Availability of polycyclic aromatic hydrocarbons to earthworms in urban soils and its implications for risk assessment.

Polycyclic aromatic hydrocarbons (PAHs) are a global problem, and in urban soils they can be found at potentially hazard levels. Nevertheless, the real risks that these contaminants pose to the environment are not well known, since the bioavailability of PAHs in urban soils has been poorly studied. Therefore, the bioavailability of PAHs in some selected urban soils from Lisbon (Portugal) was evaluated. Moreover, the applicability of a first screening phase based on total contents of PAHs was assessed. Results show that bioavailability of PAHs is reduced (low levels in earthworms, low accumulation percentages, and low biota-to-soil accumulation factors values), especially in more contaminated soils. The aging of these compounds explains this low availability, and confirms the generally accepted assumption that accumulation of PAHs in urban areas is mostly related with a long-term deposition of contaminated particles. The comparison of measured PAHs concentrations in earthworm tissues with the ones predicted based on theoretical models, reinforce that risks based on total levels are overestimated, but it can be a good initial approach for urban soils. This study also highlights the need of more reliable ecotoxicological data.

Design of selection schemes to include tick resistance in the breeding goal for Hereford and Braford cattle.

Ticks are one of the main causes of losses in cattle, causing economic impact by reducing productivity and fertility and by transmission of diseases. The objective of this study was to analyze the genetic gains obtained through different strategies to include traditional (EBV) or genomic EBV (GEBV) for tick count (TC) in selection indexes for Hereford and Braford cattle. Besides TC, we also considered traits currently included in the Delta G Breeding Program Index (DGI): preweaning gain, weaning conformation, weaning precocity, weaning muscling, postweaning gain, yearling conformation, yearling precocity, yearling muscling, and scrotal circumference. Genetic gain per generation (ΔG) was evaluated using the current DGI and including TC in 8 alternative scenarios with TC relative weightings of 10, 50, or 100% and using phenotype or GEBV. Genomic EBV accuracy () ranged between 0.1 and 0.9. As expected, increasing increases the accuracy of the index () for all scenarios in which GEBV were considered. As the relative weight of TC was increased to 50%, greater ΔG differences in relation to the baseline DGI ($53.03) scenario were observed when the GEBV information was included with equal to or greater than 0.7 only for TC (ΔG between $61.06 and $74.26) or equal to or greater than 0.5 for all traits (ΔG between $56.03 and $83.36). To achieve these accuracies for traits with low heritability, a large calibration data set would be required. Focusing only on TC, the availability of genomic information would be desirable to avoid the need to count ticks and the exposure of animals to parasitism risks. However, for = 0.7, the respective numbers for Hereford and Braford would be 4,703 and 6,522 animals. As expected, when comparing the relative index weights of 10, 50, and 100% for TC, the highest response to selection per generation (RS) for TC was in the scenario was with 100% relative weight and GEBV for this trait (SR = -0.09 SD with = 0.9). This would be the recommended scenario to form tick-resistant lines in Hereford and Braford cattle. However, with 50% relative weight for TC, including GEBV information for TC only or for all traits in index ( = 0.9), it should yield 93 or 84% of RS, respectively, compared to that obtained with full emphasis on TC (100% relative weight) and GEBV information. This indicates that in the presence of highly accurate GEBV, despite slightly slower gain for TC, indexes with 50% relative weight for TC are interesting alternatives to jointly improve tick resistance and other relevant traits.

Investigating relationships between biomarkers of exposure and environmental copper and manganese levels in house dusts from a Portuguese industrial city.

This study reports on data obtained from a pilot survey focusing on house dust and toenail metal(loids) concentrations in residents living in the industrial city of Estarreja. The study design hereby described aims at investigating relationships between human toenails and both copper and manganese levels in settled house dusts. A total of 21 households and 30 individuals were recruited for the pilot study: 19 households corresponding to 27 residents living near the industrial complex, forming the exposed group, plus 2 households and 3 residents from residential areas with no anticipated environmental contaminants that were used for comparison. Factorial analysis was used for source identification purposes. Investigation on the potential influence of environmental factors over copper and manganese levels in the toenails was carried out via questionnaire data and multiple correspondence analysis. The results show that copper concentrations are more elevated in the indoor dusts, while manganese concentrations are more elevated in the outdoor dust samples. The geometrical relationships in the datasets suggest that the backyard soil is a probable source of manganese to the indoor dust. Copper and manganese contents in the toenail clippings are more elevated in children than in adults, but the difference between the two age groups is not statistically significant (p > 0.05). Investigation of environmental factors influencing the exposure-biomarker association indicates a probable relationship between manganese contents in indoor dust and manganese levels in toenail clippings, a result that is partially supported by the bioaccessibility estimates. However, for copper, no relationship was found between indoor dusts and the biomarkers of exposure.

Assessment of the influence of traffic-related particles in urban dust using sequential selective extraction and oral bioaccessibility tests.

Urban dust is a heterogeneous mix, where traffic-related particles can combine with soil mineral compounds, forming a unique and site-specific material. These traffic-related particles are usually enriched in potentially harmful elements, enhancing the health risk for population by inhalation or ingestion. Urban dust samples from Estarreja city and traffic-related particles (brake dust and white traffic paint) were studied to understand the relative contribution of the traffic particles in the geochemical behaviour of urban dust and to evaluate the long-term impacts of the metals on an urban environment, as well as the risk to the populations. It was possible to distinguish two groups of urban dust samples according to Cu behaviour: (1) one group with low amounts of fine particles (<38 µm), low contents of organic material, high percentage of Cu in soluble phases, and low Cu bioaccessible fraction (Bf) values. This group showed similar chemical behaviour with the brake dust samples of low- to mid-range car brands (with more than 10 years old), composed by coarser wear particles; and (2) another group with greater amounts of fine particles (<38 µm), with low percentage of Cu associated with soluble phases, and with greater Cu Bf values. This group behaved similar to those found for brake dust of mid- to high-range car brands (with less than 10 years old). The results obtained showed that there is no direct correlation between the geoavailability of metals estimated by sequential selective chemical extraction (SSCE) and the in vitro oral bioaccessibility (UBM) test. Thus, oral bioaccessibility of urban dust is site specific. Geoavailability was greatly dependent on particle size, where the bioaccessibility tended to increase with a reduction in particle diameter. As anthropogenic particles showed high metal concentration and a smaller size than mineral particles, urban dusts are of major concern to the populations' health, since fine particles are easily re-suspended, easily ingested, and show high metal bioaccessibility. In addition, Estarreja is a coastal city often influenced by winds, which favours the re-suspension of small-sized contaminated particles. Even if the risk to the population does not represent an acute case, it should not be overlooked, and this study can serve as baseline study for cities under high traffic influence.

The mobility and human oral bioaccessibility of Zn and Pb in urban dusts of Estarreja (N Portugal).

Twenty-one samples of urban dust were collected from Estarreja city (Portugal). The main objective of this work was to assess the potential availability of Pb and Zn present dust samples from Estarreja city via the oral ingestion exposure route using a combination of geochemical tests: (a) using sequential extraction to identify the fractionation of the Pb and Zn within the geochemical components that make up the dust and (b) in vitro bioaccessibility (BA) measurements to identify which components are the source(s) of the bioaccessible fraction (Bf). These samples were analysed for their quasi-total contents of Pb and Zn by inductively coupled plasma mass spectrometry, for their element solid-phase distribution using selective sequential extraction method and for the Bfs of these elements using a physiologically based extraction test. The study showed that the concentrations of Zn were higher than Pb, but both are site-specific. The sequential extraction test shows that the exchangeable and acid-soluble phases are important bearing phases for Pb and Zn. The BA test showed that a high proportion of the total concentration is available for absorption into the human body (ranges from 22.5 to 84.1% for Pb and 28.7 to 86.3% for Zn).

Efeito da contagem de células somáticas sobre o rendimento e a composição físico-química do queijo muçarela / The effect of somatic cell count on yield and physico-chemical composition of Mozzarella cheese

Determinou-se o efeito da contagem de células somáticas do leite sobre o rendimento e a composição físico-química do queijo muçarela. Foram selecionadas vacas com contagem de células somáticas (CCS) <200.000 células/mL; CCS >200.000 a <400.000 células/mL; CCS >400.000 células/mL a <750.000 células/mL e CCS >750.000 células/mL e que não receberam tratamento com antimicrobianos nos dias que antecederam a obtenção do leite utilizado no processamento. Os queijos foram avaliados por meio das análises de pH, acidez, umidade, proteína, gordura, extrato seco total e desengordurado. Os queijos elaborados do leite com alta CCS >750.000 cél./mL apresentaram menor teor de proteína, maior umidade e menor rendimento industrial. Conclui-se que a elevação da CCS cursou com alterações na qualidade do queijo muçarela, o que reflete em sua composição nutricional e microbiológica, pois ocorre um incremento na atividade de água, fator intrínseco indispensável para o crescimento microbiano e consequente redução da vida de prateleira...

The effect of somatic cell count (SCC) on the yield and composition of mozzarella cheese was evaluated. Cows with different levels of SCC in their milk (<200.000 cells/mL; >200.000 to <400.000 cells/mL; >400.000 cells/mL to <750.000 cells/mL and >750.000 cells/mL) were selected. The animals had no antimicrobial treatment prior to or on milk sampling day. The mozzarella cheese quality was evaluated analyzing pH, acidity, moisture and protein content, fat, total solids and nonfat solids. The trial was replicated four times and the experimental design was analyzed through randomized blocks. The mozzarella cheese from milk with high SCC (>750.000 cells/mL) had lower protein content, higher moisture content and lower industrial yield, compared to cheese from milk with lower levels of SCC. High numbers of SCC impaired mozzarella cheese quality, which was reflected in its nutritional and microbiological composition. We observed an increase in water activity, an intrinsic and essential factor for microbial growth...

Geochemistry, mineralogy, solid-phase fractionation and oral bioaccessibility of lead in urban soils of Lisbon.

An urban survey of Lisbon, the largest city in Portugal, was carried out to investigate its environmental burden, emphasizing metallic elements and their public health impacts. This paper examines the geochemistry of lead (Pb) and its influence on human health data. A total of 51 soil samples were collected from urban recreational areas used by children to play outdoors. The semi-quantitative analysis of Pb was carried out by inductively coupled plasma mass spectrometry after an acid digestion. X-ray diffraction was used to characterize the soil mineralogy. The solid-phase distribution of Pb in the urban soils was investigated on a subset of 7 soils, out of a total of 51 samples, using a non-specific sequential extraction method coupled with chemometric analysis. Oral bioaccessibility measurements were obtained using the Unified BARGE Method developed by the Bioaccessibility Research Group of Europe. The objectives of the study are as follows: (1) investigation of Pb solid-phase distribution; (2) interpretation of Pb oral bioaccessibility measurements; (3) integration of metal geochemistry with human health data; and (4) understanding the influence of geochemistry and mineralogy on oral bioaccessibility. The results show that the bioaccessible fraction of Pb is lower when major metal fractions are associated with less soluble soil phases such as Fe oxyhydroxides, and more increased when the metal is in the highly soluble carbonate phase. However, there is some evidence that the proportion of carbonates in the soil environment is also a key control over the oral bioaccessibility of Pb, irrespective of its solid-phase fractionation.

Assessing human exposure to aluminium, chromium and vanadium through outdoor dust ingestion in the Bassin Minier de Provence, France.

The Western part of the "Bassin Minier de Provence", a former coal mining area, is still occupied by old polluting industries such as a coal-fired power plant and an alumina factory. The identified pollution sources that raise more concern in the population are the emission of gases and dusts, as well as the storage of raw and transformed materials. In 2011, a preliminary survey was carried out in the area as the first step to an exposure and health risk-assessment study. This first survey intends to assess human exposure through ingestion and health risk associated with potentially harmful elements (PHEs) in ground-level dusts collected in recreational areas used by children. Dust samples were taken at 19 sites distributed across the study area, depending on the location of public parks, public gardens, playgrounds and schools. Pseudo-total concentrations of 53 elements were determined by ICP-MS. Bioaccessible concentrations were estimated using the unified bioaccessibility method. This study presents the results obtained for Al, V and Cr, which seem to be related with industry and show similar distribution patterns. PHEs presumably related to traffic or other urban pollution sources are not discussed in this study. The highest total concentrations occur in dusts near the alumina plant that have significant amounts of Al mineral phases (gibbsite and alumina). However, in these dusts only small fractions of the elements under study are in bioaccessible forms. The highest bioaccessible fractions occur in dusts collected near the coal-fired power plant. Further investigation is required to assess potential pathways of exposure and health risk in this area.

Metal fractionation of cadmium, lead and arsenic of geogenic origin in topsoils from the Marrancos gold mineralisation, northern Portugal.

The Marrancos gold mineralisation has a chemical assemblage of Fe-As-Se-Bi-Au-Ag-Te-(Cu-Pb-Zn-Sn-W). The -200 mesh of 144 topsoil samples was analysed by ICP-MS to determine total contents of 53 elements that include potentially harmful elements like Cd, As and Pb. The soil geochemistry shows that some trace elements occur in considerably high concentrations. On the basis of data for total metal concentrations, 10 topsoil samples were selected to carry out a metal fractionation study using a selective extraction method. A set of four leaches of increasing strength was used sequentially in the soil samples. Across the study area, there is some evidence of past mining and exploration activity, indicating that these soils may be locally disturbed. The shallow mineralised quartz veins were exploited for gold by the Romans. Several galleries were constructed during the 2nd World War, probably for the exploration of quartz-cassiterite-wolframite veins. However, the main mineralised body in depth was never explored. The results of metal fractionation show different partitions for the three elements. Total Cd concentrations in these soils are low, with a median value of 0.1 mg/kg. In average, 12% of total Cd is adsorbed by clays and/or co-precipitated with carbonates, and 19% is bounded to Fe-Mn oxyhydroxides. However, the low concentrations indicate that the metal does not represent an immediate risk to human health. For Pb, metal fractionation shows that, on average, 22% of Pb is adsorbed by amorphous Fe and Mn oxides, but the samples from the northern part of the area have the major fractions of Pb in soluble forms. The low probability of exposure in this part of the study area decreases the risk posed by this heavy metal. Total As concentrations in the Marrancos soils are extremely high. A large area has As concentrations above 1,000 mg/kg. For As, metal fractions in the sulphide phase vary between 84 and 98% in the studied samples. But one sample has 20% of total As in easily reducible forms, corresponding to a partial concentration of 1,800 mg/kg that has a high probability of being bioavailable. The most labile As forms occur at the southern part of the area, where the probability of exposure is higher and the risk of human health increases in the same order. From the three studied potentially harmful elements, As is certainly the element of concern.

Lead availability in soils from Portugal's Centre Region with special reference to bioaccessibility.

Previous environmental biomonitoring studies indicated higher environmental lead (Pb) pollution levels at the districts of Aveiro and Leiria (Portugal). In evaluating the risk for human health, which is associated with contaminated soils after oral uptake, total soil concentrations have generally been held against criteria established from toxicological studies based upon the assumption that the uptake of the contaminant is similar in the toxicological studies and from the soils assessed. This assumption is not always valid, as most toxicological studies are carried out with soluble forms of the contaminants, whereas many soil contaminants are or become embedded in the soil matrix and thus exhibit limited availability. This study intends to estimate the soluble fraction of Pb in the soils from central Portugal, and to assess the bioaccessibility of Pb and, hence, infer exposure and risk for human health. Yet, as the physical-chemical properties of the soil exert some control over the solubility of Pb in the surface environment, the relation between such soil properties and the estimated soluble and/or bioaccessible fractions of Pb is also investigated. Other objective, with a more practical nature, was to give some contribution to find a suitable in vitro mimetic of the gastrointestinal tract environment. The results indicate relatively low total metal concentrations in the soils, even if differences between regions were observed. The Aveiro district has the higher total Pb concentration and the metal is in more soluble forms, that is, geoavailable. Soils with higher concentrations of soluble Pb show higher estimates of bioaccessible Pb. Soil pH seems to influence human bioaccessibility of Pb.

Altered cysteine proteinase activity in insecticide-resistant strains of the maize weevil: purification and characterization.

Insecticide resistance is usually associated with fitness costs, but such costs may be mitigated by increased energy and amino acid accumulation and mobilization as has been suggested in the maize weevil Sitophilus zeamais (Coleoptera: Curculionidae). To address this adaptation, cysteine proteinases (E.C. 3.4.22), one of the main proteinases in weevils, was purified from an insecticide-susceptible and two insecticide-resistant strains of the maize weevil (one with fitness costs, referred as resistant-cost, and the other without it, referred to as resistant no-cost) using thiol-sepharose affinity chromatography. Purification of the cysteine proteinases revealed a single 74,000 Da molecular mass band in the susceptible strain, two bands of 72,000 and 83,000 Da in the resistant cost strain, and two bands of 68,000 and 74,000 Da in the resistant no-cost strain. Purified cysteine proteinases of the three strains behaved differently regarding casein degradation and inhibition; the proteinases least sensitive to inhibition by the specific cysteine proteinase inhibitor E-64 were those from the resistant no-cost strain as indicated by their highest I(50) value. The pH and temperature profile of cysteine proteinase activity differed among strains and although substrate affinity (i.e. K(M)) of the cysteine proteinases was similar, the V(max) value for cysteine-proteinases from the resistant cost strain was 3-fold and 5-fold higher than V(max) values for the resistant no-cost and susceptible strains respectively. Cysteine proteinase activity was highest for the resistant cost strain rather than the resistant no-cost. Therefore enhanced cysteine proteinase activity is unlikely to be playing significant role in mitigating the costs usually associated with insecticide resistance.

Modified alpha-amylase activity among insecticide-resistant and -susceptible strains of the maize weevil, Sitophilus zeamais.

Fitness cost is usually associated with insecticide resistance and may be mitigated by increased energy accumulation and mobilization. Preliminary evidence in the maize weevil (Coleoptera: Curculionidae) suggested possible involvement of amylases in such phenomenon. Therefore, alpha-amylases were purified from an insecticide-susceptible and two insecticide-resistant strains (one with fitness cost [resistant cost strain], and the other without it [resistant no-cost strain]). The main alpha-amylase of each strain was purified by glycogen precipitation and ion-exchange chromatography (>or=70-fold purification,

Partial purification and characterization of trypsin-like proteinases from insecticide-resistant and -susceptible strains of the maize weevil, Sitophilus zeamais.

Serine proteinases from three strains of Sitophilus zeamais (Coleoptera: Curculionidae), one susceptible and two resistant to insecticides--one exhibiting fitness cost (resistant cost strain) and the other lacking it (resistant no-cost strain), were partially purified using an aprotinin-agarose affinity column providing purification factors ranging from 36.5 to 51.2%, with yields between 10 and 15% and activity between 529 and 875 microM/min/mg protein with the substrate N-alpha-benzoyl-L-Arg-p-nitroanilide (L-BApNA). SDS-PAGE of the purified fraction revealed a 56,000 Da molecular mass band in all strains and a 70,000 Da band more visible in the resistant no-cost strain. The purified proteinases from all strains were inhibited by phenylmethyl sulphonyl fluoride (PMSF), N-alpha-tosyl-L-lysine chloromethyl ketone (TLCK), aprotinin, benzamidine and soybean trypsin inhibitor (SBTI) characterizing them as trypsin-like serine proteinases. Trypsin-like proteinases from the resistant strains exhibited higher affinity for L-BApNA. The resistant no-cost strain exhibited V(max)-values 1.5- and 1.7-fold higher than the susceptible and resistance cost strains, respectively. A similar trend was also observed when using N-alpha-p-tosyl-L-Arg methyl ester (L-TAME) as substrate. These results provide support to the hypothesis that the enhanced serine proteinase activity may be playing a role in mitigating physiological costs associated with the maintenance of insecticide resistance mechanisms in some maize weevil strains.

Spatial patterns of dispersion and pollution sources for arsenic at Lousal mine, Portugal.

This study uses geostatistical modelling to identify hot spots of metal contamination produced by hazardous mining tailings from an inoperative Portuguese mine. Lousal is one of the many massive sulphide deposits of the Iberian Pyrite Belt. The mine is now closed, but the heavy metal enriched tailings remain at the site. Applying geostatistics to the diagnosis of this potentially contaminated area we aim to assess the quality of the soil, namely through a risk probability mapping for arsenic, for a better knowledge about the vulnerability of the soil to arsenic contamination. To achieve this aim, the initial variable was transformed into two indicator variables using the risk-based standards (intervention values) for soils, as proposed by Swartjes (1999), as the limit value. To account for the spatial structure, sample variograms were computed for the main directions of the sampling grid and a spherical model was fitted to the variables (arsenic raw data and indicator variables). The parameters of the model were used in the estimation process. To assess the vulnerability of the soil towards the mining works, a soil quality probability mapping for arsenic was carried out showing contamination probabilities in the area. The use of indicator kriging, as an alternative to other more complex kriging methods, in the soil data of the Lousal mine, produced unbiased soil quality maps.

Application of geostatistical methods to arsenic data from soil samples of the Cova dos Mouros mine (Vila Verde-Portugal).

A total of 286 soil samples were collected in the Cova dos Mouros area. All samples were dry sieved into the <200 mesh size fraction and analysed for Fe, Cu, Zn, Pb, Co, Ni, Bi and Mn by atomic absorption spectrometry (AAS) and for As, Se, Sb and Te by atomic absorption spectrometry-hydrid generation (AAS-HG). Only the results of arsenic are discussed in this paper although the survey was extended to all analysed chemical elements. The purpose of this study was to make a risk probability mapping for arsenic that would allow better knowledge about the vulnerability of the soil to arsenic contamination. To achieve this purpose, the initial variable was transformed into an indicator variable using as thresholds the risk-based standards (intervention values) for soils, as proposed by [Swartjes 1999. Risk based assessment of soil and groundwater quality in the Netherlands: Standards and remediation. J. Geochem. Explor.73 1-10]. To account for spatial structure, sample variograms were computed for the main directions of the sampling grid and a spherical model was fitted to each sample variogram (arsenic variable and indicator variables). The parameters of the spherical model fitted to the arsenic variable were used to predict arsenic concentrations at unsampled locations. A risk probability mapping was also done to assess the vulnerability of the soil towards the mining works. The parameters of the spherical model fitted to each indicator variable were used to estimate probabilities of exceeding the corresponding threshold. The use of indicator kriging as an alternative to ordinary kriging for the soil data of Cova dos Mouros produced unbiased probability maps that allowed assessment of the quality of the soil.

Exploiting micellar environment for simultaneous electrochemical determination of ascorbic acid and dopamine.

A simple and reliable method for simultaneous electrochemical determination of ascorbic acid (AA) and dopamine (DA) is presented in this work. It was based on the use of the cationic surfactant cetylpyridinium chloride (CPC) that enables the separation of the oxidation peaks potential of AA and DA. Cyclic voltammetry (CV) as well as pulse differential voltammetry (PDV) were used in order to verify the voltammetric behaviour in micellar media. In the cationic surfactant CPC, a remarkable electrostatic interaction is established with negatively charged AA, as a consequence, the oxidation peak potential shifted toward less positive potential and the peak current increased. On the other hand, the positively charged DA is repelled from the electrode surface and the oxidation peak potential shifts toward more positive potential in comparison to the bare electrode. Therefore, the common overlapped oxidation peaks of AA and DA can be circumventing by using CPC. Parameter that affects the E(pa) and I(pa) such as CPC concentration and pH were studied. Under optimised conditions, the method presented a linear response to AA and DA in the concentration range from 5 to 75 micromol L(-1) and 10 to 100 micromol L(-1), respectively. The proposed method was successfully applied to the simultaneous determination of AA and DA in dopamine hydrochloride injection (DHI) samples spiked with AA.

Percutaneous splenic embolization of the splenic artery in the treatment of hypersplenism.

Percutaneous splenectomy was performed in 6 patients with hypersplenism. Peripheral blood cell counts improved in 5 of the patients. The authors review the indications, technique and complications of percutaneous splenic embolization. It is concluded that medical splenectomy is an effective method particularly to alleviate symptoms of hypersplenism.

T and B lymphocytes in South American pemphigus foliaceus.

T and B lymphocytes were quantified in peripheral blood of thirty patients with South American pemphigus foliaceus according to their ability to form rosettes with sheep erythrocytes (E) or sheep erythrocytes sensitized with antibody an complement (EAC). When compared with the counts obtained from thirty normal subjects, a decrease was found in the total T-lymphocyte count (32-33+/-7-7 versus 46-7+/-8-7) and in the T functional lymphocyte count as detected by the active rosette test. The mean percentage of B lymphocytes within the total number of lymphocytes was not significantly different from that of normal subjects (24-0 +/- 8-2 versus 25-3+/-8-0). Lymph node sections from three pemphigus patients examined for E or EAC adherence showed depletion of T cells in the paracortical areas. The low percentage of E cells in the peripheral blood and the depletion of E cells in paracortical areas of lymph nodes from patients with South American pemphigus foliaceus may reflect an impaired cellular immunity.