Heterogeneity of asthma according to blood inflammatory patterns.

RATIONALE: There is increasing interest regarding asthma heterogeneity in relation to inflammatory patterns. OBJECTIVES: To assess phenotypic characteristics, in particular clinical presentation of the disease, in 381 well-characterised adults with asthma from the French Epidemiological study on the Genetics and Environment of Asthma (EGEA) according to their blood inflammatory pattern. METHODS: Four blood inflammatory patterns were defined according to eosinophil (EOS) and neutrophil (NEU) count cut-off points. Samples with > or =250 EOS/mm(3) were classified as EOS(hi) and those with > or =5000 NEU/mm(3) as NEU(hi). Clinical characteristics include typical asthma and chronic obstructive pulmonary disease (COPD)-like symptoms, as well as composite quantitative scores addressing the activity of the disease. RESULTS: A substantial number of those with asthma (56.2%) had the EOS(lo) pattern (<250 EOS/mm(3)). Patients with asthma who had the EOS(hi) pattern had higher immunoglobulin E (IgE), a lower forced expiratory volume in 1 s (FEV(1)) and presented a more active asthma than those with the EOS(lo) pattern. Among those with the EOS(lo) pattern, neutrophil inflammation (NEU(hi)) was related to a less frequent positive skin prick test response (OR 0.44, 95% CI 0.20 to 0.96). Among those with the EOS(hi) pattern, neutrophil inflammation did not explain current asthma or asthma activity, and was significantly related to nocturnal symptoms (OR 5.21, 95% CI 1.44 to 18.8) independently of age, sex, smoking and inhaled corticosteroid treatment. In non-smokers with asthma, COPD-like symptoms, in particular chronic phlegm, were more frequent in those with neutrophil inflammation, independent of eosinophil inflammation (OR 2.35, 95% CI 1.08 to 5.10). CONCLUSIONS: Besides eosinophilia, neutrophil inflammation assessed in the blood is related to specific characteristics of asthma. Considering simultaneously neutrophilic and eosinophilic inflammation may contribute to help to disentangle this complex disease.

Validity of the IUATLD (1986) questionnaire in the EGEA study. International Union Against Tuberculosis and Lung Disease. Epidemiological study on the Genetics and Environment of Asthma, bronchial hyperresponsiveness and atopy.

SETTING: No validity study of the IUATLD asthma-like questions has been performed in a group of well-defined, clinically-based asthmatics. OBJECTIVES: To assess the validity of the questions regarding asthmatics included in a case-control study, and to assess their validity as regards bronchial hyperresponsiveness in population-based subjects. DESIGN: Data from the case-control Epidemiological study on the Genetics and Environment of Asthma, bronchial hyperresponsiveness and atopy (EGEA) were used. The analysis concerned 201 adult asthmatic cases recruited in chest clinics through a standardised protocol and 284 population-based controls. RESULTS: The analysis of the case-control study regarding asthma showed a sensitivity of 0.56, 0.68 and 0.86 for nocturnal symptoms of cough, shortness of breath, and chest tightness, and a specificity of 0.72, 0.98 and 0.89. As regards bronchial hyperresponsiveness (PD20 < or = 4 mg) in the control group, specificity was high (0.77, 0.99 and 0.90), but sensitivity was markedly lower (0.36, 0.11 and 0.20). CONCLUSION: Asthma-like symptoms assessed by the IUATLD questionnaire have good validity, both for specificity and sensitivity, for asthma patients recruited in chest clinics. In general populations, questions have a high specificity, an important criterion in aetiological epidemiological research, and they were designed in that perspective. However their moderate sensitivity limits their usefulness as a screening test.