[Clinicopathological examination of the relation between Clara cells and smoking]

The relations between the number and cell area of Clara cells and smoking were examined in the lung tissue of 71 subjects by immunohistochemistry, using an anti-protein 1 antibody, which is a marker of Clara cells. The smokers showed significantly lower numbers of Clara cells than the non-smokers (p < 0.05). Although the mean non-smoking time in the ex-smokers was as long as 9 years, the ex-smokers showed a somewhat lower number of Clara cells than the non-smokers. The cell area of Clara cells was the same for smokers and non-smokers. We found that smoking reduces the number of Clara cells.