Assessing the trophic ecology and migration on the exposure of cape petrels and Wilson's storm petrels from Antarctica to perfluoroalkylated substances, trace and major elements

Chemical pollution is a global concern as contaminants are transported and reach even the remote regions of Antarctica. Seabirds serve as important sentinels of pollution due to their high trophic position and wide distribution. This study examines the influence of migration and trophic ecology on the exposure of two Antarctic seabirds, Wilson's storm petrel (Oceanites oceanicus - Ooc), and Cape petrel (Daption capense - Dca), to chemical elements and perfluoroalkyl substances (PFAS). Our methodology involved assessing the concentration of these pollutants in feather samples obtained from carcasses, offering a practical means for monitoring contamination. Trace and major element concentrations were comparable in both species, suggesting that migratory patterns have a minimal impact on exposure levels. However, Ooc had higher concentration of PFAS compared to Dca (mean, ng g-1dry weight, PFOA: Ooc:0.710, Dca:0.170; PFTrDA: Ooc:0.550, Dca:0.360, and PFTeDA: Ooc:1.01, Dca:0.190), indicating that migration to the more polluted Northern Hemisphere significantly affects PFAS exposure. Furthermore, while no strong associations were found between either trace elements or PFAS and the three stable isotopes (δ13C, δ15N, and δ34S), a negative association was observed between PFUnDA and δ15N, hinting at potential biodilution. The research concludes that the migratory patterns of these seabird species affect their PFAS exposure, underscoring the critical need for further exploration and understanding of these relationships to better inform conservation strategies.

Mercury exposure in Antarctic seabirds: Assessing the influence of trophic position and migration patterns

Although naturally present in the environment, mercury (Hg) input is significantly amplified by anthropogenic activities on a global scale, leading to a growing concern about the recent increase in Hg levels observed in Antarctica. This study investigated total mercury (THg) concentrations in feathers and eggs of resident and migratory Antarctic seabirds. Stable isotope data (δ15N, δ13C, and δ34S) were employed to ascertain the key factors influencing the exposure of these species to Hg. We gathered feathers and eggs from three resident species - Adélie, Gentoo, and Chinstrap penguins, as well as five migratory species - Snowy Sheathbill, Antarctic Tern, Southern Giant Petrel, Kelp Gull, and South Polar Skua. These samples were collected from Admiralty Bay, King George Island, in the Antarctica Peninsula. For all species, THg concentrations were higher in feathers (mean ± SD: 2267 ± 2480 ng g-1 dw) than in eggs (906 ± 1461 ng g-1 dw). Species occupying higher trophic positions, such as the Southern Giant Petrel (5667 ± 1500 ng g-1 dw) and South Polar Skua (4216 ± 1101 ng. g-1 dw), exhibited higher THg levels in their feathers than those at lower positions, like Antarctic Tern (1254 ± 400 ng g-1 dw) and Chinstrap Penguin (910 ± 364 ng g-1 dw). The δ15N values, which serve as a proxy for the trophic position, significantly correlated with THg concentrations. These findings reveal that trophic position influences THg concentrations in Antarctic seabirds. Migration did not appear to significantly affect the exposure of seabirds to THg, contrary to initial expectations. This research highlights the importance of evaluating the impacts of THg contamination on the Antarctic ecosystem by considering a variety of species. This multi-species approach offers critical insights into the factors that may potentially influence the exposure of these species to contaminants.

Trace elements in migratory species arriving to Antarctica according to their migration range

The levels of eighteen trace elements (TEs) were evaluated in association with stable isotopes (δ¹⁵N, δ³⁴S, and δ¹³C) in feathers and eggs of five migratory species breeding on the Antarctic Peninsula to test the factors that influence their exposure to contaminants. The feathers of seabirds migrating to the Northern Hemisphere (South polar skua) have concentrations (mean ± SD, μg. g^-1) of Li (1.71 ± 2.08) and Mg (1169.5 ± 366.8) one order of magnitude higher than southern migrants, such as Snowy sheathbill Li (0.01 ± 0.005) and Mg (499.6 ± 111.9). Feathers had significantly higher concentrations for 11 of a total of 18 metals measured compared to eggs. South polar skua have higher concentrations of all TEs in eggs compared to antarctic tern. Therefore, the present study showed that migration and trophic ecology (δ¹⁵N, δ¹³C, and δ³⁴S) influence Fe, Mn, Cu, and Se concentrations in feathers of Antarctic seabirds. The concentrations of Cu, Mn, Rb, Zn, Pb, Cd, Cr are higher than previously reported, which may be due to increased local and global human activities.

Responses of marine zooplankton indicators after five years of a dam rupture in the Doce River, Southeastern Brazil

Since November of 2015, when ore tailings from a dam rupture reached the Atlantic Ocean, researchers are trying to assess the degree of impact across the Doce River and adjacent coastal area. This study aims to use the zooplankton dynamics as a tool to evaluate the environmental impact in the coastal region, five years after the rupture, during periods of low and high river flow. Doce River flow varied from 49 to 5179 m³/s and structured the zooplankton community between periods of low and high river flow, but salinity and chlorophyll-a had stronger correlation with depth (r = 0.40 and - 0.40 respectively) than with the Doce River discharge variation along the sampling period (r < 0.2). On the other hand, inorganic particles in the water and total metal concentration (dissolved + particulate), used as tracers of the iron enriched tailing (Al, Cd, Cr, Cu, Fe, V), were correlated with fluvial discharge and showed to be the main factor driving the zooplankton community dynamics. For assessing the degree of environmental impact, we tested the ecological indexes for the zooplankton community. Margalef Richness, Pielou Evenness and Shannon-Wiener Diversity varied from 2.52, 0.40 and 1.39 (all registered during high river flow period) to 9.02, 0.85 and 3.44 (all registered during low river flow period), respectively. Along with those community indicators, we evaluated the response of representative taxonomical genera such as Paracalanus, Oikopleura and Temora, regarding the Doce River flow, and found population patterns that established a baseline for future monitoring in the region. Our results showed that the zooplankton community is more fragile when the river discharge is stronger, and this pattern is confirmed by all indicators tested.

An integrated study of the plankton community after four years of Fundão dam disaster

Mining activities can affect the environment either by the tailings releasing or dams failures. The impact of the tailings can last decades and cause chronic effects due to their toxicity. The Fundão dam collapse, a relevant environmental disaster, occurred in November 2015 in Southeastern Brazil. Tailing rich in metals reached the Doce River and arrived in the Atlantic Ocean. Previous studies revealed the acute impact of the tailings in the marine planktonic community near the Doce River mouth. The current study aims to characterize the structure of planktonic assemblages in the impacted area after four years of the disaster. Sampling occurred in November 2018, January, April, and July 2019 at 32 stations located at the marine coastal area near the Doce River mouth. Our study detected high metal concentrations in the surface waters during January 2019, when the lowest diversity and abundance of phytoplankton, lowest zooplankton diversity, and low ichthyoplankton abundance were recorded. The zooplanktonic community was structured by environmental parameters and ichthyoplankton assemblages in November 2018, January and April 2019. Nutrients and metals, mainly iron from the tailing carried by the Doce River waters to the marine environment changed the plankton community, confirming the impact of the Fundão Dam collapse in the coastal area near the Doce River mouth. The phytoplankton community, influenced by the nutrients and to a lesser extent metals concentrations, was not decisive in the zooplankton community structure. The environmental variability was driven by the meteoceanographic conditions and the Doce River flow. There was a high correlation between the zooplanktonic community and ichthyoplanktonic assemblage and the environmental factors and metals. These relations indicate the impact of the tailings from the collapse of the Fundão Dam on these communities, even after four years of the Mariana disaster.

Environmental quality assessment in a marine coastal area impacted by mining tailing using a geochemical multi-index and physical approach

Mining has been described as an important source of contaminants to the coastal zone worldwide, which is greatly intensified in the case of tailing dam ruptures. This study assessed the environmental quality of the marine coastal area impacted by a mining disaster (Fundão Mine dam collapse on 05 November 2015, Southeast Brazil) by applying a geochemical multi-index and physical approach over 18 months (from October 2018 to March 2020). Nutrients, metal(oid)s and Polycyclic Aromatic Hydrocarbons (PAHs) were integrated by quality indexes: Canadian Council of Ministers of the Environment Water Quality Index (CWQI) and the Pollution Load Index (PLI) for water quality; Sediment Quality Guideline Quotients (SQG-q metal(oid)s and SQG-q PAHs) for sediment quality. Three scenarios regarding river discharge and wave-heights (Hs) were considered: 2018/2019-wet, 2019-dry, 2019/2020-wet. An Environmental Risk Assessment framework was built to describe the overall environmental quality in regards to water and sediment quality indexes as well as physical conditions. Here we show that the worsening of environmental quality is highly associated with the decrease of water quality by metal(oid)s (total forms of As and Ni; dissolved forms of Co and Fe) during the 2019-dry scenario when river discharge was at the lowest and the highest Hs occurred. Resuspension of fine sediment and suspended Fe(III) oxy-hydroxide nanoparticles by waves seem to be the main processes for releasing metal(oid)s into the water column. CWQI and PLI showed marginal and polluted conditions for water quality, respectively, and SQG-q for metals and PAHs indicated moderate impact in the sediment during the 2019-dry period. Toxicity to pelagic and benthic fauna is expected to occur in those conditions. Recovery of environmental quality occurred during the 2019/2020-wet scenario, which could be explained by alongshore and offshore transport of sediment and the dilution of aqueous metal(oid)s by intense river discharge on the continental shelf.

Microbiological characteristics of bloodstream infections in a reference hospital in northeastern Brazil

Routine blood culture is used for the detection of bloodstream infections by aerobic and anaerobic bacteria and by common pathogenic yeasts. A retrospective study was conducted in a public hospital in Maceió-AL, by collecting data of all medical records with positive blood cultures. Out of the 2,107 blood cultures performed, 17% were positive with Staphylococcus coagulase negative (51.14%), followed by Staphylococcus aureus (11.21%) and Klebsiella pneumoniae (6.32%). Gram-positive bacteria predominated among positive blood cultures, highlighting the group of Staphylococcus coagulase-negative. While Gram-negative bacteria had a higher number of species among positive blood cultures.

Iron ore tailings as a source of nutrients to the coastal zone

The Fundão dam rupture was one of the largest environmental disasters worldwide and released millions of m³ of iron ore tailings into the Doce River basin in southeastern Brazil. Here we assessed the supply of dissolved nutrients associated to tailings in the Doce River estuary and its adjacent coastal zone. First, we observed an acute increase in dissolved silicates (From 16.26 μM to 175.47 μM) and nitrate (From 5.56 μM to 50.69 μM) in the estuary when compared to days prior to the event. Coastal marine ecosystems showed significant concentrations of nitrite (From 0.72 μM to 2.99 μM) and phosphate (From 0.09 μM to 2.30 μM) one year after the disaster, which we attribute mainly to nutrient recycling. The chronic effects include an increase in nutrient load to the coastal zone with a predominance of nitrogenous species, which may increase the limitation of phosphorus and silica to marine primary production.

Factors that influence trace element levels in blood and feathers of Pygoscelis penguins from South Shetland Islands, Antarctica

Contaminant levels are lower in Antarctica than elsewhere in the world because of its low anthropogenic activities. However, the northern region of the Antarctic Peninsula, is close to South America and experiences the greatest anthropogenic pressure in Antarctica. Here, we investigated, in two Antarctic Peninsula islands, intra and interspecific factors that influence the concentrations of 17 trace elements (TEs) in blood and feathers of three penguin species breeding sympatrically in relation to their trophic ecology assessed via a stable isotopic approach (C, N and S). Geographical location, foraging zone (δ¹³C and δ³⁴S) and diet influences the interspecific difference, and sex and maturity stage diet influence the intraspecific difference of Pygoscelis penguins. Penguins from Livingston showed higher values (mean, ng. g^-1, dry weight - dw) of Zn (103), Mn (0.3), and Fe (95) than those from King George Island (Zn: 80, Mn: 1.9, and Fe: 11). Gender-related differences were observed, as males showed significantly higher values (mean, ng. g^-1, dw) of Rb (3.4) and δ¹⁵N in blood of gentoo, and Ca (1344) in Adélie feathers. Chicks of gentoo and Adélie presented higher Zn, Mg, Ca, and Sr and lower ¹³C values in blood than adults. The highest concentrations (mean, ng. g^-1, dw) of Cd (0.2) and Cu (26), and the lowest δ¹⁵N values were found in chinstrap. Geographical, intraspecific (i.e., ontogenetic and gender-related) and interspecific differences in feeding seemed to have influenced TE and stable isotope values in these animals. The TE bioaccumulation by penguins may have also been influenced by natural enrichment in environmental levels of these elements, which seems to be the case for Fe, Zn, and Mn. However, the high level of some of the TEs (Mn, Cd, and Cr) may reflect the increase of local and global human activities.

Time-sequence development of metal(loid)s following the 2015 dam failure in the Doce river estuary, Brazil

In the context of the Doce river (Southeast Brazil) Fundão dam disaster in 2015, we monitored the changes in concentrations of metal(loid)s in water and sediment and their particulate and dissolved partitioning over time. Samples were collected before, during, and after the mine tailings arrival to the Doce river estuary (pre-impact: 12, 10, 3 and 1 day; acute stage: tailing day - TD and 1 day after - DA; chronic stage: 3 months and 1 year post-disaster). Our results show that metal(loid) concentrations significantly increased with time after the disaster and changed their chemical partitioning in the water. 35.2 mg Fe L^-1 and 14.4 mg Al L^-1 were observed in the total (unfiltered) water during the acute stage, while aqueous Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se and Zn concentrations all exceeded both Brazilian and international safe levels for water quality. The Al, Fe and Pb partitioning coefficient log (K_d) decrease in the acute stage could be related to the high colloid content in the tailings. We continued to observe high concentrations for Al, Ba, Cd, Cr, Cu, Fe, V and Zn mainly in the particulate fraction during the chronic stage. Furthermore, the Doce river estuary had been previously contaminated by As, Ba, Cr, Cu, Mn, Ni and Pb, with a further increase in sediment through the tailing release (e.g. 9-fold increase for Cr, from 3.61 ± 2.19 μg g^-1 in the pre-impact to 32.16 ± 20.94 μg·g^-1 in the chronic stage). Doce river sediments and original tailing samples were similar in metal(loid) composition for Al, As, Cd, Cr, Cu, Fe, V and Zn. As a result, these elements could be used as geochemical markers of the Fundão tailings and considering other key parameters to define a baseline for monitoring the impacts of this environmental disaster.

Can severe drought periods increase metal concentrations in mangrove sediments? A case study in eastern Brazil

Mangrove ecosystems are essential to society, providing ecological and economic services, and play a crucial role in the geochemical land-ocean interface as a sink for potentially toxic metals. This study assessed metals (Al, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sr and Zn) and arsenic in sediments from three mangrove zones (Tidal Flat, Rhizophora mangle L. and Avicennia schaueriana Stapf & Leechman ex Moldenke forests) during two seasons: spring of 2015 and autumn of 2016, with the latter being a severe drought year. Overall results suggest that Fe/Mn oxyhydroxides and clay minerals control the distribution of metal and arsenic in the Tidal Flat zone. In the mangrove forest however, sulfur and organic matter dominate complexation, with Fe mainly present as insoluble sulfide, and As, Cd, Cu and Zn as metal sulfides or organometallic complexes. In the autumn of 2016, all elements except Cd and Pb had lower concentrations compared to the spring of 2015. Cd and Pb were probably transferred from sources other than mangrove sediments, due to increased saline water intrusion, a consequence of reduced riverine flow, and precipitated in the Rhizophora mangle and Avicennia schaueriana mangrove forests. This increase of Cd and Pb in the mangrove forest suggests potential storage of metal contaminants in the organic rich areas, a change in availability and potential toxicity to fauna and flora and a need for regulatory responses to sediment quality. These results indicate a change in sediment metal contaminant dynamics with the increasing occurrence of extreme weather events - an increased risk to the ecosystem.

Formulations of Melia azedarach to Control Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae) Larvae in Corn and Plant Enhancement

We evaluated oil and powder formulations of Melia azedarach for controlling larvae of Diabrotica speciosa (Germar) in corn and plant enhancement. Five concentrations of each formulation were evaluated and compared to fipronil (negative control) and distilled water (positive control). After treatment, the number of surviving insects (larvae, pupae, and adults), the adult body weight, the sex ratio, and the longevity were recorded, while the height, dry weight of aerial part and roots, and number of leaves of plants were measured. The oil formulation at 4.0 mL reduced the larvae population of D. speciosa similarly to the insecticide fipronil, which resulted in greater height, dry weight of the root system, and number of leaves. Powder formulation at concentrations of 40, 80, and 160 mg caused larval mortality above 80%; however, these concentrations did not prevent reduction of plant height and dry weight of aerial part. Further studies assessing the residual period of M. azedarach control against D. speciosa larvae and its phytotoxicity, which are common traits associated with azadirachtin application, are necessary to subsidize the next steps of this alternative control strategy.

Automated pattern-guided principal component analysis vs expert-based immunophenotypic classification of B-cell chronic lymphoproliferative disorders: a step forward in the standardization of clinical immunophenotyping

Immunophenotypic characterization of B-cell chronic lymphoproliferative disorders (B-CLPD) is becoming increasingly complex due to usage of progressively larger panels of reagents and a high number of World Health Organization (WHO) entities. Typically, data analysis is performed separately for each stained aliquot of a sample; subsequently, an expert interprets the overall immunophenotypic profile (IP) of neoplastic B-cells and assigns it to specific diagnostic categories. We constructed a principal component analysis (PCA)-based tool to guide immunophenotypic classification of B-CLPD. Three reference groups of immunophenotypic data files-B-cell chronic lymphocytic leukemias (B-CLL; n = 10), mantle cell (MCL; n = 10) and follicular lymphomas (FL; n = 10)--were built. Subsequently, each of the 175 cases studied was evaluated and assigned to either one of the three reference groups or to none of them (other B-CLPD). Most cases (89%) were correctly assigned to their corresponding WHO diagnostic group with overall positive and negative predictive values of 89 and 96%, respectively. The efficiency of the PCA-based approach was particularly high among typical B-CLL, MCL and FL vs other B-CLPD cases. In summary, PCA-guided immunophenotypic classification of B-CLPD is a promising tool for standardized interpretation of tumor IP, their classification into well-defined entities and comprehensive evaluation of antibody panels.

Positive response to imatinib mesylate therapy for childhood chronic myeloid leukemia

Chronic myeloid leukemia (CML) is rare in the pediatric population, accounting for 2-3% of childhood leukemia cases, with an annual incidence of one case per million children. The low toxicity profile of imatinib mesylate has led to its approval as a front-line therapy in children for whom interferon treatment has failed or who have relapsed after allogeneic transplantation. We describe the positive responses of 2 children (case 1 - from a 7-year-old male since May 2005; case 2 - from a 5-year-old female since June 2006) with Philadelphia-positive chromosome CML treated with imatinib (300 mg/day, orally) for up to 28 months, as evaluated by morphological, cytogenetic, and molecular approaches. Our patients are alive, are in the chronic phase, and are in continuous morphological complete remission.

A probabilistic approach for the evaluation of minimal residual disease by multiparameter flow cytometry in leukemic B-cell chronic lymphoproliferative disorders

Multiparameter flow cytometry has become an essential tool for monitoring response to therapy in hematological malignancies, including B-cell chronic lymphoproliferative disorders (B-CLPD). However, depending on the expertise of the operator minimal residual disease (MRD) can be misidentified, given that data analysis is based on the definition of expert-based bidimensional plots, where an operator selects the subpopulations of interest. Here, we propose and evaluate a probabilistic approach based on pattern classification tools and the Bayes theorem, for automated analysis of flow cytometry data from a group of 50 B-CLPD versus normal peripheral blood B-cells under MRD conditions, with the aim of reducing operator-associated subjectivity. The proposed approach provided a tool for MRD detection in B-CLPD by flow cytometry with a sensitivity of < or =8 x 10(-5) (median of < or =2 x 10(-7)). Furthermore, in 86% of B-CLPD cases tested, no events corresponding to normal B-cells were wrongly identified as belonging to the neoplastic B-cell population at a level of < or =10(-7). Thus, this approach based on the search for minimal numbers of neoplastic B-cells similar to those detected at diagnosis could potentially be applied with both a high sensitivity and specificity to investigate for the presence of MRD in virtually all B-CLPD. Further studies evaluating its efficiency in larger series of patients, where reactive conditions and non-neoplastic disorders are also included, are required to confirm these results.

Antimicrobial activity of some medicinal plants of the Cerrado, Brazil

In order to determine the potential of Cerrado plants as sources of antimicrobial activity, the phytochemical screening of ethanol extracts from Virola surinamensis, Qualea grandiflora, Alchornea castaneifolia, Hancornia speciosa and Curatella americana traditionally used in folk medicine are reported.

Evaluation of piper cubeba extract, (-)-cubebin and its semi-synthetic derivatives against oral pathogens

The activities of the crude ethanol extract from Piper cubeba seeds, (-)-cubebin and its semi-synthetic derivatives were evaluated against oral pathogens. The crude ethanol extract was more active against Streptococcus salivarius (MIC value of 80 microg/mL). (-)-Cubebin displayed MIC values ranging from 0.20 mm for Streptococcus mitis to 0.35 mm for Enterococcus faecalis. The natural product (-)-cubebin and its semi-synthetic derivative (-)-hinokinin displayed bacteriostatic activity at all evaluated concentrations, as well as fungicidal activity against Candida albicans at 0.28 mm. The O-benzyl cubebin derivative showed fungistatic and fungicidal effects against C. albicans at 0.28 mm and 0.35 mm, respectively. Also, the other dibenzylbutyrolactone derivatives [(-)-6,6'-dinitrohinokinin and (-)-O-(N,N-dimethylaminoethyl)-cubebin] displayed bacteriostatic and fungistatic effects at the evaluated concentrations. Moreover, the semi-synthetic derivative (-)-6,6'-dinitrohinokinin was the most active compound against all the evaluated microorganisms. Therefore, it may be suggested that the presence of the carbonyl group at C-9 plus the introduction of polar groups in the aromatic rings improve the antimicrobial activity of dibenzylbutyrolactone compounds.

A new automated flow cytometry data analysis approach for the diagnostic screening of neoplastic B-cell disorders in peripheral blood samples with absolute lymphocytosis

Currently, multiparameter flow cytometry immunophenotyping is the selected method for the differential diagnostic screening between reactive lymphocytosis and neoplastic B-cell chronic lymphoproliferative disorders (B-CLPD). Despite this, current multiparameter flow cytometry data analysis approaches still remain subjective due to the need of experienced personnel for both data analysis and interpretation of the results. In this study, we describe and validate a new automated method based on vector quantization algorithms to analyze multiparameter flow cytometry immunophenotyping data in a series of 307 peripheral blood (PB) samples. Our results show that the automated method of analysis proposed compares well with currently used manual approach and significantly improves semiautomated approaches and, that by using it, a highly efficient discrimination with 100% specificity and 100% sensitivity can be made between normal/reactive PB samples and cases with B-CLPD based on the total B-cell number and/or the sIgkappa+/sIglambda+ B-cell ratio. In addition, the method proved to be able to detect the presence of pathologic neoplastic B-cells even when these are present at low frequencies (<5% of all lymphocytes in the sample) and in poor-quality samples enriched in 'noise' events.

T-lymphocyte function from peripheral blood stem-cell donors is inhibited by activated granulocytes

BACKGROUND

PBSC transplant provides 10 times more T cells than BMT However, the incidence and severity of acute GvHD is similar among recipients of both types of transplants. Studies in mouse models suggest that the similar clinical outcome in BMT and PBSCT is due to differences in the lymphokine profiles.

METHODS

PBMC, PBMC from G-CSF mobilized donors (G-PBMC)and BM mononuclear cells (BM-MC) were analyzed by flow cytometry and ELISA to detect gamma-IFN and IL-4 production. Hematoxylin and eosin staining was used to identify morphology and annexin/propidium-iodide was used for apoptosis assays.

RESULTS

We show decreased production of gamma-interferon (85%) and IL-4 (60%) in G-PBMC when compared with either PBMC or BM-MCT cells on ex vivo assays. Surprisingly, 85% of fresh G-PBMC is composed of low-density granulocytes (LDG), which undergo apoptosis after 48 h in culture. At this same time, gamma-IFN production from G-PBMC T cell was reverted. In vitro, G-CSF converts granulocytes into LDGs, able to inhibit T-cell function by H2O2 production, and not through immune-deviation towards a Th2-type phenotype.

DISCUSSION

We show that the estimated numbers of Th1 and Th2 cells infused in BMT and PBSCT do not differ significantly. These findings are discussed with reference to the relatively low incidence of acute GvHD in PBSCT shown in the literature. We suggest that these results might depend on the high number of granulocytes and progenitors infused. The potential use of granulocytes as immunosupressive short-term therapy is now being investigated by our group using a mouse experimental model.