The T_EM subset of lung CD4+ T cells is significantly decreased in COPD patients.

<p>Single cell suspensions of mechanically disaggregated human lung tissue were stained and analyzed by flow cytometry. A, B. Representative flow plots showing staining for CD62L (horizontal axis) versus CD27 (vertical axis) on gated CD4+ T cells from (A) a smoker normal spirometry and (B) a subject with COPD. Small blue numbers are the percentage of CD4+ T cells in each quadrant. C–E. Aggregated percentages of lung CD4+ T cells from smokers with normal spirometry (orange; <i>n = </i>7) and COPD subjects (blue; <i>n</i> = 15) that were (C) negative for both CD62L & CD27 (T_EM), (D) positive for both CD62L & CD27, or (E) negative for CD62L but positive for CD27. Box-&-whisker plots indicating the first & third quartiles (box), median (band) and range (whiskers). The Mann Whitney t-test was used to determine significance.