The relation between peripheral blood leukocyte counts and respiratory symptoms, atopy, lung function, and airway responsiveness in adults

Study objectives: Eosinophils and neutrophils play major roles, respectivel y, in the pathogenesis of asthma and COPD, and it is well recognized that l evels of these cells in peripheral blood are increased in relation to their pulmonary involvement. However, the relation between peripheral blood cell counts of the other major leukocyte groups and these lung diseases or mark ers of allergy or airflow obstruction is less clear. We have therefore inve stigated the association between peripheral blood levels of eosinophils, ne utrophils, basophils, monocytes, and lymphocytes and the occurrence of chro nic respiratory symptoms, atopy, lung function, and bronchial hyperresponsi veness, and the modifying effect of age, in adults, Design: A cross-sectional general population study. Setting: Data on > 2,000 British adults, who originally participated in a s tudy of diet and lung health, were analyzed using multiple linear and logis tic regression to adjust for potential confounders, including age, sex, and smoking history. Results: We found that, like eosinophils, the peripheral basophil count was increased in relation to asthma and associated symptoms, and to airway hyp erreactivity and increased total IgE, but differed from eosinophils in that basophils were unrelated to atopy, Monocytes were predominantly associated with symptoms indicative of obstructive airway disease, in similar relatio n to neutrophils, but both of these leukocyte counts were also increased in asthma patients in older age groups. Lymphocyte counts were unrelated to a ny objective or subjective marker of disease. Conclusions: If peripheral blood cell counts reflect pulmonary involvement of these leukocyte groups, basophils and monocytes may play a distinct role in the pathogenesis of allergic and nonallergic respiratory disease.