Component-resolved diagnosis with commercially available D. pteronyssinus Der p 1, Der p 2 and Der p 10: relevant markers for house dust mite allergy.

OBJECTIVE: To establish the prevalence and serum levels of IgE to commercial Der p 1, Der p 2, Der p 10 and the carbohydrate MUXF3 in house dust-mite allergic patients. To compare individual vs. allergen microarray methods. METHODS: Prevalence and serum levels of IgE to Dermatophagoides pteronyssinus extract and components Der p 1, Der p 2, Der p 10 and MUXF3, specific IgG4 to D. pteronyssinus, total serum IgE levels, and clinical features (age, asthma, rhinitis and atopic dermatitis) were determined in 123 patients (64 children) with the ImmunoCAP® method. ImmunoCAP ISAC® was performed in 24 patients. RESULTS: All patients had serum IgE to D. pteronyssinus. Prevalences of serum IgE to commercial components were Der p 1 93%, Der p 2 77% (Der p 1 or Der p 2 94%), Der p 10 28% and MUXF3 25%. Levels of D. pteronyssinus IgE strongly correlated with Der p 1 and Der p 2 IgE (r = 0.89 and 0.85 respectively), but not Der p 10 and MUXF3. ImmunoCAP® and ImmunoCAP ISAC® were concordant, but the quantitative correlation was poor. No clinical implication for the prevalence, levels, or molecular IgE reactivity profile to house dust mite components was found. CONCLUSIONS AND CLINICAL RELEVANCE: Commercially available Der p 1 and Der p 2 strongly correlate with IgE D. pteronyssinus. The lack of Der p 1 and Der p 2 IgE may help with differential diagnosis. Der p 10 serum IgE prevalence and levels suggest different patterns in food and mite-related tropomyosin sensitization. Serum IgE to carbohydrate MUXF3, although unexpectedly prevalent, were low and did not modify D. pteronyssinus IgE levels. Follow-up may be best carried out with individual rather than microarrayed components.

Fine-scale conditions across mangrove microhabitats and larval ontogeny contributes to the thermal physiology of early stage brachyurans (Crustacea: Decapoda).

Most marine ectotherms require the successful completion of a biphasic larval stage to recruit into adult populations. Recruitment of larvae into benthic habitats largely depends on biological interactions and favourable environmental conditions such as the inescapable diurnal thermal and tidal exposures. Hence, assessing how different taxa metabolically respond to variations in temperature is imperative to understand the community and ecosystem dynamics at both local and global scales. The present study aimed to investigate the effects of acute temperature variation on the physiology of stage-specific brachyuran larvae collected from different microhabitats at two mangrove forests in South Africa. Results indicate that the conditions within microhabitats, which larvae experience, likely influence their physiology, based on respirometry, to short-term acute temperature exposures. Furthermore, the larval thermal optimum shifted ontogenetically to become increasingly eurythermic as individuals developed from stage I zoea through to megalopa. Mangrove crab larvae in their early stages are hence increasingly vulnerable to acute temperature exposures, which could be particularly harmful to the persistence of populations if thermally stressful events increase in magnitude and frequency.

End-tidal CO2 analysis in sleep apnea syndrome. Conditions for use.

The diagnosis of sleep apnea syndrome (SAS) requires expensive and complex instrumentation. The purpose of the present study was to determine the value of end-tidal CO2 (EtCO2) in screening for sleep apneas. Thirty-nine patients referred to our sleep laboratory because of suspected SAS and ten normal subjects were studied. The EtCO2 was measured using an infrared spectrometer (POET) designed for simultaneous measurement of CO2 and pulse oximetry. In 29 subjects, expired gas was sampled with a nasobuccal mask (Respiron) with lateral orifices. In the other 20 subjects, sampling was done with nasobuccal prongs (Criticare) comprising a four-channel plastic tube to the mouth and the nostrils. Data from an 8-h night were transferred the following day to a microcomputer (Apple Macintosh) for processing. Apnea was defined as an absence of detection of CO2 for more than 10 s. Conventional polysomnography was performed (Respisomnographe). The number of apneas in 8 h and the apnea index (number of apneas in 1 h) were calculated after visual analysis on the screen of the polysomnograph and also with EtCO2 analysis. For recordings made with a nasobuccal mask, the regression curve between the apnea indices computed with EtCO2 and polysomnography was an order 2 polynomial curve (r = 0.76; p < 0.001), with an inflection point at 39 apneas per hour. For recordings with nasobuccal prongs, the correlation was very significant (r = 0.95; p < 0.0001), and the regression curve was linear. The EtCO2 with nasobuccal prongs appears to be a simple and reliable method for screening for SAS.

[The epidemiology of allergy to house dust mites]. / Epidémiologie de l'allergie aux acariens de la poussière de maison.

Currently, several studies show that sensitivity to mites is frequently found in the general population and in people suffering from respiratory allergic disorders. Thus 5 - 30% of the general population has positive skin tests whilst such sensitivity is found in 45 - 85% of asthmatic subjects. Certain studies have tried to establish a threshold of allergenicity beyond which the respiratory manifestations in allergic subjects became important. It seems after different studies that a threshold of 10 micrograms of antigen group I (the sum of the major antigens greater than Der p 1 and Der f 1) per gram of house dust may be a threshold beyond which the risk for the appearance of respiratory manifestation and in particular those of asthma in allergic subjects may be important. Moreover other studies tried to achieve a better understanding of the role of environmental conditions which favour the development of the mites. No or very few mites can develop if the relative internal humidity is less than 45% for an indoor temperature of 22 degrees C. These levels may be obtained in particular at altitude or in regions where the absolute outdoor humidity is low or the indoors are well heated and well ventilated. Epidemiological studies carried out in the last few years show that the relation between allergic respiratory mites disorders again show the frequency of diseases linked to the mites and the major influence of the environment as well as the idea of a tolerable allergenic threshold.

[Reactions to iodine contrast media]. / Réactions aux produits de contraste iodés.

Contrast media are used in many radiological examinations, but they are responsible for 4.6 to 8.5 percent of the toxic or anaphylactoid adverse reactions observed. The early contrast media were hyperosmolar, whereas those in current use are isosmolar and either ionic or non-ionic. The patient's age, the presence of a pre-existing disease and a history of adverse reactions to contrast media are the most important risk factors. Seventeen to 35 percent of these reactions recur. Several physiopathological mechanisms have been blamed for adverse reactions to contrast media, including complement activation, histamine release, recruitment of inflammation mediators, and antigen-antibody reaction. There is no paraclinical examination that can diagnose or predict such reactions. Various preventive tests have been studied and applied to individuals with or without history of reaction. In a population of patients with previous reaction, the administration of corticosteroids 12 h and 2 h before the radiological examination resulted in a significant reduction of the number of reactions. In patients at risk (i.e. those with previous reactions of this kind) the results varied, but in these 2 groups of subjects non-ionic products given either alone or with corticosteroids or H1-antihistaminics reduced to 1 percent the incidence of reactions. So far, tachyphylaxis has virtually played no role compared with these preventive treatments. It is concluded that patients with a history of anaphylactoid reactions who must receive another injection of contrast medium, a non-ionic product and/or the H1-antihistaminic-corticosteroid combination should be used.

[Reactions to iodinated contrast media]. / Les réactions aux produits de contraste iodés.

ICPs are used for many radiological examinations but are responsible for 4.6 to 8.5% of secondary reactions, which may perhaps be of the toxic or anaphylactoid types. Asthma, taking of beta-blockers, and previous reactions to an ICP injection are risk factors for an anaphylactoid reaction. Several mechanisms are involved but it seems to be exceptional that there is an IgE-dependent reaction. There is no paraclinical examination for diagnosis or prediction of reactions. There are hyperosmolar ICPs and others, more recent, which are non-ionic, of reduced osmolality. Non-ionic ICPs induce only a quarter of the secondary reactions of all types together and the reactions are often less severe. When a new injection, they reduce the risk of recurrence in patients who have already had reactions. The best subject protection lies in a premedication with corticosteroids and use of a non-ionic ICP. The latter should also be prescribed if possible, in all where increase in osmolality is contraindicated.

Relation between polysomnographic parameters and apnea index in obstructive sleep apnea syndrome.

We performed overnight polysomnography in 77 patients for diagnosis of sleep apnea syndrome (SAS) and assessment of severity. Patients were classified into 3 groups according to apnea index (AI): group 1 (G1; no SAS), AI < or = 10 (21 patients), group 2 (G2; moderate SAS), 10 < AI < 40 (34 patients), and group 3 (G3; severe SAS), AI > or = 40 (22 patients). In all 3 groups, 60% of the apneas were obstructive, but the proportion of mixed apnea increased from G1 to G3 (6% in G1, 12% in G2, and 24% in G3). The duration of REM sleep was shorter in G2 and G3 than in G1 (G1 61 min, G2 44 min, G3 41 min; p < 0.03). In G3 a dramatic decrease in deep sleep was noted in comparison with G1 and G2 (G1 29 min, G2 31 min, G3 10 min). The distribution of the apnea in the different sleep stages was similar in G3; in G2, 16 patients had a REM apnea predominance, but in this subgroup duration of REM sleep was longer and AI was lower than in the other 18 G2 patients. So, absence of sleep stage apnea predominance and high proportion of mixed apnea were observed in the most severe SAS.

Is systematic preoperative screening for muscle relaxant and latex allergy advisable?

We investigated a female population prior to general anaesthesia, using skin prick tests with latex and muscle relaxants to appraise the validity and feasibility of a systematic preoperative screening for these substances. Anaesthetists performed skin tests, and positive and doubtful tests were checked in our allergy department. Of 114 patients, 42 had uninterpretable tests because of dermographism (28 patients) or suppression of skin reactivity (14 patients). Among the other 72, nine had a positive or doubtful test to latex, and seven a positive or doubtful test to one or more muscle relaxants. After checking, only four sensitizations to latex and one to muscle relaxant were confirmed. In conclusion, a systematic screening for latex and muscle relaxant allergy is not advisable. In contrast, screening for latex allergy in selected high-risk groups (spina bifida, health-care workers) is necessary.

Latex allergy: allergen identification in Hevea braziliensis fractions by immunoblotting.

BACKGROUND: Latex is the cause of several clinical symptoms of allergy, but the identification of allergens is not completely known. OBJECTIVE: The aim of this report was to study the immunoreactivity of purified stable latex fractions from Hevea braziliensis. METHODS: We purified the cytoplasm of Hevea braziliensis and obtained three fractions: latex particles (LP), lutoids (L) and cytosolic serum (CS). Using Western blot, specific IgE directed to latex allergens was found in 80 patients with latex allergy. RESULTS: Five major groups of allergens migrating as 14, 25, 29, 37-45 and 50 kDa were recognized. They were unequally distributed with the latex fractions: 37-45 kDa proteins were essentially recognized in CS and LP, whereas 14 and 29 kDa proteins were mainly labelled in the L fraction. As a control, aqueous glove extracts exhibited a more restricted pattern of reactivity, because only 14 and 29 kDa proteins were recognized by patient sera. The pattern of reactivity was not correlated specifically with IgE levels, but sera from patients suffering from spina bifida reacted specifically with the minor protein of 25 kDa located in LP. CONCLUSIONS: The present results show that latex allergic patients recognize several allergens which are differently distributed in subcellular fractions extracted from H. braziliensis and aqueous GE. The L fraction and GE were enriched in low molecular weight proteins and apparently contained the same allergens.

Prevalence of latex sensitization in subjects attending health screening: implications for a perioperative screening.

BACKGROUND: Because latex is a common allergen, the rate of latex sensitization may be high in the general population. A major issue would then be to determine whether a systematic preoperative screening in the general population should be recommended. OBJECTIVE: The purpose of the study was to evaluate the prevalence of latex sensitization in a sample of the general population and to assess the role of possible risk factors. METHODS: The subjects were 258 people, aged from 20 to 40 yr, visiting a health care centre for a check-up. The protocol included: a questionnaire (occupation, symptoms of atopy, use of latex goods and possible reactions, history of previous surgery), a skin-prick test, and a CAP RAST to latex. Atopy was evaluated by a skin-prick test to common allergens and a Phadiatop test. RESULTS: Some 6.6% of the study group had either a positive skin test or a positive RAST to latex. These subjects had a four-fold higher prevalence of symptoms when wearing gloves. The rate of latex sensitization was higher by fivefold in subjects with a history of reactions to latex goods and by fourfold in atopic subjects. CONCLUSIONS: Because the rate of latex sensitization is much higher than the anticipated rate of perioperative reactions due to latex allergy, a systematic preoperative screening for latex allergy should not be recommended for adults.

Prevalence of muscle relaxant sensitivity in a general population: implications for a preoperative screening.

BACKGROUND: Muscle relaxants (MR) are responsible for 59% of peroperative anaphylactic reactions. A major issue would be to determine whether a systematic preoperative screening in the general population should be recommended. OBJECTIVE: The purpose of the study was to evaluate the prevalence of muscle relaxant sensitivity in a sample of the general population and to assess the role of possible risk factors. METHODS: Two hundred and fifty-eight subjects, aged 20-40 years, visiting a health care centre for a check-up were evaluated. Protocol included a questionnaire (occupation, symptoms of atopy, previous surgery, history of drug allergy), skin-prick tests to four commercial muscle relaxants and measurement of specific IgE against quaternary ammonium ions. Atopy was evaluated by skin-prick tests to common inhalant allergens and by a Phadiatop test. RESULTS: Of the study group, 9.3% had either a positive skin test to one or more muscle relaxant or a presence of specific IgE to quaternary ammonium ions. No risk factor was identified in the studied group. CONCLUSION: Since the rate of MR sensitivity is much higher than the anticipated rate of peroperative reactions due to allergy, a systematic preoperative screening for MR allergy should not be recommended for adults in a general population.

Association between latex sensitization and repeated latex exposure in children.

BACKGROUND: Children with spina bifida are at greater risk for latex and ethylene oxide sensitization. The authors' aim in this study was to evaluate the role of previous surgical procedures in the development of sensitization to latex and ethylene oxide. METHODS: The authors investigated 80 children 1-16 yr old, separated into 3 groups. Two groups had a history of 3 or more general anesthetics: 29 children had spina bifida (spina bifida group) and 31 had undergone multiple surgeries for another disease (multiple surgeries group). A control group of 20 children had undergone less than 1 anesthetic. Clinical manifestations with latex, perioperative anaphylactic reactions, and number of previous anesthetics were recorded. Skin prick tests with a commercial extract of latex, four common inhalant allergens, and radioallergosorbent test to latex and ethylene oxide were performed. RESULTS: The three groups did not differ significantly with respect to age, sex, and atopic status. Mean number of anesthetics was comparable in the spina bifida and the multiple surgeries group. Latex sensitization was common in the spina bifida group (59%) and in the multiple surgeries group (55%) but not in the control group (0%, P < 0.05). Ethylene oxide sensitization was significantly more frequent in the spina bifida group than in the multiple surgeries group (44% vs. 19%; P = 0.052) and strongly associated with latex sensitization. Mean number of previous anesthetics was greater in children sensitized to latex (8.4 vs. 3.9; P < 0.05). CONCLUSION: Results suggest that it is the number of surgical procedures rather than spina bifida per se that is related to sensitization to latex.