Lymphocyte and eosinophil influx into alveolar tissue in nocturnal asthma

We have shown in nocturnal asthma that alveolar tissue eosinophils are incr eased at night as compared with the proximal airway, and that they correlat e with the overnight decrement in lung function. As the CD4+ cell is though t to be the principal orchestrating cell in eosinophil recruitment, we eval uated its presence in the proximal and distal airways in nocturnal asthma. Eleven patients with nocturnal asthma (NA) and 10 patients with non-nocturn al asthma (NNA) underwent two bronchoscopies with proximal airway endobronc hial and distal alveolar tissue transbronchial biopsy in a random order at 4:00 P.M. and at 4:00 A.M. separated by 1 wk. Immunohistochemical staining and morphometric analysis were used to determine the number of CD3+, CD4+, and CD8+ cells and EG2+ eosinophils per mm(2) in the epithelium, lamina pro pria, and alveolar tissue. At 4:00 A.M., the NA group had a significantly g reater number of CD4+ cells in the alveolar tissue than the NNA group (9.8 cells/mm(2) [5.6-30.8, interquartile (IQ)] versus 1.5 cells/mm(2) [0-6.3, I Q], p = 0.04). Within the NA group, there were significantly greater number s of CD3+, CD4+, CD8+, and EG2+ cells in the proximal airway lamina propria than in the distal airway at both 4:00 P.M. and 4:00 A.M. There were no di fferences within the epithelium between the groups at either time point. On ly alveolar tissue, not airway tissue, CD4+ cells correlated inversely with the percentage predicted FEV1 at 4:00 A.M. (r = -0.68, p = 0.0018) and pos itively with the number of alveolar tissue EG2+ cells (r = 0.66, p = 0.01). These findings suggest that the CD4+ lymphocyte is increased in the alveol ar tissue at night in nocturnal asthma as compared with non-nocturnal asthm a.