We demonstrate for the first time, to our knowledge, in subjects with asthma that epithelial CD4+ cell counts at day 4 of infection correlates with total chest symptom scores, and the number of bronchial mucosal CD3+, CD4+, and CD8+ T and CD20+ B lymphocytes are associated with increased airway hyperresponsiveness. The gene discussed is CD8A; the disease is asthma.