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BACKGROUND: Asthma exacerbations are a serious public health concern due to high healthcare resource utilization, work/school productivity loss, impact on quality of life, and risk of mortality. The genetic basis of asthma exacerbations has been studied in several populations, but no prior study has performed a multi-ancestry meta-analysis of genome-wide association studies (meta-GWAS) for this trait. We aimed to identify common genetic loci associated with asthma exacerbations across diverse populations and to assess their functional role in regulating DNA methylation and gene expression. METHODS: A meta-GWAS of asthma exacerbations in 4989 Europeans, 2181 Hispanics/Latinos, 1250 Singaporean Chinese, and 972 African Americans analyzed 9.6 million genetic variants. Suggestively associated variants (p ≤ 5 × 10-5 ) were assessed for replication in 36,477 European and 1078 non-European asthma patients. Functional effects on DNA methylation were assessed in 595 Hispanic/Latino and African American asthma patients and in publicly available databases. The effect on gene expression was evaluated in silico. RESULTS: One hundred and twenty-six independent variants were suggestively associated with asthma exacerbations in the discovery phase. Two variants independently replicated: rs12091010 located at vascular cell adhesion molecule-1/exostosin like glycosyltransferase-2 (VCAM1/EXTL2) (discovery: odds ratio (ORT allele ) = 0.82, p = 9.05 × 10-6 and replication: ORT allele = 0.89, p = 5.35 × 10-3 ) and rs943126 from pantothenate kinase 1 (PANK1) (discovery: ORC allele = 0.85, p = 3.10 × 10-5 and replication: ORC allele = 0.89, p = 1.30 × 10-2 ). Both variants regulate gene expression of genes where they locate and DNA methylation levels of nearby genes in whole blood. CONCLUSIONS: This multi-ancestry study revealed novel suggestive regulatory loci for asthma exacerbations located in genomic regions participating in inflammation and host defense.
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Asma , Estudo de Associação Genômica Ampla , Asma/genética , Predisposição Genética para Doença , Hispânico ou Latino/genética , Humanos , Polimorfismo de Nucleotídeo Único , Qualidade de VidaRESUMO
BACKGROUND: Satisfaction with treatment is a patient-reported outcome shown to be associated with the patient's health-related decisions and treatment-related behavior, thereby influencing the chances of successful treatment, and is especially relevant in long-term treatment, such as allergen-specific immunotherapy (AIT). OBJECTIVE: We sought to assess the psychometric properties of the Satisfaction Scale for Patients Receiving Allergen Immunotherapy (ESPIA) questionnaire so as to determine the satisfaction of patients receiving AIT treatment. METHODS: An observational, longitudinal, multicenter study was performed on patients with allergic rhinitis (AR) undergoing AIT treatment. Sociodemographic, clinical, and patient-centered health outcomes data were gathered at the study visits. Feasibility, reliability, validity, and sensitivity to change of the prevalidated version of the ESPIA questionnaire were assessed. RESULTS: Four hundred twenty-nine patients were included (52.2% women, 33.6 years of age, 54.5% of the cases with intermittent AR and 62.5% with moderate AR). Low levels of missing items and ceiling/floor effects were found for the overall score of the ESPIA questionnaire. The overall Cronbach α value and intraclass correlation coefficient were 0.90 and 0.92, respectively. The overall score for the ESPIA questionnaire was strongly associated with months receiving AIT, AR type and intensity, presence of conjunctivitis, self-perceived health status, effect of AR on daily life, and expectations about the AIT treatment. The pattern of correlations obtained with other patient-centered health outcomes was consistent with expectations. The ESPIA questionnaire also showed good sensitivity to change for improved health status. CONCLUSION: The ESPIA questionnaire to assess patient satisfaction with respect to AIT treatment presented satisfactory psychometric properties for its use in clinical practice.
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Dessensibilização Imunológica , Hipersensibilidade/epidemiologia , Satisfação do Paciente , Adulto , Feminino , Humanos , Hipersensibilidade/terapia , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Reprodutibilidade dos Testes , Espanha/epidemiologia , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND: Evaluation of biologic therapy response is vital to monitor its effectiveness. Authors have proposed various response criteria including good responder, super-responder, non-responder, and clinical remission. OBJECTIVES: To ascertain the prevalence of response and clinical remission after long-term treatment (>6 months) of anti-IgE and anti-IL-5/IL-5Rα biologics, compare these results with existing criteria, and identify predictors for non-responders and clinical remission. METHODS: A multicenter, real-life study involving severe asthma patients in Spain. Various outcomes were assessed to gauge response and clinical remission against established criteria. RESULTS: The study included 429 patients, 209 (48.7%) omalizumab, 112 (26.1%) mepolizumab, 19 (4.4%) reslizumab and 89 (20.7%) benralizumab, with a mean treatment duration of 55.3±38.8 months. In the final year of treatment, 218 (50.8%) were super-responders, 173 (40.3%) responders, 38 (8.9%) non-responders, and clinical remission in 116 (27%), without differences among biologics. The short-term non-responders (<6 months) were 25/545 (4.6%). Substantial variations in response and clinical remission were observed when applying different published criteria. Predictors of non-response included higher BMI (OR:1.14; 95% CI:1.06-1.23; p<0.001), admissions at ICU (2.69; 1.30-5.56; p=0.01), high count of SAE (1.21; 1.03-1.42; p=0.02) before biologic treatment. High FEV1% (0.96; 0.95-0.98; p<0.001), a high ACT score (0.93; 0.88-0.99; p=0.01) before biologic treatment or NSAID-ERD (0.52; 0.29-0.91; p=0.02) showed strong associations with achieving clinical remission. CONCLUSION: A substantial proportion of severe asthma patients treated long-term with omalizumab or anti-IL5/IL-5Rα achieved a good response. Differences in response criteria highlight the need for harmonization in defining response and clinical remission in biologic therapy to enable meaningful cross-study comparisons.
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Antiasmáticos , Asma , Produtos Biológicos , Humanos , Asma/tratamento farmacológico , Produtos Biológicos/uso terapêutico , Imunossupressores/uso terapêutico , Omalizumab/uso terapêuticoRESUMO
INTRODUCTION: The definition of asthma phenotypes has not been fully established, neither there are cluster studies showing homogeneous results to solidly establish clear phenotypes. The purpose of this study was to develop a classification algorithm based on unsupervised cluster analysis, identifying clusters that represent clinically relevant asthma phenotypes that may share asthma-related outcomes. METHODS: We performed a multicentre prospective cohort study, including adult patients with asthma (N=512) from the MEGA study (Mechanisms underlying the Genesis and evolution of Asthma). A standardised clinical history was completed for each patient. Cluster analysis was performed using the kernel k-groups algorithm. RESULTS: Four clusters were identified. Cluster 1 (31.5% of subjects) includes adult-onset atopic patients with better lung function, lower BMI, good asthma control, low ICS dose, and few exacerbations. Cluster 2 (23.6%) is made of adolescent-onset atopic asthma patients with normal lung function, but low adherence to treatment (59% well-controlled) and smokers (48%). Cluster 3 (17.1%) includes adult-onset patients, mostly severe non-atopic, with overweight, the worse lung function and asthma control, and receiving combination of treatments. Cluster 4 (26.7%) consists of the elderly-onset patients, mostly female, atopic (64%), with high BMI and normal lung function, prevalence of smokers and comorbidities. CONCLUSION: We defined four phenotypes of asthma using unsupervised cluster analysis. These clusters are clinically relevant and differ from each other as regards FEV1, age of onset, age, BMI, atopy, asthma severity, exacerbations, control, social class, smoking and nasal polyps.
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Asma , Hipersensibilidade Imediata , Feminino , Masculino , Humanos , Estudos de Coortes , Estudos Prospectivos , Asma/tratamento farmacológico , Fenótipo , Análise por ConglomeradosRESUMO
BACKGROUND: Exposure to certain agents in the workplace can trigger occupational asthma or work-exacerbated asthma, both of which come under the heading of work-related asthma (WRA). Understanding the burden that WRA represents can help in the management of these patients. OBJECTIVE: To assess the influence of occupation on asthma in real life and analyze the characteristics of patients with WRA included in an asthma cohort. METHODS: This was a prospective multicenter study of a cohort of consecutive patients with asthma. A standardized clinical history was completed. Patients were classified as having WRA or non-WRA. All patients underwent respiratory function tests, FeNO test, and methacholine challenge (methacholine concentration that causes a 20% drop in FEV1) at the beginning of the study. They were classified into two groups, depending on their employment status: employed (group 1) or unemployed (group 2). RESULTS: Of the 480 patients included in the cohort, 82 (17%) received the diagnosis of WRA. Fifty-seven patients (70%) were still working. Mean age (SD) was 46 (10.69) years in group 1 and 57 (9.91) years in group 2 (P < .0001). Significant differences were observed in adherence to treatment (64.9% in group 1 vs 88% in group 2; P = .0354) and in severe asthma exacerbations (35.7% in group 1 vs 0% in group 2; P = .0172). No significant differences were observed in the rest of the variables analyzed. CONCLUSIONS: The burden of WRA in specialized asthma units is not negligible. The absence of differences in the severity of asthma, the treatment administered, alterations in lung function, and the number of exacerbations in those working versus not working may support the idea that advice regarding changing jobs should be customized for individual patients.
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Asma Ocupacional , Doenças Profissionais , Exposição Ocupacional , Humanos , Pessoa de Meia-Idade , Asma Ocupacional/diagnóstico , Testes de Provocação Brônquica , Cloreto de Metacolina , Estudos Prospectivos , AdultoRESUMO
INTRODUCTION: Asthma Control Questionnaire (ACQ) is a validated tool to measure asthma control. Cut-off points that best discriminate "well-controlled" or "not well-controlled" asthma have been suggested from the analysis of a large randomized clinical trial but they may not be adequate for daily clinical practice. AIMS: To establish cut-off points of the ACQ that best discriminate the level of control according to Global Initiative for Asthma (GINA) 2006 guidelines in patients with asthma managed at Allergology and Pulmonology Departments as well as Primary Care Centers in Spain. PATIENTS AND METHODS: An epidemiological descriptive study, with prospective data collection. Asthma control following GINA-2006 classification and 7-item ACQ was assessed. The study population was split in two parts: 2/3 for finding the cut-off points (development population) and 1/3 for validating the results (validation population). RESULTS: A total of 1,363 stable asthmatic patients were included (mean age 38 ± 14 years, 60.3% women; 69.1% non-smokers). Patient classification according to GINA-defined asthma control was: controlled 13.6%, partially controlled 34.2%, and uncontrolled 52.3%. The ACQ cut-off points that better agreed with GINA-defined asthma control categories were calculated using receiver operating curves (ROC). The analysis showed that ACQ < 0.5 was the optimal cut-off point for "controlled asthma" (sensitivity 74.1%, specificity 77.5%) and 1.00 for "uncontrolled asthma" (sensitivity 73%, specificity 88.2%). Kappa index between GINA categories and ACQ was 0.62 (p < 0.001). CONCLUSION: The ACQ cut-off points associated with GINA-defined asthma control in a real-life setting were <0.5 for controlled asthma and ≥1 for uncontrolled asthma.
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Asma/diagnóstico , Asma/terapia , Avaliação de Resultados em Cuidados de Saúde/normas , Guias de Prática Clínica como Assunto , Testes de Função Respiratória/estatística & dados numéricos , Testes de Função Respiratória/normas , Inquéritos e Questionários/normas , Adolescente , Adulto , Asma/epidemiologia , Feminino , Humanos , Internacionalidade , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde/métodos , Prevalência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espanha/epidemiologia , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Patients with mild asthma represent a substantial proportion of the population with asthma, yet there are limited data on their true burden of disease. We aimed to describe the clinical and healthcare resource utilisation (HCRU) burden of physician-assessed mild asthma. METHODS: Patients with mild asthma were included from the NOVEL observational longiTudinal studY (NOVELTY; NCT02760329), a global, 3-year, real-world prospective study of patients with asthma and/or chronic obstructive pulmonary disease from community practice (specialised and primary care). Diagnosis and severity were based on physician discretion. Clinical burden included physician-reported exacerbations and patient-reported measures. HCRU included inpatient and outpatient visits. RESULTS: Overall, 2004 patients with mild asthma were included; 22.8% experienced ≥1 exacerbation in the previous 12 months, of whom 72.3% experienced ≥1 severe exacerbation. Of 625 exacerbations reported, 48.0% lasted >1 week, 27.7% were preceded by symptomatic worsening lasting >3 days, and 50.1% required oral corticosteroid treatment. Health status was moderately impacted (St George's Respiratory Questionnaire score: 23.5 [standard deviation ± 17.9]). At baseline, 29.7% of patients had asthma symptoms that were not well controlled or very poorly controlled (Asthma Control Test score <20), increasing to 55.6% for those with ≥2 exacerbations in the previous year. In terms of HCRU, at least one unscheduled ambulatory visit for exacerbations was required by 9.5% of patients, including 9.2% requiring ≥1 emergency department visit and 1.1% requiring ≥1 hospital admission. CONCLUSIONS: In this global sample representing community practice, a significant proportion of patients with physician-assessed mild asthma had considerable clinical burden and HCRU.
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Asma , Corticosteroides/uso terapêutico , Asma/diagnóstico , Asma/tratamento farmacológico , Asma/epidemiologia , Progressão da Doença , Humanos , Estudos Longitudinais , Aceitação pelo Paciente de Cuidados de Saúde , Estudos ProspectivosRESUMO
Background and Aims: Asthma is a heterogeneous respiratory disease that encompasses different inflammatory and functional endophenotypes. Many non-invasive biomarkers has been investigated to its pathobiology. Heany et al proposed a clinical algorithm that classifies severe asthmatic patients into likely-eosinophilic phenotypes, based on accessible biomarkers: PBE, current treatment, FeNO, presence of nasal polyps (NP) and age of onset. Materials and Methods: We assessed the concordance between the algorithm proposed by Heany et al. with sputum examination, the gold standard, in 145 asthmatic patients of the MEGA cohort with varying grades of severity. Results: No correlation was found between both classifications 0.025 (CI = 0.013-0.037). Moreover, no relationship was found between sputum eosinophilia and peripheral blood eosinophilia count in the total studied population. Discussion and Conclusion: In conclusion, our results suggest that grouping the biomarkers proposed by Heany et al. are insufficient to diagnose eosinophilic phenotypes in asthmatic patients. Sputum analysis remains the gold standard to assess airway inflammation.
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BACKGROUND: The Asthma Control Questionnaire (ACQ) has not been validated in the Spanish population, and the fact that it requires spirometry poses an important limitation on its widespread use in the primary care setting in Spain. OBJECTIVE: The aim of this study was to evaluate the psychometric properties of the Spanish version of the ACQ. METHODS: In this multicenter, prospective study, consecutive adult patients with persistent asthma were recruited at 62 respiratory and allergy units across Spain. Patients were assessed at baseline and at weeks 2 and 6. The following clinical variables were recorded: lung function (forced expiratory volume in 1 second [FEV(1)]), symptoms, exacerbations, concomitant diseases, asthma severity according to the Global Initiative for Asthma international guideline, and asthma control as perceived by patients and physicians through direct ad hoc questions. The latter measures were derived specifically for this study. Patients self-completed the ACQ at all visits before the rest of the study variables were recorded. The ACQ's feasibility, validity, reliability, and sensitivity to change were assessed. Cross-sectional and longitudinal validity was assessed using the relationship between ACQ score and clinical parameters. Sensitivity to change was assessed by estimating the global effect size and the minimal important difference (MID). Reliability was assessed using estimation of the Cronbach alpha coefficient (CCalpha) and intraclass correlation coefficient (ICC). RESULTS: A total of 607 patients were included. The mean (SD) age was 45.6 (17.1) years and 61.4% of the patients were women. Of these 607, 235 (39%) had mild asthma; 246 (41%), moderate; and 126 (21%), severe. Mean (SD) time to complete the ACQ was 3.9 (4.4) minutes. The Pearson correlation coefficient in the relationship between ACQ and FEV(1) (% predicted value) was -0.23. ACQ was found to be significantly related to asthma severity and intensity and frequency of symptoms (coughing, wheezing, and dyspnea) (both, P < 0.001). Change in ACQ was significantly related to changes in FEV(1), intensity and frequency of symptoms, and number of exacerbations (all, P < 0.001). The global effect size of ACQ was 0.46 and the MID was 0.47 point of a maximum of 6. CCalpha was 0.90 and ICC was 0.86. CONCLUSION: In these adults with asthma in Spain, the Spanish version of the ACQ was found to be a reliable and valid questionnaire, suggesting that it can be used in this population as a discriminative and evaluative instrument.
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Antiasmáticos/uso terapêutico , Asma/tratamento farmacológico , Idioma , Índice de Gravidade de Doença , Inquéritos e Questionários , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Psicometria , Reprodutibilidade dos Testes , EspanhaRESUMO
BACKGROUND AND OBJECTIVE: The aim of this study was to assess the measurement properties of the Spanish version of Asthma Control Questionnaire (ACQ) when FEV1 item in the original version (ACQ-FEV1) is substituted by peak expiratory flow rate (ACQ-PEF) and when the lung function item is omitted (ACQ-wLF). MATERIAL AND METHOD: and 607 patients were enrolled in this study. Three study visits were carried out: at baseline, 2, and 6 weeks later. Validity, reliability and sensitivity to change of both ACQ versions were calculated. RESULTS: ACQ-PEF and ACQ-wLF had a correlation coefficient of 0.38 and 0.39 with no exacerbations. Both symptoms improvement and a better perception of asthma control, both by physicians and patients, were significantly related ro better scores in both versions (P <0.01). Cronbach a of ACQ-PEF and ACQ-wLF were 0.83 and 0.87, respectively. Intraclass correlation coefficients of both ACQ-PEF and ACQ-wLF were 0.9 and 0.87. Mean scores of all ACQ versions (ACQ-FEV1, ACQ-PEF and ACQ-wLF) were 1.31 (1), 1.34 (1) and 1.14 (1.1), respectively, being all differences statistically significant P < or = 0.003). CONCLUSIONS: Replacement of FEV1 by PEF, or its elimination, does not alter the measurement properties of the ACQ questionnaire. Use of ACQ simplified versions is recommended only for investigational purposes, without combining in the same analysis scores obtained with different versions of the questionnaire.
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Asma/fisiopatologia , Inquéritos e Questionários , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Asma/terapia , Feminino , Humanos , Masculino , Fluxo Expiratório Máximo , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto JovemRESUMO
The general aim of this study is to create a cohort of asthma patients with varying grades of severity in order to gain greater insight into the mechanisms underlying the genesis and course of this disease. The specific objectives focus on various studies, including imaging, lung function, inflammation, and bronchial hyperresponsiveness, to determine the relevant events that characterize the asthma population, the long-term parameters that can determine changes in the severity of patients, and the treatments that influence disease progression. The study will also seek to identify the causes of exacerbations and how this affects the course of the disease. Patients will be contacted via the outpatient clinics of the 8 participating institutions under the auspices of the Spanish Respiratory Diseases Networking System (CIBER). In the inclusion visit, a standardized clinical history will be obtained, a clinical examination, including blood pressure, body mass index, complete respiratory function tests, and FENO will be performed, and the Asthma Control Test (ACT), Morisky-Green test, Asthma Quality of Life Questionnaire (Mini AQLQ), the Sino-Nasal Outcome Test 22 (SNOT-22), and the Hospital Anxiety and Depression scale (HADS) will be administered. A specific electronic database has been designed for data collection. Exhaled breath condensate, urine and blood samples will also be collected. Non-specific bronchial hyperresponsiveness testing with methacholine will be performed and an induced sputum sample will be collected at the beginning of the study and every 24 months. A skin prick test for airborne allergens and a chest CT will be performed at the beginning of the study and repeated every 5 years.
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Asma/tratamento farmacológico , Asma/epidemiologia , Produtos Biológicos/uso terapêutico , COVID-19/epidemiologia , Adulto , Estudos de Coortes , Comorbidade , Surtos de Doenças , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , SARS-CoV-2 , Índice de Gravidade de Doença , Espanha/epidemiologiaAssuntos
Asma/diagnóstico , Testes Respiratórios , Óxido Nítrico/análise , Asma/metabolismo , Testes Respiratórios/métodos , Congressos como Assunto , Técnicas Eletroquímicas , Humanos , Comunicação Interdisciplinar , Medições Luminescentes , Padrões de Prática Médica , Espirometria , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Since barrier protection measures to avoid contact with allergens are being increasingly developed, we assessed the clinical efficacy and tolerability of a topical nasal microemulsion made of glycerol esters in patients with allergic rhinitis. METHODS: Randomized, controlled, double-blind, parallel group, multicentre, multinational clinical trial in which adult patients with allergic rhinitis or rhinoconjunctivitis due to sensitization to birch, grass or olive tree pollens received treatment with topical microemulsion or placebo during the pollen seasons. Efficacy variables included scores in the mini-RQLQ questionnaire, number and severity of nasal, ocular and lung signs and symptoms, need for symptomatic medications and patients' satisfaction with treatment. Adverse events were also recorded. RESULTS: Demographic characteristics were homogeneous between groups and mini-RQLQ scores did not differ significantly at baseline (visit 1). From symptoms recorded in the diary cards, the ME group showed statistically significant better scores for nasal congestion (0.72 vs. 1.01; p = 0.017) and mean total nasal symptoms (0.7 vs. 0.9; p = 0.045). At visit 2 (pollen season), lower values were observed in the mini-RQLQ in the ME group, although there were no statistically significant differences between groups in both full analysis set (FAS) and patients completing treatment (PPS) populations. The results obtained in the nasal symptoms domain of the mini-RQLQ at visit 2 showed the highest difference (-0.43; 95% CI: -0.88 to 0.02) for the ME group in the FAS population. The topical microemulsion was safe and well tolerated and no major discomforts were observed. Satisfaction rating with the treatment was similar between the groups. CONCLUSIONS: The topical application of the microemulsion is a feasible and safe therapy in the prevention of allergic symptoms, particularly nasal congestion. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01478425.
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BACKGROUND: Allergen-specific immunotherapy (SIT) is a treatment capable of modifying the natural course of allergy, so ensuring good adherence to SIT is fundamental. Up until now there has not existed an instrument specifically developed to measure patient satisfaction with SIT, although its assessment could help us to comprehend better and improve treatment adherence and effectiveness. The aim of this study was to develop an instrument to measure adult patient satisfaction with SIT. METHODS: Items were generated from a literature review, focus groups with allergic adult patients undergoing SIT, and a meeting with experts. Potential items were administered to allergic patients undergoing SIT in an observational, cross-sectional, multicenter study. Item reduction was based on quantitative and qualitative criteria. A preliminary assessment of feasibility, reliability, and validity of the retained items was performed. RESULTS: An initial pool of 70 items was administered to 257 patients undergoing SIT. Fifty-four items were eliminated resulting in a provisional instrument with 16 items. Factor analysis yielded four factors that were identified as perceived efficacy, activities and environment, cost-benefit balance, and overall satisfaction, explaining 74.8% of variance. Ceiling and floor effects were negligible for overall score. Overall score was associated with the type and intensity of symptoms. CONCLUSION: This is the first attempt to develop a satisfaction with SIT measure from the perspective of the allergic patient, and evidence has been found in favor of its reliability and validity.
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BACKGROUND: The conventional schedule for subcutaneous immunotherapy with allergen extracts, although efficacious and safe, is slow during the dose-increase phase. OBJECTIVE: We sought to compare the efficacy and safety of subcutaneous immunotherapy with Dermatophagoides pteronyssinus standardized extract given in a 6-week cluster period and a conventional 12-week schedule during the incremental-dose phase. METHODS: Of 239 patients with rhinitis, allergic bronchial asthma, or both caused by D pteronyssinus , 120 were randomly assigned to the cluster schedule, and 119 were randomly assigned to the conventional schedule. A biologically standardized D pteronyssinus depot extract (ALK-Abelló S.A., Madrid, Spain) was administered in a placebo-controlled, double-blind fashion during the initial phase of cluster or conventional treatment. We recorded adverse reactions, clinical efficacy, cutaneous reactivity, and serum specific immunoglobulins to D pteronyssinus before immunotherapy, when the maximum dose was reached in the cluster and conventional schedules, and after 1 year of treatment. RESULTS: The cluster schedule reduced the time to maintenance dose by 46% and caused systemic adverse reactions (all mild) after only 0.15% of injections, with no differences in comparison with the conventional schedule. Cluster immunotherapy led to decreases in asthma and rhinitis symptoms, reduced the cutaneous reactivity, and produced the increase in specific IgE and IgG 4 levels on reaching the maintenance dose in the sixth week, 6 weeks earlier than with the conventional schedule. CONCLUSION: The cluster schedule for the initial phase of immunotherapy with incremental doses of D pteronyssinus is a safe alternative to conventional immunotherapy and offers the further advantage of achieving clinical and immunologic improvements sooner.