However, they were studying expression of CD25 after in vitro stimulation which makes difficult to compare their results with the results obtained ex vivo by Barbosa et al. Interestingly, in our study we have demonstrated that patients in hypomania had a low percentage of CD4+CD25+ and CD4+CD25+ cells ex vivo compared with other groups of patients and healthy people, which seems to be their characteristic feature. Here, CD4 is linked to bipolar disorder.