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Biomedical subjects

R Einarsson

Publications and source records attributed to R Einarsson.

At least 19 recordsLinked to original sources
PubMed2003

Variability of airborne cat allergen, Fel d1, in a public place.

Allergen exposure is a risk to develop an IgE-mediated sensitization. The amount of allergen inhaled per unit time should be related to the amount present in the air, i.e. airborne allergen. Thus, measuring allergen levels in the air would be more relevant than measuring allergen levels in dust. Allergens are present in the air in very minute quantities and usually become airborne after disturbance. Large variation of allergen levels have been found in dust. In this study, we measured variability of airborne cat allergen, Fel d1, in a public place using a high-volume air-sampler. We also studied the distribution and relationship between dust and airborne cat allergens in homes and schools. Air samples were collected at three different airflow rates, i.e. 55, 40, and 30 m3 of air per hour. The concentration of airborne Fel d1 in the community gymnastic hall varied from 1 to 10 pg/m3 within a period of 3 weeks, at airflow rates 55-30 m3/h. The coefficient of variation for repeated samplings was 14-43% (day-to-day variation) and 27-38% (within-day variation). As expected, higher levels of airborne cat allergens were found in homes with cats than in cat-free environments. There was a significant relationship between cat allergen levels in dust and air (r=0.7, P<0.01). Our study demonstrates that when measuring airborne cat allergen a large variation is observed within a day and between days. The large variability of measurement may be explained by the disturbance in the environments. We suggest, that when exposure assessment is made the environment in question should be analyzed, if possible in several occasions.

Air Pollution, Indoor↗
PubMed2002

Tumour markers as early predictors of response to chemotherapy in advanced colorectal carcinoma.

BACKGROUND: To evaluate the reliability and validity of serum carcinoembryonic antigen (CEA), tissue polypeptide-specific antigen (TPS), vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in monitoring palliative chemotherapy in advanced colorectal cancer (ACRC). METHODS: Serum was prospectively collected from 87 patients with ACRC treated with first-line 5-fluorouracil and leucovorin before and 2, 4 and 10 weeks after induction. RESULTS: Eight patients had normal baseline TPS levels, and these patients had a favourable outcome with prolonged survival and a higher rate of objective responses than patients with elevated TPS levels. At 10 weeks, all responders had a decreasing TPS value. The sensitivity for a decrease of >25% using TPS was 83% and 86% for objective and subjective responses, respectively, and the specificity was 65% and 72%, respectively. CEA had, in the same setting, a sensitivity of 45% and 46%, respectively, and the specificity was 88%. VEGF was elevated in 54% of the patients and bFGF in 15% of the patients. The VEGF values decreased during therapy in 94% of the patients, but the changes in serial VEGF values did not correlate with survival or response. Tumour markers used together did not enhance the predictive values of TPS alone. CONCLUSIONS: Repeated measurements of CEA, VEGF and bFGF in serum are of limited value in monitoring chemotherapy in ACRC. TPS seems to be of greater interest, but does not predict exactly which patients are going to have a positive outcome of palliative chemotherapy.

Adenocarcinoma↗
PubMed2000

Tissue polypeptide specific antigen (TPS), a marker for differentiation between pancreatic carcinoma and chronic pancreatitis. A comparative study with CA 19-9.

BACKGROUND: The value of serum tissue polypeptide specific antigen (TPS) as a complement to CA 19-9 in the detection of pancreatic carcinoma was determined prospectively. TPS and CA 19-9 levels obtained at the time of diagnosis in patients suspected of having chronic pancreatitis or pancreatic carcinoma were evaluated in receiver operating characteristic (ROC) curve analysis. METHODS: Serum TPS and CA 19-9 levels were measured by immunoassays in 122 subjects, 48 with pancreatic carcinoma and 74 with chronic pancreatitis. RESULTS: Elevated levels of CA 19-9 were detected preoperatively in 70% of pancreatic carcinoma patients and in 19% of chronic pancreatitis patients. Elevated levels of TPS were detected in 100% of patients with pancreatic carcinoma and in 22% of patients with chronic pancreatitis. The median levels of TPS and CA 19-9 for pancreatic carcinoma were significantly higher than those for chronic pancreatitis (P < 0.0001). Increasing the upper reference value of TPS allowed for better discrimination between chronic pancreatitis and pancreatic carcinoma. ROC curve analysis showed that the introduction of 200 U/L as a decision criterion for TPS did not reduce its sensitivity but significantly improved its specificity. At a specificity of 98% for TPS, discrimination between pancreatic carcinoma and chronic pancreatitis was found to be 97%. Increasing the upper reference level for CA 19-9 to attain a specificity of 98% decreased its sensitivity from 70% to 33%. CONCLUSIONS: At an elevated cut-off level for TPS (200 U/L), almost complete discrimination between pancreatic carcinoma and chronic pancreatitis was obtained. TPS will be more useful than CA 19-9 in the differential diagnosis of pancreatic carcinoma and chronic pancreatitis.

Adult↗
PubMed2000

Prognostic significance of CA 125 and TPS levels after 3 chemotherapy courses in ovarian cancer patients.

OBJECTIVE: To evaluate the prognostic significance of and predictive value for survival of CA 125 and TPS levels after three chemotherapy courses in ovarian cancer patients. METHODS: We analyzed in a prospective multicenter study the 1- and 2-year overall survival (OS) in ovarian carcinoma patients. The prognostic significance of CA 125 and TPS levels above the discrimination value (25 kU/L and 100 U/L, respectively) was examined by univariate and multivariate analyses. RESULTS: Of the 213 cases included, 64 patients were staged as FIGO I + II and 149 patients were staged as FIGO III + IV. Tumor marker levels in stage I + II were not correlated with survival. However, stage III and IV patients with elevated levels of CA 125 or TPS after three chemotherapy courses had a worse 2-year OS (69% vs 26%, P < 0.0001 and 57% vs 20%, P < 0.0001, respectively) than patients with normal levels of the markers. In univariate analysis the result of operation (staging laparatomy and partial debulking) and advanced FIGO stage (IV) were also adverse prognostic factors. Independent factors predictive of low 2-year OS by multivariate analysis were staging laparotomy, TPS elevated, and CA 125 elevated. The only factors predictive of low 1-year OS were TPS elevated and staging laparotomy. CONCLUSIONS: Ovarian cancer patients with elevated CA 125 levels after three chemotherapy courses have a poor prognosis. However, the prognostic accuracy can be significantly increased by the parallel determination of serum TPS.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

In-house reference (IHR) preparation of Candida albicans allergen extract. A standardized extraction procedure.

A standardized, controlled procedure for preparation of an in-house reference (IHR) preparation of an allergen extract of Candida albicans is described. The procedure, based on previous studies of allergens of C. albicans, is designed to yield a maximum of allergens in optimum extraction conditions and to provide a reference preparation for further extract production. The SDS-PAGE, IgE-immunoblotting, and crossed radioimmunoelectrophoresis (CRIE) analyses showed that the procedure is reproducible with acceptable batch-to-batch variation. The variation in the content of the most important allergens, namely, proteins with molecular weights of 46, 29, and 27 kDa in the pooled final batches, is acceptable (coeff. of variation < 15%), although in the intermediate batches of different strains, the coefficient of variation may occasionally exceed 20%. A comparison with other C. albicans allergen preparations used in our previous studies is also presented. The resulting extract can be used as a reference in further extract production and also in experimental in vitro and in vivo studies.

Allergens↗
PubMed1998

Epitope specificity of 30 monoclonal antibodies against cytokeratin antigens: the ISOBM TD5-1 Workshop.

The epitope specificities of 30 monoclonal antibodies (MAbs) against the most common human cytokeratins. i.e., Nos. 8, 18, and 19, in epithelial cells were investigated in the ISOBM TD-5 Workshop. Seven research groups from universities or companies participated independently in the evaluation of the antibody specificities. The complex assembly of cytokeratins in vivo, with obligatory heterologous dimeric combinations of different cytokeratins from each of the two major groups, comprising together more than 20 different individual cytokeratins, made analysis of the antibody reactivity patterns with isolated single cytokeratins necessary. The concordance of the evaluations was striking and independent of the technologies used. As antigens purified individual cytokeratins, chemically degraded purified cytokeratins, recombinant intact and truncated cytokeratins, as well as specific synthesized shorter peptides were used. In order to elucidate the epitope specificity, reactivity patterns in ELISA assays and immunoblots with partial enzymatic degradation of the antigens were performed. Competitive cross-inhibition experiments between antibodies using antigens and antibodies in all possible combinations were performed with radioimmunometric assays, BIAcore, and ELISA technology. All 30 antibodies could convincingly be classified with regard to target cytokeratin. One MAb (192) had to be deleted due to dual specificities in both isotype and epitope specificity against its target. Six antibodies bound selectively to cytokeratin 8, 14 to cytokeratin 18, and 10 to cytokeratin 19, as demonstrated by using native, recombinant, and synthesized antigens. The immunodominant part of the molecule for all three types of cytokeratins was located in the region of amino acid (aa) 270-400. Out of the six MAbs reactive with cytokeratin 8, four MAbs, i.e., 178, 199, 202, and 206, were reactive with a sequence in the interval aa 340-365, and MAb 191 reacted with a closely related epitope. The remaining antibody, 192, presented dual specificities. At least two closely related major immunogenic epitopes could be identified in cytokeratin 8. In cytokeratin 18 four distinct epitopes could be documented, again with the dominating sequence region 270-429 as target for 10 (181, 184, 186, 188, 189, 190, 193, 196, 198, and 200) out of 14 antibodies. Since MAb 193 is known to react with the M3 epitope, aa 322-342 in cytokeratin 18, this entire group is reactive in the region close to the charge shift, in the middle of the rod 2B region, as shown by competitive binding. The remaining four anticytokeratin 18 antibodies (180, 185, 203, and 205) displayed unique, noncompetitive binding to this filament. Cytokeratin 19, reactive with altogether ten antibodies, displayed two major epitopes, all of them also within the large immunodominant region. MAbs 179, 195, 197, and 204 were reactive with the peptides aa 311-335 also known as the KS 19.1 epitope, and MAbs 182, 183, 187, 194, and 201 bound to peptide aa 346-367, known as the BM 19.21 epitope. One antibody, 231, was selectively reactive with aa 356-370 in cytokeratin 19. A complex pattern of binding specificities comprising at least ten different, noncompetitive epitopes, mainly situated in the rod portion, 2A and 2B, situated close to the charge shift in the rod of all three cytokeratins was documented. Out of the 29 classifiable antibodies, altogether 22 were reactive in this very short region, i.e., from aa 311 to 370 in all cytokeratin filaments. The remaining seven antibodies displayed unique binding properties. The implications of the findings are of significance both for immunohistochemistry and for assaying circulating heterodimeric, partially degraded complexes in patients' blood for tumor marker evaluation.

Amino Acid Sequence↗
PubMed1997

Development of IgG1 and IgG4 antibodies against beta-lactoglobulin and ovalbumin in healthy and atopic children.

BACKGROUND: The IgG responses to food antigens are preferentially restricted to the IgG1 and IgG4 subclasses. Increased levels of IgG1 and IgG4 antibodies against food allergens have been reported in girls and adults with current atopic eczema. OBJECTIVE: To study the relation between the levels of IgG1 and IgG4 antibodies against beta-lactoglobulin and ovalbumin and the development of atopic disease. MATERIAL AND METHODS: Atopic symptoms were recorded in 36 girls from birth to 7 years of age. Blood samples were taken at 3 and 8 months and at 2, 4, and 7 years. IgG1 and IgG4 antibodies were measured by ELISA. RESULTS: Anti-beta-lactoglobulin IgG1 was detected at all ages, peaking at 8 months. Anti-beta-lactoglobulin IgG4 antibodies were detected in 18 to 29 girls at different ages and the antibody levels peaked at 2 years. The levels of anti-beta-lactoglobulin IgG1 were lower in atopic, as compared with healthy individuals at 4 and 7 years (P < .01 and P < .05) and lower anti-beta-lactoglobulin IgG4 antibody levels were found in atopic individuals (P < .05) at 4 years. Anti-ovalbumin IgG1 antibodies were detected in 3/35 girls at 3 months and in 16/35 to 26/35 girls later in life. The number of positive samples and antibody levels peaked at 2 years. Anti-ovalbumin IgG4 positive samples increased from 4/33 at 8 months to 30/32 at 7 years. The levels increased up to 2 years and then remained stable. The anti-ovalbumin IgG1 antibody levels were lower in atopic girls at 4 years (P < .05), while the anti-ovalbumin IgG4 antibody levels were similar at all ages. CONCLUSION: An early IgG1 response and later appearing IgG4 antibodies to the two food antigens beta-lactoglobulin and ovalbumin are common during the first years of life. The levels were similar in the nonatopic and the atopic girls up to four years; then they tended to be lower in the first group.

Adult↗
PubMed1996

Molecular characterization of a tissue-polypeptide-specific-antigen epitope and its relationship to human cytokeratin 18.

Tissue-polypeptide-specific antigen (TPS) from the human colon adenocarcinoma cell line WiDr was purified using the monoclonal antibody M3 as a probe. Upon SDS/polyacrylamide gradient gel electrophoresis, several TPS-positive bands were detected (corresponding to 13 kDa, 22 kDa and a doublet at 42 kDa). The 13-kDa moiety was purified about 30,000-fold by a 5-step protocol. The electro-phoretically homogeneous component was obtained in a 7% yield of the total TPS activity of the crude extract. N-terminal sequence analysis showed the presence of an N-terminally truncated molecule and identified the 13-kDa TPS component as a fragment of human cytokeratin 18, with a major from starting at position 284 of the parent molecule. Laser-desorption mass spectrometry showed the presence of one major component with a molecular mass corresponding to a C-terminal end close to position 396 (which gives 12776 Da for the form with non-truncated N-terminus). The M3 antibody was also used to screen a human prostate cDNA lambda gt11 library. Four identical phage clones were detected, each producing a fusion protein with beta-galactosidase and the M3-positive component. PCR amplification showed the presence of an approximately 1200-bp insert, and sequence analysis revealed it to contain a 996-nucleotide fragment corresponding to residues 103-429 of human cytokeratin 18 (plus a non-coding human desmin artifact fragment). Smaller fragments, engineered by PCR and expressed as fusion proteins using the pET3xc vector in Escherichia coli, showed that the M3 epitope is localized to cytokeratin 18, residues 322-340. Two other TPS-active monoclonal antibodies were localized to cytokeratin 18 with similar techniques, ascribing an epitope (to M21) to residues 414-429 and another (to M24) to residues 139-297. Combined, the results demonstrate that TPS reactivity is derived from specific epitopes of human cytokeratin 18.

Antibodies, Monoclonal↗
PubMed1996

Allergens of horse dander: comparison among breeds and individual animals by immunoblotting.

Some patients who are allergic to horses have reported that they can tolerate certain breeds, and the presence of breed-specific allergens has been suggested. Breeders and patients with asthma have claimed that Bashkir horses are nonallergenic. We used sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting to determine IgE-binding profiles of extracts of dander obtained from horses of several breeds. We found considerable inter-breed and within-breed variation but no breed-specific allergens. Danders from all breeds investigated contained the most important allergens, and the allergenic content of dander from Bashkir horses was similar to that of other breeds. Difference in scale production could account for differences in sensitivity to breeds and individual horses.

Allergens↗
PubMed1996

Allergen avoidance in a day-care center.

The predominant sensitizing allergens in Swedish asthmatic children are furred pet animals. Poor ventilation and increased indoor humidity cause accumulation of pet allergens indoors. Indirect contacts with cats also increase pet allergen exposure. We investigated whether the concentration and the total amount of cat (Fel d I) and dog (Can f I) allergen in dust from various surfaces in a day-care center were influenced by extensive renovation, installation of a new ventilation system, ventilation of floors, and avoidance by families and personnel of direct and indirect contacts with pets. The cleaning routine in the day-care center was changed extensively after renovation. Old mattresses, pillowcases, curtains, sofas, and soft toys were removed, and new material were purchased. Dust was collected from various surfaces before and after renovation from table and chair surfaces, floors, curtains, mattresses, pillows, cushion-like toys, and sofas on five occasions during a 12-month period. Fel d I and Can f I allergen levels were determined by sandwich ELISA. The reduction in the total amount of both Fel d I and Can f I/sampling area was more pronounced than the reduction in the concentration of allergen/g of dust. After renovation, the mean cat and dog allergen concentration was decreased by six and 10 times, respectively. After 1 year, the total amount of cat allergen was lower in all areas (from 24 ng to < 1 ng/sampling area, P < 0.05). Already at the first sampling after renovation, the total amount of dog allergen had decreased more than 10 times. In a previous study, we found the median concentration of cat and dog allergen to be 10-30 times higher in ordinary day-care centers. Our present study demonstrates that children changing from a normal center to the renovated center would be exposed to much lower levels of cat and dog allergen. Combined measures such as installation of mechanical ventilation, ventilated floors, regular extensive cleaning, and, probably most important, avoidance of direct and indirect contacts with pets, should decrease cat and dog allergen exposure in day-care centers.

Adult↗
PubMed1996

Monitoring palliative chemotherapy in advanced gastrointestinal cancer using serial tissue polypeptide specific antigen (TPS) measurements.

Tissue polypeptide antigen specific (TPS) was analysed in serum taken prior to chemotherapy in 90 patients with advanced gastrointestinal cancer and prior to every treatment course in 68 of these patients in order to explore whether serial tumour marker measurements can be of importance in monitoring patients treated with palliative chemotherapy. Elevated TPS levels were seen in 83/90 (92%) patients (48/52 colorectal, 9/9 pancreatic, 9/11 biliary, 17/18 gastric). Baseline TPS level correlated with performance status, tumour response and survival. Based upon the change in TPS levels after the first two courses in relation to baseline, a decrease by >50% had a high sensitivity for a favourable treatment outcome (partial remission and prolonged stationary disease (90%) or a subjective response (100%)), whereas the specificity was lower (72% and 73% respectively). A similar result was seen when the TPS levels were analysed at the time of the response evaluation after 2 months (sensitivity 91 and 95%, specificity 74 and 75% for an objective or subjective response respectively). In 7 out of 15 patients with an initially favourable outcome, an increase in TPS levels of >50% at two occasions was seen 8-20 weeks prior to clinical disease progression. In advanced gastrointestinal cancer serial TPS measurements can with high accuracy early identify patients who will not benefit from the treatment. On the other hand, a response must be confirmed using other methods in the presence of a decrease, since this was also seen in non-responding patients.

Adult↗
PubMed1995

Characterization of allergenic components from house dust mite Dermatophagoides siboney. Purification of Der s 1 and Der s 2 allergens.

BACKGROUND: Allergic reactions to house dust mites of the genus Dermatophagoides play an important role in the pathogenesis of asthma and other atopic diseases. Dermatophagoides siboney has been described as a species from Cuba. Together with D. pteronyssinus and Blomia tropicalis, it is frequently found in house dust from homes of asthmatics. OBJECTIVES: The aim of this study was to investigate the allergenic composition from the house dust mite D. siboney. METHODS: The characterization of D. siboney extract was performed by SDS-gPAGE and immunoblotting. Purification of individual components was performed by affinity chromatography. RESULTS: At least 16 components between 13 and 98 kDa stained by Coomassie Blue were found. Using a panel of 35 sera from atopic mite sensitive patients 13 components reacted to different extent with patient IgE. Two components, 25 and 14 kDa, bound to specific IgE strongly and frequently, i.e. 80 and 91% of the patients, respectively. Affinity chromatography using crossreacting monoclonal antibodies to group 1 and 2 allergens resulted in purified preparations of 25 and 14 kDa proteins, which showed IgE-binding with the majority of the human sera when tested by immuno-dot. CONCLUSION: Based on the IgE binding profile of D. siboney and on the capacity to react with crossreacting monoclonal antibodies for groups 1 and 2, it is proposed to name these two allergens, 25 and 14 kDa, Der s 1 and Der s 2, respectively.

Adult↗
PubMed1995

Crossreactivity between Dermatophagoides siboney and other house dust mite allergens in sensitized asthmatic patients.

BACKGROUND: The role of Pyroglyphid mites in IgE-mediated sensitization has been well established. Although mites belonging to the genus Dermatophagoides dominate in the acarofauna of domestic dust, non-pyroglyphid mites might also be of clinical importance. In Cuba, Dermatophagoides siboney is found in dust coexisting with D. pteronyssinus and Blomia tropicalis. Dermatophagoides farinae is not found. Storage mites, such as Acarus siro, Lepidoglyphus destructor and Tyrophagus putrescentiae, might also be present. OBJECTIVES: The aim of this study was to investigate the allergenic relationships among the mites present in the environment of allergic patients in Cuba. METHODS: The crossreactivity between an extract of D. siboney and the above mentioned six mites was studied by specific IgE inhibition, using sera of mite-sensitive patients after incubation with serial dilutions of D. siboney. RESULTS: The inhibitory effect of D. siboney extract was more pronounced against D. farinae, 91%, than against D. pteronyssinus, 62%. Specific IgE to B. tropicalis, A. siro, L. destructor and T. putrescentiae were inhibited to a much lesser extent, i.e. between 47 and 58%. The correlation between IgE to D. siboney and IgE to D. pteronyssinus and D. farinae was of 0.92 and 0.90, respectively. A weaker correlation was found between D. siboney and L. destructor (0.7), A. siro (0.67), B. tropicalis (0.54) and T. putrescentiae (0.51). CONCLUSION: Thus, D. siboney seems to be most closely related to D. farinae.

Adolescent↗
PubMed1995

Mite (Der p I, Der f I), cat (Fel d I) and dog (Can f I) allergens in dust from Swedish day-care centres.

Early exposure to allergens is important for sensitization to inhalant allergens and it has been reported that there is a causal relationship between allergen exposure and bronchial asthma. We investigated the levels of major mite (Der p I/Der f I), cat (Fel d I) and dog (Can f I) allergen levels in dust collected from various locations in seven day-care centres (22 sections). The allergen levels were related to the characteristics of the day-care centres. Children and staff were questioned about contacts with animals, and cleaning personnel were asked about methods and frequency of cleaning. Mite allergen was found in nine of the 22 sections. The concentrations varied between < 16 ng/g and 106 ng/g dust (median < 16 ng/g). Mite allergen was not detected in any floor dust sample. Cat and dog allergen was detected in all centres and sections. The concentrations of dog allergen (median 4.3 micrograms/g; range < 60 ng-21 micrograms/g) were significantly higher (P < 0.05) than that of cat allergen (median 1.6 micrograms/g; range < 16 ng-22.8 micrograms/g). Higher amounts of both Fel d I and Can f I were observed on mattresses/sofas/cushion like toys and curtains than on tables/chairs and floors. The levels of cat or dog allergen on floors significantly correlated with the total number of children and staff with either a cat or a dog at home and or frequent contacts with them. Neither cleaning methods nor the frequency of cleaning influenced the allergen concentrations. The concentration of Fel d I was significantly lower (P < 0.05) in washed than in never washed curtains.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1995

Serum levels of interleukin-4, soluble CD23 and IFN gamma in relation to the development of allergic disease during the first 18 months of life.

Serum levels of Interleukin (IL)-4, Interferon (IFN)-gamma and soluble CD23 (sCD23) were analysed in a prospective study of 64 infants who were monitored from birth to 18 months of age. The findings were related to family history of atopy and the development of allergic disease in the infants. Low levels of IL-4 were detected in 10 of 63 cord blood samples (median 0.14 and range 0.32 micrograms/l). The levels then increased, both in health and atopic infants, reaching a peak at either 6 or 9 months and then decreased up to 18 months of age. The children who developed atopic disease during the first 18 months of life had significantly higher IL-4 median levels than those who did not, i.e. 0.24 (range 0.40) vs < 0.10 microgram/l at 3 months, (P < 0.001), 0.40 (range 0.95) vs 0.13 (0.19) microgram/l at 6 months (P < 0.01), 0.46 (range 0.78) vs 0.10 (0.24) microgram/l at 9 months (P < 0.001) and 0.30 (range 1.38) vs 0.10 (0.36) microgram/l at 18 months (P < 0.001). The IFN gamma levels were below the detection level, i.e. < 100 ng/l in all but 49 of the 196 serum samples that were analysed. There was no significant relationship with clinical outcome, nor with S-IgE levels. Soluble sCD23 levels increased in the infants with age. There was no association with either atopic disease, family history of allergic disease or IgE antibody levels. In conclusion, IL-4 levels in serum, but not sCD23 and IFN gamma are associated with allergic disease in infancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers↗
PubMed1995

Mite allergens in relation to home conditions and sensitization of asthmatic children from three climatic regions.

We investigated the levels of mite (Der p I and Der f I) allergen in dust from bedrooms, living rooms, kitchens, and bathrooms from 130 homes of asthmatic children in three climatic zones of Sweden. Bedroom dust samples included the child's mattress, carpets, floors, and other plain surfaces. Living-room dust samples were taken from sofas and other furniture, carpets, floors, and other plain surfaces. The allergen levels were related to home characteristics, including absolute indoor humidity (AIH), relative humidity (RH), and air changes per hour (ach). Mite allergen was detected in 62% of the homes. Levels of Der p I varied between < 16 ng and 50 micrograms/g dust, and Der f I between < 16 ng and 73 micrograms/g dust. Because we have designed a composite type of dust collection in our study, the allergen levels found tend to average down the results. Mite allergen levels were higher in homes with dampness problems, in homes with a smoker, and in homes without a basement. Homes with high absolute humidity (> or = 7 g/kg) or relative humidity (> or = 45%) and poor ventilation (< 0.5 ach) contained higher levels of mite allergens than homes with lower humidity and better ventilation. However, the number of ach measurements in homes was not high, and few homes had > 0.5 ach. Sensitization to house-dust mites was more common in southern than in northern and central Sweden. High levels of house-dust mite allergen in a temperate climate where mites are not ubiquitous are thus associated with dampness problems in homes and with tobacco smoking. Our data confirm and extend previous findings that high AIH and RH and poor ventilation increase the risk of mite infestation in homes. It seems to be important and necessary to control indoor humidity and ventilation levels, to avoid high mite allergen exposure in a temperate climate, because 34% of mite-sensitized asthmatic children were exposed to levels of mite allergen < 2 micrograms/g dust in their homes. The study also shows that mite allergen levels below the suggested threshold level (2 micrograms/g dust) are associated with mite sensitivity in children with perennial symptoms of asthma.

Allergens↗