Imbalance of circulating T-lymphocyte subpopulation in COPD and its relationship with CAT performance.

Chronic obstructive pulmonary disease (COPD) is associated with systemic effects, and T-cell-mediated immunity was involved in the COPD. COPD Assessment Test (CAT) could provide a valid, reliable, and standardized measure of COPD health status. The objective of this study was determination of lymphocyte subpopulation in patients with stable COPD (n = 52) and to ascertain if a relationship existed between T-lymphocyte subpopulation and CAT performance. The stable COPD patients were assessed with CAT, and divided into four groups with score >30 (n = 8), 20< score ≤30 (n = 16), 10< score ≤20 (n = 20), and score ≤10 (n = 8). Spearman's rank correlation was used to determine the relationship between proportion of T lymphocyte and CAT score. We found an elevated proportion of CD8(+) cells in COPD patients of the group with score >30 compared to other groups. Proportion of CD4(+) cells was significantly lower in the groups with score >30 and 20< score ≤30 when compared to groups with 10< score ≤20 and score ≤10. The CD4(+) :CD8(+) ratio was also significantly lower in the groups with score >30 and 20< score ≤30. Of note are the correlations of proportion of CD8(+) cells and CD4(+) :CD8(+) ratio with CAT performance when score >20. No correlations existed between proportion of CD4(+) , CD8(+) cells, CD4(+) :CD8(+) ratio, and CAT performance when score ≤20. Our results show that the determinants of T-lymphocyte subpopulation in COPD patients were value to assess physical conditions. We considered CD4(+) and CD8(+) T lymphocytes to be a representative and stable parameter in grading of health status in COPD patients.