Serum concentration of total soluble CD44 is elevated in smokers

Soluble CD44 isoforms have been reported as markers of specific malignancies and inflammatory diseases. However, recent reports suggest tobacco smoking may lead to an elevation in the circulating concentration of specific CD44 variants. We, therefore, investigated the effect of smoking status on circulating levels of total sCD44. Total soluble CD44 was measured by enzyme-linked immunosorbent assay in the serum of two age- and gender-matched groups consisting of smokers (n = 19) and non-smokers (n = 20). Smoking status was confirmed by analysis of serum cotinine. The concentration of total sCD44 was found to be significantly elevated in smokers compared with non-smokers (p = 0.025). The observation that total sCD44 concentration is raised in smokers may have relevance to the aetiology of smoking-associated diseases. The effect of smoking on sCD44 concentrations should be considered when assessing the role of sCD44 as a marker of inflammatory disease, cancer, or other disease processes.