Analysis of apical CFTR expression in nasal columnar epithelial cells.

<p>The percentage of cells expressing CFTR at the apical membrane was analyzed within the E- cadherin and Ezrin positive cell compartment. Per sample on average 20 cells were counted. <b>A.</b> Technical variability. For three subjects, staining was performed in duplicate or quadruplicate. Proportion of columnar epithelial cells expressing apical CFTR was compared between the duplicates. Number one represents a subject with CF. <b>B.</b> Biological variation. 10 individuals were brushed several times and apical CFTR expression in columnar epithelial cells was compared between the different time points for each individual. Number ten represents a subject with CF.</p>