Mechanisms of allergy and chemical sensitivity

Odor perception and symptoms during acrolein exposure in individuals with and without building-related symptoms

Building-related symptoms (BRS) is a significant work-related and public health problem, characterized by non-specific symptoms occurring in a particular building. The cause of BRS is unknown, but certain reactive compounds are suggested risk factors. The aim of this controlled exposure study was to investigate whether BRS cases report more odor annoyance and symptoms and show altered autonomous nervous system (ANS) response during exposure to the reactive aldehyde, acrolein in comparison with referents. Individuals with BRS (n = 18) and referents (n = 14) took part in two exposure sessions (80 min). One session contained heptane alone, and the other heptane and acrolein. Perceived odor annoyance; eye, nose, and throat symptoms; and ANS response were measured continuously. BRS cases did not experience more odor annoyance; eye, nose, and throat symptoms; or altered ANS response in comparison with referents during the exposures. Supplementary analyses revealed that BRS cases that also reported chemical intolerance perceived more symptoms than referents during acrolein exposure. Acrolein exposure at a concentration below previously reported sensory irritation detection thresholds is perceived as more irritating by a subgroup of BRS individuals compared with referents. The results of this study indicate that a subset of individuals with building related symptoms (BRS) has a lowered sensory irritation threshold towards acrolein exposure. Future guidelines on chemical exposures to acrolein should take time and individual sensitivity into account.

Multiple Chemical Sensitivity

Multiple Chemical Sensitivity (MCS), a condition also known as Chemical Sensitivity (CS), Chemical Intolerance (CI), Idiopathic Environmental Illness (IEI) and Toxicant Induced Loss of Tolerance (TILT), is an acquired multifactorial syndrome characterized by a recurrent set of debilitating symptoms. The symptoms of this controversial disorder are reported to be induced by environmental chemicals at doses far below those usually harmful to most persons. They involve a large spectrum of organ systems and typically disappear when the environmental chemicals are removed. However, no clear link has emerged among self-reported MCS symptoms and widely accepted objective measures of physiological dysfunction, and no clear dose-response relationship between exposure and symptom reactions has been observed. In addition, the underlying etiology and pathogenic processes of the disorder remain unknown and disputed, although biologic and psychologic hypotheses abound. It is currently debated whether MCS should be considered a clinical entity at all. Nevertheless, in the last few decades MCS has received considerable scientific and governmental attention in light of the many persons reporting this illness. In this review, we provide a general overview of the history, definition, demographics, prevalence, and etiologic challenges in defining and understanding MCS.

An Unusual Case of Multiple Food Allergies Comorbid with Multiple Chemical Sensitivity: A Case Report

Purpose

To report the case of a patient with multiple food allergies comorbid with multiple chemical sensitivity (MCS) who was misdiagnosed on various occasions, resulting in a negative impact on the patient's personal and social life.

Case Report

We present the case of a 43-year-old Colombian women with multiple food allergies concomitant with MCS. Symptoms started with a mild reaction to insecticides, car exhaust smoke, and perfumes and gradually evolved into a severe reaction to her environment. She also presented recurrent episodes of clinical reactivity to foods and persistent elevated IgE levels, as well as several life-threatening anaphylactic reactions. Alternative and allopathic therapies were applied, but her symptoms persisted. Various diagnoses were made before the definitive diagnosis.

Conclusion

MCS is an unusual entity of unknown pathophysiology that can, on rare occasions, coexist with food allergies. Early recognition and multidisciplinary treatment are required as these entities have a major impact on the patient's quality of life. We present the first Latin American case regarding the association of the two diseases.

Chemical Intolerance Is Associated With Altered Response Bias, not Greater Sensory Sensitivity

Chemical intolerance is a surprisingly prevalent condition or affliction characterized by adverse reactions to low levels of chemical, often odorous stimulation. Sufferers often assume that their plight is due to an uncommon sensory acuteness, yet studies repeatedly fail to reveal altered detection thresholds. Here, we investigated whether self-reported chemical intolerance is associated with altered sensory sensitivity or response bias. The sensory acuity (sensitivity; A) and sensory decision rule (criterion; B) to n-butanol was assessed using the method of constant stimuli in 82 participants with different degrees of chemical intolerance (low to high). Higher self-reported chemical intolerance was associated with a lower criterion, but not with sensitivity.

Comorbidity of Airway Inflammatory Diseases in Chemical and Building-Related Intolerance

OBJECTIVES

This study investigated comorbidity in chemical intolerance (CI) and building- related intolerance (BRI) with (i) chronic sinusitis, chronic obstructive pulmonary disease, allergic and nonallergic asthma and allergic rhinitis, and (ii) airway inflammatory symptoms.

METHODS

Data from two population-based questionnaire surveys, the Västerbotten and Österbotten Environmental Health Studies, were used. The participants were categorized as CI or BRI and referents, and binary logistic regression analysis was applied.

RESULTS

Prevalence rates for the case groups were 7.2% to 40.0% for diseases and 24.3% to 68.9% for symptoms, whereas adjusted odds ratios (ORs) were 3.4 to 26.1 for diseases and 3.3 to 17.0 for symptoms, all being significantly higher than unity. Prevalence rates and ORs were in general higher in BRI than in CI.

CONCLUSION

Inflammatory airway diseases and symptoms are associated with CI and BRI, which encourages further research regarding underlying mechanisms and treatments.

Assessment of CYP2C9, CYP2C19, and CYP2D6 Polymorphisms in Allergic Patients with Chemical Sensitivity

BACKGROUND

Self-reported chemical sensitivity (SCS) is characterized by adverse effects due to exposure to low levels of chemical substances. The clinical manifestations of SCS are similar to the allergy, and a high percentage of individuals with both diseases have been found. Various genes, especially genes of importance to the metabolism of xenobiotic compounds, have been associated with SCS.

OBJECTIVES

The purpose of this study was to investigate whether allergic individuals with chemical sensitivity differed from allergic patients without chemical sensitivity with regard to the distribution of genotype and phenotype of CYP2C9, CYP2C19, and CYP2D6 polymorphisms.

METHODS

A total of 180 patients were enrolled for this study. A questionnaire was employed to collect information on individual chemical sensitivity, while the Skin prick test and the PATCH test were used to verify the presence of an allergic condition against inhalants or contact allergens, respectively. For the evaluation of the CYP2C9, CYP2C19, and CYP2D6 polymorphisms, we used a strategy based on the amplification of the entire gene coupled to direct genomic DNA sequencing analysis.

RESULTS

Overall, a total of 15 different CYP2C9, CYP2C19, and CYP2D6 haplotypes were identified in our population. If the 5 CYP2C9 and the 2 CYP2C19 identified alleles correspond to the previously described ones, 4 of the 8 CYP2D6 haplotypes, detected in the study group, present new SNPs combinations. These new suballeles were categorized as CYP2D6*2M Sa-lento Variant 1, CYP2D6*35B Salento Variant 2, CYP2D6*41 Salento Variant 3, and CYP2D6*4P Salento Variant 4 due to the presence of the key SNPs 2,850 C>T, 31G>A, 2,988 G>A, and 1,846 G>A, respectively. When the allergic individuals are divided into 2 groups according to their SCS score, we observed that the distribution of the CYP2D6 phenotypes was significantly different between the 2 groups.

CONCLUSIONS

Our idea is that the application of the questionnaire that we have adopted has enabled us to diagnose a degree of chemical sensitivity, which results as comorbid of the allergic disease and in which a condition of poor or intermediate metabolizes for the detrimental CYP2D6 alleles, could represent a discriminant between the chemical sensitivity and the health state.

Symptoms from masked acrolein exposure suggest altered trigeminal reactivity in chemical intolerance

BACKGROUND

Chemical intolerance (CI) is a widespread occupational and public health problem characterized by symptoms that reportedly result from low-levels of chemical exposure. The mechanisms behind CI are unknown, however modifications of the chemical senses (rather than toxic processes) have been suggested as key components. The aim of this study was to investigate whether individuals with self-reported CI report more sensory irritation during masked acrolein exposure compared to controls without CI.

METHODS

Individuals with CI (n=18) and controls without CI (n=19) were exposed in an exposure chamber. Each participant took part in two exposure conditions - one with heptane (the masking compound), and one with heptane and acrolein at a dose below previously reported sensory irritation thresholds. The exposures lasted for 60min. Symptoms and confidence ratings were measured continuously throughout the exposure as were measurements of electrodermal activity and self-reported tear-film break-up time. Participants were blind to exposure condition.

RESULTS

Individuals with CI, compared with controls reported greater sensory irritation in the eyes, nose and throat when exposed to acrolein masked with heptane. There was no difference during exposure to heptane.

CONCLUSIONS

Masked exposure to acrolein at a concentration below the previously reported detection threshold is perceived as more irritating by individuals with CI compared with controls. The results indicate that there is altered trigeminal reactivity in those with CI compared to controls.

Clinical problems in patient with Ehlers-Danlos syndrome and Multiple Chemical Sensitivity undergoing total thyroidectomy

Clinical practice sometimes brings to face with situations quite peculiar, potentially dangerous for the patient's life. In the great majority of cases, pathologies associated with each other (cardiovascular, respiratory, neurological), while in other cases we can treat rare diseases or syndromes. It's considered exceptional the simultaneous presence of "rare" pathologies in a single patient. This exceptionality has been a push to treat a patient as a "unique" asking for help to deeper studies of pharmacogenetics. Our case reports the management of a patient with Ehlers-Danlos syndrome (EDS) and Multiple Chemical Sensitivity (MCS), undergoing a total thyroidectomy. We found several problems, and we tried to find effective solutions for the management of the patient during the whole peri-operative process, from a clinical, pharmacological and also from a surgical point of view.

Inflammatory Mediator Profiling of n-butanol Exposed Upper Airways in Individuals with Multiple Chemical Sensitivity

BACKGROUND

Multiple Chemical Sensitivity (MCS) is a chronic condition characterized by reports of recurrent symptoms in response to low level exposure to various chemical substances. Recent findings suggests that dysregulation of the immune system may play a role in MCS pathophysiology.

OBJECTIVES

The aim of this study was to examine baseline and low dose n-butanol-induced upper airway inflammatory response profiles in MCS subjects versus healthy controls.

METHOD

Eighteen participants with MCS and 18 age- and sex-matched healthy controls were enrolled in the study. Epithelial lining fluid was collected from the nasal cavity at three time points: baseline, within 15 minutes after being exposed to 3.7 ppm n-butanol in an exposure chamber and four hours after exposure termination. A total of 19 cytokines and chemokines were quantified. Furthermore, at baseline and during the exposure session, participants rated the perceived intensity, valence and levels of symptoms and autonomic recordings were obtained.

RESULTS

The physiological and psychophysical measurements during the n-butanol exposure session verified a specific response in MCS individuals only. However, MCS subjects and healthy controls displayed similar upper airway inflammatory mediator profiles (P>0.05) at baseline. Likewise, direct comparison of mediator levels in the MCS group and controls after n-butanol exposure revealed no significant group differences.

CONCLUSION

We demonstrate no abnormal upper airway inflammatory mediator levels in MCS subjects before or after a symptom-eliciting exposure to low dose n-butanol, implying that upper airways of MCS subjects are functionally intact at the level of cytokine and chemokine production and secretory capacity. This suggests that previous findings of increased cytokine plasma levels in MCS are unlikely to be caused by systemic priming via excessive upper airway inflammatory processes.

The role of flavor and fragrance chemicals in TRPA1 (transient receptor potential cation channel, member A1) activity associated with allergies

TRPA1 has been proposed to be associated with diverse sensory allergic reactions, including thermal (cold) nociception, hearing and allergic inflammatory conditions. Some naturally occurring compounds are known to activate TRPA1 by forming a Michael addition product with a cysteine residue of TRPA1 through covalent protein modification and, in consequence, to cause allergic reactions. The anti-allergic property of TRPA1 agonists may be due to the activation and subsequent desensitization of TRPA1 expressed in sensory neurons. In this review, naturally occurring TRPA1 antagonists, such as camphor, 1,8-cineole, menthol, borneol, fenchyl alcohol and 2-methylisoborneol, and TRPA1 agonists, including thymol, carvacrol, 1'S-1'- acetoxychavicol acetate, cinnamaldehyde, α-n-hexyl cinnamic aldehyde and thymoquinone as well as isothiocyanates and sulfides are discussed.

Allergic diseases and multiple chemical sensitivity in korean adults

Purpose

Multiple chemical sensitivity (MCS) is a clinical syndrome representing multi-organ and psychological symptoms caused by chronic exposure to various chemicals in low concentrations. We evaluated the prevalence and related factors of MCS targeting Korean adults using the Quick Environmental Exposure and Sensitivity Inventory (QEESI©).

Methods

A total of 446 participants were recruited from Severance Hospital. Participants underwent a questionnaire interview including questions on sociodemographic factors, occupational and environmental factors, allergic diseases, and the QEESI©. Among them, 379 participants completed the questionnaire and the QEESI©. According to the QEESI© interpretation results, participants were divided into very suggestive (VS) group and less suggestive (LS) group.

Results

The estimated prevalence of MCS was higher in allergic patients than non-allergic participants (19.7% and 11.3%, respectively, P=0.04). In the multivariate logistic regression analysis, ages of 30-39 (OR, 2.94; 95% CI, 1.25-6.95) and those of 40-49 (OR, 2.51; 95% CI, 1.02-6.21) were significantly related to MCS compared to those aged less than 30 years. Female sex (OR, 2.16; 95% CI, 1.11-4.18), experience of dwelling in a new house (OR, 2.05; 95% CI, 1.04-4.03), and atopic dermatitis (OR, 1.95; 95% CI, 1.04-3.69) were also significantly related to MCS. However, only age of 30-39 in the allergic group was significant in the stratified analysis.

Conclusions

The estimated prevalence of MCS was higher among allergic patients than non-allergic participants. People with experience of dwelling in a new house and atopic dermatitis were more at risk of being intolerant to chemicals. Further studies to provide the nationally representative prevalence data and clarify risk factors and mechanisms of MCS are required.

Metric properties and normative data for brief noise and electromagnetic field sensitivity scales

Aims: Lack of brief questionnaire instruments for quantifying affective reactions to and behavioral disruptions attributed to sounds and electromagnetic fields (EMFs) motivated the present development and metric evaluation of such instruments, called the 11-item Noise Sensitivity Scale (NSS-11) and the 11-item Electromagnetic Field Sensitivity Scale (EMFSS-11). Another objective was to establish normative data for these instruments. Method: Data from 3406 individuals who took part in the Västerbotten Environmental Health Study was used. The participants constitute a random sample of inhabitants in the county of Västerbotten in Sweden, aged 18 to 79 years, stratified for age and gender. The participants responded to the NSS-11 and EMFSS-11 and to additional questions for evaluation of concurrent validity. Results: The results show satisfying reliability (Cronbach α = 0.71–0.85, varying with age group and gender), concurrent validity, and unidimensionality of the NSS-11 and EMFSS-11, and that the scales generate scores with approximately normal distributions, irrespective of age group and gender. Mean scores, standard deviations, and confidence intervals constitute normative data. Conclusions: The favorable metric properties of the NSS-11 and EMFSS-11 in combination with their fast usage suggest that they are particularly useful for assessment in epidemiological studies, and have the advantage of available normative data.

Sensitivity-related illness: the escalating pandemic of allergy, food intolerance and chemical sensitivity

The prevalence of allergic-related diseases, food intolerance, and chemical sensitivities in both the pediatric and adult population has increased dramatically over the last two decades, with escalating rates of associated morbidity. Conditions of acquired allergy, food intolerance and chemical hypersensitivity are frequently the direct sequelae of a toxicant induced loss of tolerance (TILT) in response to a significant initiating toxic exposure. Following the primary toxicant insult, the individuals become sensitive to low levels of diverse and unrelated triggers in their environment such as commonly encountered chemical, inhalant or food antigens. Among sensitized individuals, exposure to assorted inciting stimuli may precipitate diverse clinical and/or immune sequelae as may be evidenced by clinical symptoms as well as varied lymphocyte, antibody, or cytokine responses in some cases. Recently recognized as a mechanism of disease development, TILT and resultant sensitivity-related illness (SRI) may involve various organ systems and evoke wide-ranging physical or neuropsychological manifestations. With escalating rates of toxicant exposure and bioaccumulation in the population-at-large, an increasing proportion of contemporary illness is the direct result of TILT and ensuing SRI. Avoidance of triggers will preclude symptoms, and desensitization immunotherapy or immune suppression may ameliorate symptomatology in some cases. Resolution of SRI generally occurs on a gradual basis following the elimination of bioaccumulated toxicity and avoidance of further initiating adverse environmental exposures. As has usually been the case throughout medical history whenever new evidence regarding disease mechanisms emerges, resistance to the translation of knowledge abounds.

Validation of guinea pig model of allergic rhinitis by oral and topical drugs

Ovalbumin-induced guinea pig model of rhinitis was assessed for its utility in the studies of rhinitis. Systemic sensitization and challenge with ovalbumin-induced rhinitis symptoms and an increase in anti-OVA-IgE and IgG titers, positive skin reactions and nasal lavage IL-4 concentration. Histopathology of nasal mucosa showed infiltration of eosinophils and other inflammatory cells consistent with the symptoms. Topical sensitization of ovalbumin yielded inconsistent symptoms of rhinitis. In systemic sensitization model, repeated challenge of ovalbumin caused similar response for at least 3 consecutive challenges. The symptoms were affected by relative humidity in the air and dosing volume of topical drugs. Sneezing and lacrimation were reduced by acute oral administration of the H1 receptor antagonists and steroids or the prophylactic oral administration of cysteinyl leukotriene (CysLT1) receptor antagonist montelukast or acute topical antihistamines, mast cell stabilizer sodium cromoglycate and anticholinergic agent ipratropium bromide, but not by a topical steroid. Nose rubbing was reduced significantly by some oral and topical antihistamines. Oral steroids offered excellent protection against all symptoms. Dexamethasone and montelukast also inhibited nasal lavage IL-4 concentration and inflammatory cell infiltration. Treatment with topical steroid fluticasone for 2 weeks had no effect on sneezing or rubbing. However, it caused complete inhibition of congestion. The cyclooxygenase inhibitor indomethacin had no effect on symptoms of rhinitis. The adrenergic alpha receptor agonist-decongestant oxymetazoline caused reduction in congestion. These results suggest that differential responsiveness to symptoms of rhinitis by a new agent can be very well profiled in the model in congruence with the mediation pathways and mechanism of action of drugs. The model provides complete symptomatic characterization of rhinitis and is a good tool for its study.

Discriminating between organic and psychological determinants of multiple chemical sensitivity: a case study

Multiple chemical sensitivity (MCS) is a controversial disorder characterized by a diverse set of debilitating symptoms purportedly induced by environmental chemicals. Many cases of putative MCS are believed to have a strong psychogenic component, making it difficult to differentiate between organic and psychogenic causes. In this case report we describe a procedure that can aid in this differentiation. A patient who met a strict set of criteria for MCS was tested on two test occasions. On the first, the patient was found to have no olfactory dysfunction, as determined from standardized olfactory tests. On the second, odorants, as well as a blank stimulus, were presented to the patient with instructions as to whether they were harmful or harmless. The patient's task was to estimate the intensity of each odorant and report any induced MCS-related symptoms. Potentially harmful odorants presented as harmless were judged significantly less intense, and triggered fewer symptoms, than harmless odorants presented as harmful. When an odorless stimulus was presented as harmful, the patient provided higher intensity evaluations and exhibited more symptoms than when it was presented as harmless. These phenomena were not present in three non-MCS controls. This straight-forward procedure allowed us to determine that the MCS symptoms of this patient were largely psychological and may be of general value for identifying psychogenic cases of MCS.

The vanilloid receptor as a putative target of diverse chemicals in multiple chemical sensitivity

The vanilloid receptor (TRPV1 or VR1), widely distributed in the central and peripheral nervous system, is activated by a broad range of chemicals similar to those implicated in Multiple Chemical Sensitivity (MCS) Syndrome. The vanilloid receptor is reportedly hyperresponsive in MCS and can increase nitric oxide levels and stimulate N-methyl-D-aspartate (NMDA) receptor activity, both of which are important features in the previously proposed central role of nitric oxide and NMDA receptors in MCS. Vanilloid receptor activity is markedly altered by multiple mechanisms, possibly providing an explanation for the increased activity in MCS and symptom masking by previous chemical exposure. Activation of this receptor by certain mycotoxins may account for some cases of sick building syndrome, a frequent precursor of MCS. Twelve types of evidence implicate the vanilloid receptor as the major target of chemicals, including volatile organic solvents (but not pesticides) in MCS.

Intranasal effects in chemically sensitive volunteers: an experimental exposure study

During inhalational exposure to irritants stimulation of the trigeminal nerve endings in the nasal mucosa or other biochemical mechanisms might initiate inflammatory processes. Increased sensitivity of this physiological system in response to chemical stimulation is postulated in subjects reporting chemical intolerance. In the present study 12 subjects reporting chemical sensitivity and 12 controls were exposed to different concentrations of the industrial solvents ethyl benzene and methyl ethyl ketone (MEK). Concentrations of various inflammatory biomarkers, namely eosinophil cationic protein (ECP), myeloperoxidase (MPO), interleukin 1β (IL-lβ), substance P (SP), and neurokinin A (NKA) were measured in nasal secretion after exposures. Before, during, and after the exposures subjects rated the severity of nasal irritations. The biomarker concentrations and reported irritations were not affected by the exposures. Regardless of substance and concentration sensitive subjects reported more nasal irritations. In conclusion, the investigated substances might possess weaker potency to elicit intranasal irritative effects than postulated.

Nasal function in self-reported chemically intolerant individuals

Nasal function has not yet been investigated under controlled exposures in individuals with self-reported Multiple Chemical Sensitivity (sMCS). Therefore, anterior rhinomanometry and acoustic rhinometry were applied in 12 individuals with sMCS, and 12 age-matched controls. The sMCS individuals and controls were selected on the basis of a standardized questionnaire. Controlled 4-hr exposures to ethylbenzene and 2-butanone were performed during 4 sessions. Exposures were close to the current German threshold limit values, and they approximated odor thresholds. Subjects with sMCS had a significant decrease in the flow value in anterior rhinomanometry, independent of substance and doses, compared with controls. This result suggests somatic reactions to the exposure. The result must be confirmed in additional studies, and pathophysiological examinations must be performed. For these investigations, anterior rhinomanometry was usable, but acoustic rhinometry can be recommended only after sufficient standardization has occurred. Furthermore, biochemical parameters of nasal mucosa must be considered.

Visits to physicians after the oxygenation of gasoline in Philadelphia

During the period between 1992 and 1997, there was an increase in levels of methyl tertiary butyl ether (MTBE) in gasoline in the Philadelphia, Pennsylvania, area. In this study, the authors analyzed billing records from clinical practices that were extensions of the University of Pennsylvania. The authors based their selections on the International Classification of Diseases-9 diagnostic codes, which were determined from (1) previous studies of methyl tertiary butyl ether conducted by the Centers for Disease Control; (2) respiratory symptoms, including asthma and wheezing; and (3) symptoms associated anecdotally with methyl tertiary butyl ether levels in gasoline. The authors normalized all data by the total number of office visits. The incidences of headache, throat irritation, allergic rhinitis, cough, nausea, dizziness, upper respiratory infections, wheezing, otitis media, skin rash, anxiety, insomnia, palpitations, generalized allergy, and malaise were increased during the period studied. Large increases occurred during the winters of 1993-1994 and 1994-1995 (during which there were high levels of MTBE), but not in the preceding summers (during which there were low levels of MTBE). This was especially true for asthma and wheezing. During the summers of 1995, 1996, and 1997, the incidences of the aforementioned symptoms increased greatly.