California Wildfires of 2008: Coarse and Fine Particulate Matter Toxicity

Background

During the last week of June 2008, central and northern California experienced thousands of forest and brush fires, giving rise to a week of severe fire-related particulate air pollution throughout the region. California experienced PM_10–2.5 (particulate matter with mass median aerodynamic diameter > 2.5 μm to < 10 μm; coarse ) and PM_2.5 (particulate matter with mass median aerodynamic diameter < 2.5 μm; fine) concentrations greatly in excess of the air quality standards and among the highest values reported at these stations since data have been collected.

Objectives

These observations prompt a number of questions about the health impact of exposure to elevated levels of PM_10–2.5 and PM_2.5 and about the specific toxicity of PM arising from wildfires in this region.

Methods

Toxicity of PM_10–2.5 and PM_2.5 obtained during the time of peak concentrations of smoke in the air was determined with a mouse bioassay and compared with PM samples collected under normal conditions from the region during the month of June 2007.

Results

Concentrations of PM were not only higher during the wildfire episodes, but the PM was much more toxic to the lung on an equal weight basis than was PM collected from normal ambient air in the region. Toxicity was manifested as increased neutrophils and protein in lung lavage and by histologic indicators of increased cell influx and edema in the lung.

Conclusions

We conclude that the wildfire PM contains chemical components toxic to the lung, especially to alveolar macrophages, and they are more toxic to the lung than equal doses of PM collected from ambient air from the same region during a comparable season.     

Stimulation of IL-8 release from epithelial cells by gas cooker PM(10): a pilot study

OBJECTIVE—To measure the effect of matter collected by a method that has a 50% efficiency for particles with an aerodynamic diameter of 10 µm (PM₁₀), generated by gas and electric cooking, on A549 epithelial cells with and without nitrogen dioxide (NO₂).
METHOD—Multiple indoor PM₁₀ samples were collected on Teflon filters during the use of gas or electric cookers. Interleukin-8 (IL-8) concentrations were measured with a sandwich enzyme linked immunosorbent assay (ELISA) system.
RESULTS—Treatment of A549 cells with PM₁₀ generated from gas cooking resulted in increased concentrations of IL-8 compared with untreated cells; particles from the electric cooker had no effect. NO₂ did not alter the concentration of IL-8.
CONCLUSION—PM₁₀ generated by gas cooking has the potential to cause proinflammatory effects in lung cells. This may have implications for susceptible people.


Keywords: indoor air pollution; PM₁₀; interleukin-8     

Safety and immunogenicity of three tetravalent dengue vaccine formulations in healthy adults in the USA

Background

A candidate recombinant, live-attenuated, CYD tetravalent dengue vaccine (CYD-TDV) has recently demonstrated immunogenicity, efficacy and good tolerability. This study was performed to evaluate three CYD-TDV formulations in adults.

Methods

This was a randomized, double-blind, multicenter, phase II trial. The vaccine formulations were: CYD-TDV 5555 (≈5 log₁₀ tissue culture infectious dose 50% [TCID₅₀] of serotypes 1–4); CYD-TDV 5553 (≈5 log₁₀ TCID₅₀ of serotypes 1–3 and ≈3 log₁₀ TCID₅₀ of serotype 4); and CYD-TDV 4444 (≈4 log₁₀ TCID₅₀ of serotypes 1–4). Vaccinations were administered at 0, 6 and 12 months. Immunogenicity was assessed using the plaque reduction neutralization test.

Results

In total, 260 individuals were enrolled. The 5555 formulation elicited a superior serotype 4 response versus the 5553 formulation, with seropositivity rates of 89.7% and 58.3%, respectively, after the second dose (between-group difference 31.4%; 95% confidence interval 18.2–43.2). After each of the three doses, seropositivity rates for serotypes 1–3 were numerically highest with CYD-TDV 5553 and lowest with the 4444 formulation; seropositivity rates for serotype 4 were similar with the 5555 and 4444 formulations, and much lower among recipients of CYD-TDV 5553. Geometric mean titers followed the same pattern as that seen with seropositivity rates. Safety/reactogenicity results were similar for all three vaccine formulations, although the percentage of participants reporting solicited injection site reactions was lower with CYD-TDV 4444 than with the other two formulations. All serious adverse events were unrelated to vaccination.

Conclusions

Reducing the dose of serotype 4 antigen (5553 formulation) creates an imbalance in the immune response to CYD-TDV. Immune responses to CYD-TDV 5555 were slightly higher than to the 4444 formulation. Development of CYD-TDV 5555 has subsequently been pursued.     

Survival analysis of long-term exposure to different sizes of airborne particulate matter and risk of infant mortality using a birth cohort in Seoul, Korea

Background

Several studies suggest that airborne particulate matter (PM) is associated with infant mortality; however, most focused on short-term exposure to larger particles.

Objectives

We evaluated associations between long-term exposure to different sizes of particles [total suspended particles (TSP), PM ≤ 10 μm in aerodynamic diameter (PM₁₀), ≤ 10–2.5 μm (PM_10–2.5), and ≤ 2.5 μm (PM_2.5)] and infant mortality in a cohort in Seoul, Korea, 2004–2007.

Methods

The study includes 359,459 births with 225 deaths. We applied extended Cox proportional hazards modeling with time-dependent covariates to three mortality categories: all causes, respiratory, and sudden infant death syndrome (SIDS). We calculated exposures from birth to death (or end of eligibility for outcome at 1 year of age) and pregnancy (gestation and each trimester) and treated exposures as time-dependent variables for subjects’ exposure for each pollutant. We adjusted by sex, gestational length, season of birth, maternal age and educational level, and heat index. Each cause of death and exposure time frame was analyzed separately.

Results

We found a relationship between gestational exposures to PM and infant mortality from all causes or respiratory causes for normal-birth-weight infants. For total mortality (all causes), risks were 1.44 (95% confidence interval, 1.06–1.97), 1.65 (1.18–2.31), 1.53 (1.22–1.90), and 1.19 (0.83–1.70) per interquartile range increase in TSP, PM₁₀, PM_2.5, and PM_10–2.5, respectively; for respiratory mortality, risks were 3.78 (1.18–12.13), 6.20 (1.50–25.66), 3.15 (1.26–7.85), and 2.86 (0.76–10.85). For SIDS, risks were 0.92 (0.33–2.58), 1.15 (0.38–3.48), 1.42 (0.71–2.87), and 0.57 (0.16–1.96), respectively.

Conclusions

Our findings provide supportive evidence of an association of long-term exposure to PM air pollution with infant mortality.     

Fine environmental particulate engenders alterations in human lung epithelial A549 cells

Particulate matter (PM), a component of urban air pollution that derives primarily from the combustion of fossil fuels, is responsible for a number of health effects in humans. Recent studies have demonstrated that the fine particles (PM(2.5)) present in high numbers in PM samples can be more harmful than larger particles, since they are more efficiently retained in the peripheral lung. In the present study, we have investigated the biological effects of PM(2.5) on human lung epithelial cell line A549. Morphological analysis performed by immunofluorescence and electron microscopy showed that fine particles interact with the cell surface, where they induce evident alterations and, subsequently, are internalized in the cytoplasm. Cytoskeletal components, in particular microfilaments and microtubules, cause modifications upon challenge with PM(2.5). Of interest, an early cell response to the fine particulate is an increase of reactive oxygen species content, which can account for the observed cytoskeletal changes and the production of proinflammatory cytokines in A549 cells. In particular, exposure to PM(2.5) promoted a dose- and time-dependent release of TNF-alpha and IL-6 in the cell medium.     

PM10 Exposure and Non-accidental Mortality in Asian Populations: A Meta-analysis of Time-series and Case-crossover Studies

Objectives

We investigated the association between particulate matter less than 10 µm in aerodynamic diameter (PM₁₀) exposure and non-accidental mortality in Asian populations by meta-analysis, using both time-series and case-crossover analysis.

Methods

Among the 819 published studies searched from PubMed and EMBASE using key words related to PM₁₀ exposure and non-accidental mortality in Asian countries, 8 time-series and 4 case-crossover studies were selected for meta-analysis after exclusion by selection criteria. We obtained the relative risk (RR) and 95% confidence intervals (CI) of non-accidental mortality per 10 µg/m³ increase of daily PM₁₀ from each study. We used Q statistics to test the heterogeneity of the results among the different studies and evaluated for publication bias using Begg funnel plot and Egger test.

Results

Testing for heterogeneity showed significance (p<0.001); thus, we applied a random-effects model. RR (95% CI) per 10 µg/m³ increase of daily PM₁₀ for both the time-series and case-crossover studies combined, time-series studies relative risk only, and case-crossover studies only, were 1.0047 (1.0033 to 1.0062), 1.0057 (1.0029 to 1.0086), and 1.0027 (1.0010 to 1.0043), respectively. The non-significant Egger test suggested that this analysis was not likely to have a publication bias.

Conclusions

We found a significant positive association between PM₁₀ exposure and non-accidental mortality among Asian populations. Continued investigations are encouraged to contribute to the health impact assessment and public health management of air pollution in Asian countries.     

Inactivated and live, attenuated influenza vaccines protect mice against influenza: Streptococcus pyogenes super-infections

Mortality associated with influenza virus super-infections is frequently due to secondary bacterial complications. To date, super-infections with Streptococcus pyogenes have been studied less extensively than those associated with Streptococcus pneumoniae. This is significant because a vaccine for S. pyogenes is not clinically available, leaving vaccination against influenza virus as our only means for preventing these super-infections. In this study, we directly compared immunity induced by two types of influenza vaccine, either inactivated influenza virus (IIV) or live, attenuated influenza virus (LAIV), for the ability to prevent super-infections. Our data demonstrate that both IIV and LAIV vaccines induce similar levels of serum antibodies, and that LAIV alone induces IgA expression at mucosal surfaces. Upon super-infection, both vaccines have the ability to limit the induction of pro-inflammatory cytokines within the lung, including IFN-γ which has been shown to contribute to mortality in previous models of super-infection. Limiting expression of these pro-inflammatory cytokines within the lungs subsequently limits recruitment of macrophages and neutrophils to pulmonary surfaces, and ultimately protects both IIV- and LAIV-vaccinated mice from mortality. Despite their overall survival, both IIV- and LAIV-vaccinated mice demonstrated levels of bacteria within the lung tissue that are similar to those seen in unvaccinated mice. Thus, influenza virus:bacteria super-infections can be limited by vaccine-induced immunity against influenza virus, but the ability to prevent morbidity is not complete.     

Atrazine Exposure Decreases Cell Proliferation in <Emphasis Type="Italic">Chinese Hamster Ovary</Emphasis> (CHO-K1) Cell Line

The aim of this study was to determine the toxic effect of atrazine at the ovarian cellular level. Chinese Hamster Ovary (CHO-K1) cell line was used to evaluate the degree of in vitro atrazine cytotoxicity and the morphological changes were followed during the cell death. Application of four bioassays confirmed that atrazine decreases ovarian cell proliferation and IC(50) were determined with each assay after 72 h of exposure. The level of apoptosis in atrazine treated cells was low.     

Mushroom tyrosinase inhibitors from mung bean (Vigna radiatae L.) extracts

A seventy percent ethanol from mung bean (Vigna radiatae L.) was extracted further with CH₂Cl₂, EtOAc and n-BuOH to afford four fractions: CH₂Cl₂-soluble, EtOAc-soluble, n-BuOH-soluble and residual extract fractions. When using l-3,4-dihydroxyphenylalanine as the substrate for mushroom tyrosinase, the EtOAc-soluble fractions showed the highest inhibitory activity. Two pure flavonoid compounds, vitexin and isovitexin, were isolated (using the enzyme assay-guided fractionation method) from the EtOAc-soluble fractions. Vitexin and isovitexin showed high inhibitory activities, with IC₅₀ values of 6.3 and 5.6 mg/ml, respectively. This is the first study on the active compositions of azuki beans against mushroom tyrosinase.     

Potential confounding of particulate matter on the short-term association between ozone and mortality in multisite time-series studies

BACKGROUND: A critical question regarding the association between short-term exposure to ozone and mortality is the extent to which this relationship is confounded by ambient exposure to particles. OBJECTIVES: We investigated whether particulate matter < 10 and < 2.5 microm in aerodynamic diameter (PM(10) and PM(2.5)) is a confounder of the ozone and mortality association using data for 98 U.S. urban communities from 1987 to 2000. METHODS: We a) estimated correlations between daily ozone and daily PM concentrations stratified by ozone or PM levels; b) included PM as a covariate in time-series models; and c) included PM as a covariate as in d), but within a subset approach considering only days with ozone below a specified value. RESULTS: Analysis was hindered by data availability. In the 93 communities with PM(10) data, only 25.0% of study days had data on both ozone and PM(10). In the 91 communities with PM(2.5) data, only 9.2% of days in the study period had data on ozone and PM(2.5). Neither PM measure was highly correlated with ozone at any level of ozone or PM. National and community-specific effect estimates of the short-term effects of ozone on mortality were robust to inclusion of PM(10) or PM(2.5) in time-series models. The robustness remains even at low ozone levels (< 10 ppb) using a subset approach. CONCLUSIONS: Results provide evidence that neither PM(10) nor PM(2.5) is a likely confounder of observed ozone and mortality relationships. Further investigation is needed to investigate potential confounding of the short-term effects of ozone on mortality by PM chemical composition.     

Genotyping of Echinococcus granulosus Isolates from Human Clinical Samples Based on Sequencing of Mitochondrial Genes in Iran,Tehran

Background

The present study was aimed to investigate molecular diversity of Echinococcus granulosus isolates collected from human clinical samples using two mitochondrial genes cox1 and nad1 in Iran.

Methods

Forty seven human hydatid cysts were collected through surgery from two hospitals in Tehran during 2010-2012. To determine the fertility of protoscoleces, the cyst fluids were subjected to morphological microscopic examinations. Protoscoleces were removed from each cyst and their total genomic DNAs were extracted. PCR was performed to amplify fragments of 450 and 400 base pair (bp) for cox1 and nad1 genes, respectively. Genotype diversity and sequence variation of the strains were studied by bioinformatics software and in comparison with those mtDNA sequences already deposited in GenBank.

Results

Sixteen, (53.3%), 13 (43.3%), and 1 (3.3%) samples were related to lung, liver, and spleen, respectively. The remained 17 unfertile samples were excluded from the study. From the 29 isolates, 86.7% (n=26) and 10% (n=3) were related to G1, and G3 genotypes, respectively. The sole isolate with G6 genotype was obtained from lung sample. Analysis of concatenated sequences of cox1+nad1 indicated the presence of 11 haplotypes among our strains that were related to genotypes G1 (n=9), G3 (n=1) and G6 (n=1).

Conclusion

In consistent to other reports from Iran, genotypes G1, G3, and G6 were observed in our human isolates. The rate of G3 genotype was however higher than other studies implying that human can be considered as a new appropriate host for G3 genotype. Further studies with more sample size from different geographic areas of Iran are needed for E. granulosus mapping.     

Interlaboratory Evaluation of in Vitro Cytotoxicity and Inflammatory Responses to Engineered Nanomaterials: The NIEHS Nano GO Consortium

Background: Differences in interlaboratory research protocols contribute to the conflicting data in the literature regarding engineered nanomaterial (ENM) bioactivity.Objectives: Grantees of a National Institute of Health Sciences (NIEHS)-funded consortium program performed two phases of in vitro testing with selected ENMs in an effort to identify and minimize sources of variability.Methods: Consortium program participants (CPPs) conducted ENM bioactivity evaluations on zinc oxide (ZnO), three forms of titanium dioxide (TiO₂), and three forms of multiwalled carbon nanotubes (MWCNTs). In addition, CPPs performed bioassays using three mammalian cell lines (BEAS-2B, RLE-6TN, and THP-1) selected in order to cover two different species (rat and human), two different lung epithelial cells (alveolar type II and bronchial epithelial cells), and two different cell types (epithelial cells and macrophages). CPPs also measured cytotoxicity in all cell types while measuring inflammasome activation [interleukin-1β (IL-1β) release] using only THP-1 cells.Results: The overall in vitro toxicity profiles of ENM were as follows: ZnO was cytotoxic to all cell types at ≥ 50 μg/mL, but did not induce IL-1β. TiO₂ was not cytotoxic except for the nanobelt form, which was cytotoxic and induced significant IL-1β production in THP-1 cells. MWCNTs did not produce cytotoxicity, but stimulated lower levels of IL-1β production in THP-1 cells, with the original MWCNT producing the most IL-1β.Conclusions: The results provide justification for the inclusion of mechanism-linked bioactivity assays along with traditional cytotoxicity assays for in vitro screening. In addition, the results suggest that conducting studies with multiple relevant cell types to avoid false-negative outcomes is critical for accurate evaluation of ENM bioactivity.     

Seasonal effect of PM10 concentrations on mortality and morbidity in Seoul, Korea: A temperature-matched case-crossover analysis

Background

Explorations of interactions between air pollution and seasonal changes have represented one approach in examining the consequences of global warming. However, only a few studies have focused on evaluating the effects of seasonal air pollution using data on both morbidity and mortality in Asia.

Method

We examined the associations between PM₁₀ concentrations and mortality and hospital admissions in Seoul, Korea for the periods 2000-2006 and 2001-2006. We employed a temperature-matched case-crossover design, where reference periods matched case days in regard to temperature (same rounded to degrees celsius (°C)), month, and year.

Results

A total of 238,826 deaths were identified, along with 98,570 and 93,553 inpatient admissions for cardiovascular and respiratory diseases, respectively. We found that the association with PM₁₀ and mortality/morbidity increased during the summer. During the study period, 10μg/m³ increase in PM₁₀ was associated with the increase in mortality by 0.28% (95% confidence interval: 0.12, 0.44), 0.51% (0.19, 0.83), and 0.59% (-0.08, 1.26) for non-accidental, cardiovascular, and respiratory causes. 10μg/m³ increase in PM₁₀ was also associated with increase in hospitalization from cardiovascular and respiratory causes by 0.77% (0.53, 1.01) and 1.19% (0.94, 1.44). In the summer, the increase in mortality and hospitalization was 0.57% (0.20, 0.93), 0.64% (-0.10, 1.38), 0.50% (-1.02, 2.05), 1.52% (0.89, 2.16), and 1.55% (0.87, 2.22).

Conclusions

This study provides evidence that the effect of PM₁₀ on mortality and morbidity varies with season and increases during the summer season.     

Toxicity of Tungsten Carbide and Cobalt-Doped Tungsten Carbide Nanoparticles in Mammalian Cells in Vitro

Background

Tungsten carbide nanoparticles are being explored for their use in the manufacture of hard metals. To develop nanoparticles for broad applications, potential risks to human health and the environment should be evaluated and taken into consideration.

Objective

We aimed to assess the toxicity of well-characterized tungsten carbide (WC) and cobaltdoped tungsten carbide (WC-Co) nanoparticle suspensions in an array of mammalian cells.

Methods

We examined acute toxicity of WC and of WC-Co (10% weight content Co) nanoparticles in different human cell lines (lung, skin, and colon) as well as in rat neuronal and glial cells (i.e., primary neuronal and astroglial cultures and the oligodendro cyte precursor cell line OLN-93). Furthermore, using electron microscopy, we assessed whether nanoparticles can be taken up by living cells. We chose these in vitro systems in order to evaluate for potential toxicity of the nanoparticles in different mammalian organs (i.e., lung, skin, intestine, and brain).

Results

Chemical–physical characterization confirmed that WC as well as WC-Co nanoparticles with a mean particle size of 145 nm form stable suspensions in serum-containing cell culture media. WC nanoparticles were not acutely toxic to the studied cell lines. However, cytotoxicity became apparent when particles were doped with Co. The most sensitive were astrocytes and colon epithelial cells. Cytotoxicity of WC-Co nanoparticles was higher than expected based on the ionic Co content of the particles. Analysis by electron microscopy demonstrated presence of WC nanoparticles within mammalian cells.

Conclusions

Our findings demonstrate that doping of WC nanoparticles with Co markedly increases their cytotoxic effect and that the presence of WC-Co in particulate form is essential to elicit this combinatorial effect.     

Low intake of vitamin B6 is associated with irritable bowel syndrome symptoms

Most subjects with irritable bowel syndrome (IBS) experience an association between symptoms and food consumption. Although dietary intake has been the focus of previous research, attention to specific nutrients has been rare. We hypothesized that there is an association between the severity of IBS symptoms and the intake of specific food groups and specific nutrients. In this cross-sectional study, 17 human subjects with IBS, as defined according to the Rome II criteria, were recruited. IBS symptoms were recorded on diary cards every evening for 7 days, and an IBS sum score was calculated (range, 0-15). Intake of food was assessed from a food diary kept by the subjects in the same period. Associations between IBS sum score and dietary intake were explored. The daily IBS sum score was 6.43 (range, 3.86- 9.09). Intake of vitamin B₆ was the only component of the diet that was significantly associated with the IBS sum score. The median daily intake of vitamin B₆ was 0.9 mg/day (range, 0.6-1.5), the recommended daily intake for men and women is 1.6 mg/day or more and 1.2 mg/day or more, respectively. A high symptom score was associated with low vitamin B₆ intake (adjusted R² = 0.583; β = −4.431; 95% confidence interval, −6.386 to −2.476; P = 0.0002). A significant inverse association between intake of vitamin B₆ and severity of IBS symptoms might have clinical implications.     

Estimated short-term effects of coarse particles on daily mortality in Stockholm, Sweden

Background: Although serious health effects associated with particulate matter (PM) with aerodynamic diameter ≤ 10 μm (PM₁₀) and ≤ 2.5 μm (PM_2.5; fine fraction) are documented in many studies, the effects of coarse PM (PM_2.5–10) are still under debate.Objective: In this study, we estimated the effects of short-term exposure of PM_2.5–10 on daily mortality in Stockholm, Sweden.Method: We collected data on daily mortality for the years 2000 through 2008. Concentrations of PM₁₀, PM_2.5, ozone, and carbon monoxide were measured simultaneously in central Stockholm. We used additive Poisson regression models to examine the association between daily mortality and PM_2.5–10 on the day of death and the day before. Effect estimates were adjusted for other pollutants (two-pollutant models) during different seasons.Results: We estimated a 1.68% increase [95% confidence interval (CI): 0.20%, 3.15%] in daily mortality per 10-μg/m³ increase in PM_2.5–10 (single-pollutant model). The association with PM_2.5–10 was stronger for November through May, when road dust is most important (1.69% increase; 95% CI: 0.21%, 3.17%), compared with the rest of the year (1.31% increase; 95% CI: –2.08%, 4.70%), although the difference was not statistically significant. When adjusted for other pollutants, particularly PM_2.5, the effect estimates per 10 μg/m³ for PM_2.5–10 decreased slightly but were still higher than corresponding effect estimates for PM_2.5.Conclusions: Our analysis shows an increase in daily mortality associated with elevated urban background levels of PM_2.5–10. Regulation of PM_2.5–10 should be considered, along with actions to specifically reduce PM_2.5–10 emissions, especially road dust suspension, in cities.     

Aqueous extracts of Lentinula edodes and Pleurotus sajor-caju exhibit high antioxidant capability and promising in vitro antitumor activity

Mushroom extracts are increasingly sold as dietary supplements because of several of their properties, including the enhancement of immune function and antitumor activity. We hypothesized that soluble polar substances present in mushroom extracts may show antioxidant and anticancer properties. This report shows that Brazilian aqueous extracts of Lentinula edodes and Pleurotus sajor-caju exert inhibitory activity against the proliferation of the human tumor cell lines laryngeal carcinoma (Hep-2) and cervical adenocarcinoma (HeLa). Cell viability was determined after using 3 different temperatures (4°C, 22°C, and 50°C) for mushroom extraction. Biochemical assays carried out in parallel indicated higher amounts of polyphenols in the L edodes extracts at all extraction temperatures investigated. The scavenging ability of the 2,2-diphenyl-1-picrylhydrazyl radical showed higher activity for L edodes extracts. Superoxide dismutase–like activity showed no statistically significant difference among the groups for the 2 tested extracts, and catalase-like activity was increased with the L edodes extracts at 4°C. The results for the cytotoxic activity from P sajor-caju extracts at 22°C revealed the half maximal inhibitory concentration values of 0.64% ± 0.02% for Hep-2 and 0.25% ± 0.02% for HeLa. A higher cytotoxic activity was found for the L edodes extract at 22°C, with half maximal inhibitory concentration values of 0.78% ± 0.02% for Hep-2 and 0.57% ± 0.01% for HeLa. Substantial morphological modifications in cells were confirmed by Giemsa staining after treatment with either extract, suggesting inhibition of proliferation and induction of apoptosis with increasing extract concentrations. These results indicate that the aqueous extracts of Brazilian L edodes and P sajor-caju mushrooms are potential sources of antioxidant and anticancer compounds. However, further investigations are needed to exploit their valuable therapeutic uses and to elucidate their modes of action.     

Interleukin-10 and Transforming Growth Factor-β in Early and Late Lesions of Patients with Leishmania major Induced Cutaneous Leishmaniasis

Background

Cutaneous leishmaniasis is a neglected parasitic disease, which imposes massive human distress and financial costs to the endemic countries. Better understanding of host immune response to the parasite leads to helpful strategies for disease control. Interleukin (IL)-10 and transforming growth factor (TGF)-β are important immune regulatory cytokines, which appear to develop non-healing forms of leishmaniasis. However, there is little information about the function of IL-10 and TGF-β in old world cutaneous leismaniasis. The aim of this study was to analyze the role of IL-10 and TGF-β in human cutaneous leishmaniasis due to Leishmania major infection.

Methods

Biopsies were obtained from lesions of twenty proven cases of L. major induced cutaneous leishmaniasis. IL-10 and TGF-β positive cells were detected by immunofluorescence staining of frozen sections and compared between two groups of patients with early and late lesions.

Results

The mean percentage of IL-10 positive cells were significantly (P= 0.035) higher in late lesions (0.51±0.24) than early ones (0.15±0.07). Similar results were obtained for TGF-β with mean percentages of 0.16±0.05 and 0.53±0.28 in early and late lesions respectively (P= 0.008).

Conclusion

IL-10 and TGF-β are present in lesions of L. major induced cutaneous leishmaniasis and contribute to the pathogenesis of long lasting disease forms.     

Interleukin-10 and Transforming Growth Factor-β in Early and Late Lesions of Patients with Leishmania major induced Cutaneous Leishmaniasis

Background

Cutaneous leishmaniasis is a neglected parasitic disease, which imposes massive human distress and financial costs to the endemic countries. Better understanding of host immune response to the parasite leads to helpful strategies for disease control. Interleukin (IL)-10 and transforming growth factor (TGF)-β are important immune regulatory cytokines, which appear to develop non-healing forms of leishmaniasis. However, there is little information about the function of IL-10 and TGF-β in old world cutaneous leismaniasis. The aim of this study was to analyze the role of IL-10 and TGF-β in human cutaneous leishmaniasis due to Leishmania major infection.

Methods

Biopsies were obtained from lesions of twenty proven cases of L. major induced cutaneous leishmaniasis. IL-10 and TGF-β positive cells were detected by immunofluorescence staining of frozen sections and compared between two groups of patients with early and late lesions.

Results

The mean percentage of IL-10 positive cells were significantly (P= 0.035) higher in late lesions (0.51±0.24) than early ones (0.15±0.07). Similar results were obtained for TGF-β with mean percentages of 0.16±0.05 and 0.53±0.28 in early and late lesions respectively (P= 0.008).

Conclusion

IL-10 and TGF-β are present in lesions of L. major induced cutaneous leishmaniasis and contribute to the pathogenesis of long lasting disease forms.