The results demonstrated that circulating and splenic levels CD3+/CD4+ and CD3+/CD8+ cells, two indices of immune cells, were significantly higher in BD than in SC and BDMSC, and significantly higher in BDMSC than in SC, whereas the circulating and spleen level of Treg+ cells (i.e., helps end an immune response), showed an opposite pattern of CD3+/CD4+ cells among the three groups. Here, CD4 is linked to Behcet disease.