD64 expression on monocytes may be associated with severe AH, suggesting a more intense immune activation in these subjects.

Intravenous immunoglobulin does not increase FcγRIIB expression levels on monocytes in children with immune thrombocytopenia

Intravenous immunoglobulin (IVIG) produces a rapid and prolonged increase in the platelet counts of children with immune thrombocytopenia (ITP). The mechanism of IVIG efficacy in a murine model of ITP has been reported to operate through an IVIG-mediated increase in the expression of the inhibitory Fc receptor FcγRIIB(CD32B) on splenic macrophages. This investigation examined whether IVIG administration results in a similar increase in FcγRIIB expression on peripheral blood CD14(+) monocytes in 20 children with ITP. FcγRIIB expression on peripheral blood monocytes was measured by flow cytometry in ITP patients, before and after IVIG therapy, as well as in control subjects. Peripheral blood monocytes were labelled with fluorescent-specific antibodies. There were no significant differences in the absolute number of [corrected] CD14(+) CD32B(+) monocytes, and [corrected] the percentages of CD14(+) CD32B(+) cells in mononuclear cells or monocytes. [corrected]. We suggest that IVIG does not increase FcγRIIB expression in peripheral blood monocytes in children with ITP.

Expression of Adhesion and Activation Molecules on Circulating Monocytes in Children with Helicobacter pylori Infection

The aim of this study was to assess the cell surface expression of adhesion (CD11a, CD11b, CD11c, CD18, CD54, and CD58) and activation (CD14, HLA-DR, and CD16) molecules on the circulating monocytes in Helicobacter pylori (H. pylori)-infected and noninfected children with gastritis, with the goal of comparing the results with those obtained from the controls. Ninety-four children were studied: 47 of them with H. pylori infection (of those 25 children after the failure of eradication therapy) and 26 children with gastritis where H. pylori infection was excluded, as well as 21 controls. H. pylori infection status was assessed based on [¹³C] urea breath test, rapid urease test, and histology. Analysis of the monocyte surface molecule expression was carried out by flow cytometry. H. pylori-infected children and children who experienced a failure of the eradication therapy differed significantly in the expression of adhesion and activation molecule on circulating monocytes. A decrease, both in the proportion of CD11c- and CD14-bearing monocytes, and the expression of CD11c and CD14 molecules on circulating monocytes, was found in children in whom the eradication therapy failed (p < .05). Low expression of CD11b (p = .04) and CD18 (p = .02) integrins on monocytes was also observed. Additionally, the percentage of HLA-DR-bearing monocytes was decreased (p = .04), while the CD16 density receptor was increased (p = .02). Compared with the controls, low percentage of CD16-positive monocytes was noted in noninfected children with gastritis (p = .01). H. pylori eradication therapy in children causes inhibition of inflammatory response via a reduction in CD11b, CD11c, and CD18 beta2 integrin monocyte expression.

Tissue factor-positive monocytes in children with sickle cell disease: correlation with biomarkers of haemolysis.

Tissue Factor (TF) initiates thrombin generation, and whole blood TF (WBTF) is elevated in sickle cell disease (SCD). We sought to identify the presence of TF-positive monocytes in SCD and their relationship with the other coagulation markers including WBTF, microparticle-associated TF, thrombin-antithrombin (TAT) complexes and D-dimer. Whether major SCD-related pathobiological processes, including haemolysis, inflammation and endothelial activation, contribute to the coagulation abnormalities was also studied. The cohort comprised children with SCD (18 HbSS, 12 HbSC, mean age 3·6 years). We demonstrated elevated levels of TF-positive monocytes in HbSS, which correlated with WBTF, TAT and D-dimer (P = 0·02 to P = 0·0003). While TF-positive monocytes, WBTF, TAT and D-dimer correlated with several biomarkers of haemolysis, inflammation and endothelial activation in univariate analyses, in multiple regression models the haemolytic markers (reticulocytes and lactate dehydrogenase) contributed exclusively to the association with all four coagulant markers evaluated. The demonstration that haemolysis is the predominant operative pathology in the associated perturbations of coagulation in HbSS at a young age provides additional evidence for the early use of therapeutic agents, such as hydroxycarbamide to reduce the haemolytic component of this disease.

Immunological characterization and transcription profiling of peripheral blood (PB) monocytes in children with autism spectrum disorders (ASD) and specific polysaccharide antibody deficiency (SPAD): case study

IntroductionThere exists a small subset of children with autism spectrum disorders (ASD) characterized by fluctuating behavioral symptoms and cognitive skills following immune insults. Some of these children also exhibit specific polysaccharide antibody deficiency (SPAD), resulting in frequent infection caused by encapsulated organisms, and they often require supplemental intravenous immunoglobulin (IVIG) (ASD/SPAD). This study assessed whether these ASD/SPAD children have distinct immunological findings in comparison with ASD/non-SPAD or non-ASD/SPAD children.Case descriptionWe describe 8 ASD/SPAD children with worsening behavioral symptoms/cognitive skills that are triggered by immune insults. These ASD/SPAD children exhibited delayed type food allergy (5/8), treatment-resistant seizure disorders (4/8), and chronic gastrointestinal (GI) symptoms (5/8) at high frequencies. Control subjects included ASD children without SPAD (N = 39), normal controls (N = 37), and non-ASD children with SPAD (N = 12).Discussion and EvaluationWe assessed their innate and adaptive immune responses, by measuring the production of pro-inflammatory and counter-regulatory cytokines by peripheral blood mononuclear cells (PBMCs) in responses to agonists of toll like receptors (TLR), stimuli of innate immunity, and T cell stimulants. Transcription profiling of PB monocytes was also assessed. ASD/SPAD PBMCs produced less proinflammatory cytokines with agonists of TLR7/8 (IL-6, IL-23), TLR2/6 (IL-6), TLR4 (IL-12p40), and without stimuli (IL-1ß, IL-6, and TNF-α) than normal controls. In addition, cytokine production of ASD/SPAD PBMCs in response to T cell mitogens (IFN-γ, IL-17, and IL-12p40) and candida antigen (Ag) (IL-10, IL-12p40) were less than normal controls. ASD/non-SPAD PBMDs revealed similar results as normal controls, while non-ASD/SPAD PBMCs revealed lower production of IL-6, IL-10 and IL-23 with a TLR4 agonist. Only common features observed between ASD/SPAD and non-ASD/SPAD children is lower IL-10 production in the absence of stimuli. Transcription profiling of PB monocytes revealed over a 2-fold up (830 and 1250) and down (653 and 1235) regulation of genes in ASD/SPAD children, as compared to normal (N = 26) and ASD/non-SPAD (N = 29) controls, respectively. Enriched gene expression of TGFBR (p < 0.005), Notch (p < 0.01), and EGFR1 (p < 0.02) pathways was found in the ASD/SPAD monocytes as compared to ASD/non-SPAD controls.ConclusionsThe Immunological findings in the ASD/SPAD children who exhibit fluctuating behavioral symptoms and cognitive skills cannot be solely attributed to SPAD. Instead, these findings may be more specific for ASD/SPAD children with the above-described clinical characteristics, indicating a possible role of these immune abnormalities in their neuropsychiatric symptoms.

Tissue factor-positive monocytes in children with sickle cell disease: correlation with biomarkers of haemolysis

Tissue factor-positive monocytes in children with sickle cell disease: correlation with biomarkers of haemolysis

Impact of imatinib on in vitro osteoclastogenic differentiation of monocytes in children and adolescents with chronic myeloid leukemia.

Background: The tyrosine kinase (TK) inhibitor imatinib (IMA) has dramatically improved the treatment results of chronic myeloid leukemia (CML) via blockade of the constitutively activated TK bcr-abl. However, IMA also inhibits other TKs like PDGFR-alpha and -beta and c-FMS, thus exerting a negative impact on the differentiation and proliferation of osteoclasts and osteoblasts. As a net result, disturbances of bone metabolism and remodeling have been described in animal models and in adult patients (pts) in vivo.

T.51. Decreased Central Memory T Cells and Increased Monocytes in Children with Invasive Staphylococcus Aureus

T.51. Decreased Central Memory T Cells and Increased Monocytes in Children with Invasive Staphylococcus Aureus

Host Inactivation of Bacterial Lipopolysaccharide Prevents Prolonged Tolerance Following Gram-Negative Bacterial Infection

A transient state of tolerance to microbial molecules accompanies many infectious diseases. Such tolerance is thought to minimize inflammation-induced injury, but it may also alter host defenses. Here we report that recovery from the tolerant state induced by Gram-negative bacteria is greatly delayed in mice that lack acyloxyacyl hydrolase (AOAH), a lipase that partially deacylates the bacterial cell-wall lipopolysaccharide (LPS). Whereas wild-type mice regained normal responsiveness within 14 days after they received an intraperitoneal injection of LPS or Gram-negative bacteria, AOAH-deficient mice had greatly reduced proinflammatory responses to a second LPS injection for at least 3 weeks. In contrast, LPS-primed Aoah- knockout mice maintained an anti-inflammatory response, evident from their plasma levels of interleukin-10 (IL-10). LPS-primed Aoah-knockout mice experiencing prolonged tolerance were highly susceptible to virulent E. coli challenge. Inactivating LPS, an immunostimulatory microbial molecule, is thus important for restoring effective host defenses following Gram-negative bacterial infection in animals.

FREQUENCIES OF PERIPHERAL BLOOD MYELOID CELLS IN HEALTHY KENYAN CHILDREN WITH α+ THALASSEMIA AND THE SICKLE CELL TRAIT

The high frequencies of both alpha+ thalassemia and the sickle cell trait (hemoglobin AS [HbAS]) found in many tropical populations are thought to reflect selection pressure from Plasmodium falciparum malaria. For HbAS, but not for alpha+ thalassemia, protection appears to be mediated by the enhanced phagocytic clearance of ring-infected erythrocytes. We have investigated the genotype-specific distributions of peripheral blood leukocyte populations in two groups of children living on the coast of Kenya: a group of healthy P. falciparum parasite-negative children sampled at cross-sectional survey during a period of low malaria transmission, and a group of children attending the hospital with acute malaria. We report distinctive distributions of peripheral blood myeloid dendritic cells and monocytes in children with alpha+ thalassemia and HbAS during healthy periods and disease, and suggest ways in which these might relate to the mechanisms of protection afforded by these conditions.

Differential expression of function-related antigens on blood monocytes in children with hemolytic uremic syndrome

Monocytes (Mo) mediate central functions in inflammation and immunity. Different subpopulations of Mo with distinct phenotype and functional properties have been described. Here, we investigate the phenotype and function of peripheral Mo from children with hemolytic uremic syndrome (HUS). For this purpose, blood samples from patients in the acute period of HUS (HUS AP) were obtained on admission before dialysis and/or transfusion. The Mo phenotypic characterization was performed on whole blood by flow cytometry, and markers associated to biological functions were selected: CD14 accounting for lipopolysaccharide (LPS) responsiveness, CD11b for adhesion, Fc receptor for immunoglobulin G type I (FcgammaRI)/CD64 for phagocytosis and cytotoxicity, and human leukocyte antigen (HLA)-DR for antigen presentation. Some of these functions were also determined. Moreover, the percentage of CD14+ CD16+ Mo was evaluated. We found that the entire HUS AP Mo population exhibited reduced CD14, CD64, and CD11b expression and decreased LPS-induced tumor necrosis factor production and Fcgamma-dependent cytotoxicity. HUS AP showed an increased percentage of CD14+ CD16+ Mo with higher CD16 and lower CD14 levels compared with the same subset from healthy children. Moreover, the CD14++ CD16- Mo subpopulation of HUS AP had a decreased HLA-DR expression, which correlated with severity. In conclusion, the Mo population from HUS AP patients presents phenotypic and functional alterations. The contribution to the pathogenesis and the possible scenarios that led to these changes are discussed.

Monocytes in children with leukemias and lymphomas -- down-regulation of HLA and costimulatory molecules.

The aim of the study was to evaluate the function of monocytes in children with leukemias and lymphomas based on the expression of critical costimulatory, activatory and adhesion molecules (CD80, CD86, HLA-DR and CD54 = ICAM-1), estimated with tricolor flow cytometry. In comparison to the control group we found a lower percentage of monocytes with costimulatory molecules (CD80 before and CD86 after lipopolysaccharide stimulation) at the time of diagnosis and of monocytes with HLA-DR molecules after remission induction. We also noted a lower percentage of monocytes with HLA-DR expression in the group with severe or therapy resistant infections. The results of our investigation suggest some defect in costimulation and antigen presentation in lymphoproliferative diseases in children.

Detection of circulating lipopolysaccharide-bound monocytes in children with gram-negative sepsis.

The possibility that gram-negative sepsis can be diagnosed by detection of lipopolysaccharide (LPS) bound on the surface of monocytes in the circulation of patients with gram-negative sepsis was investigated. Peripheral monocytes were analyzed by flow cytometer and an anti-LPS monoclonal antibody in 3 groups: children with gram-negative sepsis, children with gram-positive sepsis, and healthy children. LPS-bound monocytes were found in all patients with gram-negative sepsis but not in children with gram-positive sepsis or in healthy children. Therefore, the flow cytometry method developed for this study may be a novel method for diagnosing gram-negative sepsis.

Phagocytic function of monocytes in children with human immunodeficiency virus type 1 infection.

We investigated the phagocytic function of monocytes in 7- to 10-year-old children horizontally infected with human immunodeficiency virus type 1 (HIV-1) in comparison to that in healthy sex- and age-matched controls. CR3-mediated phagocytosis was increased in patients with HIV-associated pulmonary tuberculosis, independently of CD4 counts and p24 antigenemia.

Increased Interleukin‐1 (IL‐1) Production from LPS‐Stimulated Peripheral Blood Monocytes in Children with Febrile Convulsions

Peripheral blood mononuclear cells (MNC) from 27 children with a febrile convulsion were tested for production of interleukin-1 (IL-1) in culture. MNC stimulated with lipopolysaccharide (LPS) showed a significantly increased production of IL-1 when compared to MNC from children without convulsions but with bacterial infections (p less than 0.001), viral infections (p less than 0.005) or no infection (p less than 0.005). Children who had experienced a febrile convulsion were retested several months later; this time the IL-1 production from LPS-stimulated MNC was not different from controls. These results demonstrate that MNC at the time of febrile convulsions have increased sensitivity to LPS and possibly to other IL-1 inducers; the resulting enhanced IL-1 response from sensitized MNC may have a role in the pathogenesis of febrile convulsions.

AGE DEPENDENT MUCOSAL INFLAMMATORY CELL RESPONSE IN COELIAC DISEASE

We have studied the influence of age on the alterations of mucosal T-cells, immunoglobul in containing cells and monocytes caused by exposure to gliadin in coeliac disease (CD).Following groups were investigated: Patients with active CD aged 8-12 months (n=7), 24-55 months (n=9) and 9-54 years (n=4). Controls aged 10-29 months (n=7) and 21-76 years (n=5). Subsets of inflammatory cells were counted on frozen sections and on paraffin embeded material stained with commercial monoclonal and polyclonal antibodies.A significant increase of the number of intraepithelial lymphocytes (IEL) and lamina propria lymphocytes (LPL) was found in all age groups with active CD, as reported earlier. The ratio CD4+LPL to CDB+LPL was lower during infancy (1.0) than in older patients (1.3) due to a lower number of CD4+LPL in the infants. The same pattern was observed in the controls, with the ratio 1.1 in children and 1.6 in adults. The number of immunoglobulin containing cells (IgG, IgA, IgM) in tha lamina propria was lower in the young controls than in the adult ones. In active CD there was a marked increase of IgA containing cells in all age groups. The increase of IgM containing cells was more pronounced in the younger patients than in the older, while a minor increase of IgG containing cells occurred in all the patients. There was also a more prominent increase of monocytes in children than in adult patients. The observed differences may explain the age variation of the clinical course of coeliac disease.

Insulin binding to circulating monocytes in children with insulin-dependent and non-insulin-dependent diabetes mellitus

This study describes insulin binding to circulating monocytes in 24 children with insulin-dependent diabetes mellitus (IDDM), five children with non-insulin-dependent diabetes mellitus (NIDDM), and 10 healthy and 12 obese control children. Insulin binding to monocytes was greatly increased in untreated IDDM children with obvious ketoacidosis (5.51 +/- 3.49 vs. 1.91 +/- 0.47 pg/10(6) cells, P less than 0.01), whereas it was decreased in those without obvious ketoacidosis (1.39 +/- 0.30 vs. 1.91 +/- 0.47 pg/10(6) cells, P less than 0.01). Insulin treatment restored insulin binding almost to the level of control children in both ketoacidotic and non-ketoacidotic patients. Insulin binding to monocytes was markedly decreased in untreated NIDDM children with hyperinsulinemia compared with healthy control children (0.73 +/- 0.27 vs. 1.91 +/- 0.47 pg/10(6) cells, P less than 0.01) or obese control children (0.73 +/- 0.27 vs. 1.33 +/- 0.35 pg/10(6) cells, P less than 0.01). These data indicate that changes in insulin secretion and metabolic conditions might be involved in the fluctuation of the number of insulin receptors in IDDM children as well as in NIDDM children.