Peripheral blood lymphocyte subpopulations in schoolchildren born very preterm.

AIM To investigate whether lymphocytes or serum inflammatory markers are associated with obstructive lung disease and bronchial lability in schoolchildren born very preterm. METHOD Lymphocyte subsets were studied in the peripheral venous blood of 29 such children (median age 8.8 years). Serum eosinophil cationic protein (ECP) and myeloperoxidase (MPO) concentrations and the association between them, lymphocyte subsets, and lung function were studied. Fourteen healthy children born at term, median age 9.1 years, served as controls. T lymphocytes (CD3), T lymphocyte subpopulations (CD4 and CD8), B lymphocytes (CD19), natural killer cells (CD16+56) and activation markers of T and B lymphocytes (CD23 and CD25) were determined using flow cytometry. Lung function was measured in all children both in the clinic and at home (Vitalograph Data Storage Spirometer). RESULTS Compared with the controls, schoolchildren born very preterm had significantly lower CD4(+) T cell percentages and CD4:CD8 ratios (p < 0.05 for both), whereas natural killer cell percentages and serum ECP values were significantly higher (p < 0. 05). The very preterm schoolchildren had significantly lower spirometric values than the control group (p < 0.05)-except forced vital capacity. When all the subjects were considered together, a weak, but significant, negative association was observed between the bronchial responsiveness in peak expiratory flow, after a beta(2) agonist during home monitoring, and the CD4(+) T cell percentage (r = -0.45; p = 0.008) and the CD4:CD8 ratio (r = -0.50; p = 0.003), indicating a relation between bronchial lability and imbalance of T cell subpopulations. CONCLUSIONS These results suggest that there is an inflammatory basis for lung function abnormalities in schoolchildren born very preterm.