Social factors, allergen, endotoxin, and dust mass in mattress.

UNLABELLED: Indoor environment has been associated with allergic disease. Further, it has been observed that the prevalences of allergic sensitization are different in different social groups. We therefore investigated the association between socioeconomic status (SES) and indoor bio-contaminants. House dust samples were collected from parents' and infants' mattress from 2166 families in Munich (62.2%) and Leipzig (37.8%), Germany. Major mite allergen Der p 1 and Der f 1, cat allergen Fel d 1, and endotoxin were extracted and quantified. Parental educational level and family equivalent income were used independently as socioeconomic indicators. Indoor endotoxin, mite allergen Der p 1, and the amount of sampled dust were not associated with the social factors. Mite allergen Der f 1 was slightly associated by family SES but without a consistent pattern. In families who are not cat owners, however, a negative association between the amount of cat allergen and family SES were observed. The observed negative association between cat allergen loads and concentrations in mattress and family SES in non-cat owners' homes indicated that community is an important source of cat allergen exposure. PRACTICAL IMPLICATIONS: The study indicated that community is a major source of cat allergen exposure especially in communities of low SES.

Are house dust mite allergen levels influenced by cold winter weather?

BACKGROUND: Moisture is vitally important for house dust mites and they cannot survive in cold or hot-dry climates. AIMS OF THE STUDY: To investigate the influence of two extraordinarily cold and dry winters in 1995/1996 and 1996/1997 on house dust mite levels in German homes. METHODS: Dust samples were collected between June 1995 and December 2001 on the mattresses of 655 adults and 454 schoolchildren living in five different areas of Germany. We compared house dust mite allergen Dermatophagoides pteronyssinus (Der p 1) levels before and during the winters of 1995/1996 and 1996/1997 with levels after these winters. RESULTS: D. pteronyssinus (Der p 1) levels in samples taken after the cold winters of 1995/1996 and 1996/1997 were approximately two times lower than Der p 1 levels in dust samples collected before or during these respective winters (Geometric means: Erfurt 89 vs 33 ng/g; Hamburg 333 vs 219 ng/g; Bitterfeld, Hettstedt, and Zerbst 296 vs 180 ng/g). Except for Hamburg, the decrease in Der p 1 levels was statistically significant. D. pteronyssinus levels measured in dust samples collected in 2001 (i.e. 3 years after the two cold winters) show a statistically non-significant increase (Geometric means: Erfurt 33 vs 39 ng/g; Hamburg 219 vs 317 ng/g), suggesting that it may take a long time for mite allergen levels to increase again after a sudden decrease. CONCLUSION: We conclude that Der p 1 levels in German mattress dust samples have been approximately reduced by a factor of three to four by the two consecutive cold winters of 1995/1996 and 1996/1997.

Exposure to house dust endotoxin and allergic sensitization in adults.

BACKGROUND: It has been suggested that exposure to elevated levels of endotoxin decreases the risk of allergic sensitization. OBJECTIVE: To examine the associations between current exposure to bacterial endotoxin in house dust and allergic sensitization in adults. METHODS: In 1995-1996, we conducted a nested case-control study following a cross-sectional study performed within the European Community Respiratory Health Survey (ECRHS). Data of 350 adults aged 25-50 years was analysed. Allergic sensitization was assessed by measurement of specific immunoglobulin E (IgE) against several inhalant allergens. Living room floor dust samples were taken. The endotoxin content was quantified using a chromogenic kinetic Limulus amoebocyte lysate test. RESULTS: Multiple logistic regression analysis showed a negative association between exposure to house dust endotoxin and severe allergic sensitization. Odds ratios (95% CI) adjusted for place of residence, gender, age, and 'caseness' were 0.80 (0.64-1.00) for sensitization to >/=1 allergen and 0.72 (0.56, 0.92) for sensitization to >/=2 allergens using 3.5 kU/l as a cut-off value for sensitization. With regard to single allergens, the protective effect of endotoxin was strongest for pollen sensitization [aOR (95% CI) = 0.74 (0.58, 0.93)]. CONCLUSION: Our results indicate that current exposure to higher levels of house dust endotoxin might be associated with a decreased odds of allergic sensitization in adults.

Repeated measurements of allergens and endotoxin in settled house dust over a time period of 6 years.

BACKGROUND: Studies investigating the effect of exposure to indoor allergens and endotoxin on human respiratory health usually take dust samples only at one single point of time and consider them to be representative for the indoor biocontaminant burden during a time period of several years. This singly measured biocontaminant concentration is related to adverse respiratory outcomes such as asthma, wheeze or others. OBJECTIVE: We analysed two repeated measurements of mite and cat allergens in mattress and living room floor dust as well as endotoxin concentrations in living room floor dust. The repeated samples were taken over a time period of about 6 years. We investigated the repeatability over time of their concentrations by determining correlation coefficients and computing within- and between-home variance components. METHODS: Our analysis was based on the population of a study on Indoor Factors and Genetics in Asthma (INGA) being carried out in 1995/96 and followed up in 2000/01. Complete data were available from 152 participants. RESULTS: The measured allergen concentrations were low and a considerable percentage of the values was below the limit of detection. The crude Spearman's rank correlation coefficients between the two measurements taken in 1995/96 and 2000/01 ranged from 0.32 to 0.61 for the dust mites allergens, from 0.21 to 0.44 for cat allergen and from 0.35 to 0.51 for endotoxin. Correlations were higher if measurements were performed on the same floor or the same mattress at both sampling time-points. The within-home variance for all measured biocontaminant concentrations was of about the same order as the between-home variance. CONCLUSION: For studies like ours with low allergen and endotoxin concentrations, the repeatability of these concentrations over a time period as long as 6 years is low and a single measurement does not accurately reflect the true long-term exposure in the homes.

[Blunt testicular injury - conservative or surgical treatment?]. / Stumpfes Hodentrauma - wann konservative, wann operative Behandlung?

INTRODUCTION: Testicular trauma can be classified into blunt or penetrating injury. While every case of penetrating trauma is subjected to surgical treatment, the decision between surgery and conservative treatment must be made for each case of blunt injury. Inspection, palpation and duplex sonography may be helpful in finding the correct decision. Herein we present a case report and review of the current literature. CASE REPORT: A 14-year-old boy was admitted to an urological department after blunt scrotal trauma. Ultrasound examination revealed a peritesticular hematoma. After 9 days of conservative treatment, surgical exploration and orchidectomy for rupture of the tunica albuginea was performed. CONCLUSIONS: The following recommendations can be made for treatment of blunt testicular injury: if rupture of the testis is detected sonographically, immediate surgical exploration is indicated. Every change in testicular structure must be considered a possible sign of testicular rupture. Sonographically detected hematoceles without visible signs of rupture are not given clear recommendations in the literature. However, early surgical intervention (within 72 hours) seems to increase the likelihood of preserving the testis. In every case of unclear clinical or sonographic findings, surgical exploration of the scrotum should be done. If offers a safe and quick diaganosis with a very low complication rate.

Further characterization of IgE-binding antigens from guinea pig hair as new members of the lipocalin family.

BACKGROUND: Guinea pigs are important sources of inhalant allergens in home and working environments. However, little is known about the molecular characteristics and the relevant epitopes of guinea pig allergens. Recently, several allergens have been identified in hair extract and urine, and the major allergen Cav p 1 (20 kDa) has been characterized. OBJECTIVE: The aim of the present study was to isolate and to characterize a further major allergen from guinea pig hair with 17 kDa. METHODS: Guinea pig hair extract was fractionated using anion exchange chromatography and reverse-phase high performance liquid chromatography. Analyses were carried out by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, 2D-PAGE, immunoblotting, immunoblot inhibition, glycoprotein detection, and N-terminal amino acid sequencing. RESULTS: The nonglycosylated 17 kDa allergen, which was named Cav p 2, was purified to homogeneity. On the basis its 15 N-terminal residues, there was 69% identity with a sequence of Bos d 2, an allergenic protein from cow dander belonging to the lipocalin family. The 2D-immunoblotting analyses of guinea pig hair extract demonstrated that Cav p 2 and Cav p 1, contained several isoforms with pI values ranging from 3.6 to 5.3. The 2D-immunoblot inhibition disclosed cross-reactive IgE epitopes on the allergens Cav p 2 and Cav p 1. Furthermore, Cav p 1 can form both monomers (20 kDa) and dimers (40-42 kDa). CONCLUSION: These studies provide important information on the isoallergen character of two relevant guinea pig allergens Cav p 1 and Cav p 2 as well as on their cross-reactive properties.

The effect of storage on allergen and microbial agent levels in frozen house dust.

BACKGROUND: House dust samples collected for exposure studies are often stored for variable time periods until analysis. However, there is currently no information on the effects of dust storage on the content of biocontaminants. Therefore, associations were analysed between the levels of mite allergens (Der p 1, Der f 1), cat allergen (Fel d 1) and microbial components (endotoxin, beta(1-->3)-glucan) on the one hand and the storage duration of dust samples at -20 degrees C on the other hand. METHODS: Within the framework of a study on the influences of INdoor factors and Genetics on Asthma (INGA), dust samples were collected from living room floors between June 1995 and August 1998 and extracted according to a standardized protocol. The concentrations of Der p 1, Der f 1, Fel d 1 and beta(1-->3)-glucan were determined with specific enzyme immunoassays. Endotoxin content was quantified using a chromogenic kinetic Limulus amoebocyte lysate (LAL) test. All concentrations were expressed per gram of dust RESULTS: Dust samples (n = 1236) were obtained from 655 homes in Hamburg, Hettstedt, Zerbst and Bitterfeld. Storage duration (range 8-298 days) was grouped into four categories ( 120 d). After adjustment for city of residence and season of dust sampling, means ratios comparing categories 2-4 to the first category were not statistically significant for Der p 1, Der f 1, endotoxin and beta(1-->3 glucan). However, Fel d 1 concentrations significantly declined with increased storage times of dust samples. CONCLUSIONS: Storage of house dust at -20 degrees C for up to 10 months has no effect on mite allergen, endotoxin and beta(1-->3)-glucan levels. A potential loss of Fel d 1 during storage of frozen dust samples needs further investigations by repeated measurements of allergen in identical dust samples.

Health impacts of second-hand exposure to cat allergen Fel d 1 in infants.

BACKGROUND: Recent cross-sectional studies suggested that highest sensitization prevalences occur with moderate cat allergen exposures. We aimed to assess the impact of moderate levels of second-hand cat allergen exposure on the incidence of specific sensitization and wheezing in the framework of a birth cohort study. Therefore we restricted our analysis to infants without a cat at home since birth. METHODS: At infant's age 3 months, cat allergen levels were measured in the mattress dust of 1840 families without cats. At age 2 years, serum IgE specific to Fel d 1 was analyzed. Incidence of wheezing apart from respiratory infection was assessed by questionnaire. Logistic regression models were used to calculate adjusted odds ratios (OR) for the association between second-hand cat allergen exposure and health outcomes. RESULTS: Until age 2 years, 13 of 1301 infants (1%) were sensitized to cat allergen and 56 of 1492 infants (4%) had ever-wheezing without infection. Early exposure to second-hand cat allergen levels >or= 1 microg/g dust increased substantially the risk for specific sensitization to Fel d 1 (OR 10.9, 95% CI 3.4-35.0) and ever-wheeze without infection (OR 2.0, 95% CI 1.1-3.9) at age 2 years. CONCLUSIONS: Second-hand exposure to cat allergen in homes without cats is detrimental in terms of allergy development in infants.

Allergens and endotoxin on mothers' mattresses and total immunoglobulin E in cord blood of neonates.

The current authors examined whether mite and cat allergen and bacterial endotoxin levels in dust of the mothers' mattresses were associated with cord blood immunoglobulin (Ig)E (CB-IgE) levels in newborns. Data from 1,332 term and normal weight neonates, from an ongoing birth cohort study, influences of life-style related factors on the immune system and the development of allergies in childhood (LISA), with complete information on exposure to biocontaminants in mattress dust and CB-IgE were analysed. Two thirds of CB-IgE were undetectable (<0.35 kU x L(-1)). Thus, 0.35 and 0.45 kU x L(-1) (4th quartile) were chosen as cut-offs. Nonparametric smoothing (generalised additive models) showed statistically significant confounder-adjusted associations between elevated CB-IgE levels (> or = 0.45 kU x L(-1)) and log-transformed exposures to cat (linear), mite (inverse u-shaped), and endotoxin (u-shaped). After adjustment for covariables, elevated CB-IgE levels (logistic regression using the 1st-4th quartiles of exposure) were positively associated with high cat-allergen exposure and medium exposure to mite allergen, but were inversely associated with exposure to endotoxin. The associations were similar, but somewhat weaker, when 0.35 kU x L(-1) was used as cut-off. These results, showing an association between prenatal allergen and endotoxin exposures and immunoglobulin E production, suggest that the development of foetal immune responses may be affected.

IL-4 supplemented B-cell cultures of allergic children show reduced IgA and IgG production in response to additional stimulation with IL-10.

BACKGROUND: Cytokines play an important role in mediating immunoglobulin switch, the secretion of protective mucosal immunoglobulins, and the development of allergic diseases. This study investigates whether B cells from allergic and healthy children have different capacities to secrete immunoglobulins after stimulation with IL-4, IL-6, IL-10, IL-11, and IL13. METHODS: We analyzed the peripheral venous blood of 44 healthy probands and of 109 allergic patients with a mean age of 13 years, allergic to grass pollen, birch pollen, and house dust mites. Lymphocytes were isolated by a density gradient and B cells were enriched by using a Magnetic Activated Cell Separator (MACS) and anti-CD19 microbeads. B Cells were co-cultured with human CDw32 (Fc gammaRII) expressing mouse Ltk fibroblasts and mouse anti-human CD40 monoclonal antibodies (CD40 system). The interleukins IL-4, IL-6, IL-10, IL-11, and IL-13 were supplemented in various combinations. After 14 days, concentrations of IgE, IgG, IgA, and IgM were measured in the supernatants with ELISA. RESULTS: Suppression of IgA-, IgG, and IgM- synthesis was induced by stimulation of B cells with IL-4. After additional application of IL-10, IgA, IgG, and IgM synthesis was significantly increased. When cultures stimulated with IL-4 were additionally supplemented with IL-10, IgA, and IgG synthesis of B cells obtained from allergic individuals was significantly decreased compared to nonallergic individuals. IgE-secretion of B cells from allergic individuals was significantly increased compared to nonallergic individuals after stimulation with IL-4. CONCLUSION: Our results implicate that IL-4 is essential for the regulation of immunoglobulin class switch to IgE and that IL-4 is an important cytokine for the development of allergic diseases. The capacity of B cells in allergic children to produce less IgA and IgG in response to additional stimulation with IL-10 of cultures supplemented with IL-4 could play an important role in mediating a mucosal immune system vulnerable to allergens. This phenomenon could contribute to the pathogenesis of allergic diseases.

Predictors of cat allergen (Fel d 1) in house dust of German homes with/without cats.

BACKGROUND: Exposure to cat allergen is a major risk factor for sensitization and the development of asthma in many parts of the world. The study was designed to examine the levels of cat allergen (Fel d 1) in homes of two German cities and to detennine predictors of Fel d 1 exposure. METHODS: We collected dust samples from 405 randomly selected homes in Hamburg (n = 201) and Erfurt (n = 204). In each apartment dust samples were taken from living room floor (LR), bedroom floor (BR), and mattress surface (MA) using vacuum sampling and analyzed by two-site monoclonal antibody ELISA. Environmental variables were assessed by questionnaire to obtain information on factors supposed to have an impact on the Fel d 1 levels in house dust. The effects of possible predictors of Fel d 1 were assessed by multiple linear regression models. RESULTS: Fel d 1 was present in 98% of the homes (395/405), ranging from 0.015 to 7.278 microg/g dust (GM 0.486 microg/g). The levels were similar in floors (GM for LR 0.575 microg/g and BR 0.469 microg/g) and in MA (GM 0.424 microg/g). Higher allergen concentrations (> 2 microg/g) were detected in 99% of the homes keeping cats, in 55% of homes that had had a cat during the last year, and in 28% of the homes without a cat. Fel d 1 levels were significantly higher in homes with a cat (628-682-fold, MA, floor) and in homes in which a cat had previously lived (11-12-fold, floor, MA) than in homes that never had a cat. Furthermore, after controlling for possible other confounders, Fel d 1 levels were significantly higher in summer and in homes with low frequency of cleaning and low ventilation rate. CONCLUSION: It could be confirmed that keeping a cat has the highest impact on Fel d 1 concentration. Besides, a continuous influx of Fel d 1 in homes without cat, as a result of direct or indirect cat contact outside the home, is likely. High frequencies of dusting and ventilation might reduce cat allergens in homes with and without cats.

Predictors of high endotoxin concentrations in the settled dust of German homes.

Endotoxin concentrations in settled house dust were measured within the collaborative study named INGA (Indoor Exposure and Genetics in Asthma) together with other asthma-related indoor factors in 405 randomly selected homes in two German cities. Endotoxin was assayed using the quantitative kinetic chromogenic Limulus Amebocyte Lysate (LAL) method. The mean concentration of 2,274 ng endotoxin/g dust in living rooms is about two orders of magnitude below mean occupational exposure (e.g. agriculture). Endotoxin concentrations are higher in old buildings (means ratio = (MR) 1.52, 95% C.I.: 1.14; 2.04), and in the lower storey of the dwelling (MR = 1.30, 95% C.I.: 1.04; 1.62). Furthermore, higher endotoxin concentrations are associated with longer occupancy in the apartment (MR = 1.63, 95% C.I.: 1.21; 2.18), high utilisation of the apartment during the sampling period (MR = 2.52, 95% C.I.: 1.42; 4.47), infrequent vacuum cleaning of the carpets (MR = 1.67; 95% C.I.: 1.10; 2.54), an indifferent attitude to ventilation (MR = 1.37; 95% C.I.: 1.03; 1.82), keeping cats (MR = 1.91; 95% C.I.: 1.43; 2.55) and dogs (1.57; 95% C.I.: 1.08; 2.30), as well as the occurrence of mice (MR = 1.39; 95% C.I.: 1.00; 1.93). The season and indoor climate (operative temperature and relative humidity) did not effect endotoxin concentration. These results indicate that high endotoxin concentration in settled dust is an indicator of poor hygienic conditions in homes.

Purification and partial characterization of the major allergen, Cav p 1, from guinea pig Cavia porcellus.

BACKGROUND: Allergic reaction to guinea pig has been recognized as a problem in domestic settings and work environments for many years. Until recently, limited information was available on the properties of guinea pig allergen(s). In this study the major allergen Cav p 1 was characterized and the N-terminal amino-acid sequence was determined. METHODS AND RESULTS: Sera from 40 patients with IgE-mediated allergy to guinea pigs were investigated by means of immunoblotting using extracts prepared from guinea pig hair and urine. Three major allergens were identified within both sources with molecular weights (MW) of 8 kDa, 17 kDa and 20 kDa, respectively. From aqueous hair extracts the 20 kDa allergen (Cav p 1) was purified to homogeneity by anion exchange chromatography and reverse-phase HPLC and the N-terminal amino-acid sequence was determined. On the basis of the 15 residues, 57% identity was obtained from computer search with a sub-sequence of MUP (major urinary protein), a member of the lipocalin superfamily. Allergenic relationships among guinea pig allergens derived from various sources (hair and urine) or different animal species (mouse, rat, cat) were studied by ELISA inhibition assays. Neither urine of mouse, rat and cat, nor hair extracts of rat and cat produced appreciable inhibitions in guinea pig ELISA. CONCLUSION: Although the physicochemical characteristics of isolated Cav p 1 are very similar to those for other rodent allergens and furthermore partial sequence identity with Mus m 1 was found, it is clearly shown here to be an immunologically independent major allergen.

Pets and vermin are associated with high endotoxin levels in house dust.

BACKGROUND: Previous studies have shown that the risk for allergic sensitization is lower in children who grew up on farms and in young adults who were exposed to dogs in early childhood. A higher microbial exposure in general and in particular to endotoxin in early childhood might contribute to this lower risk of atopy. OBJECTIVE: We examined whether the presence of pets or vermin in the home is associated with higher endotoxin concentrations in settled house dust. METHODS: House dust was sampled in a standardized manner on the living room floors of 454 homes of German children aged 5-10 years (participation rate 61%). Endotoxin was assessed with a quantitative kinetic chromogenic Limulus Amebocyte Lysate (LAL) method. Associations between endotoxin levels, pets and vermin are presented as ratios of the crude and confounder adjusted geometric means (means ratios) in the category of study vs. a reference category using multiple linear regression models. RESULTS: Endotoxin concentrations in living room floor dust sampled in homes without pets and vermin were lower (1246 ng per square meter, 1519 ng endotoxin/g dust, n = 157) than those sampled in homes with pets or vermin (2267 ng per square meter, 2200 ng endotoxin/g dust, n = 296). After adjustment for city of residence, season of dust sampling, age of the building and story of the dwelling, means ratios for endotoxin expressed per gram of dust were statistically significantly increased for dog (1.64, 95% CI 1.09-2.46), for cat (1.50, 95% CI 1.03-2.18) and for cockroach (3.01, 95% CI 1.37-6.60), whereas no major statistically significant associations were found for other pets, ants and mice. CONCLUSION: Keeping a dog or a cat in the home is consistent with higher exposure to endotoxin and might therefore contribute to the lower risk of atopy in later life.

Predictors of group 5 grass-pollen allergens in settled house dust: comparison between pollination and nonpollination seasons.

BACKGROUND: Some sensitive pollen-allergic patients may experience perennial symptoms, and for these patients it is vitally important to know the concentration of grass-pollen allergens in their homes. The main objective of this study was to detect predictors associated with high grass allergen concentration in settled house dust during and outside the grass pollination season. METHODS: We detected group 5 grass-pollen allergens in dust samples from randomly selected homes of three counties in the region of Sachsen-Anhalt: Hettstedt (n=183), Zerbst (n=152), and Bitterfeld (n=119). Dust samples were collected from the floors of living rooms (LR) and children's rooms (CR) from April 1996 to March 1998. RESULTS: Phl p 5 was detected in settled house dust in 91% of the homes. The range was between undetectable (<30 ng/m2) and 4300 ng Phl p 5/m2 sampling area during grass pollination, and 1300 ng Phl p 5/m2 outside the pollination season, respectively. We observed a partially higher concentration of indoor allergenic activity several weeks after the grass-pollen peak. A positive association was found between Phl p 5 levels and total dust amounts throughout the year. Thus, we assume that grass allergens accumulate in settled house dust. During pollination, the Phl p 5 levels are 1.8 times higher in homes where vacuuming of carpets takes place only once a week or less than in those vacuumed daily. Furthermore, higher concentrations of Phl p 5 in settled floor dust can be expected in homes located within suburban areas (mean ratio [MR] 1.74) and prefabricated slab buildings (MR=1.54). CONCLUSIONS: Quite high levels of Phl p 5 accumulate in settled house dust even during periods when no grass pollen is present in the atmosphere. The removal of dust by frequent cleaning reduces the indoor exposure to grass allergens. Such information is essential to train patients in allergen avoidance.

Exposure to endotoxin decreases the risk of atopic eczema in infancy: a cohort study.

BACKGROUND: Previous studies have shown a protective effect of early exposure to cats and dogs on the development of atopic eczema, asthma, allergic rhinitis, and atopic sensitization in later life. In particular, a higher microbial exposure to endotoxin in early childhood might contribute to this effect. OBJECTIVE: We examined the associations between bacterial endotoxin in house dust and atopic eczema, infections, and wheezing during the first year of life in an ongoing birth cohort study (LISA). METHODS: Data of 1884 term and normal-weight neonates with complete information on exposure to biocontaminants and confounding variables were analyzed. House dust from the mothers' and the children's mattresses was sampled 3 months after birth. Endotoxin content was quantified by using a chromogenic kinetic limulus amoebocyte lysate test. RESULTS: During the first 6 months of life, the risk of atopic eczema was significantly decreased by endotoxin exposure in dust from mothers' mattresses in the fifth quintile (odds ratio [OR], 0.50; 95% CI, 0.28-0.88), whereas the risk was increased for respiratory infections (OR, 1.69; 95% CI, 1.25-2.28) and cough with respiratory infection, bronchitis, or both (OR, 1.73; 95% CI, 1.28-2.33). The risk of wheezing was also significantly increased during the first 6 months of life (OR, 2.37; 95% CI, 1.40-4.03). For the entire first year of life, these associations attenuated, except for the risk of wheezing, which remained significant (OR, 1.60; 95% CI, 1.10-2.30). CONCLUSION: Our findings support the hygiene hypothesis that exposure to high concentrations of endotoxin very early in life might protect against the development of atopic eczema within the first 6 months of life, along with an increased prevalence of nonspecific respiratory diseases.

Respiratory symptoms in relation to indoor exposure to mite and cat allergens and endotoxins. Indoor Factors and Genetics in Asthma (INGA) Study Group.

The authors investigated the relationship between respiratory symptoms in adults and exposure to mite and cat allergens, the role of endotoxins in house dust, the effects of mixtures of several allergens, and interactions between allergen exposure and allergic sensitization. Within a nested case-control study, 405 subjects aged 25-50 yrs from two German cities answered a standardized questionnaire. Allergen-specific immunoglobulin-E was measured. Dust samples were taken from the subjects' homes to determine exposure to mite (Dermatophagoides pteronyssinus antigen 1 Der p 1) and (D. farinae antigen 1 Der f l) and cat (cat antigen d1 Fel d 1) allergen and endotoxin content in settled house dust. Exposure to Der f 1 and Der p 1 plus Der f 1 >10 microg x g(-1) of mattress dust, respectively, increased the risk of wheeze and breathlessness (odds ratios (OR): 4.04, 95% confidence interval (CI): 1.53-10.64, OR: 2.78, 95% CI: 1.06-7.28). Fel d 1 >8 microg x g(-1) was positively associated with cough at night (OR: 2.74, 95%, CI: 1.22-.17), noteworthy also in the nonsensitized subjects. Subjects exposed to elevated concentrations of more than one allergen had an up to seven-fold increase in the risk of respiratory symptoms, compared to nonexposed subjects. Sensitized subjects exposed to elevated concentrations of Der f 1 or Fel d 1 were found to have the highest risk of asthma attacks and respiratory symptoms. No statistically significant association was found between exposure to endotoxins and respiratory health. Indoor exposure to Dermatophagoides farinae antigen 1 and cat antigen d1 is a risk factor for respiratory symptoms in adults, and for cat antigen d 1 even in nonsensitized subjects. The risk is increased if subjects are exposed to a mixture of allergens or if they are sensitized in addition to high exposure.

Beta(1-->3)-glucan in house dust of German homes: housing characteristics, occupant behavior, and relations with endotoxins, allergens, and molds.

beta(1-->3)-Glucans are potent proinflammatory agents that have been suggested to play a role in indoor-related respiratory health effects. The aim of this study was to assess whether beta(1-->3)-glucan concentrations in house dust are correlated with levels of endotoxins, allergens, and culturable mold spore counts in house dust. Further, the associations of beta(1-->3)-glucan with housing characteristics and occupant behavior were assessed. beta(1-->3)-Glucan was measured in settled house dust from living room floors of 395 homes of two German cities, Erfurt and Hamburg, with a specific enzyme immunoassay. Concentrations ranged from below the limit of detection to 19,013 microg/m(2) (22,588 microg/g dust). Concentrations per square meter were found to be correlated with endotoxins, mite and cat allergens, and culturable mold spores. Correlations were weaker when concentrations were expressed per gram of dust, indicating that variance in concentrations of all factors is largely determined by the amount of dust sampled. Associations between beta(1-->3)-glucan, housing characteristics, and occupant behavior were found for concentrations per square meter but not for concentrations per gram of dust. The following characteristics were associated with a significant increase in beta(1-->3)-glucan levels: carpets in the living room [means ratio (MR) = 1.9-2.1], keeping a dog inside (MR = 1.4), use of the home by four or more persons (MR = 1.4), use of the living room for > 180 hr/week (MR = 2.1), lower frequency of vacuum cleaning (MR = 1.6-3.0) and dust cleaning (MR = 1.2 and 1.4, respectively), and presence of mold spots during the past 12 months (MR = 1.4). We conclude that that the amount of dust sampled can be used as a proxy for hygiene and that beta(1-->3)-glucan concentrations per square meter are related to the amount of dust sampled.

Quantification of group 5 grass pollen allergens in house dust.

BACKGROUND: It is widely known and accepted that grass pollen is a major outdoor cause of hay fever. However, it is of virtual importance for grass pollen allergic patients with symptoms all the year round to know the concentration of grass pollen allergens in their homes. OBJECTIVE: The main objective of this study was to quantify the amount of grass pollen allergen in mass units (microg Phl p 5) in dust settled indoors and to detect the distribution of allergenic activity in different sampling locations of homes. Furthermore, we studied the seasonal fluctuation of allergen content in dust samples. METHODS: We adapted the two site binding assay for detection of group 5 grass pollen allergens in samples from randomly selected homes in Hamburg (n = 371), Erfurt (n = 396), Hettstedt (n = 353), Zerbst (n = 289) and Bitterfeld (n = 226), Germany. Dust samples were collected from floor of living room (LR), bedroom (BR) or children's room (CR) and mattress (MA) during period of June 1995 to August 1998. The amount of the major grass group 5 allergens was detected in microg/g dust. RESULTS: Phl p 5 was detected in 67% of the samples analysed (n = 4760). The range was between undetectable (< 0.03 microg/g dust) and 81 microg/g dust. Phl p 5 levels were significantly higher in the dust from LR (geometric mean 0.117 microg/g dust) or BR/CR floors (geometric mean 0.098 microg/g dust) than in mattresses (geometric mean 0.043 microg/g dust). We observed seasonal fluctuation of indoor Phl p 5 levels with peak in June but also annual differences. Thus Phl p 5 content indoors reflects also the different quantities of pollen counts of annual courses. During pollination period we found two times higher Phl p 5 levels (0.172 microg/g dust, P < 0.001) than outside of grass pollination season (0.095 microg/g dust). The indoor Phl p 5 levels outside of season seem to be independent of pollination before. We suppose that settled pollen grains or allergenic material from outdoor particles carried indoors via footwear and clothes accumulates in house dust. CONCLUSION: Although we not known how the allergens in settled dust are equilibrated with those in the air, the considerable high level of Phl p 5 in indoor dust even during periods when no grass pollen is present in the atmosphere may be an important cause of pollen-allergy symptoms outside of season.

Indoor determinants of Der p 1 and Der f 1 concentrations in house dust are different.

BACKGROUND: Exposure to mite allergens is a major risk factor for sensitization and the development of asthma. Der p 1 and Der f 1 content in homes and probably the proportion of both antigens is highly variable even in the same geographical area. OBJECTIVE: We investigated specific indoor determinants of Der p 1 and Der f 1 concentrations in house dust of two German cities, Erfurt and Hamburg (n = 405 homes). METHODS: Mite allergen levels were determined using monoclonal antibodies against Der p 1 and Der f 1 by the ELISA method. Indoor relative humidity and temperature were monitored continuously in the homes over 1 week. The characteristics of homes and occupants were assessed by questionnaire to obtain information on factors which may have an impact on the mite antigen concentration in house dust. These determinants were studied by multivariate regression analysis. RESULTS: The correlation between concentrations of Der p 1 and Der f 1 inside the homes was weak (r = 0.29-0.35), indicating that different determinants are relevant. Concentrations of the allergens were significantly higher on lower floors (ratios 2-8 times, Der p 1, Der f 1), on old mattresses (ratios 3-13 times, Der p 1, Der f 1), in post-war buildings (ratio 6 times, Der p 1), for non-central heating (ratio 2 times, Der p 1), for old carpets (ratio 3 times, Der p 1) and for the presence of a dog in the house (ratio 3 times, Der f 1). Furthermore, mite concentration increases with raising relative humidity (ratio 1.03 per 1%, Der p 1) and with decreasing temperature (ratio 0.86 per 1 degrees C, Der p 1) indoors. CONCLUSION: Both Der p 1 and Der f 1 concentrations should be measured in house dust, since they are only weakly correlated and have different determinants.