I.L. Bernstein

The prevalence of house dust mites, Dermatophagoides spp, and associated environmental conditions in homes in Ohio.

Abundance of the house dust mites, Dermatophagoides farinae and D. pteronyssinus, in various sites in the homes of dust-sensitive patients was sequentially monitored at approximately 3 wk intervals for 2 yr, and mite density was correlated with indoor physical and climatic factors. Significantly higher mite levels occurred on the most heavily used fabric-upholstered furniture and carpeted floor areas of the living/family room and bedrooms. Mattresses were not found to be the major foci for mites. No significant positive correlation was noted between mite abundance and frequency or thoroughness of cleaning, amount of dust, and age of furnishings or dwelling. Significantly higher mite levels occurred on carpeted floors than on noncarpeted floors. Successive vacuuming did not significantly reduce mite abundance. Mite density exhibited a seasonal fluctuation, with highest density occurring in the humid summer months and the lowest density during the dryer, late heating season. Live mites were more abundant than dead mites during the period when total abundance was high. In homes inhabited by both species, D. farinae was the dominant species, except in one home that had a significantly higher relative humidity.

Food allergy: a practice parameter

TABLE OF CONTENTS I. Preface S1 II. Glossary S2 III. Executive Summary S3 IV. Summary Statements S6 V. Classification of Major Food Allergens and Clinical Implications S11 VI. Mucosal Immune Responses Induced by Foods S12 VII. The Clinical Spectrum of Food Allergy S15 VIII. Algorithm and Annotations S18 IX. Prevalence and Epidemiology S21 X. Natural History of Food Allergy S22 XI. Risk Factors and Prevention of Food Allergy S23 XII. Cross-reactivity of Food Allergens S24 XIII. Adverse Reactions to Food Additives S30 XIV. Genetically Modified Foods S32 XV. Diagnosis of Food Allergy S33 XVI. Food-Dependent Exercise-Induced Anaphylaxis S39 XVII. Differential Diagnosis of Adverse Reactions to Foods S40 XVIII. General Management of Food Allergy S44 XIX. Management in Special Settings and Circumstances S45 XX. Future Directions S47 XXI. Appendix: Suggested Oral Challenge Methods S48 XXII. Acknowledgments S49 XXIII. References S50

Prevalence of dust mites in the homes of people with asthma living in eight different geographic areas of the United States.

The density and species prevalence of dust mites were determined at various times over a 5-year-period in 252 homes of dust mite sensitive people with asthma who lived in eight geographic areas of the United States (Cincinnati, Ohio; New Orleans, La.; Memphis, Tenn.; Galveston, Texas; Greenville, N.C.; Delray Beach, Fla.; San Diego and Los Angeles, Calif.). The most common dust mites found in the homes were Dermatophagoides farinae (DF), D. pteronyssinus (DP), Euroglyphus maynei (EM), and Blomia tropicalis. All homes in all locations contained Dermatophagoides spp. mites, but few homes were populated exclusively by either DF or DP alone. Most homes (81.7%) were coinhabitated by both DF and DP. In coinhabited homes one species was predominant and usually made up at least 75% of the total mite population. Prevalence of the dominant or only species present varied between homes within a geographic area. EM occurred in significant numbers in 35.7% of homes in New Orleans, Memphis, Galveston, Delray Beach, and San Diego. Blomia tropicalis occurred in these same cities but in low densities. For all dust samples, only 13 homes of the 252 sampled had 100 or fewer mites/gm dust, which is considered to be the threshold for sensitivity. Most homes had average mite densities of 500 or more mites/gm dust. The results of the present study suggest a significant and widespread occurrence of both DF and DP. Therefore extracts of both mite species should be considered for diagnostic tests and immunotherapy. Significant levels of EM were present in some areas. Thus sensitivity to EM should be considered in these areas.

The low prevalence of occupational asthma and antibody-dependent sensitization to diphenylmethane diisocyanate in a plant engineered for minimal exposure to diisocyanates

BACKGROUND Diisocyanate chemicals are leading causes of occupational asthma (OA). METHODS We conducted a cross-sectional study of 243 workers exposed to diphenylmethane diisocyanate (MDI) in a urethane mold plant that had been designed to minimize MDI exposure (levels were maintained below 0.005 ppm and were continuously monitored). All participants were screened by questionnaire and tests for serum antibodies to MDI-human serum albumin (HSA). On the basis of questionnaire responses, diagnoses were derived that included OA; non-OA; work-related and non-work-related rhinitis; and lower respiratory irritant responses. Serial peak expiratory flow rate studies were performed for 2 weeks in 43 workers with and in 23 workers without lower respiratory symptoms. RESULTS Results of serial peak expiratory flow rate studies were abnormal in 3 (33%) of 9 workers with OA, in 2 (50%) of 4 with non-OA, and in 2 (9%) of 23 case control subjects. A significant association was found between peak flow rate variability and a questionnaire asthma diagnosis (chi 2 p < 0.002). Physicians confirmed three cases of OA, one of which occurred in a control worker who was free of symptoms. In all three cases asthma symptoms remitted after the worker left the workplace. Serum specific IgE and IgG levels were elevated in 2 of 243 workers, one of whom was prick test positive to MDI-HSA and had had cutaneous anaphylaxis after MDI exposure. CONCLUSIONS On the basis of these cases, specific work activities associated with exposure to MDI were identified and corrective measures were instituted. Strict control and monitoring of ambient MDI exposure was associated with a low prevalence of specific sensitization to MDI and a lower than expected prevalence of OA.

Cross antigenic and allergenic properties of the house dust mite Dermatophagoides farinae and the storage mite Tyrophagus putrescentiae.

The crossed antigenicity and allergenicity of the storage mite Tyrophagus putrescentiae (TP) and the house dust mite Dermatophagoides farinae (DF) were characterized by means of crossed immunoelectrophoresis and crossed radioimmunoelectrophoresis. DF extracts exhibited 32 antigens and as many as eight were demonstrated to be allergens. DF feces exhibited 20 antigens and six of these were allergens. Twenty antigens and two allergens were demonstrated for TP. Two antigenic and allergenic determinants were shared by DF and TP, and two determinants were also shared by DF feces and TP feces. TP feces and DF shared two antigenic and allergenic determinants. Our results demonstrated that the two mites and their feces extracts contain multiple antigens and allergens.

Investigations of culture medium-free house dust mites: III. Antigens and allergens of body and fecal extract of Dermatophagoides farinae

Crossed immunoelectrophoresis (CIE) and crossed radioimmunoelectrophoresis (CRIE) were used to characterize antigens (Ags) and allergens derived from Dermatophagoides farinae (DF) culture media-free mite body and mite fecal matter extracts. CIE of DF body and DF feces extracts revealed the presence of 35 and 20 Ags, respectively. CRIE experiments demonstrated IgE binding by 14 and seven DF body and DF feces Ags, respectively, when CIE gels were incubated with reference sera from clinically mite-sensitive patients. Binding of specific IgE to the various Ags in the two extracts varied significantly both in frequency and in strength from patient to patient and within the same patients serum. Sera from some patients demonstrated IgE binding predilection for specific DF body Ags, whereas other sera exhibited greater binding preference for DF feces Ags. Homologous, heterologous, and intermediate gel CIE and CRIE clearly demonstrated that DF bodies and DF feces share some common Ags or epitopes, but the two different extracts also were quantitatively different. Some Ags and allergens originate from mite body material and are not present in mite feces. These results indicate that only extracts containing high concentrations of both body and fecal allergens should be used in clinical testing and therapy.

Antigenic and allergenic properties of the storage mite Tyrophagus putrescentiae

The antigens and allergens in the storage mite Tyrophagus putrescentiae, commonly found in grain and hay and sometimes in house dust, were characterized by crossed immunoelectrophoresis and crossed radioimmunoelectrophoresis. Three mite extracts, T. putrescentiae (TP) mite bodies, feces, and a combination of mites, feces, and culture medium (TP + CM) were studied. TP and TP + CM (primarily feces) extracts exhibited 20 and 18 antigens, respectively. By use of serum from two skin test-positive patients, autoradiograms demonstrated TP contained two allergens and TP + CM contained five allergens, three of which probably originated from feces. CM (whole wheat flour) did not stimulate antibody production in rabbits. TP feces shared 10 antigenic determinants with TP and 14 with TP + CM. Two antigens common to TP feces and TP were also shared allergens.

Heterogeneity of specific-IgE responses in workers sensitized to acid anhydride compounds

Acid anhydride compounds cause IgE-mediated respiratory sensitization in the workplace. In this study reaginic responses in four workers sensitized to phthalic anhydride (PA), hexahydrophthalic (HHPA), or himic anhydride (HA) were determined by direct RAST by use of PA-human serum albumin (HSA), HPPA-HSA, and HA-HSA methylcellulose disc substrates. RAST inhibition of binding to anhydride-HSA substrates was done with various concentrations of sodium salts, lysine, and HSA conjugates of PA, HHPA, HA, and trimellitic anhydride (TMA) in order to characterize cross-reactivity and specificity of humoral responses in these workers. Molar concentrations of anhydride bound to lysine and HSA carriers were assayed by protein hydrolysis followed by gas chromatographic analysis. Significant direct RAST binding against PA-HSA, HHPA-HSA, and HA-HSA was found in all four workers. PA-HSA-IgE binding in one PA-sensitive worker (no. 1) was inhibited significantly by PA-HSA alone and not by sodium PA or PA lysine. In contrast, another PA-sensitized worker (no. 2) exhibited 50% inhibition of PA-HSA binding by PA-HSA (1 X 10(-9) M), PA-lysine (7 X 10(-8) M), and NaPA (1 X 10(-7) M); no inhibition of PA-HSA by heterologous HHPA-, HA-, or TMA-inhibitory reagents was found in either of the PA workers. RAST binding to HHPA-HSA in the HHPA-sensitive worker was inhibited by HHPA-HSA alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Investigations of culture medium-free house dust mites. IV. Cross antigenicity and allergenicity between the house dust mites, Dermatophagoides farinae and D. pteronyssinus.

Heterologous crossed immunoelectrophoresis (CIE) analysis demonstrated that Dermatophagoides pteronyssinus body and D. farinae body extracts contained up to 21 cross-reacting antigens (Ags). Incubation of CIE gels with two mite-sensitive individual sera and a serum pool of mite-sensitive patients indicated that up to nine cross-reacting Ags bound mite-specific IgE on crossed radioimmunoelectrophoresis and were common allergens. Likewise, heterologous CIE analysis of D. pteronyssinus feces and D. farinae feces extracts demonstrated approximately 13 cross-reacting Ags. Up to eight of these cross-reacting fecal Ags bound mite feces-specific human IgE. Additional cross antigenicity and allergenicity was evident between body extract of one species and feces extract of the other species. The amount of specific IgE binding to cross-reacting Ags in interspecific extracts varied both between and within individual sera. Different cross-reacting Ags contained potent allergens, and these varied from patient to patient. Also of major significance was the fact that body and fecal extracts of each species contained Ags and allergens that were unique and species specific.

Failure of enzyme encapsulation to prevent sensitization of workers in the dry bleach industry

BDE added to dry bleach have been associated with immunologic sensitization and development of clinical allergic disease in detergent workers and occasionally in consumers. However, improved dust control and modification of the manufacturing process through encapsulation of enzyme were believed to have reduced or eliminated these problems. To determine whether or not immunologic sensitization could still develop in the detergent industry, we studied employees of a dry bleach manufacturing plant that incorporated encapsulated BDE into a consumer product. We performed air sampling for enzyme dust and total particulates, administered questionnaires, conducted physical examinations, and spirometry in 13 currently exposed, two previously exposed and nine nonexposed, employees. To assess sensitization status, RAST and ELISA were performed. Air concentrations of enzyme dust ranged from 0.002 to 1.57 micrograms/m3; all of these levels were below the TLV of 3.9 micrograms/m3. Positive BDE-specific RAST results (3.4%, 4.4%, and 8.0% binding) were obtained in three of 12 currently exposed workers. Results of personal breathing-zone air sampling indicated that these workers had high dust-exposure levels. Specificity of RAST was verified by RAST inhibition with BDE. BDE-RAST binding was not significantly elevated in the nonworkers (range: 0.6% to 1.4% binding). Positive results for specific IgG by ELISA were obtained in four of 12 currently exposed and in one of two previously exposed workers but in none of the nonexposed workers. We conclude that immunologic sensitization can develop after occupational exposure to encapsulated BDE in the dry bleach industry. We have not proved, however, that this immunologic reactivity is related to clinical sensitivity.