In the presence of TNF-α or CRP, two inflammatory markers known to be increased in OSA patients, the CCR2 mRNA expression could be further enhanced by intermittent hypoxia, suggesting a different molecular mechanism used by intermittent hypoxia to induce the mRNA expression of CCR2 in monocytes (Figure 3B and 3C, respectively). Here, CCR2 is linked to obstructive sleep apnea syndrome.