In contrast, the two kinases were differentially expressed in alveolar macrophages from COPD subjects and although both SPHK1 and SPHK2 separately correlated positively with smoking status, only SPHK1 was found to be correlated with lung function suggesting a changed mRNA expression and presumably a change in balance between the kinases and the potential involvement of SPHK1 in smoking-related COPD disease progression. The gene discussed is SPHK2; the disease is chronic obstructive pulmonary disease.