Mechanisms of Immunotoxicity: Stressors and Evaluators

The immune system defends the body against certain tumor cells and against foreign agents such as fungi, parasites, bacteria, and viruses. One of its main roles is to distinguish endogenous components from non-self-components. An unproperly functioning immune system is prone to primary immune deficiencies caused by either primary immune deficiencies such as genetic defects or secondary immune deficiencies such as physical, chemical, and in some instances, psychological stressors. In the manuscript, we will provide a brief overview of the immune system and immunotoxicology. We will also describe the biochemical mechanisms of immunotoxicants and how to evaluate immunotoxicity.

Immune System: An Emerging Player in Mediating Effects of Endocrine Disruptors on Metabolic Health

The incidence of metabolic disorders like type 2 diabetes and obesity continues to increase. In addition to the well-known contributors to these disorders, such as food intake and sedentary lifestyle, recent research in the exposure science discipline provides evidence that exposure to endocrine-disrupting chemicals like bisphenol A and phthalates via multiple routes (e.g., food, drink, skin contact) also contribute to the increased risk of metabolic disorders. Endocrine-disrupting chemicals (EDCs) can disrupt any aspect of hormone action. It is becoming increasingly clear that EDCs not only affect endocrine function but also adversely affect immune system function. In this review, we focus on human, animal, and in vitro studies that demonstrate EDC exposure induces dysfunction of the immune system, which, in turn, has detrimental effects on metabolic health. These findings highlight how the immune system is emerging as a novel player by which EDCs may mediate their effects on metabolic health. We also discuss studies highlighting mechanisms by which EDCs affect the immune system. Finally, we consider that a better understanding of the immunomodulatory roles of EDCs will provide clues to enhance metabolic function and contribute toward the long-term goal of reducing the burden of environmentally induced diabetes and obesity.

History of chemical sensitivity and diagnosis

Histories of mold, pollen, dust, food, chemicals, and electromagnetic field (EMF) sensitivities are the major categories of triggers for chemical sensitivity. They are tied together by the coherence phenomenon, where each has its own frequencies and identifiable EMF; therefore, they can be correlated. The diagnosis of chemical sensitivity can be done accurately in a less-polluted, controlled environment, as was done in these studies. The principles of diagnosis and treatment depend on total environmental and total body pollutant loads, masking or adaptation, bipolarity of response, and biochemical individuality, among others. These principles make less-polluted, controlled conditions necessary. The clinician has to use less-polluted water and organic food with individual challenges for testing, including dust, mold, pesticide, natural gas, formaldehyde, particulates, and EMF testing, which needs to be performed in less-polluted copper-screened rooms. The challenge tests for proof of chemical sensitivity include inhaled toxics within a clean booth that is chemical- and particulate-free at ambient doses in parts per million (ppm) or parts per billion (ppb). Individual foods, both organic and commercial (that are contaminated with herbicides and pesticides), are used orally. Water testing and intradermal testing are performed in a less-polluted, controlled environment. These include specific dose injections of molds, dust, and pollen that are preservative-free, individual organic foods, and individual chemicals, i.e. methane, ethane, propane, butane, hexane, formaldehyde, ethanol, car exhaust, jet fuel exhaust, and prosthetic implants (metal plates, pacemakers, mesh, etc.). Normal saline is used as a placebo. EMF testing is performed in a copper-screened room using a frequency generator. In our experience, 80% of the EMF-sensitive patients had chemical sensitivity when studied under less-polluted conditions for particulates, controlled natural gas, pesticides, and chemicals like formaldehyde.

The environment and antiphospholipid syndrome

The etiology of autoimmune diseases is multifactorial. The degree to which genetic and environmental factors influence susceptibility to autoimmune diseases is poorly defined. It is believed that versatile clinical presentations of autoimmune diseases stem from various combinations of the genetic and environmental factors. One of the newly diagnosed autoimmune diseases is the antiphospholipid syndrome (APS). APS is characterized by vascular thrombosis, and/or pregnancy morbidity associated with anticardiolipin (aCL), anti-β2-glycoprotein-I (anti-β2GPI) and lupus anticoagulant (LAC).

[Individual risks to adolescent health, caused by contaminating the air, and their relationship with the levels of specific autoantibodies]

The high levels of the air pollution create prerequisites for the development of the pathology of target organs exposed to chemical agents. Big enterprises of oil refining and chemical industry of the Irkutsk region are located in the cities of Angarsk and Sayansk. The average level of the air pollution for several years in these cities is assessed as high and moderate, respectively. The use of the personalized approach may allow to more correctly evaluate the risk for the damage to health and the body’s response to external impacts. The purpose of this study was to assess the risk offormation ofpathological processes in the body of adolescents in the conditions of inhalation exposure to chemicals, taking into account the individual load and study of the level of specific autoantibodies. The study included 373 adolescents from the city with high levels of air pollution and 188 schoolchildren from the city with a moderate level pollution. There was made an evaluation of the individual chemical hazard load on adolescents ’ body due to the air pollution, physiologicalfeatures and the organization of educational process and leisure. There were studied the levels of specific autoantibodies, reflecting the state of the organs - targets for the impact ofpollutants. The calculation of the individual chemical load allows to calculate indices of the hazard for the health problems of each individual and to identify individuals at increased risk of developing diseases of organs and systems, which are targets for exposure to pollutants. The increase in the hazard index of developing respiratory diseases was found to be accompanied by an increase of the relative content of autoantibodies against membrane antigens of the lung tissue. There was revealed the elevation in autoantibodies levels to the proteins of vascular endothelial with increasing hazard index of disturbances in the cardiovascular system in adolescents living in city with high levels of air pollution.

[Application of immuno-biochemical indices for the identification of the chronic pathology of the upper respiratory tract]

A comprehensive survey of organized children aged 14-17 years residing in the industrial centers with moderate and high levels of air pollution was performed. On the base of the examination of otorhinolaryngologist in the each of cities there was selected the group of schoolchildren with chronic pathology of the upper respiratory tract at the stage of remission. In these groups there was performed the assessment of the informativeness of immuno-biochemical indices for the identification of pathology caused by the impact of man-made factors. The most informative (relative content of autoantibodies to β2-glycoprotein-1, the average individual immunoreactivity, erythrocyte sedimentation rate, level of α1-antitrypsin) were used in the mathematical model, on the based of which it was possible to calculate the diagnostic coefficient, allowing to identify in the groups observed by ourselves, chronic pathology of upper respiratory tract, formed under the influence of ambient air pollution. The above approach can be used in the formation groups for health promotion of children exposed to the negative impact.

[Efficacy of immunomodulators in children with respiratory diseases in environmentally poor areas]

The authors evaluated the clinical efficacy and safety of the antiviral and immunomodulatory drug Isoprinosine (inosine pranobex, Teva Pharmaceutical Industries, Ltd) in the treatment of bronchopulmonary diseases in children. One hundred and fifty-two children with acute respiratory diseases and an exacerbation of recurrent respiratory diseases were followed up. The use of Isoprinosine in their combined treatment showed both positive clinical changes and a better immunogram.

[Features of the immune status in the population of urban areas with a high content of heavy metals]

The immune status was studied in of 4000 Aktobe citizens. The findings indicate that cell immunity indicators as the maximally informative parameter are of criteria significance in evaluating the influence of environmental factors on the body. A direct correlation was found between the sensitization to chromium and CD3, CD4, CD8 and the functional response of T lymphocytes to phytohemagglutinin.

[Influence of ambient air pollution on children's health in Krivoĭ Rog]

The degree and nature of surface air pollution with man-made chemicals were studied in Krivoy Rog in 1996 to 2005. The priorities of pollutants were established in the area with different forms of technogenic emissions and residential areas. Immunological parameters were studied in healthy neonates and 7-10-year-old children. There was a reduction in the major immunological parameters in both healthy neonatal infants and 7-10-year-old children and a rise in pediatric morbidity.

[Changes of human immunophenotype during adaptation to environmental factors, in different forms of pathology and their specific treatment]

The aim of the study was to elucidate mechanisms underlying variations of human immune phenotype in the course of adaptation to environmental factors, development of different forms of pathology and their specific treatment from dynamics of expression of surface CD-molecules in lymphocyte plasmolemma and immunoglobulin A, M, G levels in blood plasma. 253 assumingly healthy volunteers residing in the Moscow Megapolis exhibited a tendency toward enhanced lymphocyte apoptosis and reduced efficiency of their co-stimulation and cooperative interaction. Pathologies of different etiology were associated with the imbalance of specific and non-specific reactions of immune and biological control. Specifically, expression of CD 95 (Fas/APO-1) molecules triggering apoptosis increased in all patients with postmenopausal osteoporosis, pneumonia, and bronchial asthma but decreased in patients with rheumatic fever, erosive and ulcerative lesions in the digestive tract. Expression of surface receptors by the cells involved in "processing" of unshared antigens, their presentation by T-lymphocytes, inactivation and destruction of pathogens was enhanced only in patients with erosive and ulcerative lesions in the digestive tract. It decreased in rheumatic fever, postmenopausal osteoporosis, pneumonia, and bronchial asthma. Effective specific treatment leading to the normalization of (or tending to normalize) expression of CD molecules in lymphocytes and prevented changes in the immune and biological control system.

Temporal trends of aeroallergen sensitization over twenty-five years

BACKGROUND

Little is known about time trends of allergic respiratory disease in adults, in particular in older adults. Furthermore, few trend studies have used objective measurements of IgE sensitization against inhalant allergens.

OBJECTIVES

To investigate time trends of aeroallergen sensitization in adults over a 25-year period.

METHODS

The study includes a total of 7820 persons, aged 30, 40, 50, and 60 years, who participated in three repeated cross-sectional studies of the general population of Copenhagen, Denmark, in 1976-1977, 1982-1984, and 1999-2001, respectively. Respiratory allergy was assessed by determination of specific IgE aeroallergen sensitization in stored serum samples.

RESULTS

Over this 25-year period, a marked and statistically significant increase in the prevalence of aeroallergen sensitization had occurred. This increase was seen in all age-groups challenging the notion that the allergy epidemic only affects generations born 1960 onwards. For example, in 40-year-olds the prevalence (with 95% confidence intervals) of aeroallergen sensitization was 14.9% (12.7-17.1), 19.7% (17.1-22.3), and 27.6% (25.1-30.1) in 1976-1977, 1982-1984, and 1999-2001, respectively.

CONCLUSIONS

Our results support that the allergy epidemic has spread to older adults resulting in a continuing increase in the overall prevalence of aeroallergen sensitization and an increase in the mean age of allergic patients.

Chronic helminth infections may negatively influence immunity against tuberculosis and other diseases of public health importance

Tuberculosis (TB) has once again become a major public health threat owing to the combined effects of deteriorating socioeconomic situations and the emergence of the HIV/AIDS pandemic. The only vaccine available against TB, although effective in reducing the burden of childhood TB, shows enormous variability in its efficacy against pulmonary TB, which is the most common form of the disease in adults. Most areas of high TB incidence and poor TB vaccine efficacy have a high prevalence of intestinal helminth infections. Such infections have been shown to cause a range of immunomodulation characterized by enhanced T helper 2-type cytokine profile, high immunoglobulin E levels and upregulated regulatory T-cell activity, as well as chronic immune activation. An altered background immune profile could have adverse effects on the outcome of subsequent infections and vaccinations. In support of this hypothesis, studies conducted in animals and humans living in worm-endemic areas have shown that helminths impair resistance against a number of infections of major public health importance, including TB, malaria and HIV/AIDS. Understanding such interactions could assist in the design of vaccines against these diseases.

Excess dampness and mold growth in homes: an evidence-based review of the aeroirritant effect and its potential causes

Exposure to fungi produces respiratory disease in humans through both allergic and nonallergic mechanisms. Occupants of homes with excess dampness and mold growth often present to allergists with complaints of aeroirritant symptoms. This review describes the major epidemiological and biological studies evaluating the association of indoor dampness and mold growth with upper respiratory tract symptoms. The preponderance of epidemiological data supports a link between exposure to dampness and excess mold growth and the development of aeroirritant symptoms. In addition, biological and clinical studies evaluating potential causal substances for the aeroirritant effect, notably volatile organic compounds (VOCs), are examined in detail. These studies support the role of VOCs in contributing to the aeroirritant symptoms of occupants of damp and mold-contaminated homes.

[Effect of monohydric aliphatic alcohols on children's health]

To form the evidence base of the "environmental determination" of disease is a topical line in human ecology and environmental hygiene. The widespread use of monohydric aliphatic alcohols in industry has determined the necessity of making an in-depth study of their toxic effects on man, by taking into account their actual concentrations forming in the blood. The results of the studies have led to the conclusion that the real risk of toxic exposure of an organism to monohydric alcohols forms when the blood concentrations of butyl alcohols, propyl alcohols, and methyl alcohol are over 0.03, 1.0-1.5, and 0.5 microg/kg/cm3, respectively. Toxic exposure involves immunosuppressive, oxidative, hematoxic, and sensitizing effects and impaired hepatic etherifying function. With the higher toxicity of the compounds, the damaging action of monohydric alcohols on the organism increases and the spectrum of abnormal clinical and laboratory parameters expands.

[Allergic diseases and immunological resistance in children from a petroleum area]

The incidence of allergic diseases was studied in the children living in an oil-extracting region of the Republic of Udmurtia. A hygienic assessment of the level of environmental pollution was made in the study areas. The increased atmospheric contamination was ascertained to cause an increase in the incidence of allergic diseases in children. There was a correlation between the concentration of noxious substances as part of the ambient air and the prevalence of allergic diseases in children. The studies suggest that the children living in the oil-extracting area have worse parameters of nonspecific resistance than do the control children. The findings serve as the basis for developing measure to lower environmental pollution and to reduce the incidence of allergic diseases in children.

Occupational allergic diseases as a clinical model to approach specific environmental reactivity

Hyperreactivity to environmental factors is objectively expressed as respiratory, cutaneous and gastrointestinal disease. Approaching the diagnosis of an occupational disorder, a practical distinction was made between toxicity and allergy. The study of occupational allergic disease included particular procedures that led to standardized models and concepts. The contribution to the improvement of medical knowledge is reviewed according to selected experiences. The diagnostic aspects of asthma, rhinitis, dermatitis and urticaria are considered as regards to methodology of assessment of the occupational etiology with attention to demonstrative examples, which are worthwhile for the general medicine, too. Basic steps of risk agent identification, exposure assessment, threshold dose response measurement, allergen challenges and interaction are the original contribution of the occupational medicine to the diagnosis of allergic disorder. The clinical picture of asthma was clarified by the results of the specific bronchial provocation test, proving the important role of di-isocyanates and metal salts. Occupational rhinitis showed to be connected to asthma with predictive aspects in bakers' disease. Occupational dermatitis was linked to the development of experimental patch tests. Occupational urticaria included the concept of airborne contact allergy or nickel interactive food and occupational sensitivity. Occupational allergic diseases are emerging as a consequence of low environmental exposure, but they were remarkably studied in the past either for pathogenesis or for diagnostic procedures. Methods and acquisition are available also for the general medicine when an individual's specific reactivity is under investigation.

Development of atopy and wheezing symptoms in relation to heredity and early pet keeping in a Swedish birth cohort

The role of pet keeping during infancy for the development of allergy and asthma is still controversial. The objective of this population-based birth cohort study was to assess the development of atopy and different wheezing phenotypes during the first 4 yr of life in relation to heredity and early pet keeping. The cohort comprised all 1228 infants living in a Swedish county who were born over a 1-yr period. The parents replied to repeated questionnaires and 817 of the children were skin prick tested both at 1 and 4 yr. Cat keeping during the first year of life was associated with an increased risk of a positive skin prick test to cat at 1 yr of age [odds ratio (OR) 2.2, 95% confidence interval (CI) 0.9-5.6], but neither with sensitivity nor clinical symptoms of allergy at 4 yr. Dog keeping during the first year of life was associated with an increased risk of early-onset transient wheezing, but only in children with parental asthma (adjusted OR 4.3, 95% CI 1.5-12.1). In contrast, early dog keeping had an inverse association with sensitivity to pollen allergen at 4 yr (adjusted OR 0.3, 95% CI 0.1-0.9) and late-onset wheezing (adjusted OR 0.4, 95% CI 0.2-1.0). Thus, pet keeping during the first year of life was not associated with an increased risk of atopy at 4 yr, although a positive SPT to cat was more common at 1 yr. Our findings may even suggest that dog keeping during the first year of life might provide some protection from pollen allergy and late-onset wheezing and increase the risk of early-onset transient wheezing in children with heredity for asthma.

[Immunologic criteria of health changes caused by chemicals polluting environment in infants and pregnant women]

The authors revealed relations-hip between pregnancy disorders and changed humoral immunity parameters including production of anti-hapten antibodies to chemical pollutants (formaldehyde, nickel and lead). The authors disclosed reliable correlations between immune disorders in pregnancy and specific diseases in newborns and infants.

Analysis for Mycotoxins: The Chemist's Perspective

Mycotoxins are fungal metabolites that pose a health risk to exposed animals and humans. In recent years, concern has mounted regarding human exposure to mycotoxins via inhalation of mold spores produced in damp buildings and homes. Although mycotoxins can be detected in such buildings, reliable means for measuring an occupant's level of exposure to most mycotoxins are lacking. The author briefly reviews the chemical methods currently available for mycotoxin analysis, outlining accepted practices and discussing the limitations of these measurements.

Recent advances in understanding the mechanisms of TCDD immunotoxicity

TCDD is a highly immunosuppressive chemical that induces potent suppression of immune responses in laboratory animals. However, apart from the requisite role of the AhR and the identification of bone-marrow-derived cells as critical AhR-expressing targets, the specific cells and the underlying biochemical mechanisms by which TCDD disrupts immunological functions remain unclear. Recent data suggest that a new paradigm for the mechanism of immunotoxic action of TCDD may be more accurate, moving from one focused on the suppression of immune functions to one focused on the inappropriate activation of cells, leading to anergy or death, and the consequent premature termination of the immune response. Enhanced activation of B cells, DC and CD4+ T cells by TCDD has been described as well as the earlier disappearance of the latter two populations from peripheral lymphoid organs. Although much remains to be learned about how inappropriate cellular activation via the AhR induces immune suppression, deducing this mechanism of action and the signaling pathways involved, should lead to new insight into basic mechanisms of immune regulation.

Allergic contact dermatitis

Allergic contact dermatitis (ACD) is a common occupational and environmental health issue. In common with other forms of allergy the disease progresses in two stages; an initial phase during which sensitization is acquired, followed later (after subsequent exposure to the same chemical allergen) by elicitation of a cutaneous inflammatory reaction. The development of skin sensitization is associated with, and requires, the activation and clonal expansion of allergen responsive T lymphocytes and it is these cells that orchestrate the cutaneous allergic reaction. In recent years, much has been learned of the characteristics of immune responses to skin sensitizing chemicals and of the roles played by dendritic cells, cytokines and chemokines. Some of the more interesting cellular and molecular mechanisms are reviewed briefly in this article. A more detailed appreciation of responses induced by chemical allergens has in turn facilitated the design of novel approaches to the toxicological evaluation of skin sensitization. Real progress has been made, not only in the development of improved methods for hazard identification and characterization, but also in the application of new paradigms for risk assessment. The newer methods now available and the opportunities that exist for further advances are considered. Finally, progress has been made in the characterization of skin sensitization in humans and in the clinical management of ACD. This article seeks to consider skin sensitization and ACD in holistic fashion, bridging experimental observations with clinical disease and basic mechanisms with practical toxicology.

[Methods of preclinical diagnosis of ecologically-caused diseases]

Based on their studies, the authors have proposed simple and easy-to-use methods for preclinical diagnosis of environment-related diseases.

[Connection between changes in the nasal and mouth mucosa with immune status under the effect of environmental factors]

The paper summarizes the results of determination of the cytological status of nasal and oral mucosae in 789 preschool and school children from different cities and towns of the Russian Federation: Moscow, Klimovsk, Yaroslavl. A relationship between the mucosae, immunity, and morbidity, and environmental pollution is shown in the town of Klimovsk as an example.

Far-reaching consequences of high level air pollution on the developing immune system

The town of Dimitrovgrad in Bulgaria has a highly industrialized region with a developing chemical industry, cement and asbestos-cement production, as well as energy production. For over four decades, the main ecological problem was air pollution, but after 1989 a great economic crisis led to an abrupt decline in the level of air pollutants. The aim of the present study was to investigate the present state of humoral immunity in teenage children from Dimitrovgrad who lived under conditions of massive air pollution during their intrauterine development and first few years of childhood. Immunoglobulins IgA, IgM, and IgG were measured in 106 clinically healthy children (average age 12.68 +/- 0.56 y) from 3 schools in Dimitrovgrad and in 41 control subjects (average age 12.35 +/- 0.22 y) from the town of Nova Mahala, an area lacking massive sources of air pollution. Immunoglobulin concentration was determined by turbidimetry using an Optima (KONE) chemical analyzer. The average IgA, IgM, and IgG levels in children from Dimitrovgrad did not differ significantly from those of the control group.

Environmental risk factors (outdoor air pollution and climatic changes) and increased trend of respiratory allergy

A wealth of evidence suggests that allergic respiratory diseases such as rhinosinusitis and bronchial asthma have become more common worldwide in recent years and a great deal of etiological and pathogenic research has been carried out to evaluate the possible causes of this increasing trend. There is also some evidence that increased atmospheric concentrations of pollutants such as ozone (O3), nitric oxides (NOx), respirable particulate (PM10) and volatile organic chemicals (VOC5), which result from increased use of liquid petroleum gas or kerosene, may be linked to the increased prevalence of allergic diseases which develop more frequently in urban areas of developed countries. Since bronchial asthma is a syndrome which can be aggravated by inhaled compounds, the effects of air pollutants on health have been the focus of attention. In fact, various studies have demonstrated that inhalation of air pollutants such as O3, nitrogen dioxide (NO2) and sulfur dioxide (SO2), either individually or in combination, can enhance the airway response to inhaled allergens in atopic subjects, thus inducing asthma exacerbations. Moreover, experimental studies have shown that diesel exhaust particulate causes respiratory symptoms and is able also to modulate the immune response by increasing IgE synthesis in predisposed animals and humans. There is also some evidence that air pollutants can interact with aeroallergens in the atmosphere and/or on human airways, potentiating their effects. In fact, by inducing airway inflammation which increases epithelial permeability, some pollutants overcome the mucosal barrier and lead to allergen-induced responses. However, air pollution and climatic changes should also have an indirect effect on allergic response by influencing quantitatively and qualitatively the pollen production by allergenic plants.

The role of the T lymphocytic cell cycle and an autogenous lymphocytic factor in clinical medicine

In this study 315 individuals (25 controls, 290 chemically sensitive immunocompromised patients) were investigated. Each patient had been on a standard therapy of avoidance of pollutants, nutritional supplementation, and injections of antigens for foods, and biological inhalants, but did not attain their immunological competence. Peripheral lymphocytes were collected and DNA histograms were constructed. The flow cytometer was used to evaluate the cell cycle, haematological, and other immunological profiles. From the other portion of the blood specimen, lymphocytes were propagated in vitro, harvested, and a lysate, termed the autogenous lymphocytic factor (ALF), was prepared. When treated with ALF, 88% of these individuals showed a significant (p < 0.001) clinical improvement which correlated with laboratory findings, involving regulation of abnormal cell cycles, increase in total lymphocytes and subsets T4, T8, (p < 0.05) and cell mediated immunity (CMI) response (p < 0.001). The ALF presumably acts as a biological response modifier. The cell cycle and ALF provide clinical tools for diagnosis and regulation of immunological incompetence.

Determinants of dust mite allergen concentrations in infant bedrooms in Tasmania

BACKGROUND

High exposure to house dust mite allergen during the first year of life has been found to increase the risk of subsequent asthma and mite sensitization. Environmental factors, home construction and cleaning methods used are associated with levels of dust mites in the home.

OBJECTIVE

To investigate determinants of levels of Der p 1 and Der f 1 mite allergens in homes of infants in southern Tasmania.

METHODS

Dust samples were collected from 72 homes of infants participating in the Tasmanian Infant Health Survey (TIHS). The Der p 1 and Der f 1 allergen concentrations in these samples were measured. The TIHS interviewers obtained information from the mothers of the infants via a questionnaire, observed specified aspects of the home environment, and took readings of bedroom temperature and humidity. The effect of each item on allergen concentration in dust from bedroom floors was examined in a variety of ways. Those items which in this study appeared to be significantly related to allergen concentrations plus items which in other studies have been found to be related to allergen concentrations were then investigated further in multivariate models.

RESULTS

Der p 1 allergen concentration (microg/g) and density (microg/m2) in dust from bedroom floors were found to be related to several home environment factors. In the univariate analyses, indoor humidity, 24 h maximum temperature, number of residents and a combination of floor covering and cleaning methods appeared to have a significant effect on allergen levels. These factors remained important in the multivariate model except that indicators for mould in the bathroom and drying washing on an outside line replaced indoor humidity.

CONCLUSION

Features related to home dampness, the number of residents and floor covering and cleaning were major determinants of Der p 1 levels in the bedrooms studied.

Putting chemical and environmental sensitivities in perspective

Chemical sensitivity has been recognized for an extended period. Over the last 30 years or more, there has been a growing number of chemicals to which humans are being exposed. Some people have become sensitive to one or more of these chemicals and present this sensitivity in a wide variety of signs or symptoms. Single or multiple organ systems may become involved. This article is intended to give an overview on the existence and recognition of chemical sensitivities and how they may be diagnosed and treated. The important item is to educate physicians to the existence of chemical sensitivity and to consider this in their differential diagnosis when the patient presents with the signs, symptoms, or clinical pattern that is explained.

Changes in IgE-mediated allergy to ubiquitous inhalants after removal from or diminution of exposure to the agent causing occupational asthma

BACKGROUND

One possibility, among others, for explaining the persistence of asthma symptoms in occupational asthma (OA) after the cessation of exposure to the causal agents may be that subjects become sensitized to ubiquitous inhalants.

OBJECTIVE

The aim of this study was to evaluate the development or increase of IgE-mediated sensitization to ubiquitous allergens, both to high- and low-molecular-weight agents, in 100 subjects with OA after cessation of exposure.

METHODS

Subjects were evaluated on a first visit, at the time of diagnosis of OA, coinciding with the cessation or diminution of exposure to the causal agent, and on a second visit, 5.8+/-3.3 years afterwards. At each visit, a history of ocular, nasal and asthmatic symptoms related to exposure to common allergens was obtained together with spirometry and assessment of bronchial responsiveness to methacholine. We analysed total IgE and specific IgE to Dermatophagoides farinae, D. pteronyssinus, birch, ragweed and timothy grass pollens, cat and dog danders, and Alternaria, using enzyme allergosorbent test (EAST) from blood samples taken on each visit.

RESULTS

Total IgE levels showed a tendency to diminish. No changes were found in the number of positive EAST (presence of detectable levels of specific IgE) or in the levels of specific IgE. Although significantly more symptoms of rhinoconjunctivitis and asthma in contact with house dust (P < 0.05) and pets (P < 0.01) were reported on the second visit than on the first, no significant changes in the frequency of symptomatic sensitized subjects were found.

CONCLUSION

Subjects with OA are unlikely to develop IgE-dependent sensitization to common inhalants after removal from exposure to occupational agents.

Exposure and sensitization to environmental allergen of predominantly Hispanic children with asthma in San Diego's inner city

BACKGROUND

Environmental living conditions co-sorting with economic status may influence the disease morbidity rate of childhood asthma in ethnic minority urban poor populations.

OBJECTIVES

This study was carried out to assess exposure and sensitization to environmental allergens in southeast San Diego children with current asthma-related symptoms and to determine the utility of environmental control measures.

METHODS

Children, 9 to 12 years old, with current asthma-related symptoms were identified and enrolled at four school sites. Skin prick testing with aeroallergens was performed, and allergen in collected dust (from mattresses, pillows, and bedroom carpets) was quantified by enzyme immunoassay. Environmental control instruction and products were provided.

RESULTS

Of 41 subjects who underwent skin testing, 51.2% were reactive to environmental allergens (39% to mite, 22% to cockroach, and 9.8% to cat). Mean allergen levels for sensitized subjects were: Der p 1 (11 subjects), 18,722 ng/gm dust; Der f 1 (8 subjects), 5345 ng/gm dust; Fel d 1 (3 subjects), 214 ng/gm dust; Bla 1 (8 subjects), 7.15 U/gm dust; and Bla 2 (8 subjects) 7.13 U/gm dust. Environmental allergen exposure levels were not significantly different between sensitized and nonsensitized subjects. Environmental control measures for mite exposure were completed in six homes of sensitized subjects. One month after treatment, allergen levels fell 91.2% for Der p 1, 98.9% for Der f 1, and 88.2% for Fel d 1. One year after treatment, mite and cat allergen levels remained low. Environmental control had no consistent impact on cockroach allergen levels.

CONCLUSION

Environmental allergen sensitization and exposure may be cofactors contributing to increased disease severity in urban poor populations.

Understanding clinical immunological testing in alleged chemically induced environmental illnesses

Some believe that an abnormal immunoregulatory response based on environmental damage to T cells is fundamental to the production of symptoms in patients with alleged "multiple chemical sensitivity" and/or "environmental illness." According to this theory stimulation of T cells or T cell phenotypic subsets by environmental chemicals results in release of cytokines that can effect appropriate target cells of multiple organ systems, resulting in a wide range of symptoms. This concept is reinforced by frequent media reporting of pollution incidents and environmental disasters plus continued isolated reports of immunologic abnormalities in patients with various forms of alleged environmental illness, multiple chemical sensitivities, or other related syndromes. These include reports of slight perturbations in quantity and function of immunoglobulins, complement and its components, B cells, natural killer cells, T cells, phenotypic T cell subsets, and helper suppressor T cell ratios. There are also reports of increased or decreased interleukin levels including IL-1 and IL-2 or their receptors (IL-2R) in these patients. Such assays are not infrequently performed even though there is no evidence for their diagnostic efficacy in these alleged conditions. It is reasonable, however, to anticipate that with the wide development of assays for many of the interleukins and their receptors, these assays may become important in the future diagnosis of many autoimmune, allergic, neoplastic, and infectious diseases. At this time, however, the induction of environmental illness or multiple chemical sensitivity by exposure to trace levels of environmental "immunotoxins" is unproven and remains a matter of speculation. The reproducibility of immunologic test abnormalities reported under these conditions has not been documented, and the data have often not been analyzed statistically. Appropriate controls also have not usually been employed, nor have control values been provided in many cases. Without consideration of these factors, a patient might be erroneously diagnosed as having some form of "immune dysregulation," "environmental immune dysfunction," or "immunotoxic" syndrome on the basis of only a single panel of cellular immunologic profiles or related immunologic tests illustrating slight deviations from the norm and in the absence of overt disease on physical examination. Consideration must also be given to an understanding of biologic variability and diurnal variations in lymphoid cell numbers in interpreting cellular immunologic profiles. For example, the necessity for age and sex-matched controls, test reproducibility, quantitative versus functional assays, and the significance of major versus minor deviations from the norm must be appreciated. In addition, many other conditions can effect immunologic tests, such as medications, psychologic factors, cigarette smoking, and the presence of concurrent disease, including minor viral infections. All of these variables should be appreciated in test interpretation. Certain clinical indications for analysis of cellular components of the immune system, using flow cytometry, have been provided as guidelines although they are by no means accepted by all groups due to their current incomplete evaluation by the clinical immunology community. These suggested indications are discussed. In this article, attempts are made to outline the various quantitative and functional tests used to assess the immune system, with emphasis on "biomarker" tests to detect possible immune system "damage." Dangers involved in attempting to make clinical evaluations based on results of isolated in vitro assessment of quantity or function of immune system cellular and humoral components without considering the results of a good medical history and physical examination, the many pitfalls involved in the tests, and the many confounding variables that affect the tests are emphasized, as well as the need for proper controls...

Increased response to antigen and histamine release in smaller sensitized canine bronchi

We studied the Schultz-Dale response in vitro in large and small size branches from 3rd to 6th generation bronchi from ragweed-sensitized dogs. The response to electric field stimulation (EFS) increased after antigen from 65.56 +/- 8.11 to 78.6 +/- 9.0 mN/mm2 of smooth muscle (P < 0.01), but no topographical difference was observed. The response to ragweed (% of the response to EFS) was 158.3 +/- 12 and 67.1 +/- 11.7 in strips from small and large branches respectively (P < 0.01), while no difference was observed between generations; when clustering bronchi according to dimension, it was 129.9 +/- 13.4 in small and 71.9 +/- 19.8 in large bronchi (P < 0.01). Histamine released from small and large branches was 2.90 +/- 1.01 and 0.76 +/- 0.20 (ng/mg of tissue) respectively (P < 0.05); no difference was found between generations. In conclusion, in sensitized dogs a greater response to antigen, which involves a higher histamine release, occurs in small compared to large bronchi. We suggest that control of distribution of ventilation occurs mainly at small bronchi level, which becomes the elective tissue to study the Schultz-Dale response. Finally, the classification of bronchi into generations is inadequate to study allergic bronchospasm.