Age-related changes in blood lymphocyte subsets of Saudi Arabian healthy children

Absolute CD4 count and percentage values among Libyan patients with HIV by single-platform flow cytometry

BACKGROUND

Single-platform flow cytometry technology together with CD45-gating is becoming the method of choice for absolute CD4 T cell enumeration. Immunological assessment of HIV patients by monitoring CD4 can provide valuable information on antiviral treatment response and disease progression.

METHODS

A total of 97 HIV-positive individuals were recruited from 2 hospitals in Tripoli, Libya, and 14 healthy blood donors. The HIV-infected individuals were classified by CD4+ count into HIV-positive (>200 cells/µL) or AIDS (≤200 cells/µL) groups. CD4+ and CD8+ cell counts were determined and compared among the groups and with similar published data.

RESULTS

The mean ± SD CD4+ cell counts were 1106 ± 442.8 cells/µL in healthy individuals, 460 ± 219.7 cells/µL in the HIV-positive group, and 78 ± 64.3 cells/µL in the AIDS group. The mean ± SD CD4+/CD8+ ratio was 1.6 ± 0.58, 0.4 ± 0.22, and 0.1 ± 0.1, respectively. CD4+ counts in Libyan healthy adults might be higher than those reported in several studies in other regions, whereas CD4+ counts in Libyan AIDS patients seem lower.

CONCLUSION

Reference values for T lymphocyte counts in Libyan healthy individuals should be investigated more extensively, and the reasons why Libyan AIDS patients seem to have such lower CD4+ counts should be examined.

Can Neutrophil/Lymphocyte Ratio Assess Inflammatory Bowel Disease Activity and Severity in Children?

BACKGROUND

Laboratory markers such as white blood cells, C reactive protein, and erythrocyte sedimentation rate can aid in assessing the activity of inflammatory bowel disease but lacks sensitivity and specificity. Fecal calprotectin has higher sensitivity and specificity but it is expensive. Endoscopy is an invasive, inconvenient procedure having complications. No studies are done concerning the neutrophil/lymphocyte ratio in inflammatory bowel disease in pediatrics. The aim of this study was to assess the neutrophil/lymphocyte ratio as a laboratory marker of inflammatory bowel disease activity and severity in children.

METHODS

This is a prospective study. The study included all patients from 2 months up to 16 years who were confirmed to have inflammatory bowel disease endoscopically and histopathologically. Clinical activity score and Mayo endoscopic subscore were recorded. Laboratory investigations including white blood cells, C reactive protein, erythrocyte sedimentation rate, and fecal calprotectin were done on all patients. The neutrophil/lymphocyte ratio was calculated and correlated with different activity markers.

RESULTS

We included 50 inflammatory bowel disease patients. The mean neutrophil/lymphocyte ratio in ulcerative colitis was 1.76 ± 0.36, Crohn's disease was 1.50 ± 0.41, and it was 1.47 ± 0.14 in indeterminate colitis. Neutrophil/lymphocyte ratio was significantly correlated to erythrocyte sedimentation rate, C reactive protein, fecal calprotectin, clinical activity score, and Mayo endoscopic subscore.

CONCLUSION

Neutrophil/lymphocyte ratio can be used as an activity and severity marker in children with inflammatory bowel disease.

Age-stratified pediatric reference values of lymphocytes in the Moroccan population

The number of circulating lymphocytes is altered in a number of diseases including either increase (lymphocytosis) or decrease (lymphocytopenia). Therefore, the assessment of total blood lymphocyte numbers and the relative distribution of lymphocyte subsets is a critical front-line tool in the clinical diagnosis of a number of diseases, including pediatric diseases and disorders. However, the interpretation of this data requires comparison of patient's results to reliable reference values. Blood lymphocyte subpopulation numbers are also subject to genetic polymorphisms, immunogenic and environmental factors and vary greatly between populations. While the best practice reference values should be established within local representative populations of healthy subjects, to date, Caucasian reference values are used in Morocco due to the absence of indigenous reference values. Potential differences in blood lymphocyte subpopulation reference values between Caucasian versus Moroccan populations can adversely affect the diagnosis of pediatric and childhood diseases and disorders such as primary immunodeficiency (PID) in Morocco.

OBJECTIVE

The aim of this study was to establish the age-stratified normal reference values of blood lymphocyte subsets for the pediatric Moroccan population.

METHODS

We measured the concentration of lymphocyte subpopulations by flow cytometry from 83 Moroccan healthy subjects stratified into 5 age groups of 0-1, 1-2, 2-6, 6-12 and > 12-18 (adult).

RESULTS

The absolute and relative amounts of the main lymphocyte subsets of T-cells, B cells and Natural Killer (NK) cells were measured and compared to previously described reference values from Cameroonian, Turkish, American and Dutch populations. Additionally, we also observed an age-related decline in the absolute population sizes of lymphocyte subsets within our study group. Relative proportions of CD3+CD4+ helper T lymphocytes decreased with increasing age and by 12 years-adult age, both proportions of CD3+CD4+ helper T lymphocytes and CD3+CD8+ cytotoxic T lymphocytes, as well as CD3-CD19+ B lymphocytes were also decreased. Finally, we compared the median values and range of our Moroccan study group with that of published results from Cameroon, Turkey, USA and Netherlands and observed significant differences in median and mean values of absolute number and relative proportions of lymphocyte subsets especially at 0-1 years and 1-2 years age groups. Above age 12 years, the Moroccan values were lower. For NK cells, the Moroccan values are also lower.

CONCLUSIONS

The results of this study have a significant impact in improving the threshold values of the references intervals routinely used in the diagnosis of paediatric diseases such as PIDs or mother-to-child transmitted HIV within the Moroccan population.

Variation of B cell subsets with age in healthy Malawians

Although a number of previous studies have shown that different lymphocyte subsets, including B cells, vary with age, how different B cell subsets vary with age in Malawian population has not been shown before. We recruited Malawian participants of different ages and analyzed their venous blood samples for different B cell subsets. We found that both percentage and absolute counts of B cells varied with age peaking in the 7 to 12 months age group. Proportion of naïve B cells was highest in neonates and decreased with age whereas the percentage of memory B cells was lowest in neonates and increased with age. When we zeroed in on the age band within which the proportion of B cells was highest, both classical and activated memory B cells increased with age and the naïve followed the opposite trend. These results provide additional knowledge in our understanding of the dynamics of B cell subsets in individuals of a specific ethnicity as they age.

Age-related changes in lymphocyte subpopulations in healthy Thai children

BACKGROUND

Ethnicity and environmental factors can influence the percentages of lymphocyte subpopulations. This study aimed to assess the percentages of lymphocyte subpopulations according to age in Thai children.

METHODS

This was a cross-sectional study. The percentages of lymphocyte subpopulations were measured in umbilical cord blood and peripheral blood of healthy Thai children aged 1 month-15 years. The participants were stratified into five age groups: (a) cord blood; (b) age < 2 years; (c) age 2-5 years; (d) age 5-10 years; and (e) age 10-15 years.

RESULTS

Of 182 total samples, 32, 39, 41, 28, and 42 were from cord blood, children aged <2 years, children aged 2-5 years, children aged 5-10 years, and children aged 10-15 years, respectively. The percentages of most lymphocyte subpopulations including CD8 + T cells, CD19 + cells, γδ T cells, double-negative T cells, NK cells, and NK T cells increased significantly with age. Only the CD4+ T-cell percentage decreased in older children. Moderate correlations were observed between age and the percentages of CD4+ T cells, γδ T cells, NK cells, NK T cells, and double-negative T cells. Weak correlations were observed between age and the percentages of CD8+ T cells and CD19+ cells.

CONCLUSION

Our study demonstrated age-related changes in the percentages of lymphocyte subpopulations in Thai children, which differed from those described in other countries. Therefore, the establishment of age-specific reference values for lymphocyte subsets in each country is recommended.

Interleukin-1 Receptor Antagonist Is Associated With Pediatric Acute Respiratory Distress Syndrome and Worse Outcomes in Children With Acute Respiratory Failure

OBJECTIVES

To test whether plasma interleukin-1 receptor antagonist or variants within the gene encoding for interleukin-1ra (IL1RN), or proteins involved in regulating interleukin-1β levels or interleukin-1β response, are associated with pediatric acute respiratory distress syndrome or outcomes in mechanically ventilated children with parenchymal lung disease.

DESIGN

Prospective cohort study.

SETTING

Twenty-two PICUs participating in the multisite clinical trial, Randomized Evaluation of Sedation Titration for Respiratory Failure (U01 HL086622).

SUBJECTS

Children 2 weeks to 17 years old treated with invasive mechanical ventilation for acute airways and/or parenchymal lung disease.

MEASUREMENTS AND MAIN RESULTS

Three-hundred seventy-eight of 549 patients had pediatric acute respiratory distress syndrome; DNA and plasma were obtained from 523 of 549 and 480 of 549 patients, respectively. Plasma interleukin-1ra was highest on the day of intubation (day 0) and decreased over the subsequent 3 days (p < 0.0001). Interleukin-1ra level was higher in patients with pediatric acute respiratory distress syndrome than those without pediatric acute respiratory distress syndrome (p < 0.0001). Multivariable regression analysis of data across all days demonstrated a significant association of interleukin-1ra (odds ratio, 1.30; 95% CI, 1.10-1.52; p = 0.002) and day (p < 0.05) with pediatric acute respiratory distress syndrome, independent of age and Pediatric Risk of Mortality-III score. Analysis on individual days indicated that plasma interleukin-1ra levels were associated with pediatric acute respiratory distress syndrome on days 0 and 2, independent of age and Pediatric Risk of Mortality-III score (p = 0.04 and 0.003, respectively), however did not quite reach significance on days 1 and 3 (p = 0.06 and 0.07, respectively). Interleukin-1ra was independently associated with mortality on day 1 (p = 0.02). Interleukin-1ra also correlated with length of mechanical ventilation, measures of oxygenation, and PICU length of stay. No genetic variants were associated with pediatric acute respiratory distress syndrome.

CONCLUSIONS

Plasma interleukin-1ra is associated with pediatric acute respiratory distress syndrome, PICU length of stay, length of mechanical ventilation, and mortality in children with acute respiratory failure requiring mechanical ventilation.

Age-dependent cellular reactions of the human immune system of humanized NOD scid gamma mice on LPS stimulus

Despite sepsis being a life-threatening disease, targeted drugs that improve the therapy of affected patients are still lacking. Infants and adults differ in the maturity level of their immune system and this results in distinct reactions to Gram-negative bacteria. To study reactions of human immune cells in vivo, we used NOD scid gamma mice transplanted with human CD34⁺ stem cells to engraft a functional human immune system. Human cells undergo differentiation and maturation in these mice after transplantation and, accordingly, animals were divided into two groups: 8-13 wk and 15-22 wk after transplantation. Endotoxemia was induced by injecting LPS. Six h later, mice were euthanized. In both groups, LPS stimulation induced a decrease of CD14⁺ monocytes in peripheral blood, an up-regulation of activation markers on different cell subsets such as myeloid dendritic cells, and a release of the human cytokines TNF-α, IL-6 and IL-10. However, significant differences were detected with regard to the amounts of released cytokines, and 8-13-wk-old mice produced more IL-6, while PTX3 was mainly released by 15-22-wk-old animals. Thus, here we provide a potential model for preclinical research of sepsis in infants and adults.

A Comparative Study of SMN Protein and mRNA in Blood and Fibroblasts in Patients with Spinal Muscular Atrophy and Healthy Controls

Background

Clinical trials to test safety and efficacy of drugs for patients with spinal muscular atrophy (SMA) are currently underway. Biomarkers that document treatment-induced effects are needed because disease progression in childhood forms of SMA is slow and clinical outcome measures may lack sensitivity to detect meaningful changes in motor function in the period of 1–2 years of follow-up during randomized clinical trials.

Objective

To determine and compare SMN protein and mRNA levels in two cell types (i.e. PBMCs and skin-derived fibroblasts) from patients with SMA types 1–4 and healthy controls in relation to clinical characteristics and SMN2 copy numbers.

Materials and methods

We determined SMN1, SMN2-full length (SMN2-FL), SMN2-delta7 (SMN2-Δ7), GAPDH and 18S mRNA levels and SMN protein levels in blood and fibroblasts from a total of 150 patients with SMA and 293 healthy controls using qPCR and ELISA. We analyzed the association with clinical characteristics including disease severity and duration, and SMN2 copy number.

Results

SMN protein levels in PBMCs and fibroblasts were higher in controls than in patients with SMA (p<0.01). Stratification for SMA type did not show differences in SMN protein (p>0.1) or mRNA levels (p>0.05) in either cell type. SMN2 copy number was associated with SMN protein levels in fibroblasts (p = 0.01), but not in PBMCs (p = 0.06). Protein levels in PBMCs declined with age in patients (p<0.01) and controls (p<0.01)(power 1-beta = 0.7). Ratios of SMN2-Δ7/SMN2-FL showed a broad range, primarily explained by the variation in SMN2-Δ7 levels, even in patients with a comparable SMN2 copy number. Levels of SMN2 mRNA did not correlate with SMN2 copy number, SMA type or age in blood (p = 0.7) or fibroblasts (p = 0.09). Paired analysis between blood and fibroblasts did not show a correlation between the two different tissues with respect to the SMN protein or mRNA levels.

Conclusions

SMN protein levels differ considerably between tissues and activity is age dependent in patients and controls. SMN protein levels in fibroblasts correlate with SMN2 copy number and have potential as a biomarker for disease severity.

Clinical presentation of hemophagocytic lymphohistiocytosis in adults is less typical than in children

OBJECTIVE

Hemophagocytic lymphohistiocytosis in adults is largely underdiagnosed. To improve the rate and accuracy of diagnosis in adults, the clinical and laboratory characteristics of hemophagocytic lymphohistiocytosis were analyzed in and compared between adults and children in a Chinese cohort.

METHOD

Data from 50 hemophagocytic lymphohistiocytosis patients, including 34 adults and 16 children who fulfilled the 2004 hemophagocytic lymphohistiocytosis diagnostic criteria, were collected and analyzed.

RESULTS

1. Etiological factors: The proportion of Epstein-Barr virus infection was lower in adults compared with children, whereas fungal infection and natural killer/T cell lymphoma were more frequent in adults (P<0.05). 2. Clinical manifestations and laboratory findings: Over 90% of adults and pediatric patients presented with fever, thrombocytopenia and high serum ferritin levels. However, in adults, the proportions of hepatomegaly, splenomegaly and jaundice were much lower (P<0.01) than in children, and serous cavity effusion was more frequent in adult patients (P<0.05). More children had hemoglobin <90 g/L, total bilirubin >19 mmol/L and lactate dehydrogenase >500 U/L compared with adults (P<0.05). 3. The time interval from the onset of symptoms to clinical diagnosis was significantly shorter in pediatric patients than in adults (P<0.05).

CONCLUSIONS

Certain clinical features were different between the two groups. The less characteristic clinical presentation of hemophagocytic lymphohistiocytosis in adults may make the disease more difficult to diagnose. Our findings suggest that hemophagocytic lymphohistiocytosis should be considered when an adult patient presents with the above-mentioned symptoms.

Infants' Peripheral Blood Lymphocyte Composition Reflects Both Maternal and Post-Natal Infection with Plasmodium falciparum

Maternal parasitoses modulate fetal immune development, manifesting as altered cellular immunological activity in cord blood that may be linked to enhanced susceptibility to infections in early life. Plasmodium falciparum typifies such infections, with distinct placental infection-related changes in cord blood exemplified by expanded populations of parasite antigen-specific regulatory T cells. Here we addressed whether such early-onset cellular immunological alterations persist through infancy. Specifically, in order to assess the potential impacts of P. falciparum infections either during pregnancy or during infancy, we quantified lymphocyte subsets in cord blood and in infants' peripheral blood during the first year of life. The principal age-related changes observed, independent of infection status, concerned decreases in the frequencies of CD4⁺, NK^dim and NKT cells, whilst CD8⁺, Treg and Teff cells' frequencies increased from birth to 12 months of age. P. falciparum infections present at delivery, but not those earlier in gestation, were associated with increased frequencies of Treg and CD8⁺ T cells but fewer CD4⁺ and NKT cells during infancy, thus accentuating the observed age-related patterns. Overall, P. falciparum infections arising during infancy were associated with a reversal of the trends associated with maternal infection i.e. with more CD4⁺ cells, with fewer Treg and CD8⁺ cells. We conclude that maternal P. falciparum infection at delivery has significant and, in some cases, year-long effects on the composition of infants' peripheral blood lymphocyte populations. Those effects are superimposed on separate and independent age- as well as infant infection-related alterations that, respectively, either match or run counter to them.

Pathobiology of acute respiratory distress syndrome

The unique characteristics of pulmonary circulation and alveolar-epithelial capillary-endothelial barrier allow for maintenance of the air-filled, fluid-free status of the alveoli essential for facilitating gas exchange, maintaining alveolar stability, and defending the lung against inhaled pathogens. The hallmark of pathophysiology in acute respiratory distress syndrome is the loss of the alveolar capillary permeability barrier and the presence of protein-rich edema fluid in the alveoli. This alteration in permeability and accumulation of fluid in the alveoli accompanies damage to the lung epithelium and vascular endothelium along with dysregulated inflammation and inappropriate activity of leukocytes and platelets. In addition, there is uncontrolled activation of coagulation along with suppression of fibrinolysis and loss of surfactant. These pathophysiological changes result in the clinical manifestations of acute respiratory distress syndrome, which include hypoxemia, radiographic opacities, decreased functional residual capacity, increased physiologic deadspace, and decreased lung compliance. Resolution of acute respiratory distress syndrome involves the migration of cells to the site of injury and re-establishment of the epithelium and endothelium with or without the development of fibrosis. Most of the data related to acute respiratory distress syndrome, however, originate from studies in adults or in mature animals with very few studies performed in children or juvenile animals. The lack of studies in children is particularly problematic because the lungs and immune system are still developing during childhood and consequently the pathophysiology of pediatric acute respiratory distress syndrome may differ in significant ways from that seen in acute respiratory distress syndrome in adults. This article describes what is known of the pathophysiologic processes of pediatric acute respiratory distress syndrome as we know it today while also presenting the much greater body of evidence on these processes as elucidated by adult and animal studies. It is also our expressed intent to generate enthusiasm for larger and more in-depth investigations of the mechanisms of disease and repair specific to children in the years to come.

Lymphocytes subsets reference values in childhood

Immunophenotyping of blood lymphocyte subsets and activation markers is a basic tool in the diagnostic process of primary immunodeficiency diseases, its use becoming more and more widespread as the knowledge about these illnesses increases. However, the availability of reliable reference values, which need to be age-matched for the pediatric population, is a pre-requisite for the reliable interpretation of immunophenotyping data. Aim of this study is to analyze the lymphocyte subsets and activation markers distribution in children aged 0-18 years referring to the University Hospital of Padova and to create age-matched reference values expressed by percentiles, thus providing a valuable guideline for the interpretation of the immunophenotype.

Normal CD4 Count Range among Healthy Nigerian Population in Ilorin

BACKGROUND

For the establishment and monitoring of the immune status, CD4 count is critical.

OBJECTIVES

To determine the CD4 count range of apparently healthy Nigerians resident in Ilorin and compare with the national value.

METHODS

An automated blood analyzer was used to determine the full blood count and CD4 count. The percentage of CD4 count was derived by using other variables.

RESULTS

Of the 1205 participants, the reference CD4 count (percentage of CD4) range for adult was 400 to 1288 cells/mm³ (19%-48%) and for children was 582 to 3652 cells/mm³ (17%-50%). CD4 count and percentage of CD4 were significantly ( P = .001) higher in females than in males, and the CD4 count declined significantly with increasing age ( r = -.174, P ≤ .0001). The percentage of CD4 count shows less variation with age ( r = -.051, P = .076). Adult residents of Ilorin had significantly lower absolute mean CD4 count (808 ± 260) than that of the national reference values of 847.0 ± 307.0 cells/mm³ ( P = .001).

CONCLUSION

We therefore advocate the use of CD4 count range derived in this study is lower than that of the national reference values.

Immunological alterations in individuals exposed to metal(loid)s in the Panasqueira mining area, Central Portugal

Environmental studies performed in Panasqueira mine area (central Portugal) identified high concentrations of several metal(loid)s in environmental media, and individuals environmentally and occupationally exposed showed higher levels of As, Cr, Mg, Mn, Mo, Pb and Zn in blood, urine, hair and nails when compared to unexposed controls. To evaluate the presence of immunological alterations attributable to environmental contamination, we quantified neopterin, kynurenine, tryptophan, and nitrite concentrations in plasma, and analysed the percentage of several lymphocytes subsets, namely CD3(+), CD4(+) and CD8(+) T-cells, CD19(+) B-cells, and CD16(+)56(+) natural killer (NK) cells in a group of individuals previously tested for metal(loid) levels in different biological matrices. The environmentally exposed group had significantly lower levels of %CD8(+) and higher CD4(+)/CD8(+) ratios, whereas the occupationally exposed individuals showed significant decreases in %CD3(+) and %CD4(+), and significant increases in %CD16(+)56(+), when compared to controls. Analysed biomarkers were found to be influenced by age, particularly neopterin, kynurenine and kynurenine to tryptophan ratio (Kyn/Trp) with significantly higher levels in older individuals, and %CD3(+), %CD8(+) and %CD19(+) with significantly lower values in older individuals. Males environmentally exposed showed significantly lower values of %CD19(+) when compared to control females. The concentration of Pb in toenails was associated to the level of neopterin, kynurenine and Kyn/Trp ratio (all direct), and the concentration of Mn in blood to the level of %CD8(+), %CD19(+) (both inverse) and CD4(+)/CD8(+) ratio (direct). Overall our results show that the metal(loid) contamination in Panasqueira mine area induced immunotoxic effects in exposed populations, possibly increasing susceptibility to diseases.

Metal(loid) levels in biological matrices from human populations exposed to mining contamination--Panasqueira Mine (Portugal)

Mining activities may affect the health of miners and communities living near mining sites, and these health effects may persist even when the mine is abandoned. During mining processes various toxic wastes are produced and released into the surrounding environment, resulting in contamination of air, drinking water, rivers, plants, and soils. In a geochemical sampling campaign undertaken in the Panasqueira Mine area of central Portugal, an anomalous distribution of several metals and arsenic (As) was identified in various environmental media. Several potentially harmful elements, including As, cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), and selenium (Se), were quantified in blood, urine, hair, and nails (toe and finger) from a group of individuals living near the Panasqueira Mine who were environmentally and occupationally exposed. A group with similar demographic characteristics without known exposure to mining activities was also compared. Genotoxicity was evaluated by means of T-cell receptor (TCR) mutation assay, and percentages of different lymphocyte subsets were selected as immunotoxicity biomarkers. Inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis showed elevated levels of As, Cd, Cr, Mn, and Pb in all biological samples taken from populations living close to the mine compared to controls. Genotoxic and immunotoxic differences were also observed. The results provide evidence of an elevated potential risk to the health of populations, with environmental and occupational exposures resulting from mining activities. Further, the results emphasize the need to implement preventive measures, remediation, and rehabilitation plans for the region.

Reference values of lymphocyte subsets in healthy, HIV-negative children in Cameroon

Lymphocyte subset reference values used to monitor infectious diseases, including HIV/AIDS, tuberculosis, malaria, or other immunological disorders in healthy children in Cameroon, are lacking. Values for Caucasian cohorts are already being utilized for clinical decisions but could be inappropriate for African populations. We report here the immunological profile for children aged from birth through 6 years in Cameroon and also compare our values to data from other African and Caucasian populations. In a cohort of 352 healthy children, aged 0 to 6 years, the relative and absolute numbers of T-cell subsets, B cells, and NK lymphocytes were determined from peripheral blood collected in EDTA tubes. Samples were stained with BD Multitest reagents in Trucount tubes and analyzed by using CellQuest-Pro and FlowJo software. We evaluated about 23 different lymphocyte subsets in which the absolute number and percentage values differed significantly (P < 0.05) with age and peaked between 6 and 12 months. B-cell values were higher compared to reported values from developed countries. Differences in activated and differentiated T cells were observed in subjects between 1 and 6 years of age. The absolute CD8(+) T-cell count and the CD4(+)/CD8(+) ratio seem to depend on gender. Normal lymphocyte subsets values among children from Cameroon differ from reported values in Caucasian and some African populations. The differences observed could be due to genetic and environmental factors coupled with the methodology used. These values could be used as initial national reference guidelines as more data are assembled.

Partial efficacy of a VSV-SIV/MVA-SIV vaccine regimen against oral SIV challenge in infant macaques

Despite antiretroviral medications, the rate of pediatric HIV-1 infections through breast-milk transmission has been staggering in developing countries. Therefore, the development of a vaccine to protect vulnerable infant populations should be actively pursued. We previously demonstrated that oral immunization of newborn macaques with vesicular stomatitis virus expressing simian immunodeficiency virus genes (VSV-SIV) followed 2 weeks later by an intramuscular boost with modified vaccinia ankara virus expressing SIV (MVA-SIV) successfully induced SIV-specific T and B cell responses in multiple lymphoid tissues, including the tonsil and intestine [13]. In the current study, we tested the oral VSV-SIV prime/systemic MVA-SIV boost vaccine for efficacy against multiple oral SIVmac251 challenges starting two weeks after the booster vaccination. The vaccine did not prevent SIV infection. However, in vaccinated infants, the level of SIV-specific plasma IgA (but not IgG) at the time of challenge was inversely correlated with peak viremia. In addition, the levels of SIV-specific IgA in saliva and plasma were inversely correlated with viral load at euthanasia. Animals with tonsils that contained higher frequencies of SIV-specific TNF-α- or IFN-γ-producing CD8(+) T cells and central memory T cells at euthanasia also had lower viremia. Interestingly, a marked depletion of CD25(+)FoxP3(+)CD4(+) T cells was observed in the tonsils as well as the intestine of these animals, implying that T regulatory cells may be a major target of SIV infection in infant macaques. Overall, the data suggest that, in infant macaques orally infected with SIV, the co-induction of local antiviral cytotoxic T cells and T regulatory cells that promote the development of IgA responses may result in better control of viral replication. Thus, future vaccination efforts should be directed towards induction of IgA and mucosal T cell responses to prevent or reduce virus replication in infants.

Geno- and immunotoxic effects on populations living near a mine: a case study of Panasqueira mine in Portugal

Mining industry is a vital economic sector for many countries but it is also one of the most hazardous activities, both occupationally and environmentally. Existing studies point to several adverse effects on communities' health living near mines, effects such as mesothelioma and respiratory illnesses. Results achieved in a geochemical sampling campaign undertaken in the vicinity of São Francisco de Assis village showed an anomalous distribution of some heavy metals in soils and waters. To evaluate the effects of mining activities on human health produced by these conditions, a group of 28 individuals from São Francisco de Assis village was examined for some biological endpoints. A nonexposed group (30 individuals) with the same demographic characteristics without exposure to genotoxic compounds was also studied and data obtained from both groups compared. Results of the T-cell receptor mutation assay and micronucleus (MN) test showed significant increases in the frequencies of both mutations and MN in exposed subjects compared to controls. Data obtained in the analysis of the different lymphocyte subsets demonstrated significant decreases in percentages of CD3+ and CD4+ cells, and a significant increase in percentage of CD16/56+ cells, in exposed individuals. The results of the present study indicate an elevated risk of human environmental contamination resulting from mining activities, emphasizing the need to implement preventive measures, remediation, and rehabilitation plans. This would lead to a reduction in cancer risk not only for this particular population but for all populations exposed under similar conditions.

Age-related trends in pediatric B-cell subsets

There are few studies of the developmental changes in B-cell subsets in children. Recent data from adult populations demonstrate that alterations to B-cell subsets have functional consequences and can be helpful diagnostically. Comparable studies in children have been hindered by the lack of normative data and by significant changes with age. This study evaluated B-cell subsets by 4-color flow cytometry in 47 children of different ages. The use of a 4-color platform is compatible with broad use in clinical laboratories. We found that there are rapid changes in the B-cell compartment in infancy and early childhood. Total B-cell numbers decline early in life, and this correlates with a decline in transitional B cells and naïve B cells. The decline is most rapid between 1 and 5 years of age, with a slower decline later in childhood. In contrast, nonswitched and switched memory B cells both increase during the 1st 5 years of life. The decline in B-cell numbers did not occur until after 1 year of age, suggesting that the period after birth is a unique developmental window. These data provide a reference set for further studies on B-cell dysfunction in pediatric disorders. The changes occurring in early childhood document the need for age-related assessments and serve to underscore the B-cell-specific kinetics of immunologic development in humans.

Age-matched lymphocyte subpopulation reference values in childhood and adolescence: application of exponential regression analysis

BACKGROUND

Normal values of lymphocyte subpopulations for healthy children and adults have been published in defined age groups exclusively, which results in difficult data interpretation for patients close to the limit of contiguous age group ranges. In addition, normal values for a number of lymphocyte subpopulations have not been established to date.

OBJECTIVE

The aim of this study was to develop a model which provides continuous age-dependent reference values. This model was applied for lymphocyte subpopulations such as naïve and memory T cells as well as their activation profile with diagnostic relevance in children and adults.

STUDY DESIGN

A total of 100 blood samples, obtained from 80 healthy children and 20 adults were analysed by means of four colour-flow cytometry. Continuous age-dependent reference values were computed based on the residual values in an exponential regression model.

RESULTS

We calculated a continuous age-related regression model for both, absolute cell counts and percentages of CD3(+)CD4(+) T helper (T(H)) cells, CD3(+)CD8(+) cytotoxic T cells, CD56(+)CD3(-) natural killer (NK) cells, CD56(+)CD3(+) T cells, CD3(+)CD4(+)CD45RA(+) naïve T(H) cells, CD3(+)CD4(+)CD45RO(+) memory T(H) cells, CD3(+)CD8(+)CD45RA(+)CD28(+) naïve cytotoxic T cells, CD3(+)CD8(+)CD45RO(+) memory cytotoxic T cells, CD3(+)CD8(+)CD69(+) early activated cytotoxic T cells and CD3(+)CD8(+)HLA-DR(+) late activated cytotoxic T cells, respectively, to obtain reference values.

CONCLUSION

Based on an exponential regression model, the obtained reference values reflect the continuous maturation of lymphocyte subsets during childhood.

Establishment of a microplate assay for flow cytometric assessment and it is use for the evaluation of age-related phenotypic changes in canine whole blood leukocytes

The effectiveness of flow cytometric assays for canine use is still requiring standardization. Despite several studies using purified mononuclear cells, no methodology or reference ranges are available for immunophenotyping of whole blood leukocytes (WBL). Fresh and pre-fixed WBL were used to identify cell-subsets, (Thy-1(+)/CD5(+)/CD4(+)/CD8(+)/CD21(+) and CD14(+)) and measure MHC-II, CD45RA/CD45RB expression. We described here an efficient method for fast quantification of canine-WBL, using pre-fix in a microplate assay, which allows long-term sample storage prior to phenotyping. Decreased percentage of CD5(+)-T-cells within the lymphocyte-gate and increased percentage of CD21(+)-B-cells were observed in young animals, which led to higher T/B cell ratios in middle-aged dogs. Lower numerical counts of Thy-1(+), CD4(+), CD8(+) and CD21(+) lymphocyte were observed when compared to young animals. In addition, we identified an age-related decline of MHC-II/CD45RA expression by lymphocytes. We proposed an improved method for phenotyping of canine peripheral blood mononuclear cells (PBMC) that has significant use for researchers and veterinary clinicians. The hematological changes of senescence previously identified on PBMC could be adequately reproduced on features identified by whole blood. Furthermore, this study supplies normal range references as baseline standards for clinical purposes, besides specific immunological parameters to monitor canine aging process.

Normal values for CD4 and CD8 lymphocyte subsets in healthy Chinese adults from Shanghai

The aim of this study was to establish reference ranges for lymphocyte subsets in Chinese adults. Venous blood specimens were obtained from 614 healthy, human immunodeficiency virus (HIV)-seronegative adults in Shanghai. Flow cytometry was used to determine percentages and absolute numbers of CD4 and CD8 T lymphocytes. Mean values for CD4 and CD8 lymphocytes were 727 and 540 cells/microl, respectively, yielding a CD4/CD8 ratio of 1.49. While CD8 lymphocyte values varied with age and gender, no significant differences in CD4 lymphocyte values were observed. Shanghai adults had approximately 100 fewer CD4 lymphocytes/microl on average than Caucasians, suggesting that lower CD4 lymphocyte cutoffs for classifying and monitoring HIV infection may be needed in China.

Population-based hematologic and immunologic reference values for a healthy Ugandan population

To assess the validity of the reference values for hematologic and immunologic indices currently used in Africa, we evaluated blood samples from 3,311 human immunodeficiency virus (HIV)-negative Ugandans aged 1 week to 92 years. Erythrocyte, hemoglobin, and hematocrit levels and mean corpuscular volume all significantly increased with age (P < 0.001) and were independent of gender until the age of 13 years, after which the levels were higher in males than in females (P < 0.001). White blood cell, neutrophil, lymphocyte, basophil, and monocyte counts significantly declined with age until the age of 13 years (P < 0.001), with no differences by gender, while platelet counts declined with age (P < 0.001) and showed differences by gender only among adults older than age 24 years. CD4+- and CD8+-cell counts declined with age until the age of 18 years; thereafter, females had higher counts than males. The absolute values for many of these parameters differed from those reported for populations outside Africa, suggesting that it may be necessary to develop tables of reference values for hematologic and immunologic indices specific for the African population. This may be particularly important with regard to CD4+-cell counts among children because significant differences in absolute and percent CD4+-cell counts exist between the values for Western populations and the values for the population evaluated in our study. These differences could influence the decision to initiate antiretroviral therapy among children infected with HIV.

Age-related changes in expression of CXCR4 and CCR5 on peripheral blood leukocytes from uninfected infants born to human immunodeficiency virus type 1-infected mothers

Cross-sectional analysis of human immunodeficiency virus-exposed, uninfected infants revealed high proportions of CXCR4-expressing cells in their cord blood, which declined at 4.5 months and increased between 9 and 15 months to levels approaching those of uninfected adults. Proportions of CCR5-expressing cells, however, were very low in cord blood and subsequently increased with age.

Immunophenotyping of peripheral blood lymphocytes in Saudi men

Flow cytometry is an important tool for the diagnosis and follow-up of immunodeficiency patients, as well as for patients with leukemia and lymphoma. Lymphocytes and their subsets show variations with race. The aim of this study was to establish reference ranges for lymphocytes and their subsets in an Saudi adult population by using flow cytometry. Blood samples obtained from 209 healthy Saudi men were used for this study. All blood donors were between 18 and 44 years old. Lymphocytes and their subsets were analyzed by flow cytometry, and the absolute and percentage values were calculated. We investigated the expression of T-cell markers (CD3, CD4, and CD8), B cells (CD19), and natural killer cells (CD16 and CD56). The absolute and percent values of each cell subset were compared with published data from different populations by using the Student t test. Reference ranges, each expressed as the mean +/- the standard deviation, were as follows: leukocytes (6,335 +/- 1759), total lymphocytes (2,224 +/- 717), CD3 cells (1,618 +/- 547), CD4 cells (869 +/- 310), CD8 cells (615 +/- 278), CD19 cells (230 +/- 130), and CD3-CD16(+)/CD56+ cells (262 +/- 178). The CD4/CD8 ratio was 1.6 +/- 0.7. Our results for B cells, CD4 cells, and CD8 cells and for the CD4/CD8 ratio fell in between the reported results for Ethiopian and Dutch subjects. Our results were also different from previously reported findings in an Saudi adult population that showed no increase in CD8 T cells. We thus establish here the reference ranges for lymphocytes and their subsets in a large cohort of Saudi men. The CD8 cell count was not abnormally high, as previously reported, and fell in between previous results obtained for African and European populations.